CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Master boot record - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"2c2e829a-d7ec-4789-adc4-6f7fe2613706","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Master_boot_record","wgTitle":"Master boot record","wgCurRevisionId":1251113196,"wgRevisionId":1251113196,"wgArticleId":24782330,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Articles with short description","Short description is different from Wikidata","Use dmy dates from April 2019","Use list-defined references from January 2022","BIOS","Booting","Disk partitions"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Master_boot_record","wgRelevantArticleId":24782330,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[], "wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":100000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q624752","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false, "wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups", "ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Master boot record - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Master_boot_record"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Master_boot_record&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Master_boot_record"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Master_boot_record rootpage-Master_boot_record skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Main menu </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z">Main page</a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia">Contents</a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events">Current events</a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x">Random article</a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works">About Wikipedia</a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia">Contact us</a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia">Help</a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia">Learn to edit</a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors">Community portal</a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r">Recent changes</a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia">Upload file</a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"> Search </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Appearance </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class="">Donate</a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Master+boot+record" title="You are encouraged to create an account and log in; however, it is not mandatory" class="">Create account</a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Master+boot+record" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class="">Log in</a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Personal tools </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en">Donate</a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Master+boot+record" title="You are encouraged to create an account and log in; however, it is not mandatory"> Create account</a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Master+boot+record" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"> Log in</a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing">learn more</a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y">Contributions</a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n">Talk</a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Overview" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Overview"> <div class="vector-toc-text"> 1 Overview </div> </a> <ul id="toc-Overview-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Disk_partitioning" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Disk_partitioning"> <div class="vector-toc-text"> 2 Disk partitioning </div> </a> <button aria-controls="toc-Disk_partitioning-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Disk partitioning subsection </button> <ul id="toc-Disk_partitioning-sublist" class="vector-toc-list"> <li id="toc-Sector_layout" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Sector_layout"> <div class="vector-toc-text"> 2.1 Sector layout </div> </a> <ul id="toc-Sector_layout-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Partition_table_entries" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Partition_table_entries"> <div class="vector-toc-text"> 2.2 Partition table entries </div> </a> <ul id="toc-Partition_table_entries-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-System_bootstrapping" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#System_bootstrapping"> <div class="vector-toc-text"> 3 System bootstrapping </div> </a> <ul id="toc-System_bootstrapping-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Disk_identity" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Disk_identity"> <div class="vector-toc-text"> 4 Disk identity </div> </a> <ul id="toc-Disk_identity-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Programming_considerations" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Programming_considerations"> <div class="vector-toc-text"> 5 Programming considerations </div> </a> <button aria-controls="toc-Programming_considerations-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Programming considerations subsection </button> <ul id="toc-Programming_considerations-sublist" class="vector-toc-list"> <li id="toc-BIOS_to_MBR_interface" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#BIOS_to_MBR_interface"> <div class="vector-toc-text"> 5.1 BIOS to MBR interface </div> </a> <ul id="toc-BIOS_to_MBR_interface-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-MBR_to_VBR_interface" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#MBR_to_VBR_interface"> <div class="vector-toc-text"> 5.2 MBR to VBR interface </div> </a> <ul id="toc-MBR_to_VBR_interface-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Editing_and_replacing_contents" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Editing_and_replacing_contents"> <div class="vector-toc-text"> 6 Editing and replacing contents </div> </a> <ul id="toc-Editing_and_replacing_contents-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> 7 See also </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> 8 Notes </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> 9 References </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> 10 Further reading </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> 11 External links </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Toggle the table of contents </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">Master boot record</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 28 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-28" aria-hidden="true" > 28 languages </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B3%D8%AC%D9%84_%D8%A7%D9%84%D8%A5%D9%82%D9%84%D8%A7%D8%B9_%D8%A7%D9%84%D8%B1%D8%A6%D9%8A%D8%B3%D9%8A" title="سجل الإقلاع الرئيسي – Arabic" lang="ar" hreflang="ar" data-title="سجل الإقلاع الرئيسي" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target">العربية</a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%97%D0%B0%D0%BF%D0%B8%D1%81_%D0%B7%D0%B0_%D0%BD%D0%B0%D1%87%D0%B0%D0%BB%D0%BD%D0%BE_%D0%B7%D0%B0%D1%80%D0%B5%D0%B6%D0%B4%D0%B0%D0%BD%D0%B5" title="Запис за начално зареждане – Bulgarian" lang="bg" hreflang="bg" data-title="Запис за начално зареждане" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target">Български</a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Catalan" lang="ca" hreflang="ca" data-title="Master boot record" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target">Català</a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Czech" lang="cs" hreflang="cs" data-title="Master boot record" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target">Čeština</a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Danish" lang="da" hreflang="da" data-title="Master boot record" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target">Dansk</a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Master_Boot_Record" title="Master Boot Record – German" lang="de" hreflang="de" data-title="Master Boot Record" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target">Deutsch</a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Registro_de_arranque_principal" title="Registro de arranque principal – Spanish" lang="es" hreflang="es" data-title="Registro de arranque principal" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target">Español</a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/MBR" title="MBR – Basque" lang="eu" hreflang="eu" data-title="MBR" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target">Euskara</a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B1%DA%A9%D9%88%D8%B1%D8%AF_%D8%B1%D8%A7%D9%87%E2%80%8C%D8%A7%D9%86%D8%AF%D8%A7%D8%B2_%D8%A7%D8%B5%D9%84%DB%8C" title="رکورد راه‌انداز اصلی – Persian" lang="fa" hreflang="fa" data-title="رکورد راه‌انداز اصلی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target">فارسی</a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Master_boot_record" title="Master boot record – French" lang="fr" hreflang="fr" data-title="Master boot record" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target">Français</a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%A7%88%EC%8A%A4%ED%84%B0_%EB%B6%80%ED%8A%B8_%EB%A0%88%EC%BD%94%EB%93%9C" title="마스터 부트 레코드 – Korean" lang="ko" hreflang="ko" data-title="마스터 부트 레코드" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target">한국어</a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Catatan_but_utama" title="Catatan but utama – Indonesian" lang="id" hreflang="id" data-title="Catatan but utama" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target">Bahasa Indonesia</a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Italian" lang="it" hreflang="it" data-title="Master boot record" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target">Italiano</a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Hebrew" lang="he" hreflang="he" data-title="Master boot record" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target">עברית</a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Lombard" lang="lmo" hreflang="lmo" data-title="Master boot record" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target">Lombard</a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Master_Boot_Record" title="Master Boot Record – Hungarian" lang="hu" hreflang="hu" data-title="Master Boot Record" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target">Magyar</a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Dutch" lang="nl" hreflang="nl" data-title="Master boot record" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target">Nederlands</a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%83%9E%E3%82%B9%E3%82%BF%E3%83%BC%E3%83%96%E3%83%BC%E3%83%88%E3%83%AC%E3%82%B3%E3%83%BC%E3%83%89" title="マスターブートレコード – Japanese" lang="ja" hreflang="ja" data-title="マスターブートレコード" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target">日本語</a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Master boot record" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target">Norsk bokmål</a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Master_Boot_Record" title="Master Boot Record – Polish" lang="pl" hreflang="pl" data-title="Master Boot Record" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target">Polski</a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Master_Boot_Record" title="Master Boot Record – Portuguese" lang="pt" hreflang="pt" data-title="Master Boot Record" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target">Português</a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%93%D0%BB%D0%B0%D0%B2%D0%BD%D0%B0%D1%8F_%D0%B7%D0%B0%D0%B3%D1%80%D1%83%D0%B7%D0%BE%D1%87%D0%BD%D0%B0%D1%8F_%D0%B7%D0%B0%D0%BF%D0%B8%D1%81%D1%8C" title="Главная загрузочная запись – Russian" lang="ru" hreflang="ru" data-title="Главная загрузочная запись" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target">Русский</a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Master_boot_record" title="Master boot record – Simple English" lang="en-simple" hreflang="en-simple" data-title="Master boot record" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target">Simple English</a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Master_Boot_Record" title="Master Boot Record – Swedish" lang="sv" hreflang="sv" data-title="Master Boot Record" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target">Svenska</a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%93%D0%BE%D0%BB%D0%BE%D0%B2%D0%BD%D0%B8%D0%B9_%D0%B7%D0%B0%D0%B2%D0%B0%D0%BD%D1%82%D0%B0%D0%B6%D1%83%D0%B2%D0%B0%D0%BB%D1%8C%D0%BD%D0%B8%D0%B9_%D0%B7%D0%B0%D0%BF%D0%B8%D1%81" title="Головний завантажувальний запис – Ukrainian" lang="uk" hreflang="uk" data-title="Головний завантажувальний запис" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target">Українська</a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Boot_record" title="Boot record – Vietnamese" lang="vi" hreflang="vi" data-title="Boot record" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target">Tiếng Việt</a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E4%B8%BB%E5%BC%95%E5%AF%BC%E8%AE%B0%E5%BD%95" title="主引导记录 – Wu" lang="wuu" hreflang="wuu" data-title="主引导记录" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target">吴语</a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E4%B8%BB%E5%BC%95%E5%AF%BC%E8%AE%B0%E5%BD%95" title="主引导记录 – Chinese" lang="zh" hreflang="zh" data-title="主引导记录" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target">中文</a></li> </ul> <div class="after-portlet after-portlet-lang"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q624752#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Master_boot_record" title="View the content page [c]" accesskey="c">Article</a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Master_boot_record" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t">Talk</a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" >English </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Master_boot_record">Read</a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Master_boot_record&action=edit" title="Edit this page [e]" accesskey="e">Edit</a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Master_boot_record&action=history" title="Past revisions of this page [h]" accesskey="h">View history</a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" >Tools </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Master_boot_record">Read</a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Master_boot_record&action=edit" title="Edit this page [e]" accesskey="e">Edit</a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Master_boot_record&action=history">View history</a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Master_boot_record" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j">What links here</a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Master_boot_record" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k">Related changes</a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u">Upload file</a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q">Special pages</a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Master_boot_record&oldid=1251113196" title="Permanent link to this revision of this page">Permanent link</a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Master_boot_record&action=info" title="More information about this page">Page information</a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Master_boot_record&id=1251113196&wpFormIdentifier=titleform" title="Information on how to cite this page">Cite this page</a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMaster_boot_record">Get shortened URL</a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMaster_boot_record">Download QR code</a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Master_boot_record&action=show-download-screen" title="Download this page as a PDF file">Download as PDF</a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Master_boot_record&printable=yes" title="Printable version of this page [p]" accesskey="p">Printable version</a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Master_Boot_Record" hreflang="en">Wikimedia Commons</a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q624752" title="Structured data on this page hosted by Wikidata [g]" accesskey="g">Wikidata item</a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">First sector of a partitioned computer disk</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">This article is about an IBM PC-specific type of boot sector on partitioned media. For the first sector on non-partitioned media, see <a href="/wiki/Volume_boot_record" title="Volume boot record">volume boot record</a>.</div> A master boot record (MBR) is a type of <a href="/wiki/Boot_sector" title="Boot sector">boot sector</a> in the first block of <a href="/wiki/Disk_partitioning" title="Disk partitioning">partitioned</a> computer <a href="/wiki/Mass_storage_device" class="mw-redirect" title="Mass storage device">mass storage devices</a> like <a href="/wiki/Fixed_disk" class="mw-redirect" title="Fixed disk">fixed disks</a> or <a href="/wiki/Removable_drive" class="mw-redirect" title="Removable drive">removable drives</a> intended for use with <a href="/wiki/IBM_PC-compatible" class="mw-redirect" title="IBM PC-compatible">IBM PC-compatible</a> systems and beyond. The concept of MBRs was publicly introduced in 1983 with <a href="/wiki/PC_DOS_2.0" class="mw-redirect" title="PC DOS 2.0">PC DOS 2.0</a>. The MBR holds the information on how the disc's sectors (aka "blocks") are divided into partitions, each partition notionally containing a file system. The MBR also contains executable code to function as a loader for the installed operating system—usually by passing control over to the loader's second stage, or in conjunction with each partition's volume boot record (VBR). This MBR code is usually referred to as a boot loader. The organization of the partition table in the MBR limits the maximum addressable storage space of a partitioned disk to 2 <a href="/wiki/Tebibyte" class="mw-redirect" title="Tebibyte">TiB</a> (232 × 512 bytes).<a href="#cite_note-Microsoft_2013_2581408-1">[1]</a> Approaches to slightly raise this limit utilizing 32-bit arithmetic or 4096-byte sectors are not officially supported, as they fatally break compatibility with existing boot loaders, most MBR-compliant operating systems and associated system tools, and may cause serious data corruption when used outside of narrowly controlled system environments. Therefore, the MBR-based partitioning scheme is in the process of being superseded by the <a href="/wiki/GUID_Partition_Table" title="GUID Partition Table">GUID Partition Table</a> (GPT) scheme in new computers. A GPT can coexist with an MBR in order to provide some limited form of backward compatibility for older systems. MBRs are not present on non-partitioned media such as <a href="/wiki/Floppy" class="mw-redirect" title="Floppy">floppies</a>, <a href="/wiki/Superfloppy" class="mw-redirect" title="Superfloppy">superfloppies</a> or other storage devices configured to behave as such, nor are they necessarily present on drives used in non-PC platforms. <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Overview">Overview</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=1" title="Edit section: Overview">edit</a>]</div> Support for partitioned media, and thereby the master boot record (MBR), was introduced with IBM <a href="/wiki/PC_DOS" class="mw-redirect" title="PC DOS">PC DOS</a> 2.0 in March 1983 in order to support the 10 MB <a href="/wiki/Hard_disk" class="mw-redirect" title="Hard disk">hard disk</a> of the then-new <a href="/wiki/IBM_Personal_Computer_XT" title="IBM Personal Computer XT">IBM Personal Computer XT</a>, still using the <a href="/wiki/FAT12" class="mw-redirect" title="FAT12">FAT12</a> file system. The original version of the MBR was written by David Litton of IBM in June 1982. The partition table supported up to four primary partitions. This did not change when <a href="/wiki/FAT16" class="mw-redirect" title="FAT16">FAT16</a> was introduced as a new file system with DOS 3.0. Support for an <a href="/wiki/Extended_partition" class="mw-redirect" title="Extended partition">extended partition</a>, a special primary partition type used as a container to hold other partitions, was added with DOS 3.2, and nested logical drives inside an extended partition came with DOS 3.30. Since MS-DOS, PC DOS, OS/2 and Windows were never enabled to boot off them, the MBR format and boot code remained almost unchanged in functionality (except some third-party implementations) throughout the eras of DOS and OS/2 up to 1996. In 1996, support for <a href="/wiki/Logical_block_addressing" title="Logical block addressing">logical block addressing</a> (LBA) was introduced in Windows 95B and MS-DOS 7.10 (Not to be confused with IBM PC-DOS 7.1) in order to support disks larger than 8 GB. Disk timestamps were also introduced.<a href="#cite_note-Sedory_2004_Timestamp-2">[2]</a> This also reflected the idea that the MBR is meant to be operating system and file system independent. However, this design rule was partially compromised in more recent Microsoft implementations of the MBR, which enforce <a href="/wiki/Cylinder-head-sector" title="Cylinder-head-sector">CHS</a> access for <a href="/wiki/FAT16B" class="mw-redirect" title="FAT16B">FAT16B</a> and <a href="/wiki/FAT32" class="mw-redirect" title="FAT32">FAT32</a> partition types <a href="/wiki/Partition_type#PID_06h" title="Partition type"><style data-mw-deduplicate="TemplateStyles:r886049734">'"`UNIQ--templatestyles-00000007-QINU`"'</style>0x06</a>/<a href="/wiki/Partition_type#PID_0Bh" title="Partition type"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0B</a>, whereas LBA is used for <a href="/wiki/Partition_type#PID_0Eh" title="Partition type"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0E</a>/<a href="/wiki/Partition_type#PID_0Ch" title="Partition type"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0C</a>. Despite sometimes poor documentation of certain intrinsic details of the MBR format (which occasionally caused compatibility problems), it has been widely adopted as a de facto industry standard, due to the broad popularity of PC-compatible computers and its semi-static nature over decades. This was even to the extent of being supported by computer operating systems for other platforms. Sometimes this was in addition to other pre-existing or <a href="/wiki/Cross-platform" class="mw-redirect" title="Cross-platform">cross-platform</a> standards for bootstrapping and partitioning.<a href="#cite_note-Lucas_2003_OpenBSD-3">[3]</a> MBR partition entries and the MBR boot code used in commercial operating systems, however, are limited to 32 bits.<a href="#cite_note-Microsoft_2013_2581408-1">[1]</a> Therefore, the maximum disk size supported on disks using 512-byte sectors (whether real or emulated) by the MBR partitioning scheme (without 32-bit arithmetic) is limited to 2 TiB.<a href="#cite_note-Microsoft_2013_2581408-1">[1]</a> Consequently, a different partitioning scheme must be used for larger disks, as they have become widely available since 2010. The MBR partitioning scheme is therefore in the process of being superseded by the <a href="/wiki/GUID_Partition_Table" title="GUID Partition Table">GUID Partition Table</a> (GPT). The official approach does little more than ensuring data integrity by employing a protective MBR. Specifically, it does not provide backward compatibility with operating systems that do not support the GPT scheme as well. Meanwhile, multiple forms of hybrid MBRs have been designed and implemented by third parties in order to maintain partitions located in the first physical 2 TiB of a disk in both partitioning schemes "in parallel" and/or to allow older operating systems to boot off GPT partitions as well. The present non-standard nature of these solutions causes various compatibility problems in certain scenarios. The MBR consists of 512 or more <a href="/wiki/Byte" title="Byte">bytes</a> located in the first <a href="/wiki/Disk_sector" title="Disk sector">sector</a> of the drive. It may contain one or more of: <ul><li>A <a href="/wiki/Partition_table" class="mw-redirect" title="Partition table">partition table</a> describing the partitions of a storage device. In this context the boot sector may also be called a partition sector.</li> <li><a href="/wiki/Bootstrapping_(computing)" class="mw-redirect" title="Bootstrapping (computing)">Bootstrap code</a>: Instructions to identify the configured bootable partition, then load and execute its <a href="/wiki/Volume_boot_record" title="Volume boot record">volume boot record</a> (VBR) as a <a href="/wiki/Chain_loader" class="mw-redirect" title="Chain loader">chain loader</a>.</li> <li>Optional 32-bit disk timestamp.<a href="#cite_note-Sedory_2004_Timestamp-2">[2]</a></li> <li>Optional 32-bit disk signature.<a href="#cite_note-Norton_2002_Inside-4">[4]</a><a href="#cite_note-Graves_2004_Guide-5">[5]</a><a href="#cite_note-Andrews_2003_Upgrade-6">[6]</a><a href="#cite_note-Boswell_2003_Inside-7">[7]</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Disk_partitioning">Disk partitioning</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=2" title="Edit section: Disk partitioning">edit</a>]</div> <a href="/wiki/IBM" title="IBM">IBM</a> <a href="/wiki/PC_DOS" class="mw-redirect" title="PC DOS">PC DOS</a> 2.0 introduced the <code><a href="/wiki/FDISK" class="mw-redirect" title="FDISK">FDISK</a></code> utility to set up and maintain MBR partitions. When a storage device has been partitioned according to this scheme, its MBR contains a partition table describing the locations, sizes, and other attributes of linear regions referred to as partitions. The partitions themselves may also contain data to describe more complex partitioning schemes, such as <a href="/wiki/Extended_boot_record" title="Extended boot record">extended boot records</a> (EBRs), <a href="/wiki/BSD_disklabel" title="BSD disklabel">BSD disklabels</a>, or <a href="/wiki/Logical_Disk_Manager" title="Logical Disk Manager">Logical Disk Manager</a> metadata partitions.<a href="#cite_note-Smith_2000_Multi-Boot-8">[8]</a> The MBR is not located in a partition; it is located at a first sector of the device (physical offset 0), preceding the first partition. (The boot sector present on a non-partitioned device or within an individual partition is called a <a href="/wiki/Volume_boot_record" title="Volume boot record">volume boot record</a> instead.) In cases where the computer is running a <a href="/wiki/Dynamic_Drive_Overlay" class="mw-redirect" title="Dynamic Drive Overlay">DDO BIOS overlay</a> or <a href="/wiki/Boot_manager" class="mw-redirect" title="Boot manager">boot manager</a>, the partition table may be moved to some other physical location on the device; e.g., <a href="/wiki/Ontrack_Disk_Manager" class="mw-redirect" title="Ontrack Disk Manager">Ontrack Disk Manager</a> often placed a copy of the original MBR contents in the second sector, then hid itself from any subsequently booted OS or application, so the MBR copy was treated as if it were still residing in the first sector. <div class="mw-heading mw-heading3"><h3 id="Sector_layout">Sector layout</h3>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=3" title="Edit section: Sector layout">edit</a>]</div> By convention, there are exactly four primary partition table entries in the MBR partition table scheme, although some operating systems and system tools extended this to five (Advanced Active Partitions (AAP) with <a href="/wiki/PTS-DOS" title="PTS-DOS">PTS-DOS</a> 6.60<a href="#cite_note-Brouwer_2003_Types-2A-9">[9]</a> and <a href="/wiki/DR-DOS" title="DR-DOS">DR-DOS</a> 7.07), eight (<a href="/wiki/AST_Research" title="AST Research">AST</a> and <a href="/wiki/NEC" title="NEC">NEC</a> <a href="/wiki/MS-DOS" title="MS-DOS">MS-DOS</a> 3.x<a href="#cite_note-Brouwer_2003_Types-2B-10">[10]</a><a href="#cite_note-Sedory_2007_DOS33MBR-11">[11]</a> as well as <a href="/wiki/Storage_Dimensions" title="Storage Dimensions">Storage Dimensions</a> <a href="/wiki/SpeedStor" class="mw-redirect" title="SpeedStor">SpeedStor</a>), or even sixteen entries (with <a href="/wiki/Ontrack_Disk_Manager" class="mw-redirect" title="Ontrack Disk Manager">Ontrack Disk Manager</a>). <table class="wikitable" style="float:left; width:45%; margin:1em;"> <caption>Structure of a classical generic MBR </caption> <tbody><tr> <th>Address </th> <th style="vertical-align:middle" colspan="2">Description </th> <th style="vertical-align:middle">Size (<a href="/wiki/Byte" title="Byte">bytes</a>) </th></tr> <tr style="height:540px"> <td style="text-align:center"><code>0x0000</code> (0) </td> <td colspan="2">Bootstrap code area </td> <td style="text-align:center">446 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01BE</code> (446) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №1 </td> <td rowspan="4" style="vertical-align:middle; text-align:center">Partition table (for primary partitions) </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01CE</code> (462) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №2 </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01DE</code> (478) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №3 </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01EE</code> (494) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №4 </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01FE</code> (510) </td> <td style="text-align:center"><code>0x55</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center">Boot signature<a href="#cite_note-NB_Magic_AA55-12">[a]</a> </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01FF</code> (511) </td> <td style="text-align:center"><code>0xAA</code> </td></tr> <tr style="height:60px"> <th colspan="3" style="text-align:right;">Total size: 446 + 4×16 + 2 </th> <th style="text-align:center">512 </th></tr></tbody></table> <table class="wikitable" style="float:right; width:45%; margin:1em;"> <caption>Structure of a modern standard MBR </caption> <tbody><tr> <th>Address </th> <th style="vertical-align:middle" colspan="2">Description </th> <th style="vertical-align:middle">Size (<a href="/wiki/Byte" title="Byte">bytes</a>) </th></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x0000</code> (0)</td> <td colspan="2">Bootstrap code area (part 1) </td> <td style="text-align:center">218 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x00DA</code> (218) </td> <td style="text-align:center; background:#F2F2F2"><code>0x0000</code> </td> <td rowspan="5" style="vertical-align:middle; text-align:center; background:#F2F2F2">Disk timestamp<a href="#cite_note-Sedory_2004_Timestamp-2">[2]</a><a href="#cite_note-NB_Timestamp-13">[b]</a> (optional; Windows 95B/98/98SE/ME (MS-DOS 7.1–8.0). Alternatively, can serve as <a href="#NEWLDR_OFS_018h">OEM loader signature</a> with NEWLDR) </td> <td style="text-align:center">2 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x00DC</code> (220) </td> <td style="text-align:center; background:#F2F2F2">Original physical drive (<code>0x80</code>–<code>0xFF</code>) </td> <td style="text-align:center">1 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x00DD</code> (221) </td> <td style="text-align:center; background:#F2F2F2">Seconds (0–59) </td> <td style="text-align:center">1 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x00DE</code> (222) </td> <td style="text-align:center; background:#F2F2F2">Minutes (0–59) </td> <td style="text-align:center">1 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x00DF</code> (223) </td> <td style="text-align:center; background:#F2F2F2">Hours (0–23) </td> <td style="text-align:center">1 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x00E0</code> (224)</td> <td colspan="2">Bootstrap code area (part 2, code entry at <code>0x0000</code>) </td> <td style="text-align:center">216 (or 222) </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01B8</code> (440) </td> <td style="text-align:center; background:#F2F2F2">32-bit disk signature </td> <td rowspan="2" style="vertical-align:middle; text-align:center; background:#F2F2F2">Disk signature (optional; <a href="/wiki/Unified_Extensible_Firmware_Interface" class="mw-redirect" title="Unified Extensible Firmware Interface">UEFI</a>, Linux, <a href="/wiki/Windows_NT" title="Windows NT">Windows NT</a> family and other OSes) </td> <td style="text-align:center">4 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01BC</code> (444) </td> <td style="text-align:center; background:#F2F2F2"><code>0x0000</code> (<code>0x5A5A</code> if copy-protected) </td> <td style="text-align:center">2 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01BE</code> (446) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №1 </td> <td rowspan="4" style="vertical-align:middle; text-align:center">Partition table (for primary partitions) </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01CE</code> (462) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №2 </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01DE</code> (478) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №3 </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01EE</code> (494) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №4 </td> <td style="text-align:center">16 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01FE</code> (510) </td> <td style="text-align:center"><code>0x55</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center">Boot signature<a href="#cite_note-NB_Magic_AA55-12">[a]</a> </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr style="height:60px"> <td style="text-align:center"><code>0x01FF</code> (511) </td> <td style="text-align:center"><code>0xAA</code> </td></tr> <tr style="height:60px"> <th colspan="3" style="text-align:right;">Total size: 218 + 6 + 216 + 6 + 4×16 + 2 </th> <th style="text-align:center">512 </th></tr></tbody></table> <div style="clear:both;" class=""></div> <table class="wikitable" style="float:left; width:45%; margin:1em;"> <caption>Structure of AAP MBR </caption> <tbody><tr> <th>Address </th> <th style="vertical-align:middle" colspan="2">Description </th> <th style="vertical-align:middle">Size (<a href="/wiki/Byte" title="Byte">bytes</a>) </th></tr> <tr> <td style="text-align:center"><code>0x0000</code> (0)</td> <td colspan="2">Bootstrap code area </td> <td style="text-align:center">428 </td></tr> <tr> <td style="text-align:center"><code>0x01AC</code> (428) </td> <td style="text-align:center; background:#F2F2F2"><code>0x78</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center; background:#F2F2F2">AAP signature (optional) </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x01AD</code> (429) </td> <td style="text-align:center; background:#F2F2F2"><code>0x56</code> </td></tr> <tr> <td style="text-align:center"><code>0x01AE</code> (430) </td> <td style="text-align:center; background:#F2F2F2">AAP physical drive (<code>0x80</code>–<code>0xFE</code>; <code>0x00</code>: not used; <code>0x01</code>–<code>0x7F</code>, <code>0xFF</code>: reserved) </td> <td rowspan="6" style="vertical-align:middle; text-align:center; background:#F2F2F2">AAP record (optional) (AAP <a href="#PTE">partition entry</a> #0 with special semantics) </td> <td style="text-align:center">1 </td></tr> <tr> <td style="text-align:center"><code>0x01AF</code> (431) </td> <td style="text-align:center; background:#F2F2F2"><a href="/wiki/Cylinder-head-sector" title="Cylinder-head-sector">CHS</a> (start) address of AAP partition/image file or <a href="/wiki/Volume_boot_record" title="Volume boot record">VBR</a>/<a href="/wiki/Extended_boot_record" title="Extended boot record">EBR</a> </td> <td style="text-align:center">3 </td></tr> <tr> <td style="text-align:center"><code>0x01B2</code> (434) </td> <td style="text-align:center; background:#F2F2F2">Reserved for AAP <a href="/wiki/Partition_type" title="Partition type">partition type</a> (<code>0x00</code> if not used) (optional) </td> <td style="text-align:center">1 </td></tr> <tr> <td style="text-align:center"><code>0x01B3</code> (435) </td> <td style="text-align:center; background:#F2F2F2">Reserved for CHS end address in AAP (optional; byte at offset <code>0x01B5</code> is also used for MBR checksum (PTS DE, BootWizard); <code>0x000000</code> if not used) </td> <td style="text-align:center">3 </td></tr> <tr> <td style="text-align:center"><code>0x01B6</code> (438) </td> <td style="text-align:center; background:#F2F2F2">Start <a href="/wiki/Logical_block_addressing" title="Logical block addressing">LBA</a> of AAP image file or <a href="/wiki/Volume_boot_record" title="Volume boot record">VBR</a>/<a href="/wiki/Extended_boot_record" title="Extended boot record">EBR</a> or relative sectors of AAP partition (copied to offset <code><a href="/wiki/Design_of_the_FAT_file_system#BPB331_OFS_11h" title="Design of the FAT file system">+01Chex</a></code> in the loaded sector over the "hidden sectors" entry of a DOS 3.31 BPB (or emulation thereof) to also support EBR booting) </td> <td style="text-align:center">4 </td></tr> <tr> <td style="text-align:center"><code>0x01BA</code> (442) </td> <td style="text-align:center; background:#F2F2F2">Reserved for sectors in AAP (optional; <code>0x00000000</code> if not used) </td> <td style="text-align:center">4 </td></tr> <tr> <td style="text-align:center"><code>0x01BE</code> (446) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №1 </td> <td rowspan="4" style="vertical-align:middle; text-align:center">Partition table (for primary partitions) </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01CE</code> (462) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №2 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01DE</code> (478) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №3 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01EE</code> (494) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №4 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01FE</code> (510) </td> <td style="text-align:center"><code>0x55</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center">Boot signature<a href="#cite_note-NB_Magic_AA55-12">[a]</a> </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x01FF</code> (511) </td> <td style="text-align:center"><code>0xAA</code> </td></tr> <tr> <th colspan="3" style="text-align:right;">Total size: 428 + 2 + 16 + 4×16 + 2 </th> <th>512 </th></tr></tbody></table> <table class="wikitable" style="float:right; width:45%; margin:1em;"> <caption>Structure of NEWLDR MBR </caption> <tbody><tr> <th>Address </th> <th style="vertical-align:middle" colspan="2">Description </th> <th style="vertical-align:middle">Size (<a href="/wiki/Byte" title="Byte">bytes</a>) </th></tr> <tr> <td style="text-align:center"><code>0x0000</code> (0) </td> <td style="text-align:center; background:#F2F2F2">JMPS (<code><a href="/wiki/X86_instruction_listings" title="X86 instruction listings">EBhex</a></code>) / NEWLDR record size (often <code>0x0A</code>/<code>0x16</code>/<code>0x1C</code> for code start at <code>0x000C</code>/<code>0x0018</code>/<code>0x001E</code>) </td> <td rowspan="10" style="vertical-align:middle; text-align:center; background:#F2F2F2">NEWLDR record (optional) </td> <td style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x0002</code> (2) </td> <td style="text-align:center; background:#F2F2F2">"<code>NEWLDR</code>" signature </td> <td style="text-align:center">6 </td></tr> <tr> <td style="text-align:center"><code>0x0008</code> (8) </td> <td style="text-align:center; background:#F2F2F2">LOADER physical drive and boot flag (<code>0x80</code>–<code>0xFE</code>, <code>0x00</code>–<code>0x7E</code>, <code>0xFF</code>, <code>0x7F</code>) (if not used, this and following 3 bytes must be all 0) </td> <td style="text-align:center">1 </td></tr> <tr> <td style="text-align:center"><code>0x0009</code> (9) </td> <td style="text-align:center; background:#F2F2F2"><a href="/wiki/Cylinder-head-sector" title="Cylinder-head-sector">CHS</a> address of LOADER boot sector or image file (f.e. <a href="/wiki/IBMBIO.LDR" class="mw-redirect" title="IBMBIO.LDR">IBMBIO.LDR</a>) (<code>0x000000</code> if not used) </td> <td style="text-align:center">3 </td></tr> <tr> <td style="text-align:center"><code>0x000C</code> (12) </td> <td style="text-align:center; background:#F2F2F2">Allowed <a href="/wiki/DL_register" class="mw-redirect" title="DL register">DL</a> minimum, else take from partition table (<code>0x80</code>: default; <code>0x00</code>: always use DL; <code>0xFF</code>: always use table entry) </td> <td style="text-align:center">1 </td></tr> <tr> <td style="text-align:center"><code>0x000D</code> (13) </td> <td style="text-align:center; background:#F2F2F2">Reserved (default: <code>0x000000</code>) </td> <td style="text-align:center">3 </td></tr> <tr> <td style="text-align:center"><code>0x0010</code> (16) </td> <td style="text-align:center; background:#F2F2F2"><a href="/wiki/Logical_block_addressing" title="Logical block addressing">LBA</a> of LOADER boot sector or image file (optional; <code>0x00000000</code> if not used) </td> <td style="text-align:center">4 </td></tr> <tr> <td style="text-align:center"><code>0x0014</code> (20) </td> <td style="text-align:center; background:#F2F2F2">Patch offset of VBR boot unit (default <code>0x0000</code> if not used, else <code><a href="/wiki/Design_of_the_FAT_file_system#EBPB_OFS_19h" title="Design of the FAT file system">0024hex</a></code> or <code><a href="/wiki/Design_of_the_FAT_file_system#BSIBM_OFS_1FDh" title="Design of the FAT file system">01FDhex</a></code>) </td> <td style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x0016</code> (22) </td> <td style="text-align:center; background:#F2F2F2">Checksum (<code>0x0000</code> if not used) </td> <td style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x0018</code> (24) </td> <td style="text-align:center; background:#F2F2F2">OEM loader signature ("<code>MSWIN4</code>" for <a href="/wiki/REAL/32" class="mw-redirect" title="REAL/32">REAL/32</a>, see also offset <code><a href="#MBRNEW_OFS_0DAh">+0DAhex</a></code>, corresponds with OEM label at offset <code><a href="/wiki/Design_of_the_FAT_file_system#BSIBM_OFS_003h" title="Design of the FAT file system">+003hex</a></code> in VBRs (optional) </td> <td style="text-align:center">6 </td></tr> <tr> <td style="text-align:center">Varies </td> <td colspan="2">Bootstrap code area (code entry at <code>0x0000</code>) </td> <td style="text-align:center">Varies </td></tr> <tr> <td style="text-align:center"><code>0x01AC</code> (428) </td> <td style="text-align:center; background:#F2F2F2"><code>0x78</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center; background:#F2F2F2">AAP signature (optional) </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x01AD</code> (429) </td> <td style="text-align:center; background:#F2F2F2"><code>0x56</code> </td></tr> <tr> <td style="text-align:center"><code>0x01AE</code> (430) </td> <td style="text-align:center; background:#F2F2F2">AAP partition entry №0 with special semantics </td> <td style="text-align:center; background:#F2F2F2">AAP record (optional) </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01BE</code> (446) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №1 </td> <td rowspan="4" style="vertical-align:middle; text-align:center">Partition table (for primary partitions) </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01CE</code> (462) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №2 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01DE</code> (478) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №3 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01EE</code> (494) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №4 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01FE</code> (510) </td> <td style="text-align:center"><code>0x55</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center">Boot signature<a href="#cite_note-NB_Magic_AA55-12">[a]</a> </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x01FF</code> (511) </td> <td style="text-align:center"><code>0xAA</code> </td></tr> <tr> <th colspan="3" style="text-align:right;">Total size: 30 + 398 + 2 + 16 + 4×16 + 2 </th> <th>512 </th></tr></tbody></table> <div style="clear:both;" class=""></div> <table class="wikitable" style="float:left; width:45%; margin:1em;"> <caption>Structure of AST/NEC MS-DOS and SpeedStor MBR </caption> <tbody><tr> <th>Address </th> <th style="vertical-align:middle" colspan="2">Description </th> <th style="vertical-align:middle">Size (<a href="/wiki/Byte" title="Byte">bytes</a>) </th></tr> <tr> <td style="text-align:center"><code>0x0000</code> (0)</td> <td colspan="2">Bootstrap code area </td> <td style="text-align:center">380 </td></tr> <tr> <td style="text-align:center"><code>0x017C</code> (380) </td> <td style="text-align:center; background:#F2F2F2"><code>0x5A</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center; background:#F2F2F2">AST/NEC signature (optional; not for SpeedStor) </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x017D</code> (381) </td> <td style="text-align:center; background:#F2F2F2"><code>0xA5</code> </td></tr> <tr> <td style="text-align:center"><code>0x017E</code> (382) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> №8 </td> <td rowspan="4" style="vertical-align:middle; text-align:center; background:#F2F2F2">AST/NEC expanded partition table (optional; also for SpeedStor) </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x018E</code> (398) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> №7 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x019E</code> (414) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> №6 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01AE</code> (430) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> №5 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01BE</code> (446) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №4 </td> <td rowspan="4" style="vertical-align:middle; text-align:center">Partition table (for primary partitions) </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01CE</code> (462) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №3 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01DE</code> (478) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №2 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01EE</code> (494) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №1 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01FE</code> (510) </td> <td style="text-align:center"><code>0x55</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center">Boot signature<a href="#cite_note-NB_Magic_AA55-12">[a]</a> </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x01FF</code> (511) </td> <td style="text-align:center"><code>0xAA</code> </td></tr> <tr> <th colspan="3" style="text-align:right;">Total size: 380 + 2 + 4×16 + 4×16 + 2 </th> <th>512 </th></tr></tbody></table> <table class="wikitable" style="float:right; width:45%; margin:1em;"> <caption>Structure of Ontrack Disk Manager MBR </caption> <tbody><tr> <th>Address </th> <th style="vertical-align:middle" colspan="2">Description </th> <th style="vertical-align:middle">Size (<a href="/wiki/Byte" title="Byte">bytes</a>) </th></tr> <tr> <td style="text-align:center"><code>0x0000</code> (0)</td> <td colspan="2">Bootstrap code area </td> <td style="text-align:center">252 </td></tr> <tr> <td style="text-align:center"><code>0x00FC</code> (252) </td> <td style="text-align:center; background:#F2F2F2"><code>0xAA</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center; background:#F2F2F2">DM signature (optional) </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x00FD</code> (253) </td> <td style="text-align:center; background:#F2F2F2"><code>0x55</code> </td></tr> <tr> <td style="text-align:center"><code>0x00FE</code> (254) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td rowspan="12" style="vertical-align:middle; text-align:center; background:#F2F2F2">DM expanded partition table (optional) </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x010E</code> (270) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x011E</code> (286) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x012E</code> (302) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x013E</code> (318) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x014E</code> (334) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x015E</code> (350) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x016E</code> (366) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x017E</code> (382) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x018E</code> (398) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x019E</code> (414) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01AE</code> (430) </td> <td style="text-align:center; background:#F2F2F2"><a href="#PTE">Partition entry</a> </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01BE</code> (446) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №1 </td> <td rowspan="4" style="vertical-align:middle; text-align:center">Partition table (for primary partitions) </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01CE</code> (462) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №2 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01DE</code> (478) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №3 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01EE</code> (494) </td> <td style="text-align:center"><a href="#PTE">Partition entry</a> №4 </td> <td style="text-align:center">16 </td></tr> <tr> <td style="text-align:center"><code>0x01FE</code> (510) </td> <td style="text-align:center"><code>0x55</code> </td> <td rowspan="2" style="vertical-align:middle; text-align:center">Boot signature<a href="#cite_note-NB_Magic_AA55-12">[a]</a> </td> <td rowspan="2" style="text-align:center">2 </td></tr> <tr> <td style="text-align:center"><code>0x01FF</code> (511) </td> <td style="text-align:center"><code>0xAA</code> </td></tr> <tr> <th colspan="3" style="text-align:right;">Total size: 252 + 2 + 12×16 + 4×16 + 2 </th> <th>512 </th></tr></tbody></table> <div style="clear:both;" class=""></div> <div class="mw-heading mw-heading3"><h3 id="Partition_table_entries">Partition table entries</h3>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=4" title="Edit section: Partition table entries">edit</a>]</div> <table class="wikitable" style="float: right; width: 33%; margin: 1em;"> <caption>Layout of one 16-byte partition entry<a href="#cite_note-osdev-14">[12]</a> (all multi-byte fields are <a href="/wiki/Little-endian" class="mw-redirect" title="Little-endian">little-endian</a>) </caption> <tbody><tr> <th colspan="2" style="text-align: center;">Offset (bytes)</th> <th>Field length</th> <th>Description </th></tr> <tr> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00</td> <td></td> <td>1 byte</td> <td>Status or physical drive (bit 7 set is for active or bootable, old MBRs only accept <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00 means inactive, and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01–<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7F stand for invalid)<a href="#cite_note-15">[c]</a> </td></tr> <tr> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01</td> <td></td> <td>3 bytes</td> <td><a href="/wiki/Cylinder-head-sector" title="Cylinder-head-sector">CHS address</a> of first absolute sector in partition.<a href="#cite_note-note-2-16">[d]</a> The format is described by three bytes, see the next three rows. </td></tr> <tr> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01</td> <td>1 byte</td> <td> <table class="wikitable"> <tbody><tr> <td colspan="8" style="text-align: center;">h7–0 </td> <td rowspan="2">head<a href="#cite_note-note-3-18">[e]</a> </td></tr> <tr> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td></tr></tbody></table> </td></tr> <tr> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x02</td> <td>1 byte</td> <td> <table class="wikitable"> <tbody><tr> <td colspan="2" style="text-align: center;">c9–8 </td> <td colspan="6" style="text-align: center;">s5–0 </td> <td rowspan="2">sector in bits 5–0; bits 7–6 are high bits of cylinder<a href="#cite_note-note-3-18">[e]</a> </td></tr> <tr> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td></tr></tbody></table> </td></tr> <tr> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x03</td> <td>1 byte</td> <td> <table class="wikitable"> <tbody><tr> <td colspan="8" style="text-align: center;">c7–0 </td> <td rowspan="2">bits 7–0 of cylinder<a href="#cite_note-note-3-18">[e]</a> </td></tr> <tr> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td></tr></tbody></table> </td></tr> <tr> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x04</td> <td></td> <td>1 byte</td> <td><a href="/wiki/Partition_type" title="Partition type">Partition type</a><a href="#cite_note-Brouwer_2012_Types-1-19">[14]</a> </td></tr> <tr> <td> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x05</td> <td></td> <td>3 bytes</td> <td><a href="/wiki/Cylinder-head-sector" title="Cylinder-head-sector">CHS address</a> of last absolute sector in partition.<a href="#cite_note-note-2-16">[d]</a> The format is described by 3 bytes, see the next 3 rows. </td></tr> <tr> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x05</td> <td>1 byte</td> <td> <table class="wikitable"> <tbody><tr> <td colspan="8" style="text-align: center;">h7–0 </td> <td rowspan="2">head<a href="#cite_note-note-3-18">[e]</a> </td></tr> <tr> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td></tr></tbody></table> </td></tr> <tr> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x06</td> <td>1 byte</td> <td> <table class="wikitable"> <tbody><tr> <td colspan="2" style="text-align: center;">c9–8 </td> <td colspan="6" style="text-align: center;">s5–0 </td> <td rowspan="2">sector in bits 5–0; bits 7–6 are high bits of cylinder<a href="#cite_note-note-3-18">[e]</a> </td></tr> <tr> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td></tr></tbody></table> </td></tr> <tr> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x07</td> <td>1 byte</td> <td> <table class="wikitable"> <tbody><tr> <td colspan="8" style="text-align: center;">c7–0 </td> <td rowspan="2">bits 7–0 of cylinder </td></tr> <tr> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td> <td>x </td></tr></tbody></table> </td></tr> <tr> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x08</td> <td></td> <td>4 bytes</td> <td><a href="/wiki/Logical_block_addressing" title="Logical block addressing">LBA</a> of first absolute sector in the partition<a href="#cite_note-note-4-21">[f]</a> </td></tr> <tr> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0C</td> <td></td> <td>4 bytes</td> <td>Number of sectors in partition<a href="#cite_note-note-5-22">[g]</a> </td></tr></tbody></table> An artifact of hard disk technology from the era of the <a href="/wiki/PC_XT" class="mw-redirect" title="PC XT">PC XT</a>, the partition table subdivides a storage medium using units of <a href="/wiki/Cylinder_(disk_drive)" class="mw-redirect" title="Cylinder (disk drive)">cylinders</a>, <a href="/wiki/Disk_read-and-write_head" title="Disk read-and-write head">heads</a>, and <a href="/wiki/Disk_sector" title="Disk sector">sectors</a> (<a href="/wiki/Cylinder-head-sector" title="Cylinder-head-sector">CHS</a> addressing). These values no longer correspond to their namesakes in modern disk drives, as well as being irrelevant in other devices such as <a href="/wiki/Solid-state_drive" title="Solid-state drive">solid-state drives</a>, which do not physically have cylinders or heads. In the CHS scheme, sector indices have (almost) always begun with sector 1 rather than sector 0 by convention, and due to an error in all versions of MS-DOS/PC DOS up to including 7.10, the number of heads is generally limited to 255<a href="#cite_note-NB_RBIL_Head_Limit-23">[h]</a> instead of 256. When a CHS address is too large to fit into these fields, the <a href="/wiki/Tuple" title="Tuple">tuple</a> (1023, 254, 63) is typically used today, although on older systems, and with older disk tools, the cylinder value often wrapped around modulo the CHS barrier near 8 GB, causing ambiguity and risks of data corruption. (If the situation involves a "protective" MBR on a disk with a GPT, Intel's <a href="/wiki/Extensible_Firmware_Interface" class="mw-redirect" title="Extensible Firmware Interface">Extensible Firmware Interface</a> specification requires that the tuple (1023, 255, 63) be used.) The 10-bit cylinder value is recorded within two bytes in order to facilitate making calls to the original/legacy <a href="/wiki/INT_13h" class="mw-redirect" title="INT 13h">INT 13h</a> BIOS disk access routines, where 16 bits were divided into sector and cylinder parts, and not on byte boundaries.<a href="#cite_note-Phoenix_1989_System-BIOS-17">[13]</a> Due to the limits of CHS addressing,<a href="#cite_note-Tech-Juice_2011_Geometry-24">[16]</a><a href="#cite_note-PC-Guide_BIOS-25">[17]</a> a transition was made to using LBA, or <a href="/wiki/Logical_block_addressing" title="Logical block addressing">logical block addressing</a>. Both the partition length and partition start address are sector values stored in the partition table entries as 32-bit quantities. The sector size used to be considered fixed at 512 (29) bytes, and a broad range of important components including <a href="/wiki/Chipsets" class="mw-redirect" title="Chipsets">chipsets</a>, <a href="/wiki/Boot_sector" title="Boot sector">boot sectors</a>, <a href="/wiki/Operating_system" title="Operating system">operating systems</a>, <a href="/wiki/Database_engine" title="Database engine">database engines</a>, <a href="/wiki/Disk_partitioning" title="Disk partitioning">partitioning</a> tools, <a href="/wiki/Backup" title="Backup">backup</a> and <a href="/wiki/File_system" title="File system">file system</a> utilities and other software had this value hard-coded. Since the end of 2009, disk drives employing 4096-byte sectors (<a href="/wiki/4Kn" class="mw-redirect" title="4Kn">4Kn</a> or <a href="/wiki/Advanced_Format" title="Advanced Format">Advanced Format</a>) have been available, although the size of the sector for some of these drives was still reported as 512 bytes to the host system through conversion in the hard-drive firmware and referred to as 512 emulation drives (<a href="/wiki/512e" class="mw-redirect" title="512e">512e</a>). Since block addresses and sizes are stored in the partition table of an MBR using 32 bits, the maximum size, as well as the highest start address, of a partition using drives that have 512-byte sectors (actual or emulated) cannot exceed 2 <abbr title="TebiByte = 1024×1024×1024×1024 byte"><a href="/wiki/Tebibyte" class="mw-redirect" title="Tebibyte">TiB</a></abbr>−512 bytes (2199023255040 bytes or 4294967295 (232−1) sectors × 512 (29) bytes per sector).<a href="#cite_note-Microsoft_2013_2581408-1">[1]</a> Alleviating this capacity limitation was one of the prime motivations for the development of the GPT. Since partitioning information is stored in the MBR partition table using a beginning block address and a length, it may in theory be possible to define partitions in such a way that the allocated space for a disk with 512-byte sectors gives a total size approaching 4 TiB, if all but one partition are located below the 2 TiB limit and the last one is assigned as starting at or close to block 232−1 and specify the size as up to 232−1, thereby defining a partition that requires 33 rather than 32 bits for the sector address to be accessed. However, in practice, only certain <a href="/wiki/Logical_block_addressing#LBA48" title="Logical block addressing">LBA-48</a>-enabled operating systems, including Linux, FreeBSD and Windows 7<a href="#cite_note-Smith_2011_gdisk-26">[18]</a> that use 64-bit sector addresses internally actually support this. Due to code space constraints and the nature of the MBR partition table to only support 32 bits, boot sectors, even if enabled to support LBA-48 rather than <a href="/wiki/Logical_block_addressing" title="Logical block addressing">LBA-28</a>, often use 32-bit calculations, unless they are specifically designed to support the full address range of LBA-48 or are intended to run on 64-bit platforms only. Any boot code or operating system using 32-bit sector addresses internally would cause addresses to wrap around accessing this partition and thereby result in serious data corruption over all partitions. For disks that present a sector size other than 512 bytes, such as <a href="/wiki/USB" title="USB">USB</a> <a href="/wiki/External_drive" class="mw-redirect" title="External drive">external drives</a>, there are limitations as well. A sector size of 4096 results in an eight-fold increase in the size of a partition that can be defined using MBR, allowing partitions up to 16 TiB (232 × 4096 bytes) in size.<a href="#cite_note-Superuser_2013-27">[19]</a> Versions of Windows more recent than Windows XP support the larger sector sizes, as well as Mac OS X, and <a href="/wiki/Linux" title="Linux">Linux</a> has supported larger sector sizes since 2.6.31<a href="#cite_note-Seagate_4K-28">[20]</a> or 2.6.32,<a href="#cite_note-Western-Digital_1-29">[21]</a> but issues with boot loaders, partitioning tools and computer BIOS implementations present certain limitations,<a href="#cite_note-IBM_4K-30">[22]</a> since they are often hard-wired to reserve only 512 bytes for sector buffers, causing memory to become overwritten for larger sector sizes. This may cause unpredictable behaviour as well, and therefore should be avoided when compatibility and standard conformity is an issue. Where a data storage device has been partitioned with the GPT scheme, the master boot record will still contain a partition table, but its only purpose is to indicate the existence of the GPT and to prevent utility programs that understand only the MBR partition table scheme from creating any partitions in what they would otherwise see as free space on the disk, thereby accidentally erasing the GPT. <div class="mw-heading mw-heading2"><h2 id="System_bootstrapping">System bootstrapping</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=5" title="Edit section: System bootstrapping">edit</a>]</div> On <a href="/wiki/IBM_PC-compatible" class="mw-redirect" title="IBM PC-compatible">IBM PC-compatible</a> computers, the <a href="/wiki/Bootstrapping" title="Bootstrapping">bootstrapping</a> <a href="/wiki/Firmware" title="Firmware">firmware</a> (contained within the <a href="/wiki/Read-only_memory" title="Read-only memory">ROM</a> <a href="/wiki/BIOS" title="BIOS">BIOS</a>) loads and executes the master boot record.<a href="#cite_note-OSDev_2011_MBR-31">[23]</a> The <a href="/wiki/PC_XT" class="mw-redirect" title="PC XT">PC/XT (type 5160)</a> used an <a href="/wiki/Intel_8088" title="Intel 8088">Intel 8088</a> <a href="/wiki/Computer_processor" class="mw-redirect" title="Computer processor">microprocessor</a>. In order to remain compatible, all x86 BIOS architecture systems start with the microprocessor in an <a href="/wiki/X86#Operating_modes" title="X86">operating mode</a> referred to as <a href="/wiki/Real_mode" title="Real mode">real mode</a>. The BIOS reads the MBR from the storage device into <a href="/wiki/Physical_memory" class="mw-redirect" title="Physical memory">physical memory</a>, and then it directs the microprocessor to the start of the boot code. The BIOS will switch the processor to real mode, then begin to execute the MBR program, and so the beginning of the MBR is expected to contain real-mode <a href="/wiki/Machine_code" title="Machine code">machine code</a>.<a href="#cite_note-OSDev_2011_MBR-31">[23]</a> Since the BIOS bootstrap routine loads and runs exactly one sector from the physical disk, having the partition table in the MBR with the boot code simplifies the design of the MBR program. It contains a small program that loads the <a href="/wiki/Volume_Boot_Record" class="mw-redirect" title="Volume Boot Record">Volume Boot Record</a> (VBR) of the targeted partition. Control is then passed to this code, which is responsible for loading the actual operating system. This process is known as <a href="/wiki/Chain_loading" title="Chain loading">chain loading</a>. Popular MBR code programs were created for booting <a href="/wiki/PC_DOS" class="mw-redirect" title="PC DOS">PC DOS</a> and <a href="/wiki/MS-DOS" title="MS-DOS">MS-DOS</a>, and similar boot code remains in wide use. These boot sectors expect the <code>FDISK</code> partition table scheme to be in use and scans the list of partitions in the MBR's embedded partition table to find the only one that is marked with the active flag.<a href="#cite_note-Sedory_2003_MBR200-32">[24]</a> It then loads and runs the <a href="/wiki/Volume_boot_record" title="Volume boot record">volume boot record</a> (VBR) of the active partition. There are alternative boot code implementations, some of which are installed by <a href="/wiki/Boot_manager" class="mw-redirect" title="Boot manager">boot managers</a>, which operate in a variety of ways. Some MBR code loads additional code for a boot manager from the first track of the disk, which it assumes to be "free" space that is not allocated to any disk partition, and executes it. A MBR program may interact with the user to determine which partition on which drive should boot, and may transfer control to the MBR of a different drive. Other MBR code contains a list of disk locations (often corresponding to the contents of <a href="/wiki/Computer_file" title="Computer file">files</a> in a <a href="/wiki/Filesystem" class="mw-redirect" title="Filesystem">filesystem</a>) of the remainder of the boot manager code to load and to execute. (The first relies on behavior that is not universal across all disk partitioning utilities, most notably those that read and write GPTs. The last requires that the embedded list of disk locations be updated when changes are made that would relocate the remainder of the code.) On machines that do not use <a href="/wiki/X86" title="X86">x86</a> processors, or on x86 machines with non-BIOS firmware such as <a href="/wiki/Open_Firmware" title="Open Firmware">Open Firmware</a> or <a href="/wiki/Extensible_Firmware_Interface" class="mw-redirect" title="Extensible Firmware Interface">Extensible Firmware Interface</a> (EFI) firmware, this design is unsuitable, and the MBR is not used as part of the system bootstrap.<a href="#cite_note-Singh_2009_OSX-33">[25]</a> EFI firmware is instead capable of directly understanding the GPT partitioning scheme and the <a href="/wiki/File_Allocation_Table" title="File Allocation Table">FAT</a> filesystem format, and loads and runs programs held as files in the <a href="/wiki/EFI_System_partition" class="mw-redirect" title="EFI System partition">EFI System partition</a>.<a href="#cite_note-Boyne_2011_EFI-Boot-34">[26]</a> The MBR will be involved only insofar as it might contain a partition table for compatibility purposes if the GPT partition table scheme has been used. There is some MBR replacement code that emulates EFI firmware's bootstrap, which makes non-EFI machines capable of booting from disks using the GPT partitioning scheme. It detects a GPT, places the processor in the correct operating mode, and loads the EFI compatible code from disk to complete this task. <div class="mw-heading mw-heading2"><h2 id="Disk_identity">Disk identity</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=6" title="Edit section: Disk identity">edit</a>]</div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Qtparted-usb-hdd-snapshot.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/87/Qtparted-usb-hdd-snapshot.png/300px-Qtparted-usb-hdd-snapshot.png" decoding="async" width="300" height="225" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/87/Qtparted-usb-hdd-snapshot.png/450px-Qtparted-usb-hdd-snapshot.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/87/Qtparted-usb-hdd-snapshot.png/600px-Qtparted-usb-hdd-snapshot.png 2x" data-file-width="1024" data-file-height="768" /></a><figcaption>Information contained in the partition table of an external hard drive as it appears in the utility program <a href="/wiki/QtParted" title="QtParted">QtParted</a>, running under Linux (with KDE)</figcaption></figure> In addition to the bootstrap code and a partition table, master boot records may contain a <a href="#DISK_ID">disk signature</a>. This is a 32-bit value that is intended to identify uniquely the disk medium (as opposed to the disk unit—the two not necessarily being the same for removable hard disks). The disk signature was introduced by Windows NT version 3.5, but it is now used by several operating systems, including the <a href="/wiki/Linux_kernel" title="Linux kernel">Linux kernel</a> version 2.6 and later. Linux tools can use the NT disk signature to determine which disk the machine booted from.<a href="#cite_note-Domsch_2003_EDD-35">[27]</a> Windows NT (and later Microsoft operating systems) uses the disk signature as an index to all the partitions on any disk ever connected to the computer under that OS; these signatures are kept in <a href="/wiki/Windows_Registry" title="Windows Registry">Windows Registry</a> keys, primarily for storing the persistent mappings between disk partitions and drive letters. It may also be used in Windows NT <a href="/wiki/BOOT.INI" class="mw-redirect" title="BOOT.INI">BOOT.INI</a> files (though most do not), to describe the location of bootable Windows NT (or later) partitions.<a href="#cite_note-Microsoft_KB227704-36">[28]</a> One key (among many), where NT disk signatures appear in a Windows 2000/XP registry, is: <pre>HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices\ </pre> If a disk's signature stored in the MBR was <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">A8 E1 B9 D2 (in that order) and its first partition corresponded with logical drive C: under Windows, then the <code>REG_BINARY</code> data under the key value <code>\DosDevices\C:</code> would be: <pre>A8 E1 B9 D2 00 7E 00 00 00 00 00 00 </pre> The first four bytes are said disk signature. (In other keys, these bytes may appear in reverse order from that found in the MBR sector.) These are followed by eight more bytes, forming a 64-bit integer, in <a href="/wiki/Little-endian" class="mw-redirect" title="Little-endian">little-endian</a> notation, which are used to locate the byte offset of this partition. In this case, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">00 7E corresponds to the hexadecimal value <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7E00 (32,256). Under the assumption that the drive in question reports a sector size of 512 bytes, then dividing this byte offset by 512 results in 63, which is the physical sector number (or LBA) containing the first sector of the partition (unlike the sector count used in the sectors value of CHS tuples, which counts from one, the absolute or LBA sector value starts <a href="/wiki/Zero-based_numbering" title="Zero-based numbering">counting from zero</a>). If this disk had another partition with the values <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">00 F8 93 71 02 following the disk signature (under, e.g., the key value <code>\DosDevices\D:</code>), it would begin at byte offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00027193F800 (10,495,457,280), which is also the first byte of physical sector 20,498,940. Starting with <a href="/wiki/Windows_Vista" title="Windows Vista">Windows Vista</a>, the disk signature is also stored in the <a href="/wiki/Boot_Configuration_Data" class="mw-redirect" title="Boot Configuration Data">Boot Configuration Data</a> (BCD) store, and the boot process depends on it.<a href="#cite_note-Multibooters_Vista-MBR-37">[29]</a> If the disk signature changes, cannot be found or has a conflict, Windows is unable to boot.<a href="#cite_note-Russinovich_2011_Disk-Signature-38">[30]</a> Unless Windows is forced to use the overlapping part of the LBA address of the Advanced Active Partition entry as pseudo-disk signature, Windows' usage is conflictive with the Advanced Active Partition feature of PTS-DOS 7 and DR-DOS 7.07, in particular if their boot code is located outside the first 8 GB of the disk, so that LBA addressing must be used. <div class="mw-heading mw-heading2"><h2 id="Programming_considerations">Programming considerations</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=7" title="Edit section: Programming considerations">edit</a>]</div> The MBR originated in the <a href="/wiki/PC_XT" class="mw-redirect" title="PC XT">PC XT</a>.<a href="#cite_note-Sakamoto_2010_MBR-39">[31]</a> <a href="/wiki/IBM_PC-compatible" class="mw-redirect" title="IBM PC-compatible">IBM PC-compatible</a> computers are <a href="/wiki/Endianness" title="Endianness">little-endian</a>, which means the <a href="/wiki/Computer_processor" class="mw-redirect" title="Computer processor">processor</a> stores numeric values spanning two or more bytes in memory <a href="/wiki/Least_significant_byte" class="mw-redirect" title="Least significant byte">least significant byte</a> first. The format of the MBR on media reflects this convention. Thus, the MBR signature will appear in a <a href="/wiki/Disk_editor" title="Disk editor">disk editor</a> as the sequence <code>55 AA</code>.<a href="#cite_note-NB_Magic_AA55-12">[a]</a> The bootstrap sequence in the BIOS will load the first valid MBR that it finds into the computer's <a href="/wiki/Physical_memory" class="mw-redirect" title="Physical memory">physical memory</a> at <a href="/wiki/Memory_address" title="Memory address">address</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00 to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7FFF.<a href="#cite_note-Sakamoto_2010_MBR-39">[31]</a> The last instruction executed in the BIOS code will be a "jump" to that address in order to direct execution to the beginning of the MBR copy. The primary validation for most BIOSes is the signature at offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01FE, although a BIOS implementer may choose to include other checks, such as verifying that the MBR contains a valid partition table without entries referring to sectors beyond the reported capacity of the disk. To the BIOS, removable (e.g. floppy) and fixed disks are essentially the same. For either, the BIOS reads the first physical sector of the media into RAM at absolute address <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00, checks the signature in the last two bytes of the loaded sector, and then, if the correct signature is found, transfers control to the first byte of the sector with a jump (JMP) instruction. The only real distinction that the BIOS makes is that (by default, or if the boot order is not configurable) it attempts to boot from the first removable disk before trying to boot from the first fixed disk. From the perspective of the BIOS, the action of the MBR loading a volume boot record into RAM is exactly the same as the action of a floppy disk volume boot record loading the object code of an operating system loader into RAM. In either case, the program that the BIOS loaded is going about the work of chain loading an operating system. While the MBR <a href="/wiki/Boot_sector" title="Boot sector">boot sector</a> code expects to be loaded at physical address <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00,<a href="#cite_note-NB_Load-address-40">[i]</a> all the memory from physical address <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0501 (address <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0500 is the last one used by a Phoenix BIOS)<a href="#cite_note-Phoenix_1989_System-BIOS-17">[13]</a> to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7FFF,<a href="#cite_note-Sakamoto_2010_MBR-39">[31]</a> later relaxed to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0xFFFF<a href="#cite_note-Compaq-Phoenix-Intel_1996_BBS101-41">[32]</a> (and sometimes<a href="#cite_note-NB_EBDA-42">[j]</a> up to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x9000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0xFFFF)‍—‌the end of the first 640 <abbr title="1 KB = 1024 bytes">KB</abbr>‍—‌is available in real mode.<a href="#cite_note-NB_free-memory-43">[k]</a> The <code>INT 12h</code> <a href="/wiki/BIOS_interrupt_call" title="BIOS interrupt call">BIOS interrupt call</a> may help in determining how much memory can be allocated safely (by default, it simply reads the base memory size in KB from <a href="/wiki/Memory_segmentation" title="Memory segmentation">segment</a>:offset location <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0040:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0013, but it may be hooked by other resident pre-boot software like BIOS overlays, <a href="/wiki/Remote_Program_Loader" class="mw-redirect" title="Remote Program Loader">RPL</a> code or viruses to reduce the reported amount of available memory in order to keep other boot stage software like boot sectors from overwriting them). The last 66 bytes of the 512-byte MBR are reserved for the partition table and other information, so the MBR boot sector program must be small enough to fit within 446 bytes of memory or less. The MBR code examines the partition table, selects a suitable partition and loads the program that will perform the next stage of the boot process, usually by making use of INT 13h <a href="/wiki/BIOS_interrupt_call" title="BIOS interrupt call">BIOS calls</a>. The MBR bootstrap code loads and runs (a boot loader- or operating system-dependent) <a href="/wiki/Volume_boot_record" title="Volume boot record">volume boot record</a> code that is located at the beginning of the "active" partition. The volume boot record will fit within a 512-byte sector, but it is safe for the MBR code to load additional sectors to accommodate boot loaders longer than one sector, provided they do not make any assumptions on what the sector size is. In fact, at least 1 KB of RAM is available at address <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00 in every IBM XT- and AT-class machine, so a 1 KB sector could be used with no problem. Like the MBR, a volume boot record normally expects to be loaded at address <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00. This derives from the fact that the volume boot record design originated on unpartitioned media, where a volume boot record would be directly loaded by the BIOS boot procedure; as mentioned above, the BIOS treats MBRs and volume boot records (VBRs)<a href="#cite_note-NB_VBRs-44">[l]</a> exactly alike. Since this is the same location where the MBR is loaded, one of the first tasks of an MBR is to <a href="/wiki/Self-relocation" title="Self-relocation">relocate</a> itself somewhere else in memory. The relocation address is determined by the MBR, but it is most often <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0600 (for MS-DOS/PC DOS, OS/2 and Windows MBR code) or <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0060:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000 (most DR-DOS MBRs). (Even though both of these segmented addresses resolve to the same physical memory address in real mode, for <a href="/wiki/Apple_Darwin" class="mw-redirect" title="Apple Darwin">Apple Darwin</a> to boot, the MBR must be relocated to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0600 instead of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0060:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000, since the code depends on the DS:SI pointer to the partition entry provided by the MBR, but it erroneously refers to it via <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:SI only.<a href="#cite_note-Elliott_2009_Darwin-45">[33]</a>) It is important not to relocate to other addresses in memory because many <a href="/wiki/Volume_boot_record" title="Volume boot record">VBRs</a> will assume a certain standard memory layout when loading their boot file. The Status field in a partition table record is used to indicate an active partition. Standard-conformant MBRs will allow only one partition marked active and use this as part of a sanity-check to determine the existence of a valid partition table. They will display an error message, if more than one partition has been marked active. Some non-standard MBRs will not treat this as an error condition and just use the first marked partition in the row. Traditionally, values other than <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00 (not active) and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 (active) were invalid and the bootstrap program would display an error message upon encountering them. However, the <a href="/wiki/Plug_and_Play_BIOS_Specification" class="mw-redirect" title="Plug and Play BIOS Specification">Plug and Play BIOS Specification</a> and <a href="/wiki/BIOS_Boot_Specification" class="mw-redirect" title="BIOS Boot Specification">BIOS Boot Specification</a> (BBS) allowed other devices to become bootable as well since 1994.<a href="#cite_note-Compaq-Phoenix-Intel_1996_BBS101-41">[32]</a><a href="#cite_note-Compaq-Phoenix-Intel_1994_PnP10A-46">[34]</a> Consequently, with the introduction of MS-DOS 7.10 (Windows 95B) and higher, the MBR started to treat a set bit 7 as active flag and showed an error message for values <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01..<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7F only. It continued to treat the entry as physical drive unit to be used when loading the corresponding partition's VBR later on, thereby now also accepting other boot drives than <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 as valid, however, MS-DOS did not make use of this extension by itself. Storing the actual physical drive number in the partition table does not normally cause backward compatibility problems, since the value will differ from <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 only on drives other than the first one (which have not been bootable before, anyway). However, even with systems enabled to boot off other drives, the extension may still not work universally, for example, after the BIOS assignment of physical drives has changed when drives are removed, added or swapped. Therefore, per the <a href="/wiki/BIOS_Boot_Specification" class="mw-redirect" title="BIOS Boot Specification">BIOS Boot Specification</a> (BBS),<a href="#cite_note-Compaq-Phoenix-Intel_1996_BBS101-41">[32]</a> it is best practice for a modern MBR accepting bit 7 as active flag to pass on the DL value originally provided by the BIOS instead of using the entry in the partition table. <div class="mw-heading mw-heading3"><h3 id="BIOS_to_MBR_interface">BIOS to MBR interface</h3>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=8" title="Edit section: BIOS to MBR interface">edit</a>]</div> The MBR is loaded at memory location <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00 and with the following <a href="/wiki/CPU" class="mw-redirect" title="CPU">CPU</a> registers set up when the prior bootstrap loader (normally the <a href="/wiki/Initial_Program_Loader" class="mw-redirect" title="Initial Program Loader">IPL</a> in the BIOS) passes execution to it by jumping to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00 in the CPU's <a href="/wiki/Real_mode" title="Real mode">real mode</a>. <ul><li><a href="/wiki/CS_register" class="mw-redirect" title="CS register">CS</a>:<a href="/wiki/IP_register" class="mw-redirect" title="IP register">IP</a> = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00 (fixed)</li></ul> <dl><dd>Some Compaq BIOSes erroneously use <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x07C0:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000 instead. While this resolves to the same location in real mode memory, it is non-standard and should be avoided, since MBR code assuming certain register values or not written to be relocatable may not work otherwise.</dd></dl> <ul><li><a href="/wiki/DL_register" class="mw-redirect" title="DL register">DL</a> = boot drive unit (<a href="/wiki/Fixed_disk" class="mw-redirect" title="Fixed disk">fixed disks</a> / <a href="/wiki/Removable_drive" class="mw-redirect" title="Removable drive">removable drives</a>: <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 = first, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x81 = second, ..., <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0xFE; <a href="/wiki/Floppy" class="mw-redirect" title="Floppy">floppies</a> / <a href="/wiki/Superfloppy" class="mw-redirect" title="Superfloppy">superfloppies</a>: <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00 = first, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01 = second, ..., <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7E; values <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7F and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0xFF are reserved for ROM / remote drives and must not be used on disk).<a href="#cite_note-Paul_1997-47">[35]</a><a href="#cite_note-Paul_2017-48">[36]</a></li></ul> <dl><dd>DL is supported by IBM BIOSes as well as most other BIOSes. The Toshiba T1000 BIOS is known not to support this properly, and some old Wyse 286 BIOSes use DL values greater or equal to 2 for fixed disks (thereby reflecting the logical drive numbers under DOS rather than the physical drive numbers of the BIOS). USB sticks configured as removable drives typically get an assignment of DL = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x81, etc. However, some rare BIOSes erroneously presented them under DL = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01, just as if they were configured as superfloppies.</dd> <dd>A standard conformant BIOS assigns numbers greater or equal to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 exclusively to fixed disk / removable drives, and traditionally only values <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00 were passed on as physical drive units during boot. By convention, only fixed disks / removable drives are partitioned, therefore, the only DL value a MBR could see traditionally was <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80. Many MBRs were coded to ignore the DL value and work with a hard-wired value (normally <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80), anyway.</dd> <dd>The <a href="/wiki/Plug_and_Play_BIOS_Specification" class="mw-redirect" title="Plug and Play BIOS Specification">Plug and Play BIOS Specification</a> and <a href="/wiki/BIOS_Boot_Specification" class="mw-redirect" title="BIOS Boot Specification">BIOS Boot Specification</a> (BBS) allow other devices to become bootable as well since 1994.<a href="#cite_note-Compaq-Phoenix-Intel_1996_BBS101-41">[32]</a><a href="#cite_note-Compaq-Phoenix-Intel_1994_PnP10A-46">[34]</a> The later recommends that MBR and VBR code should use DL rather than internally hardwired defaults.<a href="#cite_note-Compaq-Phoenix-Intel_1996_BBS101-41">[32]</a> This will also ensure compatibility with various non-standard assignments (see examples above), as far as the MBR code is concerned.</dd> <dd>Bootable CD-ROMs following the <a href="/wiki/El_Torito_(CD-ROM_standard)" class="mw-redirect" title="El Torito (CD-ROM standard)">El Torito</a> specification may contain disk images mounted by the BIOS to occur as floppy or superfloppies on this interface. DL values of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00 and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01 may also be used by <a href="/wiki/Protected_Area_Run_Time_Interface_Extension_Services" class="mw-redirect" title="Protected Area Run Time Interface Extension Services">Protected Area Run Time Interface Extension Services</a> (PARTIES) and <a href="/wiki/Trusted_Computing_Group" title="Trusted Computing Group">Trusted Computing Group</a> (TCG) BIOS extensions in Trusted mode to access otherwise invisible PARTIES partitions, disk image files located via the <a href="/wiki/Boot_Engineering_Extension_Record" class="mw-redirect" title="Boot Engineering Extension Record">Boot Engineering Extension Record</a> (BEER) in the last physical sector of a hard disk's <a href="/wiki/Host_Protected_Area" class="mw-redirect" title="Host Protected Area">Host Protected Area</a> (HPA). While designed to emulate floppies or superfloppies, MBR code accepting these non-standard DL values allows to use images of partitioned media at least in the boot stage of operating systems.</dd></dl> <ul><li><a href="/wiki/DH_register" class="mw-redirect" title="DH register">DH</a> bit 5 = 0: device supported through <a href="/wiki/INT_13h" class="mw-redirect" title="INT 13h">INT 13h</a>; else: don't care (should be zero). DH is supported by some IBM BIOSes.</li> <li>Some of the other registers may typically also hold certain register values (DS, ES, SS = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000; SP = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0400) with original IBM ROM BIOSes, but this is nothing to rely on, as other BIOSes may use other values. For this reason, MBR code by IBM, Microsoft, Digital Research, etc. never did take any advantage of it. Relying on these register values in boot sectors may also cause problems in chain-boot scenarios.</li></ul> Systems with <a href="/wiki/Plug-and-Play" class="mw-redirect" title="Plug-and-Play">Plug-and-Play</a> BIOS or BBS support will provide a pointer to PnP data in addition to DL:<a href="#cite_note-Compaq-Phoenix-Intel_1996_BBS101-41">[32]</a><a href="#cite_note-Compaq-Phoenix-Intel_1994_PnP10A-46">[34]</a> <ul><li>DL = boot drive unit (see above)</li> <li><a href="/wiki/ES_register" class="mw-redirect" title="ES register">ES</a>:<a href="/wiki/DI_register" class="mw-redirect" title="DI register">DI</a> = points to "<code>$PnP</code>" installation check structure</li></ul> <dl><dd>This information allows the boot loader in the MBR (or VBR, if passed on) to actively interact with the BIOS or a resident PnP / BBS BIOS overlay in memory in order to configure the boot order, etc., however, this information is ignored by most standard MBRs and VBRs. Ideally, ES:DI is passed on to the VBR for later use by the loaded operating system, but PnP-enabled operating systems typically also have fallback methods to retrieve the PnP BIOS entry point later on so that most operating systems do not rely on this.</dd></dl> <div class="mw-heading mw-heading3"><h3 id="MBR_to_VBR_interface">MBR to VBR interface</h3>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=9" title="Edit section: MBR to VBR interface">edit</a>]</div> By convention, a standard conformant MBR passes execution to a successfully loaded VBR, loaded at memory location <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00, by jumping to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00 in the CPU's real mode with the following registers maintained or specifically set up: <ul><li>CS:IP = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000:<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00<a href="#cite_note-NB_CS-IP-49">[m]</a> (constant)</li> <li>DL = boot drive unit (see above)</li></ul> <dl><dd>MS-DOS 2.0–7.0 / PC DOS 2.0–6.3 MBRs do not pass on the DL value received on entry, but they rather use the boot status entry in the partition table entry of the selected primary partition as physical boot drive unit. Since this is, by convention, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 in most MBR partition tables, it won't change things unless the BIOS attempted to boot off a physical device other than the first fixed disk / removable drive in the row. This is also the reason why these operating systems cannot boot off a second hard disk, etc. Some FDISK tools allow to mark partitions on secondary disks as "active" as well. In this situation, knowing that these operating systems cannot boot off other drives anyway, some of them continue to use the traditionally fixed value of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 as active marker, whereas others use values corresponding with the currently assigned physical drive unit (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x81, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x82), thereby allowing booting from other drives, at least in theory. In fact, this will work with many MBR codes, which take a set bit 7 of the boot status entry as active flag rather than insisting on <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80, however, MS-DOS/PC DOS MBRs are hard-wired to accept the fixed value of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 only. Storing the actual physical drive number in the partition table will also cause problems, when the BIOS assignment of physical drives changes, for example when drives are removed, added or swapped. Therefore, for a normal MBR accepting bit 7 as active flag and otherwise just using and passing on to the VBR the DL value originally provided by the BIOS allows for maximum flexibility. MS-DOS 7.1–8.0 MBRs have changed to treat bit 7 as active flag and any values <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01..<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7F as invalid, but they still take the physical drive unit from the partition table rather than using the DL value provided by the BIOS. DR-DOS 7.07 extended MBRs treat bit 7 as active flag and use and pass on the BIOS DL value by default (including non-standard values <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00..<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01 used by some BIOSes also for partitioned media), but they also provide a special <a href="#NEWLDR">NEWLDR</a> configuration block in order to support alternative boot methods in conjunction with LOADER and REAL/32 as well as to change the detail behaviour of the MBR, so that it can also work with drive values retrieved from the partition table (important in conjunction with LOADER and AAPs, see NEWLDR offset <code><a href="#NEWLDR_OFS_00Ch">0x000C</a></code>), translate Wyse non-standard drive units <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x02..<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7F to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80..<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0xFD, and optionally fix up the drive value (stored at offset <code><a href="/wiki/Design_of_the_FAT_file_system#EBPB_OFS_19h" title="Design of the FAT file system">0x019</a></code> in the <a href="/wiki/Extended_BIOS_Parameter_Block" class="mw-redirect" title="Extended BIOS Parameter Block">Extended BIOS Parameter Block</a> (EBPB) or at sector offset <code><a href="/wiki/Design_of_the_FAT_file_system#BSIBM_OFS_1FDh" title="Design of the FAT file system">0x01FD</a></code>) in loaded VBRs before passing execution to them (see NEWLDR offset <code><a href="#NEWLDR_OFS_014h">0x0014</a></code>)—this also allows other boot loaders to use NEWLDR as a chain-loader, configure its in-memory image on the fly and "tunnel" the loading of VBRs, EBRs, or AAPs through NEWLDR.</dd></dl> <ul><li>The contents of DH and ES:DI should be preserved by the MBR for full Plug-and-Play support (see above), however, many MBRs, including those of MS-DOS 2.0–8.0 / PC DOS 2.0–6.3 and Windows NT/2000/XP, do not. (This is unsurprising, since those versions of DOS predate the Plug-and-Play BIOS standard, and previous standards and conventions indicated no requirements to preserve any register other than DL.) Some MBRs set DH to 0.</li></ul> The MBR code passes additional information to the VBR in many implementations: <ul><li>DS:SI = points to the 16-byte <a href="/wiki/MBR_partition_table" class="mw-redirect" title="MBR partition table">MBR partition table</a> entry (in the relocated MBR) corresponding with the activated VBR. <a href="/wiki/PC-MOS" class="mw-redirect" title="PC-MOS">PC-MOS</a> 5.1 depends on this to boot if no partition in the partition table is flagged as bootable. In conjunction with LOADER, <a href="/wiki/Multiuser_DOS" title="Multiuser DOS">Multiuser DOS</a> and <a href="/wiki/REAL/32" class="mw-redirect" title="REAL/32">REAL/32</a> boot sectors use this to locate the boot sector of the active partition (or another bootstrap loader like IBMBIO.LDR at a fixed position on disk) if the boot file (LOADER.SYS) could not be found. <a href="/wiki/PTS-DOS" title="PTS-DOS">PTS-DOS</a> 6.6 and <a href="/wiki/S/DOS" class="mw-redirect" title="S/DOS">S/DOS</a> 1.0 use this in conjunction with their <a href="/wiki/Advanced_Active_Partition" class="mw-redirect" title="Advanced Active Partition">Advanced Active Partition</a> (AAP) feature. In addition to support for LOADER and AAPs, DR-DOS 7.07 can use this to determine the necessary INT 13h access method when using its dual CHS/LBA VBR code and it will update the boot drive / status flag field in the partition entry according to the effectively used DL value. <a href="/wiki/Apple_Darwin" class="mw-redirect" title="Apple Darwin">Darwin</a> bootloaders (Apple's <code>boot1h</code>, <code>boot1u</code>, and David Elliott's <code>boot1fat32</code>) depend on this pointer as well, but additionally they don't use DS, but assume it to be set to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0000 instead.<a href="#cite_note-Elliott_2009_Darwin-45">[33]</a> This will cause problems if this assumption is incorrect. The MBR code of OS/2, MS-DOS 2.0 to 8.0, PC DOS 2.0 to 7.10 and Windows NT/2000/XP provides this same interface as well, although these systems do not use it. The Windows Vista/7 MBRs no longer provide this DS:SI pointer. While some extensions only depend on the 16-byte partition table entry itself, other extensions may require the whole 4 (or 5 entry) partition table to be present as well.</li> <li>DS:<a href="/wiki/BP_register" class="mw-redirect" title="BP register">BP</a> = optionally points to the 16-byte <a href="/wiki/MBR_partition_table" class="mw-redirect" title="MBR partition table">MBR partition table</a> entry (in the relocated MBR) corresponding with the activated VBR. This is identical to the pointer provided by DS:SI (see above) and is provided by MS-DOS 2.0–8.0, PC DOS 2.0–7.10, Windows NT/2000/XP/Vista/7 MBRs. It is, however, not supported by most third-party MBRs.</li></ul> Under DR-DOS 7.07 an extended interface may be optionally provided by the extended MBR and in conjunction with LOADER: <ul><li><a href="/wiki/AX_register" class="mw-redirect" title="AX register">AX</a> = magic signature indicating the presence of this NEWLDR extension (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x0EDC)</li> <li>DL = boot drive unit (see above)</li> <li>DS:SI = points to the 16-byte <a href="/wiki/MBR_partition_table" class="mw-redirect" title="MBR partition table">MBR partition table</a> entry used (see above)</li> <li>ES:<a href="/wiki/BX_register" class="mw-redirect" title="BX register">BX</a> = start of boot sector or NEWLDR sector image (typically <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x7C00)</li> <li><a href="/wiki/CX_register" class="mw-redirect" title="CX register">CX</a> = reserved</li></ul> In conjunction with GPT, an <a href="/wiki/Enhanced_Disk_Drive_Specification" class="mw-redirect" title="Enhanced Disk Drive Specification">Enhanced Disk Drive Specification</a> (EDD) 4 <a href="/wiki/Hybrid_MBR" class="mw-redirect" title="Hybrid MBR">Hybrid MBR</a> proposal recommends another extension to the interface:<a href="#cite_note-Elliott_2010_EDD4-Hybrid-MBR-50">[37]</a> <ul><li><a href="/wiki/EAX_register" class="mw-redirect" title="EAX register">EAX</a> = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x54504721 ("<code>!GPT</code>")</li> <li>DL = boot drive unit (see above)</li> <li>DS:SI = points to a Hybrid MBR handover structure, consisting of a 16-byte dummy <a href="/wiki/MBR_partition_table" class="mw-redirect" title="MBR partition table">MBR partition table</a> entry (with all bits set except for the boot flag at offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00 and the <a href="/wiki/Partition_type" title="Partition type">partition type</a> at offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x04) followed by additional data. This is partially compatible with the older DS:SI extension discussed above, if only the 16-byte partition entry, not the whole partition table is required by these older extensions.</li></ul> <dl><dd>Since older operating systems (including their VBRs) do not support this extension nor are they able to address sectors beyond the 2 TiB barrier, a GPT-enabled hybrid boot loader should still emulate the 16-byte dummy MBR partition table entry if the boot partition is located within the first 2 TiB.<a href="#cite_note-NB_Hybrid_MBR-51">[n]</a></dd></dl> <ul><li>ES:DI = points to "<code>$PnP</code>" installation check structure (see above)</li></ul> <div class="mw-heading mw-heading2"><h2 id="Editing_and_replacing_contents">Editing and replacing contents</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=10" title="Edit section: Editing and replacing contents">edit</a>]</div> Though it is possible to manipulate the <a href="/wiki/Byte" title="Byte">bytes</a> in the MBR sector directly using various <a href="/wiki/Disk_editor" title="Disk editor">disk editors</a>, there are tools to write fixed sets of functioning code to the MBR. Since MS-DOS 5.0, the program <code><a href="/wiki/FDISK" class="mw-redirect" title="FDISK">FDISK</a></code> has included the switch <code>/MBR</code>, which will rewrite the MBR code.<a href="#cite_note-Microsoft_KB69013-52">[38]</a> Under <a href="/wiki/Windows_2000" title="Windows 2000">Windows 2000</a> and <a href="/wiki/Windows_XP" title="Windows XP">Windows XP</a>, the <a href="/wiki/Recovery_Console" title="Recovery Console">Recovery Console</a> can be used to write new MBR code to a storage device using its <code>fixmbr</code> command. Under <a href="/wiki/Windows_Vista" title="Windows Vista">Windows Vista</a> and <a href="/wiki/Windows_7" title="Windows 7">Windows 7</a>, the <a href="/wiki/Recovery_Environment" class="mw-redirect" title="Recovery Environment">Recovery Environment</a> can be used to write new MBR code using the <code>BOOTREC /FIXMBR</code> command. Some third-party utilities may also be used for directly editing the contents of partition tables (without requiring any knowledge of hexadecimal or disk/sector editors), such as <a href="/wiki/MBRwizard" title="MBRwizard">MBRWizard</a>.<a href="#cite_note-NB_PTEDIT32-53">[o]</a> <code>dd</code> is a POSIX command commonly used to read or write any location on a storage device, MBR included. In <a href="/wiki/Linux" title="Linux">Linux</a>, ms-sys may be used to install a Windows MBR. The <a href="/wiki/GRUB" class="mw-redirect" title="GRUB">GRUB</a> and <a href="/wiki/LILO_(boot_loader)" class="mw-redirect" title="LILO (boot loader)">LILO</a> projects have tools for writing code to the MBR sector, namely <code>grub-install</code> and <code>lilo -mbr</code>. The GRUB Legacy interactive console can write to the MBR, using the <code>setup</code> and <code>embed</code> commands, but GRUB2 currently requires <code>grub-install</code> to be run from within an operating system. Various programs are able to create a "<a href="/wiki/Backup" title="Backup">backup</a>" of both the primary partition table and the logical partitions in the extended partition. Linux <code>sfdisk</code> (on a <a href="/wiki/SystemRescueCD" class="mw-redirect" title="SystemRescueCD">SystemRescueCD</a>) is able to save a backup of the primary and extended partition table. It creates a file that can be read in a text editor, or this file can be used by sfdisk to restore the primary/extended partition table. An example command to back up the partition table is <code>sfdisk -d /dev/hda > hda.out</code> and to restore is <code>sfdisk /dev/hda < hda.out</code>. It is possible to copy the partition table from one disk to another this way, useful for setting up mirroring, but sfdisk executes the command without prompting/warnings using <code>sfdisk -d /dev/sda | sfdisk /dev/sdb</code>.<a href="#cite_note-Linux_MAN_sfdisk-54">[39]</a> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=11" title="Edit section: See also">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 22em;"> <ul><li><a href="/wiki/Extended_boot_record" title="Extended boot record">Extended boot record</a> (EBR)</li> <li><a href="/wiki/Volume_boot_record" title="Volume boot record">Volume boot record</a> (VBR)</li> <li><a href="/wiki/GUID_Partition_Table" title="GUID Partition Table">GUID Partition Table</a> (GPT)</li> <li><a href="/wiki/BIOS_Boot_partition" class="mw-redirect" title="BIOS Boot partition">BIOS Boot partition</a></li> <li><a href="/wiki/EFI_System_partition" class="mw-redirect" title="EFI System partition">EFI System partition</a></li> <li><a href="/wiki/Boot_engineering_extension_record" class="mw-redirect" title="Boot engineering extension record">Boot engineering extension record</a> (BEER)</li> <li><a href="/wiki/Host_protected_area" title="Host protected area">Host protected area</a> (HPA)</li> <li><a href="/wiki/Device_configuration_overlay" title="Device configuration overlay">Device configuration overlay</a> (DCO)</li> <li><a href="/wiki/Apple_partition_map" class="mw-redirect" title="Apple partition map">Apple partition map</a> (APM)</li> <li><a href="/wiki/Amiga_rigid_disk_block" title="Amiga rigid disk block">Amiga rigid disk block</a> (RDB)</li> <li><a href="/wiki/Volume_Table_of_Contents" title="Volume Table of Contents">Volume Table of Contents</a> (VTOC)</li> <li><a href="/wiki/BSD_disklabel" title="BSD disklabel">BSD disklabel</a></li> <li><a href="/wiki/Boot_loader" class="mw-redirect" title="Boot loader">Boot loader</a></li> <li><a href="/wiki/Disk_cloning" title="Disk cloning">Disk cloning</a></li> <li><a href="/wiki/Recovery_disc" title="Recovery disc">Recovery disc</a></li> <li><a href="/wiki/GNU_Parted" title="GNU Parted">GNU Parted</a></li> <li><a href="/wiki/Partition_alignment" title="Partition alignment">Partition alignment</a></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=12" title="Edit section: Notes">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1184024115"><div class="div-col" style="column-width: 35em;"> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-lower-alpha"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-NB_Magic_AA55-12">^ <a href="#cite_ref-NB_Magic_AA55_12-0">a</a> <a href="#cite_ref-NB_Magic_AA55_12-1">b</a> <a href="#cite_ref-NB_Magic_AA55_12-2">c</a> <a href="#cite_ref-NB_Magic_AA55_12-3">d</a> <a href="#cite_ref-NB_Magic_AA55_12-4">e</a> <a href="#cite_ref-NB_Magic_AA55_12-5">f</a> <a href="#cite_ref-NB_Magic_AA55_12-6">g</a> The signature at offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01FE in boot sectors is <code>55hex AAhex</code>, that is <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x55 at offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01FE and <code>AAhex</code> at offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01FF. Since <a href="/wiki/Little-endian" class="mw-redirect" title="Little-endian">little-endian</a> representation must be assumed in the context of <a href="/wiki/IBM_PC" class="mw-redirect" title="IBM PC">IBM PC</a> compatible machines, this can be written as 16-bit word <code>AA55hex</code> in programs for <a href="/wiki/Intel_x86" class="mw-redirect" title="Intel x86">x86</a> processors (note the swapped order), whereas it would have to be written as <code>55AAhex</code> in programs for other CPU architectures using a <a href="/wiki/Big-endian" class="mw-redirect" title="Big-endian">big-endian</a> representation. Since this has been mixed up numerous times in books and even in original Microsoft reference documents, this article uses the offset-based byte-wise on-disk representation to avoid any possible misinterpretation. </li> <li id="cite_note-NB_Timestamp-13"><a href="#cite_ref-NB_Timestamp_13-0">^</a> In order to ensure the integrity of the MBR boot loader code, it is important that the bytes at <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00DA to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00DF are never changed, unless either all six bytes represent a value of 0 or the whole MBR bootstrap loader code (except for the (extended) partition table) is replaced at the same time as well. This includes resetting these values to <code>00 00 00 00 00 00hex</code> unless the code stored in the MBR is known. Windows adheres to this rule. </li> <li id="cite_note-15"><a href="#cite_ref-15">^</a> Originally, status values other than <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x00 and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x80 were invalid, but modern MBRs treat the bit 7 as active flag and use this entry to store the physical boot unit. </li> <li id="cite_note-note-2-16">^ <a href="#cite_ref-note-2_16-0">a</a> <a href="#cite_ref-note-2_16-1">b</a> The starting sector fields are limited to 1023+1 cylinders, 255+1 heads, and 63 sectors; ending sector fields have the same limitations. </li> <li id="cite_note-note-3-18">^ <a href="#cite_ref-note-3_18-0">a</a> <a href="#cite_ref-note-3_18-1">b</a> <a href="#cite_ref-note-3_18-2">c</a> <a href="#cite_ref-note-3_18-3">d</a> <a href="#cite_ref-note-3_18-4">e</a> The range for sector is 1 through 63; the range for cylinder is 0 through 1023; the range for head is 0 through 255 inclusive.<a href="#cite_note-Phoenix_1989_System-BIOS-17">[13]</a> </li> <li id="cite_note-note-4-21"><a href="#cite_ref-note-4_21-0">^</a> This entry is used by operating systems in certain circumstances; in such cases the CHS addresses are ignored.<a href="#cite_note-Microsoft_2000_LBA-Blocks-20">[15]</a> </li> <li id="cite_note-note-5-22"><a href="#cite_ref-note-5_22-0">^</a> Zero is reserved and must not be used in normal partition entries. This entry is used by operating systems in certain circumstances; in such cases the CHS addresses are ignored.<a href="#cite_note-Microsoft_2000_LBA-Blocks-20">[15]</a> </li> <li id="cite_note-NB_RBIL_Head_Limit-23"><a href="#cite_ref-NB_RBIL_Head_Limit_23-0">^</a> "Quote: [Most] versions of MS-DOS (including MS-DOS 7 [Windows 95]) have a bug which prevents booting on hard disks with 256 heads (FFh), so many modern BIOSes provide mappings with at most 255 (FEh) heads." <a href="/wiki/RBIL" class="mw-redirect" title="RBIL">RBIL</a><a href="#cite_note-RBIL_html-55">[40]</a><a href="#cite_note-RBIL_archive_text-56">[41]</a> </li> <li id="cite_note-NB_Load-address-40"><a href="#cite_ref-NB_Load-address_40-0">^</a> The address <code>0000hex</code>:<code>7C00hex</code> is the first byte of the 32nd KB of RAM. The loading of the boot program at this address historically was the reason why, while the minimum RAM size of an original IBM PC (type 5150) was 16 KB, 32 KB were required for the disk option in the IBM XT. </li> <li id="cite_note-NB_EBDA-42"><a href="#cite_ref-NB_EBDA_42-0">^</a> If there is an <a href="/w/index.php?title=Extended_BIOS_Data_Area&action=edit&redlink=1" class="new" title="Extended BIOS Data Area (page does not exist)">EBDA</a>, the available memory ends below it. </li> <li id="cite_note-NB_free-memory-43"><a href="#cite_ref-NB_free-memory_43-0">^</a> Very old machines may have less than 640 KB (<code>A0000hex</code> or 655,360 bytes) of memory. In theory, only 32 KB (up to <code>0000hex</code>:<code>7FFFhex</code>) or 64 KB (up to <code>0000hex</code>:<code>FFFFhex</code>) are guaranteed to exist; this would be the case on an IBM XT-class machine equipped with only the required minimum amount of memory for a disk system. </li> <li id="cite_note-NB_VBRs-44"><a href="#cite_ref-NB_VBRs_44-0">^</a> This applies when the BIOS handles a VBR, which is when it is in the first physical sector of unpartitioned media. Otherwise, the BIOS has nothing to do with the VBR. The design of VBRs is such as it is because VBRs originated solely on unpartitioned floppy disk media—the type 5150 IBM PC originally had no hard disk option—and the partitioning system using an MBR was later developed as an adaptation to put more than one volume, each beginning with its own VBR as-already-defined, onto a single fixed disk. By this design, essentially the MBR emulates the BIOS boot routine, doing the same things the BIOS would do to process this VBR and set up the initial operating environment for it just as if the BIOS had found that VBR on an unpartitioned medium. </li> <li id="cite_note-NB_CS-IP-49"><a href="#cite_ref-NB_CS-IP_49-0">^</a> IP is set as a result of the jump. CS may be set to 0 either by executing a far jump or by loading the register value explicitly before executing a near jump. (It is impossible for jumped-to x86 code to detect whether a near or far jump was used to reach it [unless the code that made the jump separately passes this information in some way].) </li> <li id="cite_note-NB_Hybrid_MBR-51"><a href="#cite_ref-NB_Hybrid_MBR_51-0">^</a> This is not part of the above mentioned proposal, but a natural consequence of pre-existing conditions. </li> <li id="cite_note-NB_PTEDIT32-53"><a href="#cite_ref-NB_PTEDIT32_53-0">^</a> For example, PowerQuest's Partition Table Editor (PTEDIT32.EXE), which runs under Windows operating systems, is still available here: <a rel="nofollow" class="external text" href="ftp://ftp.symantec.com/public/english_us_canada/tools/pq/utilities/PTEDIT32.zip">Symantec's FTP site</a>. </li> </ol></div></div> </div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=13" title="Edit section: References">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-Microsoft_2013_2581408-1">^ <a href="#cite_ref-Microsoft_2013_2581408_1-0">a</a> <a href="#cite_ref-Microsoft_2013_2581408_1-1">b</a> <a href="#cite_ref-Microsoft_2013_2581408_1-2">c</a> <a href="#cite_ref-Microsoft_2013_2581408_1-3">d</a> <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://support.microsoft.com/kb/2581408">"Windows support for hard disks that are larger than 2 TB"</a>. 1. <a href="/wiki/Microsoft" title="Microsoft">Microsoft</a>. 2013-06-26. 2581408. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170427084734/https://support.microsoft.com/en-us/help/2581408/windows-support-for-hard-disks-that-are-larger-than-2-tb">Archived</a> from the original on 2017-04-27. Retrieved 2013-08-28.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Windows+support+for+hard+disks+that+are+larger+than+2+TB&rft.series=1&rft.pub=Microsoft&rft.date=2013-06-26&rft_id=http%3A%2F%2Fsupport.microsoft.com%2Fkb%2F2581408&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Sedory_2004_Timestamp-2">^ <a href="#cite_ref-Sedory_2004_Timestamp_2-0">a</a> <a href="#cite_ref-Sedory_2004_Timestamp_2-1">b</a> <a href="#cite_ref-Sedory_2004_Timestamp_2-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSedory2004" class="citation web cs1">Sedory, Daniel B. (2004). <a rel="nofollow" class="external text" href="http://thestarman.pcministry.com/asm/mbr/mystery.htm">"The Mystery Bytes (or the Drive/Timestamp Bytes) of the MS-Windows 95B, 98, 98SE and Me Master Boot Record (MBR)"</a>. Master Boot Records. thestarman.pcministry.com. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824002828/http://thestarman.pcministry.com/asm/mbr/mystery.htm">Archived</a> from the original on 2017-08-24. Retrieved 2012-08-25.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Master+Boot+Records&rft.atitle=The+Mystery+Bytes+%28or+the+Drive%2FTimestamp+Bytes%29+of+the+MS-Windows+95B%2C+98%2C+98SE+and+Me+Master+Boot+Record+%28MBR%29&rft.date=2004&rft.aulast=Sedory&rft.aufirst=Daniel+B.&rft_id=http%3A%2F%2Fthestarman.pcministry.com%2Fasm%2Fmbr%2Fmystery.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Lucas_2003_OpenBSD-3"><a href="#cite_ref-Lucas_2003_OpenBSD_3-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLucas2003" class="citation book cs1">Lucas, Michael (2003). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=wuUuTXMkNx8C&pg=PA72">Absolute OpenBSD: Unix for the practical paranoid</a>. p. 73. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781886411999" title="Special:BookSources/9781886411999"><bdi>9781886411999</bdi></a>. Retrieved 2011-04-09. <q>Every operating system includes tools to manage MBR partitions. Unfortunately, every operating system handles MBR partitions in a slightly different manner.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Absolute+OpenBSD%3A+Unix+for+the+practical+paranoid&rft.pages=73&rft.date=2003&rft.isbn=9781886411999&rft.aulast=Lucas&rft.aufirst=Michael&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DwuUuTXMkNx8C%26pg%3DPA72&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Norton_2002_Inside-4"><a href="#cite_ref-Norton_2002_Inside_4-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNortonClark2002" class="citation book cs1"><a href="/wiki/Peter_Norton" title="Peter Norton">Norton, Peter</a>; Clark, Scott (2002). <a rel="nofollow" class="external text" href="https://archive.org/details/peternortonsnewi00pete/page/360">Peter Norton's New Inside the PC</a>. <a href="/wiki/Sams_Publishing" title="Sams Publishing">Sams Publishing</a>. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/peternortonsnewi00pete/page/360">360–361</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-672-32289-7" title="Special:BookSources/0-672-32289-7"><bdi>0-672-32289-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Peter+Norton%27s+New+Inside+the+PC&rft.pages=360-361&rft.pub=Sams+Publishing&rft.date=2002&rft.isbn=0-672-32289-7&rft.aulast=Norton&rft.aufirst=Peter&rft.au=Clark%2C+Scott&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fpeternortonsnewi00pete%2Fpage%2F360&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Graves_2004_Guide-5"><a href="#cite_ref-Graves_2004_Guide_5-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGraves2004" class="citation book cs1">Graves, Michael W. (2004). A+ Guide To PC Hardware Maintenance and Repair. Thomson Delmar. p. 276. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/1-4018-5230-0" title="Special:BookSources/1-4018-5230-0"><bdi>1-4018-5230-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A%2B+Guide+To+PC+Hardware+Maintenance+and+Repair&rft.pages=276&rft.pub=Thomson+Delmar&rft.date=2004&rft.isbn=1-4018-5230-0&rft.aulast=Graves&rft.aufirst=Michael+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Andrews_2003_Upgrade-6"><a href="#cite_ref-Andrews_2003_Upgrade_6-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAndrews2003" class="citation book cs1">Andrews, Jean (2003). <a rel="nofollow" class="external text" href="https://archive.org/details/upgraderepairwit0000andr/page/646">Upgrade and Repair with Jean Andrews</a>. Thomson Course Technology. p. <a rel="nofollow" class="external text" href="https://archive.org/details/upgraderepairwit0000andr/page/646">646</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/1-59200-112-2" title="Special:BookSources/1-59200-112-2"><bdi>1-59200-112-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Upgrade+and+Repair+with+Jean+Andrews&rft.pages=646&rft.pub=Thomson+Course+Technology&rft.date=2003&rft.isbn=1-59200-112-2&rft.aulast=Andrews&rft.aufirst=Jean&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fupgraderepairwit0000andr%2Fpage%2F646&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Boswell_2003_Inside-7"><a href="#cite_ref-Boswell_2003_Inside_7-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBoswell2003" class="citation book cs1">Boswell, William (2003). Inside Windows Server 2003. <a href="/wiki/Addison-Wesley_Professional" class="mw-redirect" title="Addison-Wesley Professional">Addison-Wesley Professional</a>. p. 13. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7357-1158-5" title="Special:BookSources/0-7357-1158-5"><bdi>0-7357-1158-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Inside+Windows+Server+2003&rft.pages=13&rft.pub=Addison-Wesley+Professional&rft.date=2003&rft.isbn=0-7357-1158-5&rft.aulast=Boswell&rft.aufirst=William&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Smith_2000_Multi-Boot-8"><a href="#cite_ref-Smith_2000_Multi-Boot_8-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSmith2000" class="citation book cs1">Smith, Roderick W. (2000). <a rel="nofollow" class="external text" href="https://archive.org/details/isbn_9780789722836/page/260">The Multi-Boot Configuration Handbook</a>. <a href="/wiki/Que_Publishing" class="mw-redirect" title="Que Publishing">Que Publishing</a>. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/isbn_9780789722836/page/260">260–261</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7897-2283-6" title="Special:BookSources/0-7897-2283-6"><bdi>0-7897-2283-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Multi-Boot+Configuration+Handbook&rft.pages=260-261&rft.pub=Que+Publishing&rft.date=2000&rft.isbn=0-7897-2283-6&rft.aulast=Smith&rft.aufirst=Roderick+W.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fisbn_9780789722836%2Fpage%2F260&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Brouwer_2003_Types-2A-9"><a href="#cite_ref-Brouwer_2003_Types-2A_9-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrouwer2004" class="citation web cs1"><a href="/wiki/Andries_Evert_Brouwer" class="mw-redirect" title="Andries Evert Brouwer">Brouwer, Andries Evert</a> (2004-04-22) [2000]. <a rel="nofollow" class="external text" href="http://www.win.tue.nl/~aeb/partitions/partition_types-2.html">"Properties of partition tables"</a>. Partition types. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824112413/http://www.win.tue.nl/~aeb/partitions/partition_types-2.html">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24. <q>Matthias [R.] Paul writes: "[…] <a href="/wiki/PTS-DOS" title="PTS-DOS">PTS-DOS</a> [uses] a special fifth partition entry in front of the other four entries in the MBR and corresponding AAP-aware MBR bootstrap code. […]"</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Partition+types&rft.atitle=Properties+of+partition+tables&rft.date=2004-04-22&rft.aulast=Brouwer&rft.aufirst=Andries+Evert&rft_id=http%3A%2F%2Fwww.win.tue.nl%2F~aeb%2Fpartitions%2Fpartition_types-2.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Brouwer_2003_Types-2B-10"><a href="#cite_ref-Brouwer_2003_Types-2B_10-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrouwer2004" class="citation web cs1"><a href="/wiki/Andries_Evert_Brouwer" class="mw-redirect" title="Andries Evert Brouwer">Brouwer, Andries Evert</a> (2004-04-22) [2000]. <a rel="nofollow" class="external text" href="http://www.win.tue.nl/~aeb/partitions/partition_types-2.html">"Properties of partition tables"</a>. Partition types. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824112413/http://www.win.tue.nl/~aeb/partitions/partition_types-2.html">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24. <q>Some OEM systems, such as AST DOS (type <code><a href="/wiki/Partition_type#PID_14h" title="Partition type">14hex</a></code>) and NEC DOS (type <code><a href="/wiki/Partition_type#PID_24h" title="Partition type">24hex</a></code>) had 8 instead of 4 partition entries in their MBR sectors. (Matthias R. Paul).</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Partition+types&rft.atitle=Properties+of+partition+tables&rft.date=2004-04-22&rft.aulast=Brouwer&rft.aufirst=Andries+Evert&rft_id=http%3A%2F%2Fwww.win.tue.nl%2F~aeb%2Fpartitions%2Fpartition_types-2.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> (NB. <a href="/wiki/NEC" title="NEC">NEC</a> <a href="/wiki/MS-DOS" title="MS-DOS">MS-DOS</a> 3.30 and <a href="/wiki/AST_Research" title="AST Research">AST</a> MS-DOS partition tables with eight entries are preceded with a signature <code>A55Ahex</code> at offset <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x017C.) </li> <li id="cite_note-Sedory_2007_DOS33MBR-11"><a href="#cite_ref-Sedory_2007_DOS33MBR_11-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSedory2007" class="citation web cs1">Sedory, Daniel B. (2007-05-18) [2003]. <a rel="nofollow" class="external text" href="http://thestarman.pcministry.com/asm/mbr/DOS33MBR.htm">"Notes on the Differences in one OEM version of the DOS 3.30 MBR"</a>. Master Boot Records. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824003525/http://thestarman.pcministry.com/asm/mbr/DOS33MBR.htm">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24. <q>When we added partitions to this NEC table, the first one was placed at offsets <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01EE through <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734">0x01FD and the next entry was added just above it. So, the entries are inserted and listed backwards from that of a normal Table. Thus, looking at such a Table with a disk editor or partition listing utility, it would show the first entry in a NEC eight-entry table as being the last one (fourth entry) in a normal Partition Table.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Master+Boot+Records&rft.atitle=Notes+on+the+Differences+in+one+OEM+version+of+the+DOS+3.30+MBR&rft.date=2007-05-18&rft.aulast=Sedory&rft.aufirst=Daniel+B.&rft_id=http%3A%2F%2Fthestarman.pcministry.com%2Fasm%2Fmbr%2FDOS33MBR.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> (NB. Shows an 8-entry partition table and where its boot code differs from MS-DOS 3.30.) </li> <li id="cite_note-osdev-14"><a href="#cite_ref-osdev_14-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://wiki.osdev.org/Partition_Table">"Partition Table"</a>. osdev.org. 2017-03-18 [2007-03-06]. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824123235/http://wiki.osdev.org/Partition_Table">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Partition+Table&rft.pub=osdev.org&rft.date=2017-03-18&rft_id=http%3A%2F%2Fwiki.osdev.org%2FPartition_Table&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Phoenix_1989_System-BIOS-17">^ <a href="#cite_ref-Phoenix_1989_System-BIOS_17-0">a</a> <a href="#cite_ref-Phoenix_1989_System-BIOS_17-1">b</a> <a href="#cite_ref-Phoenix_1989_System-BIOS_17-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1">System BIOS for IBM PC/XT/AT Computers and Compatibles. <a href="/wiki/Phoenix_Technologies" title="Phoenix Technologies">Phoenix</a> technical reference. <a href="/wiki/Addison-Wesley" title="Addison-Wesley">Addison-Wesley</a>. 1989. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-201-51806-6" title="Special:BookSources/0-201-51806-6"><bdi>0-201-51806-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=System+BIOS+for+IBM+PC%2FXT%2FAT+Computers+and+Compatibles&rft.series=Phoenix+technical+reference&rft.pub=Addison-Wesley&rft.date=1989&rft.isbn=0-201-51806-6&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Brouwer_2012_Types-1-19"><a href="#cite_ref-Brouwer_2012_Types-1_19-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrouwer2013" class="citation web cs1"><a href="/wiki/Andries_Evert_Brouwer" class="mw-redirect" title="Andries Evert Brouwer">Brouwer, Andries Evert</a> (2013) [1995]. <a rel="nofollow" class="external text" href="http://www.win.tue.nl/~aeb/partitions/partition_types-1.html">"List of partition identifiers for PCs"</a>. Partition types. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824112750/http://www.win.tue.nl/~aeb/partitions/partition_types-1.html">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Partition+types&rft.atitle=List+of+partition+identifiers+for+PCs&rft.date=2013&rft.aulast=Brouwer&rft.aufirst=Andries+Evert&rft_id=http%3A%2F%2Fwww.win.tue.nl%2F~aeb%2Fpartitions%2Fpartition_types-1.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Microsoft_2000_LBA-Blocks-20">^ <a href="#cite_ref-Microsoft_2000_LBA-Blocks_20-0">a</a> <a href="#cite_ref-Microsoft_2000_LBA-Blocks_20-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWood2002" class="citation book cs1">Wood, Sybil (2002). <a rel="nofollow" class="external text" href="https://archive.org/details/microsoftwindows00wood/page/18">Microsoft Windows 2000 Server Operations Guide</a>. <a href="/wiki/Microsoft_Press" title="Microsoft Press">Microsoft Press</a>. p. <a rel="nofollow" class="external text" href="https://archive.org/details/microsoftwindows00wood/page/18">18</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-73561796-4" title="Special:BookSources/978-0-73561796-4"><bdi>978-0-73561796-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Microsoft+Windows+2000+Server+Operations+Guide&rft.pages=18&rft.pub=Microsoft+Press&rft.date=2002&rft.isbn=978-0-73561796-4&rft.aulast=Wood&rft.aufirst=Sybil&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fmicrosoftwindows00wood%2Fpage%2F18&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Tech-Juice_2011_Geometry-24"><a href="#cite_ref-Tech-Juice_2011_Geometry_24-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20130204205616/http://www.tech-juice.org/2011/08/08/an-introduction-to-hard-disk-geometry/">"An Introduction to Hard Disk Geometry"</a>. Tech Juice. 2012-12-06 [2011-08-08]. Archived from <a rel="nofollow" class="external text" href="http://www.tech-juice.org/2011/08/08/an-introduction-to-hard-disk-geometry/">the original</a> on 2013-02-04.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Tech+Juice&rft.atitle=An+Introduction+to+Hard+Disk+Geometry&rft.date=2012-12-06&rft_id=http%3A%2F%2Fwww.tech-juice.org%2F2011%2F08%2F08%2Fan-introduction-to-hard-disk-geometry%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-PC-Guide_BIOS-25"><a href="#cite_ref-PC-Guide_BIOS_25-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKozierok2001" class="citation web cs1">Kozierok, Charles M. (2001-04-17). <a rel="nofollow" class="external text" href="http://www.pcguide.com/ref/hdd/bios/bios.htm">"BIOS and the Hard Disk"</a>. The PC Guide. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170617080653/http://www.pcguide.com/ref/hdd/bios/bios.htm">Archived</a> from the original on 2017-06-17. Retrieved 2013-04-19.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+PC+Guide&rft.atitle=BIOS+and+the+Hard+Disk&rft.date=2001-04-17&rft.aulast=Kozierok&rft.aufirst=Charles+M.&rft_id=http%3A%2F%2Fwww.pcguide.com%2Fref%2Fhdd%2Fbios%2Fbios.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Smith_2011_gdisk-26"><a href="#cite_ref-Smith_2011_gdisk_26-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSmith2011" class="citation web cs1">Smith, Robert (2011-06-26). <a rel="nofollow" class="external text" href="http://www.rodsbooks.com/gdisk/workarounds.html">"Working Around MBR's Limitations"</a>. GPT fdisk Tutorial. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824114940/http://www.rodsbooks.com/gdisk/workarounds.html">Archived</a> from the original on 2017-08-24. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=GPT+fdisk+Tutorial&rft.atitle=Working+Around+MBR%27s+Limitations&rft.date=2011-06-26&rft.aulast=Smith&rft.aufirst=Robert&rft_id=http%3A%2F%2Fwww.rodsbooks.com%2Fgdisk%2Fworkarounds.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Superuser_2013-27"><a href="#cite_ref-Superuser_2013_27-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://superuser.com/questions/562331/mbr-partition-with-more-than-2-tb">"More than 2 TiB on a MBR disk"</a>. superuser.com. 2013-03-07. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824122749/https://superuser.com/questions/562331/mbr-partition-with-more-than-2-tb">Archived</a> from the original on 2017-08-24. Retrieved 2013-10-22.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=More+than+2+TiB+on+a+MBR+disk&rft.pub=superuser.com&rft.date=2013-03-07&rft_id=http%3A%2F%2Fsuperuser.com%2Fquestions%2F562331%2Fmbr-partition-with-more-than-2-tb&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Seagate_4K-28"><a href="#cite_ref-Seagate_4K_28-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.seagate.com/tech-insights/advanced-format-4k-sector-hard-drives-master-ti/">"Transition to Advanced Format 4K Sector Hard Drives"</a>. Tech Insight. <a href="/wiki/Seagate_Technology" title="Seagate Technology">Seagate Technology</a>. 2012. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824194910/http://www.seagate.com/de/de/tech-insights/advanced-format-4k-sector-hard-drives-master-ti/">Archived</a> from the original on 2017-08-24. Retrieved 2013-04-19.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Tech+Insight&rft.atitle=Transition+to+Advanced+Format+4K+Sector+Hard+Drives&rft.date=2012&rft_id=http%3A%2F%2Fwww.seagate.com%2Ftech-insights%2Fadvanced-format-4k-sector-hard-drives-master-ti%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Western-Digital_1-29"><a href="#cite_ref-Western-Digital_1_29-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCalvert2011" class="citation web cs1">Calvert, Kelvin (2011-03-16). <a rel="nofollow" class="external text" href="http://products.wdc.com/library/whitepapers/eng/2579-771660.pdf">"WD AV‐GP Large Capacity Hard Drives"</a> (PDF). <a href="/wiki/Western_Digital" title="Western Digital">Western Digital</a>. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WD+AV%E2%80%90GP+Large+Capacity+Hard+Drives&rft.pub=Western+Digital&rft.date=2011-03-16&rft.aulast=Calvert&rft.aufirst=Kelvin&rft_id=http%3A%2F%2Fproducts.wdc.com%2Flibrary%2Fwhitepapers%2Feng%2F2579-771660.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-IBM_4K-30"><a href="#cite_ref-IBM_4K_30-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSmith2010" class="citation web cs1">Smith, Roderick W. (2010-04-27). <a rel="nofollow" class="external text" href="http://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/">"Linux on 4KB-sector disks: Practical advice"</a>. DeveloperWorks. <a href="/wiki/IBM" title="IBM">IBM</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824115221/https://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/">Archived</a> from the original on 2017-08-24. Retrieved 2013-04-19.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=DeveloperWorks&rft.atitle=Linux+on+4KB-sector+disks%3A+Practical+advice&rft.date=2010-04-27&rft.aulast=Smith&rft.aufirst=Roderick+W.&rft_id=http%3A%2F%2Fwww.ibm.com%2Fdeveloperworks%2Flinux%2Flibrary%2Fl-4kb-sector-disks%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-OSDev_2011_MBR-31">^ <a href="#cite_ref-OSDev_2011_MBR_31-0">a</a> <a href="#cite_ref-OSDev_2011_MBR_31-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://wiki.osdev.org/index.php?title=MBR_(x86)&oldid=12904">"MBR (x86)"</a>. OSDev Wiki. OSDev.org. 2012-03-05. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824003752/http://wiki.osdev.org/index.php?title=MBR_(x86)&oldid=12904">Archived</a> from the original on 2017-08-24. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=OSDev+Wiki&rft.atitle=MBR+%28x86%29&rft.date=2012-03-05&rft_id=http%3A%2F%2Fwiki.osdev.org%2Findex.php%3Ftitle%3DMBR_%28x86%29%26oldid%3D12904&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Sedory_2003_MBR200-32"><a href="#cite_ref-Sedory_2003_MBR200_32-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSedory2003" class="citation web cs1">Sedory, Daniel B. (2003-07-30). <a rel="nofollow" class="external text" href="http://thestarman.pcministry.com/asm/mbr/200MBR.htm">"IBM DOS 2.00 Master Boot Record"</a>. The Starman's Realm. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824003921/http://thestarman.pcministry.com/asm/mbr/200MBR.htm">Archived</a> from the original on 2017-08-24. Retrieved 2011-07-22.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=IBM+DOS+2.00+Master+Boot+Record&rft.pub=The+Starman%27s+Realm&rft.date=2003-07-30&rft.aulast=Sedory&rft.aufirst=Daniel+B.&rft_id=http%3A%2F%2Fthestarman.pcministry.com%2Fasm%2Fmbr%2F200MBR.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Singh_2009_OSX-33"><a href="#cite_ref-Singh_2009_OSX_33-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSingh2009" class="citation web cs1">Singh, Amit (2009-12-25) [December 2003]. <a rel="nofollow" class="external text" href="http://osxbook.com/book/bonus/ancient/whatismacosx/arch_boot.html">"Booting Mac OS X"</a>. Mac OS X Internals: The Book. Retrieved 2011-07-22.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Booting+Mac+OS+X&rft.pub=Mac+OS+X+Internals%3A+The+Book&rft.date=2009-12-25&rft.aulast=Singh&rft.aufirst=Amit&rft_id=http%3A%2F%2Fosxbook.com%2Fbook%2Fbonus%2Fancient%2Fwhatismacosx%2Farch_boot.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Boyne_2011_EFI-Boot-34"><a href="#cite_ref-Boyne_2011_EFI-Boot_34-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFde_Boyne_Pollard2011" class="citation web cs1">de Boyne Pollard, Jonathan (2011-07-10). <a rel="nofollow" class="external text" href="http://jdebp.eu./FGA/efi-boot-process.html">"The EFI boot process"</a>. Frequently Given Answers. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824004128/http://jdebp.eu./FGA/efi-boot-process.html">Archived</a> from the original on 2017-08-24. Retrieved 2011-07-22.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Frequently+Given+Answers&rft.atitle=The+EFI+boot+process&rft.date=2011-07-10&rft.aulast=de+Boyne+Pollard&rft.aufirst=Jonathan&rft_id=http%3A%2F%2Fjdebp.eu.%2FFGA%2Fefi-boot-process.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Domsch_2003_EDD-35"><a href="#cite_ref-Domsch_2003_EDD_35-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDomsch2005" class="citation web cs1">Domsch, Matt (2005-03-22) [2003-12-19]. <a rel="nofollow" class="external text" href="https://lkml.org/lkml/2003/12/19/139">"Re: RFC 2.6.0 EDD enhancements"</a>. Linux Kernel Mailing List. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824004143/https://lkml.org/lkml/2003/12/19/139">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Linux+Kernel+Mailing+List&rft.atitle=Re%3A+RFC+2.6.0+EDD+enhancements&rft.date=2005-03-22&rft.aulast=Domsch&rft.aufirst=Matt&rft_id=https%3A%2F%2Flkml.org%2Flkml%2F2003%2F12%2F19%2F139&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Microsoft_KB227704-36"><a href="#cite_ref-Microsoft_KB227704_36-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://support.microsoft.com/kb/227704">"Windows may use Signature() syntax in the BOOT.INI file"</a>. KnowledgeBase. <a href="/wiki/Microsoft" title="Microsoft">Microsoft</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=KnowledgeBase&rft.atitle=Windows+may+use+Signature%28%29+syntax+in+the+BOOT.INI+file&rft_id=http%3A%2F%2Fsupport.microsoft.com%2Fkb%2F227704&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Multibooters_Vista-MBR-37"><a href="#cite_ref-Multibooters_Vista-MBR_37-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcTavish2014" class="citation web cs1">McTavish (February 2014). <a rel="nofollow" class="external text" href="http://www.multibooters.co.uk/mbr.html">"Vista's MBR Disk Signature"</a>. Multibooters: Dual and Multibooting with Vista. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824120323/http://www.multibooters.co.uk/mbr.html">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Multibooters%3A+Dual+and+Multibooting+with+Vista&rft.atitle=Vista%27s+MBR+Disk+Signature&rft.date=2014-02&rft.au=McTavish&rft_id=http%3A%2F%2Fwww.multibooters.co.uk%2Fmbr.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Russinovich_2011_Disk-Signature-38"><a href="#cite_ref-Russinovich_2011_Disk-Signature_38-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRussinovich2011" class="citation web cs1"><a href="/wiki/Mark_Russinovich" title="Mark Russinovich">Russinovich, Mark</a> (2011-11-08). <a rel="nofollow" class="external text" href="http://blogs.technet.com/b/markrussinovich/archive/2011/11/08/3463572.aspx">"Fixing Disk Signature Collisions"</a>. Mark Russinovich's Blog. <a href="/wiki/Microsoft" title="Microsoft">Microsoft</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824120420/https://blogs.technet.microsoft.com/markrussinovich/2011/11/06/fixing-disk-signature-collisions/">Archived</a> from the original on 2017-08-24. Retrieved 2013-04-19.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Mark+Russinovich%27s+Blog&rft.atitle=Fixing+Disk+Signature+Collisions&rft.date=2011-11-08&rft.aulast=Russinovich&rft.aufirst=Mark&rft_id=http%3A%2F%2Fblogs.technet.com%2Fb%2Fmarkrussinovich%2Farchive%2F2011%2F11%2F08%2F3463572.aspx&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Sakamoto_2010_MBR-39">^ <a href="#cite_ref-Sakamoto_2010_MBR_39-0">a</a> <a href="#cite_ref-Sakamoto_2010_MBR_39-1">b</a> <a href="#cite_ref-Sakamoto_2010_MBR_39-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSakamoto2010" class="citation web cs1">Sakamoto, Masahiko (2010-05-13). <a rel="nofollow" class="external text" href="http://www.glamenv-septzen.net/en/view/6">"Why BIOS loads MBR into <code>0x7C00</code> in x86?"</a>. Glamenv-Septzen.net. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824002951/https://www.glamenv-septzen.net/en/view/6">Archived</a> from the original on 2017-08-24. Retrieved 2011-05-04.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Why+BIOS+loads+MBR+into+%3Ccode%3E0x7C00%3C%2Fcode%3E+in+x86%3F&rft.pub=Glamenv-Septzen.net&rft.date=2010-05-13&rft.aulast=Sakamoto&rft.aufirst=Masahiko&rft_id=http%3A%2F%2Fwww.glamenv-septzen.net%2Fen%2Fview%2F6&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Compaq-Phoenix-Intel_1996_BBS101-41">^ <a href="#cite_ref-Compaq-Phoenix-Intel_1996_BBS101_41-0">a</a> <a href="#cite_ref-Compaq-Phoenix-Intel_1996_BBS101_41-1">b</a> <a href="#cite_ref-Compaq-Phoenix-Intel_1996_BBS101_41-2">c</a> <a href="#cite_ref-Compaq-Phoenix-Intel_1996_BBS101_41-3">d</a> <a href="#cite_ref-Compaq-Phoenix-Intel_1996_BBS101_41-4">e</a> <a href="#cite_ref-Compaq-Phoenix-Intel_1996_BBS101_41-5">f</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCompaq_Computer_CorporationPhoenix_Technologies_Ltd.Intel_Corporation1996" class="citation web cs1"><a href="/wiki/Compaq_Computer_Corporation" class="mw-redirect" title="Compaq Computer Corporation">Compaq Computer Corporation</a>; <a href="/wiki/Phoenix_Technologies_Ltd." class="mw-redirect" title="Phoenix Technologies Ltd.">Phoenix Technologies Ltd.</a>; <a href="/wiki/Intel_Corporation" class="mw-redirect" title="Intel Corporation">Intel Corporation</a> (1996-01-11). <a rel="nofollow" class="external text" href="https://acpica.org/sites/acpica/files/specsbbs101.pdf">"BIOS Boot Specification 1.01"</a> (PDF). 1.01. ACPICA. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824121219/https://acpica.org/sites/acpica/files/specsbbs101.pdf">Archived</a> (PDF) from the original on 2017-08-24. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=BIOS+Boot+Specification+1.01&rft.series=1.01&rft.pub=ACPICA&rft.date=1996-01-11&rft.au=Compaq+Computer+Corporation&rft.au=Phoenix+Technologies+Ltd.&rft.au=Intel+Corporation&rft_id=https%3A%2F%2Facpica.org%2Fsites%2Facpica%2Ffiles%2Fspecsbbs101.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> <a rel="nofollow" class="external autonumber" href="https://web.archive.org/web/20160414104624/http://www.phoenix.com/resources/specs-bbs101.pdf">[1]</a> </li> <li id="cite_note-Elliott_2009_Darwin-45">^ <a href="#cite_ref-Elliott_2009_Darwin_45-0">a</a> <a href="#cite_ref-Elliott_2009_Darwin_45-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFElliott2009" class="citation web cs1">Elliott, David F. (2009-10-12). <a rel="nofollow" class="external text" href="http://tgwbd.org/blog/2009/10/12/why-does-the-standard-mbr-set-SI/">"Why does the "standard" MBR set SI?"</a>. tgwbd.org. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824122006/http://tgwbd.org/blog/2009/10/12/why-does-the-standard-mbr-set-SI/">Archived</a> from the original on 2017-08-24. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=tgwbd.org&rft.atitle=Why+does+the+%22standard%22+MBR+set+SI%3F&rft.date=2009-10-12&rft.aulast=Elliott&rft.aufirst=David+F.&rft_id=http%3A%2F%2Ftgwbd.org%2Fblog%2F2009%2F10%2F12%2Fwhy-does-the-standard-mbr-set-SI%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Compaq-Phoenix-Intel_1994_PnP10A-46">^ <a href="#cite_ref-Compaq-Phoenix-Intel_1994_PnP10A_46-0">a</a> <a href="#cite_ref-Compaq-Phoenix-Intel_1994_PnP10A_46-1">b</a> <a href="#cite_ref-Compaq-Phoenix-Intel_1994_PnP10A_46-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCompaq_Computer_CorporationPhoenix_Technologies_Ltd.Intel_Corporation1994" class="citation web cs1"><a href="/wiki/Compaq_Computer_Corporation" class="mw-redirect" title="Compaq Computer Corporation">Compaq Computer Corporation</a>; <a href="/wiki/Phoenix_Technologies_Ltd." class="mw-redirect" title="Phoenix Technologies Ltd.">Phoenix Technologies Ltd.</a>; <a href="/wiki/Intel_Corporation" class="mw-redirect" title="Intel Corporation">Intel Corporation</a> (1994-05-05). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824121146/http://download.intel.com/support/motherboards/desktop/sb/pnpbiosspecificationv10a.pdf">"Plug and Play BIOS Specification 1.0A"</a> (PDF). 1.0A. <a href="/wiki/Intel" title="Intel">Intel</a>. Archived from <a rel="nofollow" class="external text" href="http://download.intel.com/support/motherboards/desktop/sb/pnpbiosspecificationv10a.pdf">the original</a> (PDF) on 2017-08-24. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Plug+and+Play+BIOS+Specification+1.0A&rft.series=1.0A&rft.pub=Intel&rft.date=1994-05-05&rft.au=Compaq+Computer+Corporation&rft.au=Phoenix+Technologies+Ltd.&rft.au=Intel+Corporation&rft_id=http%3A%2F%2Fdownload.intel.com%2Fsupport%2Fmotherboards%2Fdesktop%2Fsb%2Fpnpbiosspecificationv10a.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Paul_1997-47"><a href="#cite_ref-Paul_1997_47-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaul1997" class="citation web cs1">Paul, Matthias R. (1997-10-02) [1997-09-29]. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20031004074600/http://www-student.informatik.uni-bonn.de/~frinke/ibmbioa3.zip">"Caldera OpenDOS 7.01/7.02 Update Alpha 3 IBMBIO.COM - README.TXT and BOOT.TXT - A short description of how OpenDOS is booted"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.uni-bonn.de/~uzs180/download/ibmbioa3.zip">the original</a> on 2003-10-04. Retrieved 2009-03-29.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Caldera+OpenDOS+7.01%2F7.02+Update+Alpha+3+IBMBIO.COM+-+README.TXT+and+BOOT.TXT+-+A+short+description+of+how+OpenDOS+is+booted&rft.date=1997-10-02&rft.aulast=Paul&rft.aufirst=Matthias+R.&rft_id=http%3A%2F%2Fwww.uni-bonn.de%2F~uzs180%2Fdownload%2Fibmbioa3.zip&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> <a rel="nofollow" class="external autonumber" href="https://web.archive.org/web/20181225154705/http://mirror.macintosharchive.org/max1zzz.co.uk/+Windows%20&%20DOS/DOS/System/Novell/Support/Bins/Op702src.zip">[2]</a> </li> <li id="cite_note-Paul_2017-48"><a href="#cite_ref-Paul_2017_48-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaul2017" class="citation web cs1">Paul, Matthias R. (2017-08-14) [2017-08-07]. <a rel="nofollow" class="external text" href="http://hpmuseum.org/forum/thread-8774-post-77196.html#pid77196">"The continuing saga of Windows 3.1 in enhanced mode on OmniBook 300"</a>. MoHPC - the Museum of HP Calculators. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20180501185933/http://hpmuseum.org/forum/thread-8774-post-77196.html">Archived</a> from the original on 2018-05-01. Retrieved 2018-05-01. <q>[…] SYS […] /O[:nnn] Override IPL reported boot drive unit (n=0..126, 128..254). […] Preparing target disk... Choosing FAT12 CHS Boot Sector (requires IPL to report boot unit). Treating target as diskette or superfloppy medium (boot drive unit 0). Writing new Boot Sector... […]</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MoHPC+-+the+Museum+of+HP+Calculators&rft.atitle=The+continuing+saga+of+Windows+3.1+in+enhanced+mode+on+OmniBook+300&rft.date=2017-08-14&rft.aulast=Paul&rft.aufirst=Matthias+R.&rft_id=http%3A%2F%2Fhpmuseum.org%2Fforum%2Fthread-8774-post-77196.html%23pid77196&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> (NB. SYS writes <a href="/wiki/Volume_boot_record" title="Volume boot record">volume boot records</a> rather than master boot records, but their incoming register interface is similar (with extensions) since they could both be loaded initially by the underlying system.) </li> <li id="cite_note-Elliott_2010_EDD4-Hybrid-MBR-50"><a href="#cite_ref-Elliott_2010_EDD4-Hybrid-MBR_50-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFElliott2010" class="citation web cs1">Elliott, Robert (2010-01-04). <a rel="nofollow" class="external text" href="http://www.t13.org/Documents/UploadedDocuments/docs2010/e09127r3-EDD-4_Hybrid_MBR_boot_code_annex.pdf">"EDD-4 Hybrid MBR boot code annex"</a> (PDF). <a href="/wiki/Hewlett_Packard" class="mw-redirect" title="Hewlett Packard">Hewlett Packard</a>, T13 Technical Committee. e09127r3. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824121640/http://www.t13.org/Documents/UploadedDocuments/docs2010/e09127r3-EDD-4_Hybrid_MBR_boot_code_annex.pdf">Archived</a> (PDF) from the original on 2017-08-24. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=EDD-4+Hybrid+MBR+boot+code+annex&rft.pub=Hewlett+Packard%2C+T13+Technical+Committee&rft.date=2010-01-04&rft.aulast=Elliott&rft.aufirst=Robert&rft_id=http%3A%2F%2Fwww.t13.org%2FDocuments%2FUploadedDocuments%2Fdocs2010%2Fe09127r3-EDD-4_Hybrid_MBR_boot_code_annex.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Microsoft_KB69013-52"><a href="#cite_ref-Microsoft_KB69013_52-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://support.microsoft.com/kb/69013">"FDISK /MBR rewrites the Master Boot Record"</a>. Support. 1. <a href="/wiki/Microsoft" title="Microsoft">Microsoft</a>. 2011-09-23. 69013. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170208102308/https://support.microsoft.com/en-us/help/69013/fdisk-mbr-rewrites-the-master-boot-record">Archived</a> from the original on 2017-02-08. Retrieved 2013-04-19.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Support&rft.atitle=FDISK+%2FMBR+rewrites+the+Master+Boot+Record&rft.date=2011-09-23&rft_id=http%3A%2F%2Fsupport.microsoft.com%2Fkb%2F69013&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-Linux_MAN_sfdisk-54"><a href="#cite_ref-Linux_MAN_sfdisk_54-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://linux.die.net/man/8/sfdisk">"sfdisk(8) – Linux man page"</a>. die.net. 2013 [2007]. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824121954/https://linux.die.net/man/8/sfdisk">Archived</a> from the original on 2017-08-24. Retrieved 2013-04-20.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=die.net&rft.atitle=sfdisk%288%29+%E2%80%93+Linux+man+page&rft.date=2013&rft_id=http%3A%2F%2Flinux.die.net%2Fman%2F8%2Fsfdisk&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-RBIL_html-55"><a href="#cite_ref-RBIL_html_55-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrown2000" class="citation web cs1"><a href="/wiki/Ralf_D._Brown" class="mw-redirect" title="Ralf D. Brown">Brown, Ralf D.</a> (2000-07-16). <a rel="nofollow" class="external text" href="http://www.delorie.com/djgpp/doc/rbinter/id/13/6.html">"Ralf Browns Interrupt List (v61 html)"</a>. Delorie Software. Retrieved 2016-11-03.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Ralf+Browns+Interrupt+List+%28v61+html%29&rft.pub=Delorie+Software&rft.date=2000-07-16&rft.aulast=Brown&rft.aufirst=Ralf+D.&rft_id=http%3A%2F%2Fwww.delorie.com%2Fdjgpp%2Fdoc%2Frbinter%2Fid%2F13%2F6.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> </li> <li id="cite_note-RBIL_archive_text-56"><a href="#cite_ref-RBIL_archive_text_56-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrown2000" class="citation web cs1"><a href="/wiki/Ralf_D._Brown" class="mw-redirect" title="Ralf D. Brown">Brown, Ralf D.</a> (2000-07-16). <a rel="nofollow" class="external text" href="https://www.cs.cmu.edu/~ralf/interrupt-list/inter61b.zip">"B-1302: INT 13 - DISK - READ SECTOR(S) INTO MEMORY"</a>. <a href="/wiki/Ralf_Brown%27s_Interrupt_List" title="Ralf Brown's Interrupt List">Ralf Brown's Interrupt List</a> (RBIL) (61 ed.). Retrieved 2016-11-03.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Ralf+Brown%27s+Interrupt+List+%28RBIL%29&rft.atitle=B-1302%3A+INT+13+-+DISK+-+READ+SECTOR%28S%29+INTO+MEMORY&rft.date=2000-07-16&rft.aulast=Brown&rft.aufirst=Ralf+D.&rft_id=https%3A%2F%2Fwww.cs.cmu.edu%2F~ralf%2Finterrupt-list%2Finter61b.zip&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> (NB. See file INTERRUP.B inside archive "INTER61A.ZIP.) </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=14" title="Edit section: Further reading">edit</a>]</div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGilbert1996" class="citation web cs1">Gilbert, Howard (1996-01-01) [1995]. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160303210749/http://www.yale.edu/pclt/BOOT/PARTITIO.HTM">"Partitions and Volumes"</a>. PC Lube & Tune. Archived from <a rel="nofollow" class="external text" href="http://www.yale.edu/pclt/BOOT/PARTITIO.HTM">the original</a> on 2016-03-03.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=PC+Lube+%26+Tune&rft.atitle=Partitions+and+Volumes&rft.date=1996-01-01&rft.aulast=Gilbert&rft.aufirst=Howard&rft_id=http%3A%2F%2Fwww.yale.edu%2Fpclt%2FBOOT%2FPARTITIO.HTM&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKnights2004" class="citation web cs1">Knights, Ray (2004-12-22) [2000-12-16]. <a rel="nofollow" class="external text" href="http://www.rayknights.org/pc_boot/pc_boot.htm">"Ray's Place"</a>. MBR and Windows Boot Sectors (includes code disassembly and explanations of boot process). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824133034/http://www.rayknights.org/pc_boot/pc_boot.htm">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MBR+and+Windows+Boot+Sectors+%28includes+code+disassembly+and+explanations+of+boot+process%29&rft.atitle=Ray%27s+Place&rft.date=2004-12-22&rft.aulast=Knights&rft.aufirst=Ray&rft_id=http%3A%2F%2Fwww.rayknights.org%2Fpc_boot%2Fpc_boot.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLandis2002" class="citation web cs1">Landis, Hale (2002-05-06). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140701052540/http://www.ata-atapi.com/hiwmbr.html">"Master Boot Record"</a>. How It Works. Archived from <a rel="nofollow" class="external text" href="http://www.ata-atapi.com/hiwmbr.html">the original</a> on 2014-07-01.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=How+It+Works&rft.atitle=Master+Boot+Record&rft.date=2002-05-06&rft.aulast=Landis&rft.aufirst=Hale&rft_id=http%3A%2F%2Fwww.ata-atapi.com%2Fhiwmbr.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSedory2015" class="citation web cs1">Sedory, Daniel B. (2015-06-25) [2007]. <a rel="nofollow" class="external text" href="http://thestarman.pcministry.com/asm/mbr/index.html">"MBRs (Master Boot Records)"</a>. Boot Records Revealed. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170824133321/http://thestarman.pcministry.com/asm/mbr/index.html">Archived</a> from the original on 2017-08-24. Retrieved 2017-08-24.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Boot+Records+Revealed&rft.atitle=MBRs+%28Master+Boot+Records%29&rft.date=2015-06-25&rft.aulast=Sedory&rft.aufirst=Daniel+B.&rft_id=http%3A%2F%2Fthestarman.pcministry.com%2Fasm%2Fmbr%2Findex.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaster+boot+record" class="Z3988"> <a rel="nofollow" class="external autonumber" href="https://web.archive.org/web/20070510140812/http://mirror.href.com/thestarman/asm/mbr/index.html">[3]</a> <a rel="nofollow" class="external autonumber" href="http://thestarman.narod.ru/asm/mbr/index.html">[4]</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2>[<a href="/w/index.php?title=Master_boot_record&action=edit&section=15" title="Edit section: External links">edit</a>]</div> <ul><li><a rel="nofollow" class="external text" href="http://wiki.osdev.org/MBR_(x86)">Article on master boot record</a></li> <li><a rel="nofollow" class="external text" href="https://neosmart.net/wiki/mbr-boot-process/">The MBR and how it fits into the BIOS boot process</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Firmware_and_booting" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="3"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Firmware_and_booting" title="Template:Firmware and booting"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Firmware_and_booting" title="Template talk:Firmware and booting"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Firmware_and_booting" title="Special:EditPage/Template:Firmware and booting"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Firmware_and_booting" style="font-size:114%;margin:0 4em"><a href="/wiki/Firmware" title="Firmware">Firmware</a> and <a href="/wiki/Booting" title="Booting">booting</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Processes</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Booting_process_of_Windows" title="Booting process of Windows">Windows</a> <ul><li><a href="/wiki/Architecture_of_Windows_9x#Boot_sequence" title="Architecture of Windows 9x">9x</a></li> <li><a href="/wiki/Booting_process_of_Windows_NT" class="mw-redirect" title="Booting process of Windows NT">NT</a></li></ul></li> <li><a href="/wiki/Booting_process_of_Linux" title="Booting process of Linux">Linux</a> <ul><li><a href="/wiki/Booting_process_of_Android_devices" title="Booting process of Android devices">Android</a></li></ul></li></ul> </div></td><td class="noviewer navbox-image" rowspan="10" style="width:1px;padding:0 0 0 2px"><div><a href="/wiki/File:WD_Blue_WD5000LPVX_-_controller_-_Winbond_25X20CLVIG-0182.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/WD_Blue_WD5000LPVX_-_controller_-_Winbond_25X20CLVIG-0182.jpg/100px-WD_Blue_WD5000LPVX_-_controller_-_Winbond_25X20CLVIG-0182.jpg" decoding="async" width="100" height="100" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/WD_Blue_WD5000LPVX_-_controller_-_Winbond_25X20CLVIG-0182.jpg/150px-WD_Blue_WD5000LPVX_-_controller_-_Winbond_25X20CLVIG-0182.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f8/WD_Blue_WD5000LPVX_-_controller_-_Winbond_25X20CLVIG-0182.jpg/200px-WD_Blue_WD5000LPVX_-_controller_-_Winbond_25X20CLVIG-0182.jpg 2x" data-file-width="1535" data-file-height="1535" /></a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Booting <a href="/wiki/Firmware#Computers" title="Firmware">firmware</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Types</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Proprietary_firmware" title="Proprietary firmware">Proprietary firmware</a></li> <li><a href="/wiki/Open-source_firmware" title="Open-source firmware">Open-source firmware</a></li> <li><a href="/wiki/Custom_firmware" title="Custom firmware">Custom firmware</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Interfaces</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/UEFI" title="UEFI">UEFI</a></li> <li><a href="/wiki/BIOS" title="BIOS">BIOS</a> <ul><li><a href="/wiki/Video_BIOS" title="Video BIOS">Video BIOS</a></li></ul></li> <li><a href="/wiki/Open_Firmware" title="Open Firmware">Open Firmware</a></li> <li><a href="/wiki/ACPI" title="ACPI">ACPI</a></li> <li><a href="/wiki/MultiProcessor_Specification" title="MultiProcessor Specification">MultiProcessor Specification</a></li> <li><a href="/wiki/Advanced_Power_Management" title="Advanced Power Management">APM</a></li> <li><a href="/wiki/Legacy_Plug_and_Play" title="Legacy Plug and Play">Legacy Plug and Play</a></li> <li><a href="/wiki/ARC_(specification)" title="ARC (specification)">AlphaBIOS</a></li> <li><a href="/wiki/SRM_firmware" title="SRM firmware">SRM</a></li> <li><a href="/wiki/Simple_Firmware_Interface" title="Simple Firmware Interface">SFI</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Implementations</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/SeaBIOS" title="SeaBIOS">SeaBIOS</a></li> <li><a href="/wiki/Award_Software" title="Award Software">Award BIOS</a></li> <li><a href="/wiki/American_Megatrends" title="American Megatrends">American Megatrends</a> <ul><li><a href="/wiki/AMIBIOS" class="mw-redirect" title="AMIBIOS">AMIBIOS</a></li> <li><a href="/wiki/AMI_Aptio" class="mw-redirect" title="AMI Aptio">AMI Aptio</a></li></ul></li> <li><a href="/wiki/Insyde_Software" title="Insyde Software">InsydeH2O</a></li> <li><a href="/wiki/Phoenix_Technologies" title="Phoenix Technologies">Phoenix SecureCore UEFI</a></li> <li><a href="/wiki/TianoCore_EDK_II" title="TianoCore EDK II">TianoCore EDK II</a></li> <li><a href="/wiki/OpenBIOS" title="OpenBIOS">OpenBIOS</a></li> <li><a href="/wiki/Coreboot" title="Coreboot">Coreboot</a></li> <li><a href="/wiki/Libreboot" title="Libreboot">Libreboot</a></li> <li><a href="/wiki/LinuxBoot" title="LinuxBoot">LinuxBoot</a></li> <li><a href="/wiki/Kickstart_(Amiga)" title="Kickstart (Amiga)">Kickstart</a></li> <li><a href="/wiki/Run-Time_Abstraction_Services" title="Run-Time Abstraction Services">Run-Time Abstraction Services</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Hybrid firmware bootloader</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Common_Firmware_Environment" title="Common Firmware Environment">Common Firmware Environment</a> </li> <li><a href="/wiki/Das_U-Boot" title="Das U-Boot">Das U-Boot</a></li> <li><a href="/wiki/ARCS_(computing)" title="ARCS (computing)">ARCS</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Bootloaders" class="mw-redirect" title="Bootloaders">Bootloaders</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bootloader_unlocking" title="Bootloader unlocking">Bootloader unlocking</a></li> <li><a href="/wiki/Comparison_of_bootloaders" title="Comparison of bootloaders">Comparison of bootloaders</a></li></ul> </div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Implementations" scope="row" class="navbox-group" style="width:1%">Implementations</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Acronis_OS_Selector" class="mw-redirect" title="Acronis OS Selector">Acronis OS Selector</a></li> <li><a href="/wiki/Barebox" title="Barebox">Barebox</a></li> <li><a href="/wiki/BootManager" class="mw-redirect" title="BootManager">BootManager</a></li> <li><a href="/wiki/BootX_(Apple)" title="BootX (Apple)">BootX (Apple)</a></li> <li><a href="/wiki/BootX_(Linux)" title="BootX (Linux)">BootX (Linux)</a></li> <li><a href="/wiki/GNU_GRUB" title="GNU GRUB">GNU GRUB</a></li> <li><a href="/wiki/IBoot" title="IBoot">iBoot</a></li> <li><a href="/wiki/Systemd-boot" title="Systemd-boot">systemd-boot</a></li> <li><a href="/wiki/Loadlin" title="Loadlin">loadlin</a></li> <li><a href="/wiki/NTLDR" title="NTLDR">NTLDR</a></li> <li><a href="/wiki/OpeniBoot" title="OpeniBoot">OpeniBoot</a></li> <li><a href="/wiki/RedBoot" title="RedBoot">RedBoot</a></li> <li><a href="/wiki/REFInd" title="REFInd">rEFInd</a></li> <li><a href="/wiki/REFIt" title="REFIt">rEFIt</a></li> <li><a href="/wiki/SYSLINUX" title="SYSLINUX">SYSLINUX</a></li> <li><a href="/wiki/Windows_Boot_Manager" title="Windows Boot Manager">Windows Boot Manager</a></li> <li><a href="/wiki/XOSL" title="XOSL">xOSL</a></li> <li><a href="/wiki/Yaboot" title="Yaboot">Yaboot</a></li> <li><a href="/wiki/Plop_Boot_Manager" title="Plop Boot Manager">Plop Boot Manager</a></li> <li><a href="/wiki/MILO_(bootloader)" title="MILO (bootloader)">MILO</a></li></ul> </div></td></tr></tbody></table><div> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Partition layouts</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/GUID_Partition_Table" title="GUID Partition Table">GUID Partition Table</a></li> <li><a class="mw-selflink selflink">Master boot record</a></li> <li><a href="/wiki/Apple_Partition_Map" title="Apple Partition Map">Apple Partition Map</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/System_partition_and_boot_partition" title="System partition and boot partition">Partitions</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/EFI_system_partition" title="EFI system partition">EFI system partition</a></li> <li><a href="/wiki/BIOS_boot_partition" title="BIOS boot partition">BIOS boot partition</a></li> <li><a href="/wiki//boot/" title="/boot/">/boot/</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Utilities</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Software</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Flashrom_(utility)" title="Flashrom (utility)">flashrom</a></li> <li><a href="/wiki/Fwupd" title="Fwupd">fwupd</a></li> <li><a href="/wiki/UEFITool" title="UEFITool">UEFITool</a></li> <li><a href="/wiki/Odin_(firmware_flashing_software)" title="Odin (firmware flashing software)">Odin</a> <ul><li><a href="/wiki/Odin_(firmware_flashing_software)#Heimdall" title="Odin (firmware flashing software)">Heimdall</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Hardware</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bus_Pirate" title="Bus Pirate">Bus Pirate</a></li> <li><a href="/wiki/Raspberry_Pi" title="Raspberry Pi">Raspberry Pi</a></li> <li><a href="/wiki/FTDI" title="FTDI">ft2232</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Network_booting" title="Network booting">Network boot</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Preboot_Execution_Environment" title="Preboot Execution Environment">Preboot Execution Environment</a> <ul><li><a href="/wiki/GPXE" title="GPXE">gPXE</a></li> <li><a href="/wiki/IPXE" title="IPXE">iPXE</a></li></ul></li> <li><a href="/wiki/NetBoot" title="NetBoot">NetBoot</a></li> <li><a href="/wiki/Remote_Initial_Program_Load" title="Remote Initial Program Load">Remote Initial Program Load</a></li> <li><a href="/wiki/Wake-on-LAN" title="Wake-on-LAN">Wake-on-LAN</a></li> <li><a href="/wiki/Wake-on-ring" title="Wake-on-ring">Wake-on-ring</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">ROM variants</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Read-only_memory" title="Read-only memory">ROM</a></li> <li><a href="/wiki/Programmable_ROM" title="Programmable ROM">PROM</a></li> <li><a href="/wiki/EPROM" title="EPROM">EPROM</a></li> <li><a href="/wiki/EEPROM" title="EEPROM">EEPROM</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Boot_ROM" title="Boot ROM">Boot ROM</a></li> <li><a href="/wiki/ROM_hacking" title="ROM hacking">ROM hacking</a></li> <li><a href="/wiki/ROM_image" title="ROM image">ROM image</a></li> <li><a href="/wiki/Execute_in_place" title="Execute in place">Execute in place</a></li> <li><a href="/wiki/Devicetree" title="Devicetree">Devicetree</a></li> <li><a href="/wiki/Fastboot" title="Fastboot">Fastboot</a></li> <li><a href="/wiki/Instant-on" title="Instant-on">Instant-on</a></li> <li><a href="/wiki/Power-on_self-test" title="Power-on self-test">Power-on self-test</a></li> <li><a href="/wiki/Qualcomm_EDL_mode" title="Qualcomm EDL mode">EDL mode</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Master_boot_record&oldid=1251113196">https://en.wikipedia.org/w/index.php?title=Master_boot_record&oldid=1251113196</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:BIOS" title="Category:BIOS">BIOS</a></li><li><a href="/wiki/Category:Booting" title="Category:Booting">Booting</a></li><li><a href="/wiki/Category:Disk_partitions" title="Category:Disk partitions">Disk partitions</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:Use_dmy_dates_from_April_2019" title="Category:Use dmy dates from April 2019">Use dmy dates from April 2019</a></li><li><a href="/wiki/Category:Use_list-defined_references_from_January_2022" title="Category:Use list-defined references from January 2022">Use list-defined references from January 2022</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 14 October 2024, at 13:42 (UTC).</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Master_boot_record&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f69cdc8f6-vkl22","wgBackendResponseTime":135,"wgPageParseReport":{"limitreport":{"cputime":"1.049","walltime":"1.191","ppvisitednodes":{"value":9161,"limit":1000000},"postexpandincludesize":{"value":162820,"limit":2097152},"templateargumentsize":{"value":15418,"limit":2097152},"expansiondepth":{"value":16,"limit":100},"expensivefunctioncount":{"value":4,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":208608,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 981.927 1 -total"," 43.20% 424.240 2 Template:Reflist"," 29.47% 289.398 37 Template:Cite_web"," 12.68% 124.521 4 Template:Navbox"," 12.35% 121.265 1 Template:Firmware_and_booting"," 9.12% 89.520 1 Template:Short_description"," 8.22% 80.678 116 Template:Anchor"," 6.20% 60.841 2 Template:Pagetype"," 5.37% 52.713 8 Template:Cite_book"," 5.07% 49.828 126 Template:Mono"]},"scribunto":{"limitreport-timeusage":{"value":"0.531","limit":"10.000"},"limitreport-memusage":{"value":7933970,"limit":52428800}},"cachereport":{"origin":"mw-web.codfw.main-f69cdc8f6-g2nql","timestamp":"20241122145530","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Master boot record","url":"https:\/\/en.wikipedia.org\/wiki\/Master_boot_record","sameAs":"http:\/\/www.wikidata.org\/entity\/Q624752","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q624752","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2002-06-07T20:09:18Z","dateModified":"2024-10-14T13:42:53Z","headline":"special type of boot sector at the very beginning of partitioned computer mass storage devices"}</script> </body> </html>