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class="vector-toc-numb">2</span> <span>Data organization and representation</span> </div> </a> <ul id="toc-Data_organization_and_representation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Hierarchy_of_storage" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Hierarchy_of_storage"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Hierarchy of storage</span> </div> </a> <button aria-controls="toc-Hierarchy_of_storage-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Hierarchy of storage subsection</span> </button> <ul id="toc-Hierarchy_of_storage-sublist" class="vector-toc-list"> <li id="toc-Primary_storage" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Primary_storage"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Primary storage</span> </div> </a> <ul id="toc-Primary_storage-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Secondary_storage" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Secondary_storage"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Secondary storage</span> </div> </a> <ul id="toc-Secondary_storage-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Tertiary_storage" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Tertiary_storage"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Tertiary storage</span> </div> </a> <ul id="toc-Tertiary_storage-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Off-line_storage" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Off-line_storage"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Off-line storage</span> </div> </a> <ul id="toc-Off-line_storage-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Characteristics_of_storage" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Characteristics_of_storage"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Characteristics of storage</span> </div> </a> <button aria-controls="toc-Characteristics_of_storage-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Characteristics of storage subsection</span> </button> <ul id="toc-Characteristics_of_storage-sublist" class="vector-toc-list"> <li id="toc-Volatility" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Volatility"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Volatility</span> </div> </a> <ul id="toc-Volatility-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Mutability" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Mutability"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Mutability</span> </div> </a> <ul id="toc-Mutability-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Accessibility" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Accessibility"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>Accessibility</span> </div> </a> <ul id="toc-Accessibility-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Addressability" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Addressability"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Addressability</span> </div> </a> <ul id="toc-Addressability-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Capacity" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Capacity"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.5</span> <span>Capacity</span> </div> </a> <ul id="toc-Capacity-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Performance" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Performance"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.6</span> <span>Performance</span> </div> </a> <ul id="toc-Performance-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Energy_use" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Energy_use"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.7</span> <span>Energy use</span> </div> </a> <ul id="toc-Energy_use-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Security" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Security"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.8</span> <span>Security</span> </div> </a> <ul id="toc-Security-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Vulnerability_and_reliability" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Vulnerability_and_reliability"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.9</span> <span>Vulnerability and reliability</span> </div> </a> <ul id="toc-Vulnerability_and_reliability-sublist" class="vector-toc-list"> <li id="toc-Error_detection" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Error_detection"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.9.1</span> <span>Error detection</span> </div> </a> <ul id="toc-Error_detection-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </li> <li id="toc-Storage_media" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Storage_media"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Storage media</span> </div> </a> <button aria-controls="toc-Storage_media-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Storage media subsection</span> </button> <ul id="toc-Storage_media-sublist" class="vector-toc-list"> <li id="toc-Semiconductor" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Semiconductor"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Semiconductor</span> </div> </a> <ul id="toc-Semiconductor-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Magnetic" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Magnetic"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2</span> <span>Magnetic</span> </div> </a> <ul id="toc-Magnetic-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Optical" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Optical"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.3</span> <span>Optical</span> </div> </a> <ul id="toc-Optical-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Paper" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Paper"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.4</span> <span>Paper</span> </div> </a> <ul id="toc-Paper-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other_storage_media_or_substrates" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_storage_media_or_substrates"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.5</span> <span>Other storage media or substrates</span> </div> </a> <ul id="toc-Other_storage_media_or_substrates-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Related_technologies" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Related_technologies"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Related technologies</span> </div> </a> <button aria-controls="toc-Related_technologies-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Related technologies subsection</span> </button> <ul id="toc-Related_technologies-sublist" class="vector-toc-list"> <li id="toc-Redundancy" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Redundancy"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Redundancy</span> </div> </a> <ul id="toc-Redundancy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Network_connectivity" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Network_connectivity"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>Network connectivity</span> </div> </a> <ul id="toc-Network_connectivity-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Robotic_storage" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Robotic_storage"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.3</span> <span>Robotic storage</span> </div> </a> <ul id="toc-Robotic_storage-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>See also</span> </div> </a> <button aria-controls="toc-See_also-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle See also subsection</span> </button> <ul id="toc-See_also-sublist" class="vector-toc-list"> <li id="toc-Primary_storage_topics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Primary_storage_topics"> <div class="vector-toc-text"> <span class="vector-toc-numb">7.1</span> <span>Primary storage topics</span> </div> </a> <ul id="toc-Primary_storage_topics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Secondary,_tertiary_and_off-line_storage_topics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Secondary,_tertiary_and_off-line_storage_topics"> <div class="vector-toc-text"> <span class="vector-toc-numb">7.2</span> <span>Secondary, tertiary and off-line storage topics</span> </div> </a> <ul id="toc-Secondary,_tertiary_and_off-line_storage_topics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Data_storage_conferences" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Data_storage_conferences"> <div class="vector-toc-text"> <span class="vector-toc-numb">7.3</span> <span>Data storage conferences</span> </div> </a> <ul id="toc-Data_storage_conferences-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Notes</span> </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"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>References</span> </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"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-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" title="Table of Contents" > <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" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </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"><span class="mw-page-title-main">Computer data storage</span></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 60 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-60" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">60 languages</span> </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%AA%D8%AE%D8%B2%D9%8A%D9%86_%D8%A8%D9%8A%D8%A7%D9%86%D8%A7%D8%AA_%D8%A7%D9%84%D8%AD%D8%A7%D8%B3%D9%88%D8%A8" title="تخزين بيانات الحاسوب – Arabic" lang="ar" hreflang="ar" data-title="تخزين بيانات الحاسوب" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Komp%C3%BCter_m%C9%99lumatlar%C4%B1n%C4%B1n_saxlanmas%C4%B1" title="Kompüter məlumatlarının saxlanması – Azerbaijani" lang="az" hreflang="az" data-title="Kompüter məlumatlarının saxlanması" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-azb mw-list-item"><a href="https://azb.wikipedia.org/wiki/%DA%A9%D8%A7%D9%85%D9%BE%DB%8C%D9%88%D8%AA%D8%B1_%D8%AF%DB%8C%D8%AA%D8%A7_%D8%B3%D8%A7%D8%AE%D9%84%D8%A7%D9%85%D8%A7%D8%B3%DB%8C" title="کامپیوتر دیتا ساخلاماسی – South Azerbaijani" lang="azb" hreflang="azb" data-title="کامپیوتر دیتا ساخلاماسی" data-language-autonym="تۆرکجه" data-language-local-name="South Azerbaijani" class="interlanguage-link-target"><span>تۆرکجه</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%95%E0%A6%AE%E0%A7%8D%E0%A6%AA%E0%A6%BF%E0%A6%89%E0%A6%9F%E0%A6%BE%E0%A6%B0_%E0%A6%AE%E0%A7%87%E0%A6%AE%E0%A6%B0%E0%A6%BF" title="কম্পিউটার মেমরি – Bangla" lang="bn" hreflang="bn" data-title="কম্পিউটার মেমরি" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A1%D1%8A%D1%85%D1%80%D0%B0%D0%BD%D0%B5%D0%BD%D0%B8%D0%B5_%D0%BD%D0%B0_%D0%BA%D0%BE%D0%BC%D0%BF%D1%8E%D1%82%D1%8A%D1%80%D0%BD%D0%B8_%D0%B4%D0%B0%D0%BD%D0%BD%D0%B8" title="Съхранение на компютърни данни – Bulgarian" lang="bg" hreflang="bg" data-title="Съхранение на компютърни данни" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Memorija_ra%C4%8Dunara" title="Memorija računara – Bosnian" lang="bs" hreflang="bs" data-title="Memorija računara" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Memor_elektronek" title="Memor elektronek – Breton" lang="br" hreflang="br" data-title="Memor elektronek" data-language-autonym="Brezhoneg" data-language-local-name="Breton" class="interlanguage-link-target"><span>Brezhoneg</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Mem%C3%B2ria_d%27ordinador" title="Memòria d'ordinador – Catalan" lang="ca" hreflang="ca" data-title="Memòria d'ordinador" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Elektronick%C3%A1_pam%C4%9B%C5%A5" title="Elektronická paměť – Czech" lang="cs" hreflang="cs" data-title="Elektronická paměť" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Digital_hukommelse" title="Digital hukommelse – Danish" lang="da" hreflang="da" data-title="Digital hukommelse" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/M%C3%A4lu_(arvuti)" title="Mälu (arvuti) – Estonian" lang="et" hreflang="et" data-title="Mälu (arvuti)" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%9C%CE%BD%CE%AE%CE%BC%CE%B7_%CF%85%CF%80%CE%BF%CE%BB%CE%BF%CE%B3%CE%B9%CF%83%CF%84%CE%AE" title="Μνήμη υπολογιστή – Greek" lang="el" hreflang="el" data-title="Μνήμη υπολογιστή" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Memoria_(inform%C3%A1tica)" title="Memoria (informática) – Spanish" lang="es" hreflang="es" data-title="Memoria (informática)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Memoro_(komputiko)" title="Memoro (komputiko) – Esperanto" lang="eo" hreflang="eo" data-title="Memoro (komputiko)" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Memoria_(informatika)" title="Memoria (informatika) – Basque" lang="eu" hreflang="eu" data-title="Memoria (informatika)" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B0%D8%AE%DB%8C%D8%B1%D9%87%E2%80%8C%D8%B3%D8%A7%D8%B2%DB%8C_%D8%AF%D8%A7%D8%AF%D9%87_%D8%B1%D8%A7%DB%8C%D8%A7%D9%86%D9%87" title="ذخیره‌سازی داده رایانه – Persian" lang="fa" hreflang="fa" data-title="ذخیره‌سازی داده رایانه" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/M%C3%A9moire_(informatique)" title="Mémoire (informatique) – French" lang="fr" hreflang="fr" data-title="Mémoire (informatique)" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/St%C3%B3r%C3%A1il_sonra%C3%AD_r%C3%ADomhaireachta" title="Stóráil sonraí ríomhaireachta – Irish" lang="ga" hreflang="ga" data-title="Stóráil sonraí ríomhaireachta" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Memoria_principal" title="Memoria principal – Galician" lang="gl" hreflang="gl" data-title="Memoria principal" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EA%B8%B0%EC%96%B5_%EC%9E%A5%EC%B9%98" title="기억 장치 – Korean" lang="ko" hreflang="ko" data-title="기억 장치" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%80%D5%A1%D5%B4%D5%A1%D5%AF%D5%A1%D6%80%D5%A3%D5%B9%D5%A1%D5%B5%D5%AB%D5%B6_%D5%B0%D5%AB%D5%B7%D5%B8%D5%B2%D5%B8%D6%82%D5%A9%D5%B5%D5%B8%D6%82%D5%B6" title="Համակարգչային հիշողություն – Armenian" lang="hy" hreflang="hy" data-title="Համակարգչային հիշողություն" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%95%E0%A4%82%E0%A4%AA%E0%A5%8D%E0%A4%AF%E0%A5%82%E0%A4%9F%E0%A4%B0_%E0%A4%B8%E0%A5%8D%E0%A4%AE%E0%A5%83%E0%A4%A4%E0%A4%BF" title="कंप्यूटर स्मृति – Hindi" lang="hi" hreflang="hi" data-title="कंप्यूटर स्मृति" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-ilo mw-list-item"><a href="https://ilo.wikipedia.org/wiki/Pagidulinan_ti_datos_ti_kompiuter" title="Pagidulinan ti datos ti kompiuter – Iloko" lang="ilo" hreflang="ilo" data-title="Pagidulinan ti datos ti kompiuter" data-language-autonym="Ilokano" data-language-local-name="Iloko" class="interlanguage-link-target"><span>Ilokano</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Penyimpanan_data_komputer" title="Penyimpanan data komputer – Indonesian" lang="id" hreflang="id" data-title="Penyimpanan data komputer" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-zu mw-list-item"><a href="https://zu.wikipedia.org/wiki/Isiqoqonga_mininingo_sesiCikizi" title="Isiqoqonga mininingo sesiCikizi – Zulu" lang="zu" hreflang="zu" data-title="Isiqoqonga mininingo sesiCikizi" data-language-autonym="IsiZulu" data-language-local-name="Zulu" class="interlanguage-link-target"><span>IsiZulu</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Memoria_(elettronica)" title="Memoria (elettronica) – Italian" lang="it" hreflang="it" data-title="Memoria (elettronica)" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%99%E1%83%9D%E1%83%9B%E1%83%9E%E1%83%98%E1%83%A3%E1%83%A2%E1%83%94%E1%83%A0%E1%83%98%E1%83%A1_%E1%83%9B%E1%83%94%E1%83%AE%E1%83%A1%E1%83%98%E1%83%94%E1%83%A0%E1%83%94%E1%83%91%E1%83%90" title="კომპიუტერის მეხსიერება – Georgian" lang="ka" hreflang="ka" data-title="კომპიუტერის მეხსიერება" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%9A%D0%BE%D0%BC%D0%BF%D1%8C%D1%8E%D1%82%D0%B5%D1%80_%D0%B6%D0%B0%D0%B4%D1%8B%D1%81%D1%8B" title="Компьютер жадысы – Kazakh" lang="kk" hreflang="kk" data-title="Компьютер жадысы" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Kifaa_cha_kutunzia" title="Kifaa cha kutunzia – Swahili" lang="sw" hreflang="sw" data-title="Kifaa cha kutunzia" data-language-autonym="Kiswahili" data-language-local-name="Swahili" class="interlanguage-link-target"><span>Kiswahili</span></a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Memoria_computatralis" title="Memoria computatralis – Latin" lang="la" hreflang="la" data-title="Memoria computatralis" data-language-autonym="Latina" data-language-local-name="Latin" class="interlanguage-link-target"><span>Latina</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Atminties_%C4%AFrenginys" title="Atminties įrenginys – Lithuanian" lang="lt" hreflang="lt" data-title="Atminties įrenginys" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Mem%C3%B3ria_(sz%C3%A1m%C3%ADt%C3%A1stechnika)" title="Memória (számítástechnika) – Hungarian" lang="hu" hreflang="hu" data-title="Memória (számítástechnika)" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%92%D0%BD%D0%B0%D1%82%D1%80%D0%B5%D1%88%D0%BD%D0%BE_%D0%BF%D0%B0%D0%BC%D1%82%D0%B5%D1%9A%D0%B5" title="Внатрешно памтење – Macedonian" lang="mk" hreflang="mk" data-title="Внатрешно памтење" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%AE%E0%A5%87%E0%A4%AE%E0%A4%B0%E0%A5%80" title="मेमरी – Marathi" lang="mr" hreflang="mr" data-title="मेमरी" data-language-autonym="मराठी" data-language-local-name="Marathi" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Storan_data_komputer" title="Storan data komputer – Malay" lang="ms" hreflang="ms" data-title="Storan data komputer" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-mwl mw-list-item"><a href="https://mwl.wikipedia.org/wiki/Mim%C3%B3ria_de_cumputador" title="Mimória de cumputador – Mirandese" lang="mwl" hreflang="mwl" data-title="Mimória de cumputador" data-language-autonym="Mirandés" data-language-local-name="Mirandese" class="interlanguage-link-target"><span>Mirandés</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%A1%D0%B0%D0%BD%D0%B0%D1%85_%D0%BE%D0%B9" title="Санах ой – Mongolian" lang="mn" hreflang="mn" data-title="Санах ой" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Computergeheugen" title="Computergeheugen – Dutch" lang="nl" hreflang="nl" data-title="Computergeheugen" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E8%A8%98%E6%86%B6%E8%A3%85%E7%BD%AE" title="記憶装置 – Japanese" lang="ja" hreflang="ja" data-title="記憶装置" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Datalager" title="Datalager – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Datalager" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-mhr mw-list-item"><a href="https://mhr.wikipedia.org/wiki/%D0%A8%D0%B0%D1%80%D0%BD%D1%8B%D1%88" title="Шарныш – Eastern Mari" lang="mhr" hreflang="mhr" data-title="Шарныш" data-language-autonym="Олык марий" data-language-local-name="Eastern Mari" class="interlanguage-link-target"><span>Олык марий</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%95%E0%A9%B0%E0%A8%AA%E0%A8%BF%E0%A8%8A%E0%A8%9F%E0%A8%B0_%E0%A8%A1%E0%A8%BE%E0%A8%9F%E0%A8%BE_%E0%A8%B8%E0%A8%9F%E0%A9%8B%E0%A8%B0%E0%A9%87%E0%A8%9C" title="ਕੰਪਿਊਟਰ ਡਾਟਾ ਸਟੋਰੇਜ – Punjabi" lang="pa" hreflang="pa" data-title="ਕੰਪਿਊਟਰ ਡਾਟਾ ਸਟੋਰੇਜ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Pami%C4%99%C4%87_komputerowa" title="Pamięć komputerowa – Polish" lang="pl" hreflang="pl" data-title="Pamięć komputerowa" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Armazenamento_de_dados_de_computador" title="Armazenamento de dados de computador – Portuguese" lang="pt" hreflang="pt" data-title="Armazenamento de dados de computador" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Memoria_sistemelor_de_calcul" title="Memoria sistemelor de calcul – Romanian" lang="ro" hreflang="ro" data-title="Memoria sistemelor de calcul" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Memoria_kompjuterike" title="Memoria kompjuterike – Albanian" lang="sq" hreflang="sq" data-title="Memoria kompjuterike" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Computer_data_storage" title="Computer data storage – Simple English" lang="en-simple" hreflang="en-simple" data-title="Computer data storage" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Pam%C3%A4%C5%A5_(po%C4%8D%C3%ADta%C4%8D)" title="Pamäť (počítač) – Slovak" lang="sk" hreflang="sk" data-title="Pamäť (počítač)" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Notranji_pomnilnik" title="Notranji pomnilnik – Slovenian" lang="sl" hreflang="sl" data-title="Notranji pomnilnik" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%DA%A9%DB%86%DA%AF%DB%95%DB%8C_%D8%AF%D8%B1%D8%A7%D9%88%DB%95%DB%8C_%DA%A9%DB%86%D9%85%D9%BE%DB%8C%D9%88%D8%AA%DB%95%D8%B1" title="کۆگەی دراوەی کۆمپیوتەر – Central Kurdish" lang="ckb" hreflang="ckb" data-title="کۆگەی دراوەی کۆمپیوتەر" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Datorminne" title="Datorminne – Swedish" lang="sv" hreflang="sv" data-title="Datorminne" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%95%E0%B0%82%E0%B0%AA%E0%B1%8D%E0%B0%AF%E0%B1%82%E0%B0%9F%E0%B0%B0%E0%B1%8D_%E0%B0%A1%E0%B1%87%E0%B0%9F%E0%B0%BE_%E0%B0%B8%E0%B1%8D%E0%B0%9F%E0%B1%8B%E0%B0%B0%E0%B1%87%E0%B0%9C%E0%B1%8D" title="కంప్యూటర్ డేటా స్టోరేజ్ – Telugu" lang="te" hreflang="te" data-title="కంప్యూటర్ డేటా స్టోరేజ్" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%AB%E0%B8%99%E0%B9%88%E0%B8%A7%E0%B8%A2%E0%B9%80%E0%B8%81%E0%B9%87%E0%B8%9A%E0%B8%82%E0%B9%89%E0%B8%AD%E0%B8%A1%E0%B8%B9%E0%B8%A5%E0%B8%84%E0%B8%AD%E0%B8%A1%E0%B8%9E%E0%B8%B4%E0%B8%A7%E0%B9%80%E0%B8%95%E0%B8%AD%E0%B8%A3%E0%B9%8C" title="หน่วยเก็บข้อมูลคอมพิวเตอร์ – Thai" lang="th" hreflang="th" data-title="หน่วยเก็บข้อมูลคอมพิวเตอร์" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Bilgisayar_veri_depolama" title="Bilgisayar veri depolama – Turkish" lang="tr" hreflang="tr" data-title="Bilgisayar veri depolama" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9A%D0%BE%D0%BC%D0%BF%27%D1%8E%D1%82%D0%B5%D1%80%D0%BD%D0%B0_%D0%BF%D0%B0%D0%BC%27%D1%8F%D1%82%D1%8C" title="Комп'ютерна пам'ять – Ukrainian" lang="uk" hreflang="uk" data-title="Комп'ютерна пам'ять" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%DA%A9%D9%85%D9%BE%DB%8C%D9%88%D9%B9%D8%B1_%DA%88%DB%8C%D9%B9%D8%A7_%D8%A7%D8%B3%D9%B9%D9%88%D8%B1%DB%8C%D8%AC" title="کمپیوٹر ڈیٹا اسٹوریج – Urdu" lang="ur" hreflang="ur" data-title="کمپیوٹر ڈیٹا اسٹوریج" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/L%C6%B0u_tr%E1%BB%AF_d%E1%BB%AF_li%E1%BB%87u_m%C3%A1y_t%C3%ADnh" title="Lưu trữ dữ liệu máy tính – Vietnamese" lang="vi" hreflang="vi" data-title="Lưu trữ dữ liệu máy tính" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E7%94%B5%E8%84%91%E6%95%B0%E6%8D%AE%E5%AD%98%E5%82%A8%E5%99%A8" title="电脑数据存储器 – Wu" lang="wuu" hreflang="wuu" data-title="电脑数据存储器" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E9%9B%BB%E8%85%A6%E8%B3%87%E6%96%99%E5%84%B2%E5%AD%98" title="電腦資料儲存 – Cantonese" lang="yue" hreflang="yue" data-title="電腦資料儲存" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a 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of digital data readable by computers</div> <p class="mw-empty-elt"> </p> <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">For broader coverage of this topic, see <a href="/wiki/Data_storage" title="Data storage">Data storage</a>.</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:DDR2_ram_mounted.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e8/DDR2_ram_mounted.jpg/220px-DDR2_ram_mounted.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e8/DDR2_ram_mounted.jpg/330px-DDR2_ram_mounted.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e8/DDR2_ram_mounted.jpg/440px-DDR2_ram_mounted.jpg 2x" data-file-width="1600" data-file-height="1067" /></a><figcaption>1 <a href="/wiki/Gibibyte" class="mw-redirect" title="Gibibyte">GiB</a> of <a href="/wiki/SDRAM" class="mw-redirect" title="SDRAM">SDRAM</a> mounted in a <a href="/wiki/Computer" title="Computer">computer</a>. An example of <i>primary storage</i>.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:IBM_DJNA-351520_Hard_Disk_A.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/IBM_DJNA-351520_Hard_Disk_A.jpg/220px-IBM_DJNA-351520_Hard_Disk_A.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/IBM_DJNA-351520_Hard_Disk_A.jpg/330px-IBM_DJNA-351520_Hard_Disk_A.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e4/IBM_DJNA-351520_Hard_Disk_A.jpg/440px-IBM_DJNA-351520_Hard_Disk_A.jpg 2x" data-file-width="3872" data-file-height="2592" /></a><figcaption>15 <a href="/wiki/Gigabyte" title="Gigabyte">GB</a> <a href="/wiki/Parallel_ATA" title="Parallel ATA">PATA</a> hard disk drive (HDD) from 1999. When connected to a computer it serves as <i>secondary</i> storage.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Super_DLTtape_I.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Super_DLTtape_I.jpg/220px-Super_DLTtape_I.jpg" decoding="async" width="220" height="177" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Super_DLTtape_I.jpg/330px-Super_DLTtape_I.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/23/Super_DLTtape_I.jpg/440px-Super_DLTtape_I.jpg 2x" data-file-width="800" data-file-height="644" /></a><figcaption>160 <a href="/wiki/Gigabyte" title="Gigabyte">GB</a> <a href="/wiki/Digital_Linear_Tape" title="Digital Linear Tape">SDLT</a> <a href="/wiki/Tape_cartridge" title="Tape cartridge">tape cartridge</a>, an example of <i>off-line</i> storage. When used within a robotic <a href="/wiki/Tape_library" title="Tape library">tape library</a>, it is classified as <i>tertiary</i> storage instead.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Sony_CRX310S-Internal-PC-DVD-Drive-Opened.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Sony_CRX310S-Internal-PC-DVD-Drive-Opened.jpg/220px-Sony_CRX310S-Internal-PC-DVD-Drive-Opened.jpg" decoding="async" width="220" height="151" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Sony_CRX310S-Internal-PC-DVD-Drive-Opened.jpg/330px-Sony_CRX310S-Internal-PC-DVD-Drive-Opened.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/70/Sony_CRX310S-Internal-PC-DVD-Drive-Opened.jpg/440px-Sony_CRX310S-Internal-PC-DVD-Drive-Opened.jpg 2x" data-file-width="3930" data-file-height="2700" /></a><figcaption>Read/Write DVD drive with cradle for media extended</figcaption></figure> <p><b>Computer data storage</b> or <b>digital data storage</b> is a technology consisting of <a href="/wiki/Computer" title="Computer">computer</a> components and <a href="/wiki/Data_storage" title="Data storage">recording media</a> that are used to retain <a href="/wiki/Digital_data" title="Digital data">digital data</a>. It is a core function and fundamental component of computers.<sup id="cite_ref-Patterson_1-0" class="reference"><a href="#cite_note-Patterson-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 15–16">: 15–16 </span></sup> </p><p>The <a href="/wiki/Central_processing_unit" title="Central processing unit">central processing unit</a> (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a <a href="/wiki/Storage_hierarchy" class="mw-redirect" title="Storage hierarchy">storage hierarchy</a>,<sup id="cite_ref-Patterson_1-1" class="reference"><a href="#cite_note-Patterson-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 468–473">: 468–473 </span></sup> which puts fast but expensive and small storage options close to the CPU and slower but less expensive and larger options further away. Generally, the fast<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup> technologies are referred to as "memory", while slower persistent technologies are referred to as "storage". </p><p>Even the first computer designs, <a href="/wiki/Charles_Babbage" title="Charles Babbage">Charles Babbage</a>'s <a href="/wiki/Analytical_Engine" class="mw-redirect" title="Analytical Engine">Analytical Engine</a> and <a href="/wiki/Percy_Ludgate" title="Percy Ludgate">Percy Ludgate</a>'s Analytical Machine, clearly distinguished between processing and memory (Babbage stored numbers as rotations of gears, while Ludgate stored numbers as displacements of rods in shuttles). This distinction was extended in the <a href="/wiki/Von_Neumann_architecture" title="Von Neumann architecture">Von Neumann architecture</a>, where the CPU consists of two main parts: The <a href="/wiki/Control_unit" title="Control unit">control unit</a> and the <a href="/wiki/Arithmetic_logic_unit" title="Arithmetic logic unit">arithmetic logic unit</a> (ALU). The former controls the flow of data between the CPU and memory, while the latter performs arithmetic and <a href="/wiki/Bitwise_operation" title="Bitwise operation">logical operations</a> on data. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Functionality">Functionality</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=1" title="Edit section: Functionality"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Without a significant amount of memory, a computer would merely be able to perform fixed operations and immediately output the result. It would have to be reconfigured to change its behavior. This is acceptable for devices such as desk <a href="/wiki/Calculator" title="Calculator">calculators</a>, <a href="/wiki/Digital_signal_processing" title="Digital signal processing">digital signal processors</a>, and other specialized devices. <a href="/wiki/Von_Neumann_architecture" title="Von Neumann architecture">Von Neumann</a> machines differ in having a memory in which they store their operating <a href="/wiki/Instruction_set_architecture#Instructions" title="Instruction set architecture">instructions</a> and data.<sup id="cite_ref-Patterson_1-2" class="reference"><a href="#cite_note-Patterson-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 20">: 20 </span></sup> Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program, but can simply be <a href="/wiki/Computer_programming" title="Computer programming">reprogrammed</a> with new in-memory instructions; they also tend to be simpler to design, in that a relatively simple processor may keep <a href="/wiki/State_(computer_science)" title="State (computer science)">state</a> between successive computations to build up complex procedural results. Most modern computers are von Neumann machines. </p> <div class="mw-heading mw-heading2"><h2 id="Data_organization_and_representation">Data organization and representation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=2" title="Edit section: Data organization and representation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A modern <a href="/wiki/Computer" title="Computer">digital computer</a> represents <a href="/wiki/Data" title="Data">data</a> using the <a href="/wiki/Binary_numeral_system" class="mw-redirect" title="Binary numeral system">binary numeral system</a>. Text, numbers, pictures, audio, and nearly any other form of information can be converted into a string of <a href="/wiki/Bit" title="Bit">bits</a>, or binary digits, each of which has a value of 0 or 1. The most common unit of storage is the <a href="/wiki/Byte" title="Byte">byte</a>, equal to 8 bits. A piece of information can be handled by any computer or device whose storage space is large enough to accommodate <i>the binary representation of the piece of information</i>, or simply <a href="/wiki/Data_(computing)" class="mw-redirect" title="Data (computing)">data</a>. For example, the <a href="/wiki/Complete_works_of_Shakespeare" class="mw-redirect" title="Complete works of Shakespeare">complete works of Shakespeare</a>, about 1250 pages in print, can be stored in about five <a href="/wiki/Megabyte" title="Megabyte">megabytes</a> (40 million bits) with one byte per character. </p><p>Data are <a href="/wiki/Encoded" class="mw-redirect" title="Encoded">encoded</a> by assigning a bit pattern to each <a href="/wiki/Character_(computing)" title="Character (computing)">character</a>, <a href="/wiki/Numerical_digit" title="Numerical digit">digit</a>, or <a href="/wiki/Multimedia" title="Multimedia">multimedia</a> object. Many standards exist for encoding (e.g. <a href="/wiki/Character_encoding" title="Character encoding">character encodings</a> like <a href="/wiki/ASCII" title="ASCII">ASCII</a>, image encodings like <a href="/wiki/JPEG" title="JPEG">JPEG</a>, and video encodings like <a href="/wiki/MPEG-4" title="MPEG-4">MPEG-4</a>). </p><p>By adding bits to each encoded unit, redundancy allows the computer to detect errors in coded data and correct them based on mathematical algorithms. Errors generally occur in low probabilities due to <a href="/wiki/Random" class="mw-redirect" title="Random">random</a> bit value flipping, or "physical bit fatigue", loss of the physical bit in the storage of its ability to maintain a distinguishable value (0 or 1), or due to errors in inter or intra-computer communication. A random <a href="/wiki/RAM_parity" title="RAM parity">bit flip</a> (e.g. due to random <a href="/wiki/Radiation" title="Radiation">radiation</a>) is typically corrected upon detection. A bit or a group of malfunctioning physical bits (the specific defective bit is not always known; group definition depends on the specific storage device) is typically automatically fenced out, taken out of use by the device, and replaced with another functioning equivalent group in the device, where the corrected bit values are restored (if possible). The <a href="/wiki/Cyclic_redundancy_check" title="Cyclic redundancy check">cyclic redundancy check</a> (CRC) method is typically used in communications and storage for <a href="/wiki/Error_detection" class="mw-redirect" title="Error detection">error detection</a>. A detected error is then retried. </p><p><a href="/wiki/Data_compression" title="Data compression">Data compression</a> methods allow in many cases (such as a database) to represent a string of bits by a shorter bit string ("compress") and reconstruct the original string ("decompress") when needed. This utilizes substantially less storage (tens of percent) for many types of data at the cost of more computation (compress and decompress when needed). Analysis of the trade-off between storage cost saving and costs of related computations and possible delays in data availability is done before deciding whether to keep certain data compressed or not. </p><p>For <a href="/wiki/Data_security" title="Data security">security reasons</a>, certain types of data (e.g. <a href="/wiki/Credit_card" title="Credit card">credit card</a> information) may be kept <a href="/wiki/Encrypted" class="mw-redirect" title="Encrypted">encrypted</a> in storage to prevent the possibility of unauthorized information reconstruction from chunks of storage snapshots. </p> <div class="mw-heading mw-heading2"><h2 id="Hierarchy_of_storage">Hierarchy of storage</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=3" title="Edit section: Hierarchy of storage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Memory_hierarchy" title="Memory hierarchy">Memory hierarchy</a></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Computer_storage_types.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Computer_storage_types.svg/350px-Computer_storage_types.svg.png" decoding="async" width="350" height="499" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Computer_storage_types.svg/525px-Computer_storage_types.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Computer_storage_types.svg/700px-Computer_storage_types.svg.png 2x" data-file-width="705" data-file-height="1005" /></a><figcaption>Various forms of storage, divided according to their distance from the <a href="/wiki/Central_processing_unit" title="Central processing unit">central processing unit</a>. The fundamental components of a general-purpose computer are <a href="/wiki/Arithmetic_and_logic_unit" class="mw-redirect" title="Arithmetic and logic unit">arithmetic and logic unit</a>, <a href="/wiki/Control_unit" title="Control unit">control circuitry</a>, storage space, and <a href="/wiki/Input/output" title="Input/output">input/output</a> devices. Technology and capacity as in common <a href="/wiki/Home_computer" title="Home computer">home computers</a> around 2005.</figcaption></figure> <p>Generally, the lower a storage is in the hierarchy, the lesser its <a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">bandwidth</a> and the greater its access <a href="/wiki/Latency_(engineering)" title="Latency (engineering)">latency</a> is from the CPU. This traditional division of storage to primary, secondary, tertiary, and off-line storage is also guided by cost per bit. </p><p>In contemporary usage, <i>memory</i> is usually fast but temporary <a href="/wiki/Semiconductor_memory" title="Semiconductor memory">semiconductor</a> <a href="/wiki/Random-access_memory" title="Random-access memory">read-write memory</a>, typically <a href="/wiki/DRAM" class="mw-redirect" title="DRAM">DRAM</a> (dynamic RAM) or other such devices. <i>Storage</i> consists of storage devices and their media not directly accessible by the <a href="/wiki/CPU" class="mw-redirect" title="CPU">CPU</a> (<a href="/wiki/Secondary_storage" class="mw-redirect" title="Secondary storage">secondary</a> or <a href="/wiki/Tertiary_storage" class="mw-redirect" title="Tertiary storage">tertiary storage</a>), typically <a href="/wiki/Hard_disk_drive" title="Hard disk drive">hard disk drives</a>, <a href="/wiki/Optical_disc" title="Optical disc">optical disc</a> drives, and other devices slower than RAM but <a href="/wiki/Non-volatile" class="mw-redirect" title="Non-volatile">non-volatile</a> (retaining contents when powered down).<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>Historically, <i>memory</i> has, depending on technology, been called <i>central memory</i>, <i>core memory</i>, <i>core storage</i>, <i>drum</i>, <i>main memory</i>, <i>real storage</i>, or <i>internal memory</i>. Meanwhile, slower persistent storage devices have been referred to as <i>secondary storage</i>, <i>external memory</i>, or <i>auxiliary/peripheral storage</i>. </p> <div class="mw-heading mw-heading3"><h3 id="Primary_storage">Primary storage</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=4" title="Edit section: Primary storage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Computer_memory" title="Computer memory">Computer memory</a></div> <p><i>Primary storage</i> (also known as <i>main memory</i>, <i>internal memory</i>, or <i>prime memory</i>), often referred to simply as <i>memory</i>, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in a uniform manner. </p><p>Historically, <a href="/wiki/History_of_computing_hardware" title="History of computing hardware">early computers</a> used <a href="/wiki/Delay-line_memory" title="Delay-line memory">delay lines</a>, <a href="/wiki/Williams_tube" title="Williams tube">Williams tubes</a>, or rotating <a href="/wiki/Drum_memory" title="Drum memory">magnetic drums</a> as primary storage. By 1954, those unreliable methods were mostly replaced by <a href="/wiki/Magnetic-core_memory" title="Magnetic-core memory">magnetic-core memory</a>. Core memory remained dominant until the 1970s, when advances in <a href="/wiki/Integrated_circuit" title="Integrated circuit">integrated circuit</a> technology allowed <a href="/wiki/Semiconductor_memory" title="Semiconductor memory">semiconductor memory</a> to become economically competitive. </p><p>This led to modern <a href="/wiki/Random-access_memory" title="Random-access memory">random-access memory</a> (RAM). It is small-sized, light, but quite expensive at the same time. The particular types of RAM used for primary storage are <a href="/wiki/Volatile_memory" title="Volatile memory">volatile</a>, meaning that they lose the information when not powered. Besides storing opened programs, it serves as <a href="/wiki/Page_cache" title="Page cache">disk cache</a> and <a href="/wiki/Write_buffer" title="Write buffer">write buffer</a> to improve both reading and writing performance. Operating systems borrow RAM capacity for caching so long as it's not needed by running software.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> Spare memory can be utilized as <a href="/wiki/RAM_drive" title="RAM drive">RAM drive</a> for temporary high-speed data storage. </p><p>As shown in the diagram, traditionally there are two more sub-layers of the primary storage, besides main large-capacity RAM: </p> <ul><li><a href="/wiki/Processor_register" title="Processor register">Processor registers</a> are located inside the processor. Each register typically holds a <a href="/wiki/Word_(computer_architecture)" title="Word (computer architecture)">word</a> of data (often 32 or 64 bits). CPU instructions instruct the <a href="/wiki/Arithmetic_logic_unit" title="Arithmetic logic unit">arithmetic logic unit</a> to perform various calculations or other operations on this data (or with the help of it). Registers are the fastest of all forms of computer data storage.</li> <li><a href="/wiki/Processor_cache" class="mw-redirect" title="Processor cache">Processor cache</a> is an intermediate stage between ultra-fast registers and much slower main memory. It was introduced solely to improve the performance of computers. Most actively used information in the main memory is just duplicated in the cache memory, which is faster, but of much lesser capacity. On the other hand, main memory is much slower, but has a much greater storage capacity than processor registers. Multi-level <a href="/wiki/Memory_hierarchy" title="Memory hierarchy">hierarchical cache</a> setup is also commonly used—<i>primary cache</i> being smallest, fastest and located inside the processor; <i>secondary cache</i> being somewhat larger and slower.</li></ul> <p>Main memory is directly or indirectly connected to the central processing unit via a <i>memory bus</i>. It is actually two buses (not on the diagram): an <a href="/wiki/Address_bus" class="mw-redirect" title="Address bus">address bus</a> and a <a href="/wiki/Data_bus" class="mw-redirect" title="Data bus">data bus</a>. The CPU firstly sends a number through an address bus, a number called <a href="/wiki/Memory_address" title="Memory address">memory address</a>, that indicates the desired location of data. Then it reads or writes the data in the <a href="/wiki/Memory_cell_(computing)" title="Memory cell (computing)">memory cells</a> using the data bus. Additionally, a <a href="/wiki/Memory_management_unit" title="Memory management unit">memory management unit</a> (MMU) is a small device between CPU and RAM recalculating the actual memory address, for example to provide an abstraction of <a href="/wiki/Virtual_memory" title="Virtual memory">virtual memory</a> or other tasks. </p><p>As the RAM types used for primary storage are volatile (uninitialized at start up), a computer containing only such storage would not have a source to read instructions from, in order to start the computer. Hence, <a href="/wiki/Non-volatile_memory" title="Non-volatile memory">non-volatile primary storage</a> containing a small startup program (<a href="/wiki/BIOS" title="BIOS">BIOS</a>) is used to <a href="/wiki/Bootstrapping#Computing" title="Bootstrapping">bootstrap</a> the computer, that is, to read a larger program from non-volatile <i>secondary</i> storage to RAM and start to execute it. A non-volatile technology used for this purpose is called ROM, for <a href="/wiki/Read-only_memory" title="Read-only memory">read-only memory</a> (the terminology may be somewhat confusing as most ROM types are also capable of <i><a href="/wiki/Random_access" title="Random access">random access</a></i>). </p><p>Many types of "ROM" are not literally <i>read only</i>, as updates to them are possible; however it is slow and memory must be erased in large portions before it can be re-written. Some <a href="/wiki/Embedded_system" title="Embedded system">embedded systems</a> run programs directly from ROM (or similar), because such programs are rarely changed. Standard computers do not store non-rudimentary programs in ROM, and rather, use large capacities of secondary storage, which is non-volatile as well, and not as costly. </p><p>Recently, <i>primary storage</i> and <i>secondary storage</i> in some uses refer to what was historically called, respectively, <i>secondary storage</i> and <i>tertiary storage</i>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>The primary storage, including <a href="/wiki/Read-only_memory" title="Read-only memory">ROM</a>, <a href="/wiki/EEPROM" title="EEPROM">EEPROM</a>, <a href="/wiki/NOR_flash" class="mw-redirect" title="NOR flash">NOR flash</a>, and <a href="/wiki/Random_access_memory" class="mw-redirect" title="Random access memory">RAM</a>,<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> are usually <a href="/wiki/Byte-addressable" class="mw-redirect" title="Byte-addressable">byte-addressable</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Secondary_storage">Secondary storage</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=5" title="Edit section: Secondary storage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><i>Secondary storage</i> (also known as <i>external memory</i> or <i>auxiliary storage</i>) differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfer the desired data to primary storage. Secondary storage is non-volatile (retaining data when its power is shut off). Modern computer systems typically have two orders of magnitude more secondary storage than primary storage because secondary storage is less expensive. </p><p>In modern computers, <a href="/wiki/Hard_disk_drive" title="Hard disk drive">hard disk drives</a> (HDDs) or <a href="/wiki/Solid-state_drive" title="Solid-state drive">solid-state drives</a> (SSDs) are usually used as secondary storage. The <a href="/wiki/Access_time" title="Access time">access time</a> per byte for HDDs or SSDs is typically measured in <a href="/wiki/Millisecond" title="Millisecond">milliseconds</a> (thousandths of a second), while the access time per byte for primary storage is measured in <a href="/wiki/Nanosecond" title="Nanosecond">nanoseconds</a> (billionths of a second). Thus, secondary storage is significantly slower than primary storage. Rotating <a href="/wiki/Optical_disc_drive" title="Optical disc drive">optical storage</a> devices, such as <a href="/wiki/CD" class="mw-redirect" title="CD">CD</a> and <a href="/wiki/DVD" title="DVD">DVD</a> drives, have even longer access times. Other examples of secondary storage technologies include <a href="/wiki/USB_flash_drive" title="USB flash drive">USB flash drives</a>, <a href="/wiki/Floppy_disk" title="Floppy disk">floppy disks</a>, <a href="/wiki/Magnetic-tape_data_storage" title="Magnetic-tape data storage">magnetic tape</a>, <a href="/wiki/Paper_tape" class="mw-redirect" title="Paper tape">paper tape</a>, <a href="/wiki/Punched_card" title="Punched card">punched cards</a>, and <a href="/wiki/RAM_drive" title="RAM drive">RAM disks</a>. </p><p>Once the <a href="/wiki/Disk_read/write_head" class="mw-redirect" title="Disk read/write head">disk read/write head</a> on HDDs reaches the proper placement and the data, subsequent data on the track are very fast to access. To reduce the seek time and rotational latency, data are transferred to and from disks in large contiguous blocks. Sequential or block access on disks is orders of magnitude faster than random access, and many sophisticated paradigms have been developed to design efficient algorithms based on sequential and block access. Another way to reduce the I/O bottleneck is to use multiple disks in parallel to increase the bandwidth between primary and secondary memory.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>Secondary storage is often formatted according to a <a href="/wiki/File_system" title="File system">file system</a> format, which provides the abstraction necessary to organize data into <a href="/wiki/Computer_file" title="Computer file">files</a> and <a href="/wiki/Directory_(computing)" title="Directory (computing)">directories</a>, while also providing <a href="/wiki/Metadata" title="Metadata">metadata</a> describing the owner of a certain file, the access time, the access permissions, and other information. </p><p>Most computer <a href="/wiki/Operating_system" title="Operating system">operating systems</a> use the concept of <a href="/wiki/Virtual_memory" title="Virtual memory">virtual memory</a>, allowing the utilization of more primary storage capacity than is physically available in the system. As the primary memory fills up, the system moves the least-used chunks (<a href="/wiki/Page_(computer_memory)" title="Page (computer memory)">pages</a>) to a swap file or page file on secondary storage, retrieving them later when needed. If a lot of pages are moved to slower secondary storage, the system performance is degraded. </p><p>The secondary storage, including <a href="/wiki/Hard_disk_drive" title="Hard disk drive">HDD</a>, <a href="/wiki/Optical_disc_drive" title="Optical disc drive">ODD</a> and <a href="/wiki/Solid_state_drive" class="mw-redirect" title="Solid state drive">SSD</a>, are usually block-addressable. </p> <div class="mw-heading mw-heading3"><h3 id="Tertiary_storage">Tertiary storage</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=6" title="Edit section: Tertiary storage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Nearline_storage" title="Nearline storage">Nearline storage</a> and <a href="/wiki/Cloud_storage" title="Cloud storage">Cloud storage</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:StorageTek_Powderhorn_tape_library.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c9/StorageTek_Powderhorn_tape_library.jpg/220px-StorageTek_Powderhorn_tape_library.jpg" decoding="async" width="220" height="293" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c9/StorageTek_Powderhorn_tape_library.jpg/330px-StorageTek_Powderhorn_tape_library.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c9/StorageTek_Powderhorn_tape_library.jpg/440px-StorageTek_Powderhorn_tape_library.jpg 2x" data-file-width="768" data-file-height="1024" /></a><figcaption>A large <a href="/wiki/Tape_library" title="Tape library">tape library</a>, with tape cartridges placed on shelves in the front, and a robotic arm moving in the back. The visible height of the library is about 180 cm.</figcaption></figure> <p><i>Tertiary storage</i> or <i>tertiary memory</i><sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> is a level below secondary storage. Typically, it involves a robotic mechanism which will <i>mount</i> (insert) and <i>dismount</i> removable mass storage media into a storage device according to the system's demands; such data are often copied to secondary storage before use. It is primarily used for archiving rarely accessed information since it is much slower than secondary storage (e.g. 5–60 seconds vs. 1–10 milliseconds). This is primarily useful for extraordinarily large data stores, accessed without human operators. Typical examples include <a href="/wiki/Tape_libraries" class="mw-redirect" title="Tape libraries">tape libraries</a> and <a href="/wiki/Optical_jukebox" title="Optical jukebox">optical jukeboxes</a>. </p><p>When a computer needs to read information from the tertiary storage, it will first consult a catalog <a href="/wiki/Database" title="Database">database</a> to determine which tape or disc contains the information. Next, the computer will instruct a <a href="/wiki/Industrial_robot" title="Industrial robot">robotic arm</a> to fetch the medium and place it in a drive. When the computer has finished reading the information, the robotic arm will return the medium to its place in the library. </p><p>Tertiary storage is also known as <i><a href="/wiki/Nearline_storage" title="Nearline storage">nearline storage</a></i> because it is "near to online". The formal distinction between online, nearline, and offline storage is:<sup id="cite_ref-pearson2010_9-0" class="reference"><a href="#cite_note-pearson2010-9"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> <ul><li>Online storage is immediately available for I/O.</li> <li>Nearline storage is not immediately available, but can be made online quickly without human intervention.</li> <li>Offline storage is not immediately available, and requires some human intervention to become online.</li></ul> <p>For example, always-on spinning hard disk drives are online storage, while spinning drives that spin down automatically, such as in massive arrays of idle disks (<a href="/wiki/Non-RAID_drive_architectures#MAID" title="Non-RAID drive architectures">MAID</a>), are nearline storage. Removable media such as <a href="/wiki/Tape_cartridges" class="mw-redirect" title="Tape cartridges">tape cartridges</a> that can be automatically loaded, as in <a href="/wiki/Tape_libraries" class="mw-redirect" title="Tape libraries">tape libraries</a>, are nearline storage, while tape cartridges that must be manually loaded are offline storage. </p> <div class="mw-heading mw-heading3"><h3 id="Off-line_storage">Off-line storage</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=7" title="Edit section: Off-line storage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><i>Off-line storage</i> is computer data storage on a medium or a device that is not under the control of a <a href="/wiki/Central_processing_unit" title="Central processing unit">processing unit</a>.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> The medium is recorded, usually in a secondary or tertiary storage device, and then physically removed or disconnected. It must be inserted or connected by a human operator before a computer can access it again. Unlike tertiary storage, it cannot be accessed without human interaction. </p><p><a href="/wiki/Off-line" class="mw-redirect" title="Off-line">Off-line</a> storage is used to <a href="/wiki/Data_communication" title="Data communication">transfer information</a> since the detached medium can easily be physically transported. Additionally, it is useful for cases of disaster, where, for example, a fire destroys the original data, a medium in a remote location will be unaffected, enabling <a href="/wiki/IT_disaster_recovery" title="IT disaster recovery">disaster recovery</a>. Off-line storage increases general <a href="/wiki/Information_security" title="Information security">information security</a> since it is physically inaccessible from a computer, and data confidentiality or integrity cannot be affected by computer-based attack techniques. Also, if the information stored for archival purposes is rarely accessed, off-line storage is less expensive than tertiary storage. </p><p>In modern personal computers, most secondary and tertiary storage media are also used for off-line storage. Optical discs and flash memory devices are the most popular, and to a much lesser extent removable hard disk drives; older examples include floppy disks and Zip disks. In enterprise uses, magnetic tape cartridges are predominant; older examples include open-reel magnetic tape and punched cards. </p> <div class="mw-heading mw-heading2"><h2 id="Characteristics_of_storage">Characteristics of storage</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=8" title="Edit section: Characteristics of storage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Samsung-1GB-DDR2-Laptop-RAM.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Samsung-1GB-DDR2-Laptop-RAM.jpg/250px-Samsung-1GB-DDR2-Laptop-RAM.jpg" decoding="async" width="250" height="158" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Samsung-1GB-DDR2-Laptop-RAM.jpg/375px-Samsung-1GB-DDR2-Laptop-RAM.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Samsung-1GB-DDR2-Laptop-RAM.jpg/500px-Samsung-1GB-DDR2-Laptop-RAM.jpg 2x" data-file-width="2840" data-file-height="1800" /></a><figcaption>A 1 GiB module of <a href="/wiki/SO-DIMM" class="mw-redirect" title="SO-DIMM">laptop</a> <a href="/wiki/DDR2_SDRAM" title="DDR2 SDRAM">DDR2</a> <a href="/wiki/RAM" class="mw-redirect" title="RAM">RAM</a></figcaption></figure> <p>Storage technologies at all levels of the storage hierarchy can be differentiated by evaluating certain core characteristics as well as measuring characteristics specific to a particular implementation. These core characteristics are volatility, mutability, accessibility, and addressability. For any particular implementation of any storage technology, the characteristics worth measuring are capacity and performance. </p> <table class="wikitable" style="text-align:center;"> <caption>Overview </caption> <tbody><tr> <th>Characteristic </th> <th><a href="/wiki/Hard_disk_drive" title="Hard disk drive">Hard disk drive</a> </th> <th><a href="/wiki/Optical_disc" title="Optical disc">Optical disc</a> </th> <th><a href="/wiki/Flash_memory" title="Flash memory">Flash memory</a> </th> <th><a href="/wiki/Random-access_memory" title="Random-access memory">Random-access memory</a> </th> <th><a href="/wiki/Linear_Tape-Open" title="Linear Tape-Open">Linear tape-open</a> </th></tr> <tr> <th>Technology </th> <td>Magnetic disk </td> <td><a href="/wiki/Laser" title="Laser">Laser</a> beam </td> <td colspan="2">Semiconductor </td> <td>Magnetic tape </td></tr> <tr> <th>Volatility </th> <td>No </td> <td>No </td> <td>No </td> <td>Volatile </td> <td>No </td></tr> <tr> <th>Random access </th> <td>Yes </td> <td>Yes </td> <td>Yes </td> <td>Yes </td> <td>No </td></tr> <tr> <th><a href="/wiki/Latency_(engineering)" title="Latency (engineering)">Latency</a> (access time) </th> <td><a href="/wiki/Hard_disk_drive_performance_characteristics" title="Hard disk drive performance characteristics">~15 ms</a> (swift) </td> <td>~150 ms (moderate) </td> <td>None (instant) </td> <td>None (instant) </td> <td>Lack of random access (very slow) </td></tr> <tr> <th>Controller </th> <td>Internal </td> <td>External </td> <td><a href="/wiki/Flash_memory_controller" title="Flash memory controller">Internal</a> </td> <td>Internal </td> <td>External </td></tr> <tr> <th>Failure with imminent <a href="/wiki/Data_loss" title="Data loss">data loss</a> </th> <td><a href="/wiki/Head_crash" title="Head crash">Head crash</a> </td> <td>— </td> <td colspan="2"><a href="/wiki/Failure_of_electronic_components" title="Failure of electronic components">Circuitry</a> </td> <td>— </td></tr> <tr> <th>Error detection </th> <td>Diagnostic (<a href="/wiki/Self-Monitoring,_Analysis_and_Reporting_Technology" title="Self-Monitoring, Analysis and Reporting Technology">S.M.A.R.T.</a>) </td> <td><a href="/wiki/Optical_disc#Surface_error_scanning" title="Optical disc">Error rate measurement</a> </td> <td>Indicated by downward spikes in transfer rates </td> <td>(Short-term storage) </td> <td>Unknown </td></tr> <tr> <th>Price per space </th> <td>Low </td> <td>Low </td> <td>High </td> <td>Very high </td> <td>Very low (but expensive drives) </td></tr> <tr> <th>Price per unit </th> <td>Moderate </td> <td>Low </td> <td>Moderate </td> <td>High </td> <td>Moderate (but expensive drives) </td></tr> <tr> <th>Main application </th> <td>Mid-term archival, routine backups, server, workstation storage expansion </td> <td>Long-term archival, <a href="/wiki/Hard_copy" title="Hard copy">hard copy</a> distribution </td> <td>Portable electronics; operating system </td> <td>Real-time </td> <td>Long-term archival </td></tr> </tbody></table> <div class="mw-heading mw-heading3"><h3 id="Volatility">Volatility</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=9" title="Edit section: Volatility"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Non-volatile_memory" title="Non-volatile memory">Non-volatile memory</a> retains the stored information even if not constantly supplied with electric power. It is suitable for long-term storage of information. <a href="/wiki/Volatile_memory" title="Volatile memory">Volatile memory</a> requires constant power to maintain the stored information. The fastest memory technologies are volatile ones, although that is not a universal rule. Since the primary storage is required to be very fast, it predominantly uses volatile memory. </p><p><a href="/wiki/Dynamic_random-access_memory" title="Dynamic random-access memory">Dynamic random-access memory</a> is a form of volatile memory that also requires the stored information to be periodically reread and rewritten, or <a href="/wiki/Memory_refresh" title="Memory refresh">refreshed</a>, otherwise it would vanish. <a href="/wiki/Static_random-access_memory" title="Static random-access memory">Static random-access memory</a> is a form of volatile memory similar to DRAM with the exception that it never needs to be refreshed as long as power is applied; it loses its content when the power supply is lost. </p><p>An <a href="/wiki/Uninterruptible_power_supply" title="Uninterruptible power supply">uninterruptible power supply</a> (UPS) can be used to give a computer a brief window of time to move information from primary volatile storage into non-volatile storage before the batteries are exhausted. Some systems, for example <a href="/wiki/EMC_Symmetrix" title="EMC Symmetrix">EMC Symmetrix</a>, have integrated batteries that maintain volatile storage for several minutes. </p> <div class="mw-heading mw-heading3"><h3 id="Mutability">Mutability</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=10" title="Edit section: Mutability"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dt>Read/write storage or mutable storage</dt> <dd>Allows information to be overwritten at any time. A computer without some amount of read/write storage for primary storage purposes would be useless for many tasks. Modern computers typically use read/write storage also for secondary storage.</dd> <dt>Slow write, fast read storage</dt> <dd>Read/write storage which allows information to be overwritten multiple times, but with the write operation being much slower than the read operation. Examples include <a href="/wiki/CD-RW" title="CD-RW">CD-RW</a> and <a href="/wiki/SSD" class="mw-redirect" title="SSD">SSD</a>.</dd> <dt>Write once storage</dt> <dd><a href="/wiki/Write_once_read_many" title="Write once read many">Write once read many</a> (WORM) allows the information to be written only once at some point after manufacture. Examples include semiconductor <a href="/wiki/Programmable_read-only_memory" class="mw-redirect" title="Programmable read-only memory">programmable read-only memory</a> and <a href="/wiki/CD-R" title="CD-R">CD-R</a>.</dd> <dt>Read only storage</dt> <dd>Retains the information stored at the time of manufacture. Examples include <a href="/wiki/Read-only_memory#Factory_programmed" title="Read-only memory">mask ROM ICs</a> and <a href="/wiki/CD-ROM" title="CD-ROM">CD-ROM</a>.</dd></dl> <div class="mw-heading mw-heading3"><h3 id="Accessibility">Accessibility</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=11" title="Edit section: Accessibility"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dt><a href="/wiki/Random_access" title="Random access">Random access</a></dt> <dd>Any location in storage can be accessed at any moment in approximately the same amount of time. Such characteristic is well suited for primary and secondary storage. Most <a href="/wiki/Semiconductor_memories" class="mw-redirect" title="Semiconductor memories">semiconductor memories</a>, <a href="/wiki/Flash_memory" title="Flash memory">flash memories</a> and <a href="/wiki/Hard_disk_drive" title="Hard disk drive">hard disk drives</a> provide random access, though both semiconductor and flash memories have minimal <a href="/wiki/Latency_(engineering)" title="Latency (engineering)">latency</a> when compared to hard disk drives, as no mechanical parts need to be moved.</dd> <dt><a href="/wiki/Sequential_access" title="Sequential access">Sequential access</a></dt> <dd>The accessing of pieces of information will be in a serial order, one after the other; therefore the time to access a particular piece of information depends upon which piece of information was last accessed. Such characteristic is typical of off-line storage.</dd></dl> <div class="mw-heading mw-heading3"><h3 id="Addressability">Addressability</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=12" title="Edit section: Addressability"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dt>Location-addressable</dt> <dd>Each individually accessible unit of information in storage is selected with its numerical <a href="/wiki/Memory_address" title="Memory address">memory address</a>. In modern computers, location-addressable storage usually limits to primary storage, accessed internally by computer programs, since location-addressability is very efficient, but burdensome for humans.</dd> <dt><a href="/wiki/File_system" title="File system">File addressable</a></dt> <dd>Information is divided into <i><a href="/wiki/Computer_file" title="Computer file">files</a></i> of variable length, and a particular file is selected with <a href="/wiki/Human-readable" class="mw-redirect" title="Human-readable">human-readable</a> directory and file names. The underlying device is still location-addressable, but the <a href="/wiki/Operating_system" title="Operating system">operating system</a> of a computer provides the file system <a href="/wiki/Abstraction_(computer_science)" title="Abstraction (computer science)">abstraction</a> to make the operation more understandable. In modern computers, secondary, tertiary and off-line storage use file systems.</dd> <dt><a href="/wiki/Content-addressable_memory" title="Content-addressable memory">Content-addressable</a></dt> <dd>Each individually accessible unit of information is selected based on the basis of (part of) the contents stored there. <a href="/wiki/Content-addressable_storage" title="Content-addressable storage">Content-addressable storage</a> can be implemented using <a href="/wiki/Software" title="Software">software</a> (computer program) or <a href="/wiki/Computer_hardware" title="Computer hardware">hardware</a> (computer device), with hardware being faster but more expensive option. Hardware content addressable memory is often used in a computer's <a href="/wiki/CPU_cache" title="CPU cache">CPU cache</a>.</dd></dl> <div class="mw-heading mw-heading3"><h3 id="Capacity">Capacity</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=13" title="Edit section: Capacity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dt>Raw capacity</dt> <dd>The total amount of stored information that a storage device or medium can hold. It is expressed as a quantity of <a href="/wiki/Bit" title="Bit">bits</a> or <a href="/wiki/Byte" title="Byte">bytes</a> (e.g. 10.4 <a href="/wiki/Megabyte" title="Megabyte">megabytes</a>).</dd> <dt><a href="/wiki/Memory_storage_density" class="mw-redirect" title="Memory storage density">Memory storage density</a></dt> <dd>The compactness of stored information. It is the storage capacity of a medium divided with a unit of length, area or volume (e.g. 1.2 megabytes per square inch).</dd></dl> <div class="mw-heading mw-heading3"><h3 id="Performance">Performance</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=14" title="Edit section: Performance"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dt><a href="/wiki/Latency_(engineering)" title="Latency (engineering)">Latency</a></dt> <dd>The time it takes to access a particular location in storage. The relevant <a href="/wiki/Unit_of_measurement" title="Unit of measurement">unit of measurement</a> is typically <a href="/wiki/Nanosecond" title="Nanosecond">nanosecond</a> for primary storage, <a href="/wiki/Millisecond" title="Millisecond">millisecond</a> for secondary storage, and <a href="/wiki/Second" title="Second">second</a> for tertiary storage. It may make sense to separate read latency and write latency (especially for non-volatile memory) and in case of sequential access storage, minimum, maximum and average latency.</dd> <dt><a href="/wiki/Hard_disk_drive_performance_characteristics#Data_transfer_rate" title="Hard disk drive performance characteristics">Throughput</a></dt> <dd>The rate at which information can be read from or written to the storage. In computer data storage, throughput is usually expressed in terms of megabytes per second (MB/s), though <a href="/wiki/Bit_rate" title="Bit rate">bit rate</a> may also be used. As with latency, read rate and write rate may need to be differentiated. Also accessing media sequentially, as opposed to randomly, typically yields maximum throughput.</dd> <dt>Granularity</dt> <dd>The size of the largest "chunk" of data that can be efficiently accessed as a single unit, e.g. without introducing additional latency.</dd> <dt>Reliability</dt> <dd>The probability of spontaneous bit value change under various conditions, or overall <a href="/wiki/Failure_rate" title="Failure rate">failure rate</a>.</dd></dl> <p>Utilities such as <a href="/wiki/Hdparm" title="Hdparm">hdparm</a> and <a href="/wiki/Sar_(Unix)" title="Sar (Unix)">sar</a> can be used to measure IO performance in Linux. </p> <div class="mw-heading mw-heading3"><h3 id="Energy_use">Energy use</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=15" title="Edit section: Energy use"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>Storage devices that reduce fan usage automatically shut-down during inactivity, and low power hard drives can reduce energy consumption by 90 percent.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup></li> <li>2.5-inch hard disk drives often consume less power than larger ones.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> Low capacity <a href="/wiki/Solid-state_drive" title="Solid-state drive">solid-state drives</a> have no moving parts and consume less power than hard disks.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-xbitSSDvsHD_17-0" class="reference"><a href="#cite_note-xbitSSDvsHD-17"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> Also, memory may use more power than hard disks.<sup id="cite_ref-xbitSSDvsHD_17-1" class="reference"><a href="#cite_note-xbitSSDvsHD-17"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> Large caches, which are used to avoid hitting the <a href="/wiki/Memory_wall" class="mw-redirect" title="Memory wall">memory wall</a>, may also consume a large amount of power.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Security">Security</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=16" title="Edit section: Security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Hardware-based_full_disk_encryption" title="Hardware-based full disk encryption">Full disk encryption</a>, <a href="/wiki/Disk_encryption_software" title="Disk encryption software">volume and virtual disk encryption, andor file/folder encryption</a> is readily available for most storage devices.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p><p>Hardware memory encryption is available in Intel Architecture, supporting Total Memory Encryption (TME) and page granular memory encryption with multiple keys (MKTME).<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> and in <a href="/wiki/SPARC" title="SPARC">SPARC</a> M7 generation since October 2015.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Vulnerability_and_reliability">Vulnerability and reliability</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=17" title="Edit section: Vulnerability and reliability"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:S.M.A.R.T._warning.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/S.M.A.R.T._warning.png/220px-S.M.A.R.T._warning.png" decoding="async" width="220" height="233" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/S.M.A.R.T._warning.png/330px-S.M.A.R.T._warning.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f8/S.M.A.R.T._warning.png/440px-S.M.A.R.T._warning.png 2x" data-file-width="730" data-file-height="774" /></a><figcaption>S.M.A.R.T. software warning suggests impending hard drive failure.</figcaption></figure> <p>Distinct types of data storage have different points of failure and various methods of <a href="/wiki/Predictive_failure_analysis" title="Predictive failure analysis">predictive failure analysis</a>. </p><p>Vulnerabilities that can instantly lead to total loss are <a href="/wiki/Head_crash" title="Head crash">head crashing</a> on mechanical hard drives and <a href="/wiki/Failure_of_electronic_components" title="Failure of electronic components">failure of electronic components</a> on flash storage. </p> <div class="mw-heading mw-heading4"><h4 id="Error_detection">Error detection</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=18" title="Edit section: Error detection"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:QPxTool_DVD_error_rate_graph.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/85/QPxTool_DVD_error_rate_graph.png/220px-QPxTool_DVD_error_rate_graph.png" decoding="async" width="220" height="130" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/85/QPxTool_DVD_error_rate_graph.png/330px-QPxTool_DVD_error_rate_graph.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/85/QPxTool_DVD_error_rate_graph.png/440px-QPxTool_DVD_error_rate_graph.png 2x" data-file-width="902" data-file-height="535" /></a><figcaption><a href="/wiki/Optical_disc#Surface_error_scanning" title="Optical disc">Error rate measurement</a> on a <a href="/wiki/DVD%2BR" class="mw-redirect" title="DVD+R">DVD+R</a>. The minor errors are correctable and within a healthy range.</figcaption></figure> <p>Impending failure on <a href="/wiki/Hard_disk_drive" title="Hard disk drive">hard disk drives</a> is estimable using S.M.A.R.T. diagnostic data that includes the <a href="/wiki/Power-on_hours" title="Power-on hours">hours of operation</a> and the count of spin-ups, though its reliability is disputed.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> </p><p>Flash storage may experience downspiking transfer rates as a result of accumulating errors, which the <a href="/wiki/Flash_memory_controller" title="Flash memory controller">flash memory controller</a> attempts to correct. </p><p>The health of <a href="/wiki/Optical_media" class="mw-redirect" title="Optical media">optical media</a> can be determined by <a href="/wiki/Optical_disc#Surface_error_scanning" title="Optical disc">measuring correctable minor errors</a>, of which high counts signify deteriorating and/or low-quality media. Too many consecutive minor errors can lead to data corruption. Not all vendors and models of <a href="/wiki/Optical_disc_drive" title="Optical disc drive">optical drives</a> support error scanning.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Storage_media"><span class="anchor" id="media"></span>Storage media</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=19" title="Edit section: Storage media"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>As of 2011<sup class="plainlinks noexcerpt noprint asof-tag update" style="display:none;"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Computer_data_storage&action=edit">[update]</a></sup>, the most commonly used data storage media are semiconductor, magnetic, and optical, while paper still sees some limited usage. Some other fundamental storage technologies, such as all-flash arrays (AFAs) are proposed for development. </p> <div class="mw-heading mw-heading3"><h3 id="Semiconductor">Semiconductor</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=20" title="Edit section: Semiconductor"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Semiconductor_memory" title="Semiconductor memory">Semiconductor memory</a></div> <p><a href="/wiki/Semiconductor_memory" title="Semiconductor memory">Semiconductor memory</a> uses <a href="/wiki/Semiconductor" title="Semiconductor">semiconductor</a>-based <a href="/wiki/Integrated_circuit" title="Integrated circuit">integrated circuit</a> (IC) chips to store information. Data are typically stored in <a href="/wiki/Metal%E2%80%93oxide%E2%80%93semiconductor" class="mw-redirect" title="Metal–oxide–semiconductor">metal–oxide–semiconductor</a> (MOS) <a href="/wiki/Memory_cell_(computing)" title="Memory cell (computing)">memory cells</a>. A semiconductor memory chip may contain millions of memory cells, consisting of tiny <a href="/wiki/MOSFET" title="MOSFET">MOS field-effect transistors</a> (MOSFETs) and/or <a href="/wiki/MOSFET#MOS_capacitor" title="MOSFET">MOS capacitors</a>. Both <i>volatile</i> and <i>non-volatile</i> forms of semiconductor memory exist, the former using standard MOSFETs and the latter using <a href="/wiki/Floating-gate_MOSFET" title="Floating-gate MOSFET">floating-gate MOSFETs</a>. </p><p>In modern computers, primary storage almost exclusively consists of dynamic volatile semiconductor <a href="/wiki/Random-access_memory" title="Random-access memory">random-access memory</a> (RAM), particularly <a href="/wiki/Dynamic_random-access_memory" title="Dynamic random-access memory">dynamic random-access memory</a> (DRAM). Since the turn of the century, a type of non-volatile <a href="/wiki/Floating-gate" class="mw-redirect" title="Floating-gate">floating-gate</a> semiconductor memory known as <a href="/wiki/Flash_memory" title="Flash memory">flash memory</a> has steadily gained share as off-line storage for home computers. Non-volatile semiconductor memory is also used for secondary storage in various advanced electronic devices and specialized computers that are designed for them. </p><p>As early as 2006, <a href="/wiki/Laptop" title="Laptop">notebook</a> and <a href="/wiki/Desktop_computer" title="Desktop computer">desktop computer</a> manufacturers started using flash-based <a href="/wiki/Solid-state_drive" title="Solid-state drive">solid-state drives</a> (SSDs) as default configuration options for the secondary storage either in addition to or instead of the more traditional HDD.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Magnetic">Magnetic</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=21" title="Edit section: Magnetic"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <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 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href="/wiki/Template:Magnetic_storage_media" title="Template:Magnetic storage media"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Magnetic_storage_media" title="Template talk:Magnetic storage media"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Magnetic_storage_media" title="Special:EditPage/Template:Magnetic storage media"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Magnetic_storage_media26" style="font-size:114%;margin:0 4em"><a href="/wiki/Magnetic_storage" title="Magnetic storage">Magnetic storage</a> media</div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Wire_recording" title="Wire recording">Wire</a> (1898)</li> <li><a href="/wiki/Magnetic_tape" title="Magnetic tape">Tape</a> (1928)</li> <li><a href="/wiki/Drum_memory" title="Drum memory">Drum</a> (1932)</li> <li><a href="/wiki/Magnetic-core_memory" title="Magnetic-core memory">Ferrite core</a> (1949)</li> <li><a href="/wiki/Hard_disk_drive" title="Hard disk drive">Hard disk</a> (1956)</li> <li><a href="/wiki/Magnetic_stripe_card" class="mw-redirect" title="Magnetic stripe card">Stripe card</a> (1956)</li> <li><a href="/wiki/Magnetic_ink_character_recognition" title="Magnetic ink character recognition">MICR</a> (1956)</li> <li><a href="/wiki/Thin-film_memory" title="Thin-film memory">Thin film</a> (1962)</li> <li><a href="/wiki/NCR_CRAM" title="NCR CRAM">CRAM</a> (1962)</li> <li><a href="/wiki/Twistor_memory" title="Twistor memory">Twistor</a> (~1968)</li> <li><a href="/wiki/Floppy_disk" title="Floppy disk">Floppy disk</a> (1969)</li> <li><a href="/wiki/Bubble_memory" title="Bubble memory">Bubble</a> (~1970)</li> <li><a href="/wiki/Magnetoresistive_random-access_memory" class="mw-redirect" title="Magnetoresistive random-access memory">MRAM</a> (1995)</li> <li><a href="/wiki/Racetrack_memory" title="Racetrack memory">Racetrack</a> (2008)</li></ul> </div></td></tr></tbody></table></div> <p><a href="/wiki/Magnetic_storage" title="Magnetic storage">Magnetic storage</a> uses different patterns of <a href="/wiki/Magnetization" title="Magnetization">magnetization</a> on a <a href="/wiki/Magnetically" class="mw-redirect" title="Magnetically">magnetically</a> coated surface to store information. Magnetic storage is <i>non-volatile</i>. The information is accessed using one or more read/write heads which may contain one or more recording transducers. A read/write head only covers a part of the surface so that the head or medium or both must be moved relative to another in order to access data. In modern computers, magnetic storage will take these forms: </p> <ul><li><a href="/wiki/Disk_storage" title="Disk storage">Magnetic disk</a>; <ul><li><a href="/wiki/Floppy_disk" title="Floppy disk">Floppy disk</a>, used for off-line storage;</li> <li><a href="/wiki/Hard_disk_drive" title="Hard disk drive">Hard disk drive</a>, used for secondary storage.</li></ul></li> <li><a href="/wiki/Magnetic-tape_data_storage" title="Magnetic-tape data storage">Magnetic tape</a>, used for tertiary and off-line storage;</li> <li><a href="/wiki/Carousel_memory" title="Carousel memory">Carousel memory</a> (magnetic rolls).</li></ul> <p>In early computers, magnetic storage was also used as: </p> <ul><li>Primary storage in a form of <a href="/wiki/Drum_memory" title="Drum memory">magnetic memory</a>, or <a href="/wiki/Core_memory" class="mw-redirect" title="Core memory">core memory</a>, <a href="/wiki/Core_rope_memory" title="Core rope memory">core rope memory</a>, <a href="/wiki/Thin-film_memory" title="Thin-film memory">thin-film memory</a> and/or <a href="/wiki/Twistor_memory" title="Twistor memory">twistor memory</a>;</li> <li>Tertiary (e.g. <a href="/wiki/NCR_CRAM" title="NCR CRAM">NCR CRAM</a>) or off line storage in the form of magnetic cards;</li> <li>Magnetic tape was then often used for secondary storage.</li></ul> <p>Magnetic storage does not have a definite limit of rewriting cycles like flash storage and re-writeable optical media, as altering magnetic fields causes no physical wear. Rather, their life span is limited by mechanical parts.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Optical">Optical</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=22" title="Edit section: Optical"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Optical_storage_media170" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Optical_storage_media" title="Template:Optical storage media"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Optical_storage_media" title="Template talk:Optical storage media"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Optical_storage_media" title="Special:EditPage/Template:Optical storage media"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Optical_storage_media170" style="font-size:114%;margin:0 4em"><a href="/wiki/Optical_storage" title="Optical storage">Optical storage</a> media</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Blu-ray" title="Blu-ray">Blu-ray</a> (2006)</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/Blu-ray_Disc_recordable" title="Blu-ray Disc recordable">BD-R</a> (2006)</li> <li><a href="/wiki/Blu-ray_Disc_recordable" title="Blu-ray Disc recordable">BD-RE</a> (2006)</li> <li><a href="/wiki/Blu-ray_Disc_recordable" title="Blu-ray Disc recordable">BD-R XL</a> (2010)</li> <li><a href="/wiki/Blu-ray_Disc_recordable" title="Blu-ray Disc recordable">BD-RE XL</a> (2010)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Professional_Disc" title="Professional Disc">Professional Disc</a> (2003)</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/Professional_Disc#Professional_Disc_for_Data_(PDD)" title="Professional Disc">PDD</a> (2004)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/DVD" title="DVD">DVD</a> (1995)</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/DVD_recordable" title="DVD recordable">DVD-R</a> (1997)</li> <li><a href="/wiki/DVD-RW" class="mw-redirect" title="DVD-RW">DVD-RW</a> (1999)</li> <li><a href="/wiki/DVD%2BRW" class="mw-redirect" title="DVD+RW">DVD+RW</a> (2001)</li> <li><a href="/wiki/DVD%2BR" class="mw-redirect" title="DVD+R">DVD+R</a> (2002)</li> <li><a href="/wiki/DVD%2BR_DL" title="DVD+R DL">DVD+R DL</a> (2004)</li> <li><a href="/wiki/DVD-R_DL" title="DVD-R DL">DVD-R DL</a> (2005)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Compact_disc" title="Compact disc">Compact disc</a> (1982)</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/CD-R" title="CD-R">CD-R</a> (1988)</li> <li><a href="/wiki/CD-i" title="CD-i">CD-i</a> (1991)</li> <li><a href="/wiki/CD-RW" title="CD-RW">CD-RW</a> (1997)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Discontinued</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/Microform" title="Microform">Microform</a> (1870)</li> <li><a href="/wiki/Optical_tape" title="Optical tape">Optical tape</a> (20th century)</li> <li><a href="/wiki/Optical_disc" title="Optical disc">Optical disc</a> (20th century)</li> <li><a href="/wiki/LaserDisc" title="LaserDisc">LaserDisc</a> (1978)</li> <li><a href="/wiki/Write_once_read_many" title="Write once read many">WORM</a> (1979)</li> <li><a href="/wiki/GD-ROM" title="GD-ROM">GD-ROM</a> (1997)</li> <li><a href="/wiki/MIL-CD" class="mw-redirect" title="MIL-CD">MIL-CD</a> (1999)</li> <li><a href="/wiki/DataPlay" title="DataPlay">DataPlay</a> (2002)</li> <li><a href="/wiki/Ultra_Density_Optical" title="Ultra Density Optical">UDO</a> (2003)</li> <li><a href="/wiki/Professional_Disc" title="Professional Disc">ProData</a> (2003)</li> <li><a href="/wiki/Universal_Media_Disc" title="Universal Media Disc">UMD</a> (2004)</li> <li><a href="/wiki/HD_DVD" title="HD DVD">HD DVD</a> (2006)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Magneto-optic_Kerr_effect" title="Magneto-optic Kerr effect">Magneto-optic Kerr effect</a> (1877)</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/Magneto-optical_drive" title="Magneto-optical drive">MO disc</a> (1980s)</li> <li><a href="/wiki/MiniDisc" title="MiniDisc">MiniDisc</a> (1992)</li> <li><a href="/wiki/MD_Data" title="MD Data">MD Data</a> (1993)</li> <li><a href="/wiki/Hi-MD" title="Hi-MD">Hi-MD</a> (2004)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Optical Assist</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/Laser_turntable" title="Laser turntable">Laser turntable</a> (1986)</li> <li><a href="/wiki/Floptical" title="Floptical">Floptical</a> (1991)</li> <li><a href="/wiki/Digital_Linear_Tape" title="Digital Linear Tape">Super DLT</a> (1998)</li></ul> </div></td></tr></tbody></table></div> <p><a href="/wiki/Optical_storage" title="Optical storage">Optical storage</a>, the typical <a href="/wiki/Optical_disc" title="Optical disc">optical disc</a>, stores information in deformities on the surface of a circular disc and reads this information by illuminating the surface with a <a href="/wiki/Laser_diode" title="Laser diode">laser diode</a> and observing the reflection. Optical disc storage is <i>non-volatile</i>. The deformities may be permanent (read only media), formed once (write once media) or reversible (recordable or read/write media). The following forms are in common use as of 2009<sup class="plainlinks noexcerpt noprint asof-tag update" style="display:none;"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Computer_data_storage&action=edit">[update]</a></sup>:<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p> <ul><li><a href="/wiki/CD" class="mw-redirect" title="CD">CD</a>, <a href="/wiki/CD-ROM" title="CD-ROM">CD-ROM</a>, <a href="/wiki/DVD" title="DVD">DVD</a>, <a href="/wiki/BD-ROM" class="mw-redirect" title="BD-ROM">BD-ROM</a>: Read only storage, used for mass distribution of digital information (music, video, computer programs);</li> <li><a href="/wiki/CD-R" title="CD-R">CD-R</a>, <a href="/wiki/DVD-R" class="mw-redirect" title="DVD-R">DVD-R</a>, <a href="/wiki/DVD%2BR" class="mw-redirect" title="DVD+R">DVD+R</a>, <a href="/wiki/BD-R" class="mw-redirect" title="BD-R">BD-R</a>: Write once storage, used for tertiary and off-line storage;</li> <li><a href="/wiki/CD-RW" title="CD-RW">CD-RW</a>, <a href="/wiki/DVD-RW" class="mw-redirect" title="DVD-RW">DVD-RW</a>, <a href="/wiki/DVD%2BRW" class="mw-redirect" title="DVD+RW">DVD+RW</a>, <a href="/wiki/DVD-RAM" title="DVD-RAM">DVD-RAM</a>, <a href="/wiki/BD-RE" class="mw-redirect" title="BD-RE">BD-RE</a>: Slow write, fast read storage, used for tertiary and off-line storage;</li> <li><a href="/wiki/Ultra_Density_Optical" title="Ultra Density Optical">Ultra Density Optical</a> or UDO is similar in capacity to <a href="/wiki/Blu-ray_Disc_recordable" title="Blu-ray Disc recordable">BD-R or BD-RE</a> and is slow write, fast read storage used for tertiary and off-line storage.</li></ul> <p><a href="/wiki/Magneto-optical_drive" title="Magneto-optical drive">Magneto-optical disc storage</a> is optical disc storage where the magnetic state on a <a href="/wiki/Ferromagnetic" class="mw-redirect" title="Ferromagnetic">ferromagnetic</a> surface stores information. The information is read optically and written by combining magnetic and optical methods. Magneto-optical disc storage is <i>non-volatile</i>, <i>sequential access</i>, slow write, fast read storage used for tertiary and off-line storage. </p><p><a href="/wiki/3D_optical_data_storage" title="3D optical data storage">3D optical data storage</a> has also been proposed. </p><p>Light induced magnetization melting in magnetic photoconductors has also been proposed for high-speed low-energy consumption magneto-optical storage.<sup id="cite_ref-Náfrádi_2016_32-0" class="reference"><a href="#cite_note-Náfrádi_2016-32"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Paper">Paper</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=23" title="Edit section: Paper"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Paper_data_storage_media43" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Paper_data_storage_media" title="Template:Paper data storage media"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Paper_data_storage_media" title="Template talk:Paper data storage media"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Paper_data_storage_media" title="Special:EditPage/Template:Paper data storage media"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Paper_data_storage_media43" style="font-size:114%;margin:0 4em"><a href="/wiki/Paper_data_storage" title="Paper data storage">Paper data storage</a> media</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Antiquity</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/Writing" title="Writing">Writing</a> on <a href="/wiki/Papyrus" title="Papyrus">papyrus</a> (c. 3000 BCE)</li> <li><a href="/wiki/Paper" title="Paper">Paper</a> (105 CE)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Modern</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/Index_card" title="Index card">Index card</a> (1640s)</li> <li><a href="/wiki/Punched_tape" title="Punched tape">Punched tape</a> (mid-1800s)</li> <li><a href="/wiki/Punched_card" title="Punched card">Punched card</a> (1880s)</li> <li><a href="/wiki/Edge-notched_card" title="Edge-notched card">Edge-notched card</a> (1904)</li> <li><a href="/wiki/Optical_mark_recognition" title="Optical mark recognition">Optical mark recognition</a> (1930s)</li> <li><a href="/wiki/Barcode" title="Barcode">Barcode</a> (1948)</li></ul> </div></td></tr></tbody></table></div> <p><a href="/wiki/Paper_data_storage" title="Paper data storage">Paper data storage</a>, typically in the form of <a href="/wiki/Paper_tape" class="mw-redirect" title="Paper tape">paper tape</a> or <a href="/wiki/Punched_card" title="Punched card">punched cards</a>, has long been used to store information for automatic processing, particularly before general-purpose computers existed. Information was recorded by punching holes into the paper or cardboard medium and was read mechanically (or later optically) to determine whether a particular location on the medium was solid or contained a hole. <a href="/wiki/Barcode" title="Barcode">Barcodes</a> make it possible for objects that are sold or transported to have some computer-readable information securely attached. </p><p>Relatively small amounts of digital data (compared to other digital data storage) may be backed up on paper as a <a href="/wiki/Matrix_barcode" class="mw-redirect" title="Matrix barcode">matrix barcode</a> for very long-term storage, as the longevity of paper typically exceeds even magnetic data storage.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Other_storage_media_or_substrates">Other storage media or substrates</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=24" title="Edit section: Other storage media or substrates"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dt>Vacuum-tube memory</dt> <dd>A <a href="/wiki/Williams_tube" title="Williams tube">Williams tube</a> used a <a href="/wiki/Cathode-ray_tube" title="Cathode-ray tube">cathode-ray tube</a>, and a <a href="/wiki/Selectron_tube" title="Selectron tube">Selectron tube</a> used a large <a href="/wiki/Vacuum_tube" title="Vacuum tube">vacuum tube</a> to store information. These primary storage devices were short-lived in the market, since the Williams tube was unreliable, and the Selectron tube was expensive.</dd></dl> <dl><dt>Electro-acoustic memory</dt> <dd><a href="/wiki/Delay-line_memory" title="Delay-line memory">Delay-line memory</a> used <a href="/wiki/Longitudinal_wave" title="Longitudinal wave">sound waves</a> in a substance such as <a href="/wiki/Mercury_(element)" title="Mercury (element)">mercury</a> to store information. Delay-line memory was dynamic volatile, cycle sequential read/write storage, and was used for primary storage.</dd></dl> <dl><dt><a href="/wiki/Optical_tape" title="Optical tape">Optical tape</a></dt> <dd>is a medium for optical storage, generally consisting of a long and narrow strip of plastic, onto which patterns can be written and from which the patterns can be read back. It shares some technologies with cinema film stock and optical discs, but is compatible with neither. The motivation behind developing this technology was the possibility of far greater storage capacities than either magnetic tape or optical discs.</dd></dl> <dl><dt><a href="/wiki/Phase-change_memory" title="Phase-change memory">Phase-change memory</a></dt> <dd>uses different mechanical phases of <a href="/wiki/Phase-change_material" title="Phase-change material">phase-change material</a> to store information in an X–Y addressable matrix and reads the information by observing the varying <a href="/wiki/Electrical_resistance" class="mw-redirect" title="Electrical resistance">electrical resistance</a> of the material. Phase-change memory would be non-volatile, random-access read/write storage, and might be used for primary, secondary and off-line storage. Most rewritable and many write-once optical disks already use phase-change material to store information.</dd></dl> <dl><dt><a href="/wiki/Holographic_data_storage" title="Holographic data storage">Holographic data storage</a></dt> <dd>stores information optically inside <a href="/wiki/Crystal" title="Crystal">crystals</a> or <a href="/wiki/Photopolymer" title="Photopolymer">photopolymers</a>. Holographic storage can utilize the whole volume of the storage medium, unlike optical disc storage, which is limited to a small number of surface layers. Holographic storage would be non-volatile, sequential-access, and either write-once or read/write storage. It might be used for secondary and off-line storage. See <a href="/wiki/Holographic_Versatile_Disc" title="Holographic Versatile Disc">Holographic Versatile Disc</a> (HVD).</dd></dl> <dl><dt><a href="/wiki/Molecular_memory" title="Molecular memory">Molecular memory</a></dt> <dd>stores information in <a href="/wiki/Polymer" title="Polymer">polymer</a> that can store electric charge. Molecular memory might be especially suited for primary storage. The theoretical storage capacity of molecular memory is 10 terabits per square inch (16 Gbit/mm<sup>2</sup>).<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup></dd></dl> <dl><dt>Magnetic photoconductors</dt> <dd>store magnetic information, which can be modified by low-light illumination.<sup id="cite_ref-Náfrádi_2016_32-1" class="reference"><a href="#cite_note-Náfrádi_2016-32"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup></dd></dl> <dl><dt><a href="/wiki/DNA_digital_data_storage" title="DNA digital data storage">DNA</a></dt> <dd>stores information in DNA <a href="/wiki/Nucleotide" title="Nucleotide">nucleotides</a>. It was first done in 2012, when researchers achieved a ratio of 1.28 petabytes per gram of DNA. In March 2017 scientists reported that a new algorithm called a DNA fountain achieved 85% of the theoretical limit, at 215 petabytes per gram of DNA.<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup></dd></dl> <div class="mw-heading mw-heading2"><h2 id="Related_technologies">Related technologies</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=25" title="Edit section: Related technologies"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Redundancy">Redundancy</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=26" title="Edit section: Redundancy"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Disk_mirroring" title="Disk mirroring">Disk mirroring</a> and <a href="/wiki/RAID" title="RAID">RAID</a></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Replication_(computing)#Disk_storage_replication" title="Replication (computing)">Storage replication</a></div> <p>While a group of bits malfunction may be resolved by error detection and correction mechanisms (see above), storage device malfunction requires different solutions. The following solutions are commonly used and valid for most storage devices: </p> <ul><li><b>Device <a href="/wiki/Disk_mirroring" title="Disk mirroring">mirroring</a> (replication)</b> – A common solution to the problem is constantly maintaining an identical copy of device content on another device (typically of the same type). The downside is that this doubles the storage, and both devices (copies) need to be updated simultaneously with some overhead and possibly some delays. The upside is the possible concurrent reading of the same data group by two independent processes, which increases performance. When one of the replicated devices is detected to be defective, the other copy is still operational and is being utilized to generate a new copy on another device (usually available operational in a pool of stand-by devices for this purpose).</li> <li><b>Redundant array of independent disks</b> (<b><a href="/wiki/RAID" title="RAID">RAID</a></b>) – This method generalizes the device mirroring above by allowing one device in a group of devices to fail and be replaced with the content restored (Device mirroring is RAID with <i>n=2</i>). RAID groups of <i>n=5</i> or <i>n=6</i> are common. <i>n>2</i> saves storage, when compared with <i>n=2</i>, at the cost of more processing during both regular operation (with often reduced performance) and defective device replacement.</li></ul> <p>Device mirroring and typical RAID are designed to handle a single device failure in the RAID group of devices. However, if a second failure occurs before the RAID group is completely repaired from the first failure, then data can be lost. The probability of a single failure is typically small. Thus the probability of two failures in the same RAID group in time proximity is much smaller (approximately the probability squared, i.e., multiplied by itself). If a database cannot tolerate even such a smaller probability of data loss, then the RAID group itself is replicated (mirrored). In many cases such mirroring is done geographically remotely, in a different storage array, to handle recovery from disasters (see disaster recovery above). </p> <div class="mw-heading mw-heading3"><h3 id="Network_connectivity">Network connectivity</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=27" title="Edit section: Network connectivity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A secondary or tertiary storage may connect to a computer utilizing <a href="/wiki/Computer_network" title="Computer network">computer networks</a>. This concept does not pertain to the primary storage, which is shared between multiple processors to a lesser degree. </p> <ul><li><a href="/wiki/Direct-attached_storage" title="Direct-attached storage">Direct-attached storage</a> (DAS) is a traditional mass storage, that does not use any network. This is still a most popular approach. This <a href="/wiki/Retronym" title="Retronym">retronym</a> was coined recently, together with NAS and SAN.</li> <li><a href="/wiki/Network-attached_storage" title="Network-attached storage">Network-attached storage</a> (NAS) is mass storage attached to a computer which another computer can access at file level over a <a href="/wiki/Local_area_network" title="Local area network">local area network</a>, a private <a href="/wiki/Wide_area_network" title="Wide area network">wide area network</a>, or in the case of <a href="/wiki/Online_file_storage" class="mw-redirect" title="Online file storage">online file storage</a>, over the <a href="/wiki/Internet" title="Internet">Internet</a>. NAS is commonly associated with the <a href="/wiki/Network_File_System" title="Network File System">NFS</a> and <a href="/wiki/CIFS/SMB" class="mw-redirect" title="CIFS/SMB">CIFS/SMB</a> protocols.</li> <li><a href="/wiki/Storage_area_network" title="Storage area network">Storage area network</a> (SAN) is a specialized network, that provides other computers with storage capacity. The crucial difference between NAS and SAN, is that NAS presents and manages file systems to client computers, while SAN provides access at block-addressing (raw) level, leaving it to attaching systems to manage data or file systems within the provided capacity. SAN is commonly associated with <a href="/wiki/Fibre_Channel" title="Fibre Channel">Fibre Channel</a> networks.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Robotic_storage">Robotic storage</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=28" title="Edit section: Robotic storage"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Large quantities of individual magnetic tapes, and optical or magneto-optical discs may be stored in robotic tertiary storage devices. In tape storage field they are known as <a href="/wiki/Tape_libraries" class="mw-redirect" title="Tape libraries">tape libraries</a>, and in optical storage field <a href="/wiki/Optical_jukebox" title="Optical jukebox">optical jukeboxes</a>, or optical disk libraries per analogy. The smallest forms of either technology containing just one drive device are referred to as <a href="/wiki/Tape_library#Autoloaders" title="Tape library">autoloaders</a> or <a href="/wiki/Record_changer" title="Record changer">autochangers</a>. </p><p>Robotic-access storage devices may have a number of slots, each holding individual media, and usually one or more picking robots that traverse the slots and load media to built-in drives. The arrangement of the slots and picking devices affects performance. Important characteristics of such storage are possible expansion options: adding slots, modules, drives, robots. Tape libraries may have from 10 to more than 100,000 slots, and provide <a href="/wiki/Terabyte" class="mw-redirect" title="Terabyte">terabytes</a> or <a href="/wiki/Petabyte" class="mw-redirect" title="Petabyte">petabytes</a> of near-line information. Optical jukeboxes are somewhat smaller solutions, up to 1,000 slots. </p><p>Robotic storage is used for <a href="/wiki/Backup" title="Backup">backups</a>, and for high-capacity archives in imaging, medical, and video industries. <a href="/wiki/Hierarchical_storage_management" title="Hierarchical storage management">Hierarchical storage management</a> is a most known archiving strategy of automatically <i>migrating</i> long-unused files from fast hard disk storage to libraries or jukeboxes. If the files are needed, they are <i>retrieved</i> back to disk. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=29" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Wikiversity_logo_2017.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/40px-Wikiversity_logo_2017.svg.png" decoding="async" width="40" height="33" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/60px-Wikiversity_logo_2017.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/80px-Wikiversity_logo_2017.svg.png 2x" data-file-width="626" data-file-height="512" /></a></span></div> <div class="side-box-text plainlist">Wikiversity has learning resources about <i><b><a href="https://en.wikiversity.org/wiki/Computer_data_storage" class="extiw" title="v:Computer data storage"> Computer data storage</a></b></i></div></div> </div> <div class="mw-heading mw-heading3"><h3 id="Primary_storage_topics">Primary storage topics</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=30" title="Edit section: Primary storage topics"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Aperture_(computer_memory)" title="Aperture (computer memory)">Aperture (computer memory)</a></li> <li><a href="/wiki/Dynamic_random-access_memory" title="Dynamic random-access memory">Dynamic random-access memory</a> (DRAM)</li> <li><a href="/wiki/CAS_latency" title="CAS latency">Memory latency</a></li> <li><a href="/wiki/Mass_storage" title="Mass storage">Mass storage</a></li> <li><a href="/wiki/Memory_cell_(disambiguation)" class="mw-redirect mw-disambig" title="Memory cell (disambiguation)">Memory cell (disambiguation)</a></li> <li><a href="/wiki/Memory_management" title="Memory management">Memory management</a> <ul><li><a href="/wiki/Memory_leak" title="Memory leak">Memory leak</a></li> <li><a href="/wiki/Virtual_memory" title="Virtual memory">Virtual memory</a></li></ul></li> <li><a href="/wiki/Memory_protection" title="Memory protection">Memory protection</a></li> <li><a href="/wiki/Page_address_register" title="Page address register">Page address register</a></li> <li><a href="/wiki/Stable_storage" title="Stable storage">Stable storage</a></li> <li><a href="/wiki/Static_random-access_memory" title="Static random-access memory">Static random-access memory</a> (SRAM)</li></ul> <div class="mw-heading mw-heading3"><h3 id="Secondary,_tertiary_and_off-line_storage_topics"><span id="Secondary.2C_tertiary_and_off-line_storage_topics"></span>Secondary, tertiary and off-line storage topics</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=31" title="Edit section: Secondary, tertiary and off-line storage topics"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Cloud_storage" title="Cloud storage">Cloud storage</a><sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Hybrid_cloud_storage" title="Hybrid cloud storage">Hybrid cloud storage</a></li> <li><a href="/wiki/Data_deduplication" title="Data deduplication">Data deduplication</a></li> <li><a href="/wiki/Data_proliferation" title="Data proliferation">Data proliferation</a></li> <li><a href="/wiki/Data_storage_tag" title="Data storage tag">Data storage tag</a> used for capturing research data</li> <li><a href="/wiki/Disk_utility" title="Disk utility">Disk utility</a></li> <li><a href="/wiki/File_system" title="File system">File system</a> <ul><li><a href="/wiki/List_of_file_formats" title="List of file formats">List of file formats</a></li> <li><a href="/wiki/Global_filesystem" class="mw-redirect" title="Global filesystem">Global filesystem</a></li></ul></li> <li><a href="/wiki/Flash_memory" title="Flash memory">Flash memory</a></li> <li><a href="/wiki/Geoplexing" title="Geoplexing">Geoplexing</a></li> <li><a href="/wiki/Information_repository" title="Information repository">Information repository</a></li> <li><a href="/wiki/Noise-predictive_maximum-likelihood_detection" title="Noise-predictive maximum-likelihood detection">Noise-predictive maximum-likelihood detection</a></li> <li><a href="/wiki/Object_storage" title="Object storage">Object(-based) storage</a></li> <li><a href="/wiki/Removable_media" title="Removable media">Removable media</a></li> <li><a href="/wiki/Solid-state_drive" title="Solid-state drive">Solid-state drive</a></li> <li><a href="/wiki/Hard_disk_drive#Spindle" title="Hard disk drive">Spindle</a></li> <li><a href="/wiki/Virtual_tape_library" title="Virtual tape library">Virtual tape library</a></li> <li><a href="/wiki/Wait_state" title="Wait state">Wait state</a></li> <li><a href="/wiki/Write_buffer" title="Write buffer">Write buffer</a></li> <li><a href="/wiki/Write_protection" title="Write protection">Write protection</a></li> <li><a href="/wiki/Cold_data" title="Cold data">Cold data</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="Data_storage_conferences">Data storage conferences</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=32" title="Edit section: Data storage conferences"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Storage_Networking_World" title="Storage Networking World">Storage Networking World</a></li> <li><a href="/wiki/Storage_World_Conference" title="Storage World Conference">Storage World Conference</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=33" title="Edit section: Notes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <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"><ol class="references"> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">Most contemporary computers use volatile technologies (which lose data when power is off); early computers used both volatile and persistent technologies.</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=34" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><style data-mw-deduplicate="TemplateStyles:r1041539562">.mw-parser-output .citation{word-wrap:break-word}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}</style><span class="citation 1037C"><span class="noviewer" typeof="mw:File"><span><img alt="Public Domain" src="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/12px-PD-icon.svg.png" decoding="async" width="12" height="12" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/18px-PD-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/24px-PD-icon.svg.png 2x" data-file-width="196" data-file-height="196" /></span></span> This article incorporates <a href="/wiki/Copyright_status_of_works_by_the_federal_government_of_the_United_States" title="Copyright status of works by the federal government of the United States">public domain material</a> from <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 cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20220122224547/https://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm"><i>Federal Standard 1037C</i></a>. <a href="/wiki/General_Services_Administration" title="General Services Administration">General Services Administration</a>. Archived from <a rel="nofollow" class="external text" href="https://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm">the original</a> on 22 January 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Federal+Standard+1037C&rft.pub=General+Services+Administration&rft_id=https%3A%2F%2Fwww.its.bldrdoc.gov%2Ffs-1037%2Ffs-1037c.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </p> <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-Patterson-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Patterson_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Patterson_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Patterson_1-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPattersonHennessy2005" class="citation book cs1">Patterson, David A.; Hennessy, John L. (2005). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/isbn_9781558606043"><i>Computer organization and design: The hardware/software interface</i></a></span> (3rd ed.). <a href="/wiki/Amsterdam" title="Amsterdam">Amsterdam</a>: <a href="/wiki/Morgan_Kaufmann_Publishers" title="Morgan Kaufmann Publishers">Morgan Kaufmann Publishers</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/1-55860-604-1" title="Special:BookSources/1-55860-604-1"><bdi>1-55860-604-1</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/56213091">56213091</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Computer+organization+and+design%3A+The+hardware%2Fsoftware+interface&rft.place=Amsterdam&rft.edition=3rd&rft.pub=Morgan+Kaufmann+Publishers&rft.date=2005&rft_id=info%3Aoclcnum%2F56213091&rft.isbn=1-55860-604-1&rft.aulast=Patterson&rft.aufirst=David+A.&rft.au=Hennessy%2C+John+L.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fisbn_9781558606043&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><i>Storage</i> as defined in Microsoft Computing Dictionary, 4th Ed. (c)1999 or in The Authoritative Dictionary of IEEE Standard Terms, 7th Ed., (c) 2000.</span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html">"Documentation for /proc/sys/vm/ — The Linux Kernel documentation"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Documentation+for+%2Fproc%2Fsys%2Fvm%2F+%E2%80%94+The+Linux+Kernel+documentation&rft_id=https%3A%2F%2Fwww.kernel.org%2Fdoc%2Fhtml%2Flatest%2Fadmin-guide%2Fsysctl%2Fvm.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><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/20080910151628/http://searchstorage.techtarget.com/topics/0,295493,sid5_tax298620,00.html">"Primary storage or storage hardware (shows usage of term "primary storage" meaning "hard disk storage")"</a>. <i>searchstorage.techtarget.com</i>. Archived from <a rel="nofollow" class="external text" href="http://searchstorage.techtarget.com/topics/0,295493,sid5_tax298620,00.html">the original</a> on 10 September 2008<span class="reference-accessdate">. Retrieved <span class="nowrap">18 June</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=searchstorage.techtarget.com&rft.atitle=Primary+storage+or+storage+hardware+%28shows+usage+of+term+%22primary+storage%22+meaning+%22hard+disk+storage%22%29&rft_id=http%3A%2F%2Fsearchstorage.techtarget.com%2Ftopics%2F0%2C295493%2Csid5_tax298620%2C00.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=QGPHAl9GE-IC&dq=size+of+a+memory+address&pg=PA321"><i>The Essentials of Computer Organization and Architecture</i></a>. Jones & Bartlett Learning. 2006. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7637-3769-6" title="Special:BookSources/978-0-7637-3769-6"><bdi>978-0-7637-3769-6</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+Essentials+of+Computer+Organization+and+Architecture&rft.pub=Jones+%26+Bartlett+Learning&rft.date=2006&rft.isbn=978-0-7637-3769-6&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DQGPHAl9GE-IC%26dq%3Dsize%2Bof%2Ba%2Bmemory%2Baddress%26pg%3DPA321&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._S._Vitter2008" class="citation book cs1"><a href="/wiki/J._S._Vitter" class="mw-redirect" title="J. S. Vitter">J. S. Vitter</a> (2008). <a rel="nofollow" class="external text" href="http://www.ittc.ku.edu/~jsv/Papers/Vit.IO_book.pdf"><i>Algorithms and data structures for external memory</i></a> <span class="cs1-format">(PDF)</span>. Series on foundations and trends in theoretical computer science. Hanover, MA: now Publishers. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-60198-106-6" title="Special:BookSources/978-1-60198-106-6"><bdi>978-1-60198-106-6</bdi></a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110104233254/http://www.ittc.ku.edu/~jsv/Papers/Vit.IO_book.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 4 January 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Algorithms+and+data+structures+for+external+memory&rft.place=Hanover%2C+MA&rft.series=Series+on+foundations+and+trends+in+theoretical+computer+science&rft.pub=now+Publishers&rft.date=2008&rft.isbn=978-1-60198-106-6&rft.au=J.+S.+Vitter&rft_id=http%3A%2F%2Fwww.ittc.ku.edu%2F~jsv%2FPapers%2FVit.IO_book.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><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.eecs.berkeley.edu/Pubs/TechRpts/1994/CSD-94-847.pdf">"A thesis on tertiary storage"</a> <span class="cs1-format">(PDF)</span>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20070927233543/http://www.eecs.berkeley.edu/Pubs/TechRpts/1994/CSD-94-847.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 27 September 2007<span class="reference-accessdate">. Retrieved <span class="nowrap">18 June</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=A+thesis+on+tertiary+storage&rft_id=http%3A%2F%2Fwww.eecs.berkeley.edu%2FPubs%2FTechRpts%2F1994%2FCSD-94-847.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-pearson2010-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-pearson2010_9-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPearson2010" class="citation web cs1">Pearson, Tony (2010). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20151124110253/https://www.ibm.com/developerworks/community/blogs/InsideSystemStorage/entry/the_correct_use_of_the_term_nearline2?lang=en">"Correct use of the term nearline"</a>. <i>IBM developer-works, inside system storage</i>. Archived from <a rel="nofollow" class="external text" href="https://www.ibm.com/developerworks/community/blogs/InsideSystemStorage/entry/the_correct_use_of_the_term_nearline2">the original</a> on 24 November 2015<span class="reference-accessdate">. Retrieved <span class="nowrap">16 August</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=IBM+developer-works%2C+inside+system+storage&rft.atitle=Correct+use+of+the+term+nearline&rft.date=2010&rft.aulast=Pearson&rft.aufirst=Tony&rft_id=https%3A%2F%2Fwww.ibm.com%2Fdeveloperworks%2Fcommunity%2Fblogs%2FInsideSystemStorage%2Fentry%2Fthe_correct_use_of_the_term_nearline2&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNational_Communications_System1996" class="citation techreport cs1"><a href="/wiki/National_Communications_System" title="National Communications System">National Communications System</a> (7 August 1996). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090302235918/http://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm"><i>Federal Standard 1037C – Telecommunications: Glossary of Telecommunication Terms</i></a> (Technical report). General Services Administration. FS-1037C. Archived from <a rel="nofollow" class="external text" href="http://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm">the original</a> on 2 March 2009<span class="reference-accessdate">. Retrieved <span class="nowrap">8 October</span> 2007</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=Federal+Standard+1037C+%E2%80%93+Telecommunications%3A+Glossary+of+Telecommunication+Terms&rft.pub=General+Services+Administration&rft.date=1996-08-07&rft.au=National+Communications+System&rft_id=http%3A%2F%2Fwww.its.bldrdoc.gov%2Ffs-1037%2Ffs-1037c.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span> See also article <a href="/wiki/Federal_standard_1037C" class="mw-redirect" title="Federal standard 1037C">Federal standard 1037C</a>.</span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><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/20081221131054/http://springlightcfl.com/consumer/energy_savings_calculator.aspx">"Energy savings calculator"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.springlightcfl.com/consumer/energy_savings_calculator.aspx">the original</a> on 21 December 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Energy+savings+calculator&rft_id=http%3A%2F%2Fwww.springlightcfl.com%2Fconsumer%2Fenergy_savings_calculator.aspx&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><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/20080805092907/http://www.simpletech.com/content/eco-friendly-redrive">"How much of the [re]drive is actually eco-friendly?"</a>. <i>Simple tech</i>. Archived from <a rel="nofollow" class="external text" href="http://www.simpletech.com/content/eco-friendly-redrive">the original</a> on 5 August 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Simple+tech&rft.atitle=How+much+of+the+%5Bre%5Ddrive+is+actually+eco-friendly%3F&rft_id=http%3A%2F%2Fwww.simpletech.com%2Fcontent%2Feco-friendly-redrive&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMike_Chin2004" class="citation web cs1">Mike Chin (8 March 2004). <a rel="nofollow" class="external text" href="http://www.silentpcreview.com/article145-page1.html">"IS the Silent PC Future 2.5-inches wide?"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20080720000101/http://www.silentpcreview.com/article145-page1.html">Archived</a> from the original on 20 July 2008<span class="reference-accessdate">. Retrieved <span class="nowrap">2 August</span> 2008</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=IS+the+Silent+PC+Future+2.5-inches+wide%3F&rft.date=2004-03-08&rft.au=Mike+Chin&rft_id=http%3A%2F%2Fwww.silentpcreview.com%2Farticle145-page1.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMike_Chin2002" class="citation web cs1">Mike Chin (18 September 2002). <a rel="nofollow" class="external text" href="http://www.silentpcreview.com/article29-page2.html">"Recommended hard drives"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20080905085853/http://www.silentpcreview.com/article29-page2.html">Archived</a> from the original on 5 September 2008<span class="reference-accessdate">. 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Archived from <a rel="nofollow" class="external text" href="http://techreport.com/articles.x/10334/13">the original</a> on 26 January 2012<span class="reference-accessdate">. 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Archived from <a rel="nofollow" class="external text" href="https://swisdev.oracle.com/_files/What-Is-SSM.html">the original</a> on 21 January 2019<span class="reference-accessdate">. Retrieved <span class="nowrap">28 December</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Introduction+to+SPARC+M7+and+silicon+secured+memory+%28SSM%29&rft.pub=swisdev.oracle.com&rft_id=https%3A%2F%2Fswisdev.oracle.com%2F_files%2FWhat-Is-SSM.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.backblaze.com/blog/what-smart-stats-indicate-hard-drive-failures/">"What S.M.A.R.T. hard disk errors actually tell us"</a>. <i>Backblaze</i>. 6 October 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Backblaze&rft.atitle=What+S.M.A.R.T.+hard+disk+errors+actually+tell+us&rft.date=2016-10-06&rft_id=https%3A%2F%2Fwww.backblaze.com%2Fblog%2Fwhat-smart-stats-indicate-hard-drive-failures%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://qpxtool.sourceforge.io/faq.html">"QPxTool - check the quality"</a>. <i>qpxtool.sourceforge.io</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=qpxtool.sourceforge.io&rft.atitle=QPxTool+-+check+the+quality&rft_id=https%3A%2F%2Fqpxtool.sourceforge.io%2Ffaq.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><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/20101230081543/http://www.extremetech.com/article2/0,1558,1966644,00.asp">"New Samsung notebook replaces hard drive with flash"</a>. <i>Extreme tech</i>. 23 May 2006. 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Micron technology. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/https://www.micron.com/-/media/client/global/documents/products/white-paper/5210_ssd_vs_hdd_endurance_white_paper.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 9 October 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Comparing+SSD+and+HDD+endurance+in+the+age+of+QLC+SSDs&rft.pub=Micron+technology&rft_id=https%3A%2F%2Fwww.micron.com%2F-%2Fmedia%2Fclient%2Fglobal%2Fdocuments%2Fproducts%2Fwhite-paper%2F5210_ssd_vs_hdd_endurance_white_paper.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.stellarinfo.co.in/kb/ssd-vs-hdd.php">"Comparing SSD and HDD - A comprehensive comparison of the storage drives"</a>. <i>www.stellarinfo.co.in</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.stellarinfo.co.in&rft.atitle=Comparing+SSD+and+HDD+-+A+comprehensive+comparison+of+the+storage+drives&rft_id=https%3A%2F%2Fwww.stellarinfo.co.in%2Fkb%2Fssd-vs-hdd.php&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><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/20090822172353/http://www.dvddemystified.com/dvdfaq.html">"The DVD FAQ - A comprehensive reference of DVD technologies"</a>. 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switched magnetism in photovoltaic perovskite CH3NH3(Mn:Pb)I3"</a>. <i>Nature Communications</i>. <b>7</b>: 13406. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/1611.08205">1611.08205</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2016NatCo...713406N">2016NatCo...713406N</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fncomms13406">10.1038/ncomms13406</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123013">5123013</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/27882917">27882917</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature+Communications&rft.atitle=Optically+switched+magnetism+in+photovoltaic+perovskite+CH3NH3%28Mn%3APb%29I3&rft.volume=7&rft.pages=13406&rft.date=2016-11-24&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC5123013%23id-name%3DPMC&rft_id=info%3Abibcode%2F2016NatCo...713406N&rft_id=info%3Aarxiv%2F1611.08205&rft_id=info%3Apmid%2F27882917&rft_id=info%3Adoi%2F10.1038%2Fncomms13406&rft.aulast=N%C3%A1fr%C3%A1di&rft.aufirst=B%C3%A1lint&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC5123013&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.extremetech.com/extreme/134427-a-paper-based-backup-solution-not-as-stupid-as-it-sounds">"A paper-based backup solution (not as stupid as it sounds)"</a>. 14 August 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=A+paper-based+backup+solution+%28not+as+stupid+as+it+sounds%29&rft.date=2012-08-14&rft_id=https%3A%2F%2Fwww.extremetech.com%2Fextreme%2F134427-a-paper-based-backup-solution-not-as-stupid-as-it-sounds&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a 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class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20090301235710/https://www.sciencedaily.com//releases//2009//02//090219141438.htm">"New method of self-assembling nanoscale elements could transform data storage industry"</a>. <i>sciencedaily.com</i>. 1 March 2009. 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Retrieved <span class="nowrap">18 June</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=sciencedaily.com&rft.atitle=New+method+of+self-assembling+nanoscale+elements+could+transform+data+storage+industry&rft.date=2009-03-01&rft_id=https%3A%2F%2Fwww.sciencedaily.com%2Freleases%2F2009%2F02%2F090219141438.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFYong" class="citation news cs1">Yong, Ed. <a rel="nofollow" class="external text" href="https://www.theatlantic.com/science/archive/2017/03/this-speck-of-dna-contains-a-movie-a-computer-virus-and-an-amazon-gift-card/518373/">"This speck of DNA contains a movie, a computer virus, and an Amazon gift card"</a>. <i>The Atlantic</i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170303010826/https://www.theatlantic.com/science/archive/2017/03/this-speck-of-dna-contains-a-movie-a-computer-virus-and-an-amazon-gift-card/518373/">Archived</a> from the original on 3 March 2017<span class="reference-accessdate">. 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Retrieved <span class="nowrap">3 March</span> 2017</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=phys.org&rft.atitle=Researchers+store+computer+operating+system+and+short+movie+on+DNA&rft_id=https%3A%2F%2Fphys.org%2Fnews%2F2017-03-short-movie-dna.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.science.org/content/article/dna-could-store-all-worlds-data-one-room">"DNA could store all of the world's data in one room"</a>. Science Magazine. 2 March 2017. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170302225525/http://www.sciencemag.org/news/2017/03/dna-could-store-all-worlds-data-one-room">Archived</a> from the original on 2 March 2017<span class="reference-accessdate">. Retrieved <span class="nowrap">3 March</span> 2017</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=DNA+could+store+all+of+the+world%27s+data+in+one+room&rft.pub=Science+Magazine&rft.date=2017-03-02&rft_id=https%3A%2F%2Fwww.science.org%2Fcontent%2Farticle%2Fdna-could-store-all-worlds-data-one-room&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFErlichZielinski2017" class="citation journal cs1">Erlich, Yaniv; Zielinski, Dina (2 March 2017). <a rel="nofollow" class="external text" href="https://zenodo.org/record/889697">"DNA Fountain enables a robust and efficient storage architecture"</a>. <i>Science</i>. <b>355</b> (6328): <span class="nowrap">950–</span>954. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2017Sci...355..950E">2017Sci...355..950E</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.aaj2038">10.1126/science.aaj2038</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/28254941">28254941</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:13470340">13470340</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=DNA+Fountain+enables+a+robust+and+efficient+storage+architecture&rft.volume=355&rft.issue=6328&rft.pages=%3Cspan+class%3D%22nowrap%22%3E950-%3C%2Fspan%3E954&rft.date=2017-03-02&rft_id=info%3Adoi%2F10.1126%2Fscience.aaj2038&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A13470340%23id-name%3DS2CID&rft_id=info%3Apmid%2F28254941&rft_id=info%3Abibcode%2F2017Sci...355..950E&rft.aulast=Erlich&rft.aufirst=Yaniv&rft.au=Zielinski%2C+Dina&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F889697&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://zenbit.tech/blog/disaster-recovery-on-aws-cloud/">"Disaster Recovery on AWS Cloud"</a>. 18 August 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Disaster+Recovery+on+AWS+Cloud&rft.date=2023-08-18&rft_id=https%3A%2F%2Fzenbit.tech%2Fblog%2Fdisaster-recovery-on-aws-cloud%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Computer_data_storage&action=edit&section=35" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGoda,_K.Kitsuregawa,_M.2012" class="citation journal cs1">Goda, K.; Kitsuregawa, M. (2012). <a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FJPROC.2012.2189787">"The history of storage systems"</a>. <i><a href="/wiki/Proceedings_of_the_IEEE" title="Proceedings of the IEEE">Proceedings of the IEEE</a></i>. <b>100</b>: <span class="nowrap">1433–</span>1440. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FJPROC.2012.2189787">10.1109/JPROC.2012.2189787</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+IEEE&rft.atitle=The+history+of+storage+systems&rft.volume=100&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1433-%3C%2Fspan%3E1440&rft.date=2012&rft_id=info%3Adoi%2F10.1109%2FJPROC.2012.2189787&rft.au=Goda%2C+K.&rft.au=Kitsuregawa%2C+M.&rft_id=https%3A%2F%2Fdoi.org%2F10.1109%252FJPROC.2012.2189787&rfr_id=info%3Asid%2Fen.wikipedia.org%3AComputer+data+storage" class="Z3988"></span></li> <li><a rel="nofollow" class="external text" href="http://www.computerhistory.org/revolution/memory-storage/8">Memory & storage</a>, Computer history museum</li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Basic_computer_components192" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Basic_computer_components" title="Template:Basic computer components"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Basic_computer_components" title="Template talk:Basic computer components"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Basic_computer_components" title="Special:EditPage/Template:Basic computer components"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Basic_computer_components192" style="font-size:114%;margin:0 4em">Basic <a href="/wiki/Computer" title="Computer">computer</a> <a href="/wiki/Computer_hardware" title="Computer hardware">components</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Input_device" title="Input device">Input devices</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%"><a href="/wiki/Pointing_device" title="Pointing device">Pointing devices</a></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/Graphics_tablet" title="Graphics tablet">Graphics tablet</a></li> <li><a href="/wiki/Game_controller" title="Game controller">Game controller</a></li> <li><a href="/wiki/Light_pen" title="Light pen">Light pen</a></li> <li><a href="/wiki/Computer_mouse" title="Computer mouse">Mouse</a> <ul><li><a href="/wiki/Optical_mouse" title="Optical mouse">Optical</a></li></ul></li> <li><a href="/wiki/Optical_trackpad" title="Optical trackpad">Optical trackpad</a></li> <li><a href="/wiki/Pointing_stick" title="Pointing stick">Pointing stick</a></li> <li><a href="/wiki/Touchpad" title="Touchpad">Touchpad</a></li> <li><a href="/wiki/Touchscreen" title="Touchscreen">Touchscreen</a></li> <li><a href="/wiki/Trackball" title="Trackball">Trackball</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</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/Computer_keyboard" title="Computer keyboard">Keyboard</a></li> <li><a href="/wiki/Image_scanner" title="Image scanner">Image scanner</a></li> <li><a href="/wiki/Graphics_card" title="Graphics card">Graphics card</a> <ul><li><a href="/wiki/Graphics_processing_unit" title="Graphics processing unit">GPU</a></li></ul></li> <li><a href="/wiki/Microphone" title="Microphone">Microphone</a></li> <li><a href="/wiki/Refreshable_braille_display" title="Refreshable braille display">Refreshable braille display</a></li> <li><a href="/wiki/Sound_card" title="Sound card">Sound card</a> <ul><li><a href="/wiki/Sound_chip" title="Sound chip">Sound chip</a></li></ul></li> <li><a href="/wiki/Webcam" title="Webcam">Webcam</a> <ul><li><a href="/wiki/Softcam" title="Softcam">Softcam</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Output_device" title="Output device">Output devices</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/Computer_monitor" title="Computer monitor">Monitor</a> <ul><li><a href="/wiki/Electronic_visual_display" title="Electronic visual display">Screen</a></li></ul></li> <li><a href="/wiki/Refreshable_braille_display" title="Refreshable braille display">Refreshable braille display</a></li> <li><a href="/wiki/Printer_(computing)" title="Printer (computing)">Printer</a> <ul><li><a href="/wiki/Plotter" title="Plotter">Plotter</a></li></ul></li> <li><a href="/wiki/Computer_speakers" title="Computer speakers">Speakers</a></li> <li><a href="/wiki/Sound_card" title="Sound card">Sound card</a></li> <li><a href="/wiki/Graphics_card" title="Graphics card">Graphics card</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Removable_media" title="Removable media">Removable <br /> data storage</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/Disk_pack" title="Disk pack">Disk pack</a></li> <li><a href="/wiki/Floppy_disk" title="Floppy disk">Floppy disk</a></li> <li><a href="/wiki/Optical_disc" title="Optical disc">Optical disc</a> <ul><li><a href="/wiki/Compact_disc" title="Compact disc">CD</a></li> <li><a href="/wiki/DVD" title="DVD">DVD</a></li> <li><a href="/wiki/Blu-ray" title="Blu-ray">Blu-ray</a></li></ul></li> <li><a href="/wiki/Flash_memory" title="Flash memory">Flash memory</a> <ul><li><a href="/wiki/Memory_card" title="Memory card">Memory card</a></li> <li><a href="/wiki/USB_flash_drive" title="USB flash drive">USB flash drive</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Computer_case" title="Computer case">Computer case</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/Central_processing_unit" title="Central processing unit">Central processing unit</a> <ul><li><a href="/wiki/Microprocessor" title="Microprocessor">Microprocessor</a></li></ul></li> <li><a href="/wiki/Motherboard" title="Motherboard">Motherboard</a></li> <li><a href="/wiki/Computer_memory" title="Computer memory">Memory</a> <ul><li><a href="/wiki/Random-access_memory" title="Random-access memory">RAM</a></li> <li><a href="/wiki/Nonvolatile_BIOS_memory" title="Nonvolatile BIOS memory">BIOS</a></li></ul></li> <li><a class="mw-selflink selflink">Data storage</a> <ul><li><a href="/wiki/Hard_disk_drive" title="Hard disk drive">HDD</a></li> <li><a href="/wiki/Solid-state_drive" title="Solid-state drive">SSD</a> (<a href="/wiki/SATA" title="SATA">SATA</a> / <a href="/wiki/NVM_Express" title="NVM Express">NVMe</a>)</li> <li><a href="/wiki/Solid-state_hybrid_drive" class="mw-redirect" title="Solid-state hybrid drive">SSHD</a></li></ul></li> <li><a href="/wiki/Power_supply_unit_(computer)" title="Power supply unit (computer)">Power supply</a> <ul><li><a href="/wiki/Switched-mode_power_supply" title="Switched-mode power supply">SMPS</a></li></ul></li> <li><a href="/wiki/MOSFET" title="MOSFET">MOSFET</a> <ul><li><a href="/wiki/Power_MOSFET" title="Power MOSFET">Power MOSFET</a></li> <li><a href="/wiki/Voltage_regulator_module" title="Voltage regulator module">VRM</a></li></ul></li> <li><a href="/wiki/Network_interface_controller" title="Network interface controller">Network interface controller</a></li> <li><a href="/wiki/Fax_modem" title="Fax modem">Fax modem</a></li> <li><a href="/wiki/Expansion_card" title="Expansion card">Expansion card</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Computer_port_(hardware)" title="Computer port (hardware)">Ports</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%">Current</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/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/USB" title="USB">USB</a></li> <li><a href="/wiki/Thunderbolt_(interface)" title="Thunderbolt (interface)">Thunderbolt</a></li> <li><a href="/wiki/Phone_connector_(audio)" title="Phone connector (audio)">Analog audio jack</a></li> <li><a href="/wiki/DisplayPort" title="DisplayPort">DisplayPort</a></li> <li><a href="/wiki/HDMI" title="HDMI">HDMI</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Obsolete</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/IEEE_1394" title="IEEE 1394">FireWire</a> (IEEE 1394)</li> <li><a href="/wiki/Parallel_port" title="Parallel port">Parallel port</a></li> <li><a href="/wiki/Serial_port" title="Serial port">Serial port</a></li> <li><a href="/wiki/Game_port" title="Game port">Game port</a></li> <li><a href="/wiki/PS/2_port" title="PS/2 port">PS/2 port</a></li> <li><a href="/wiki/Serial_ATA#eSATA" class="mw-redirect" title="Serial ATA">eSATA</a></li> <li><a href="/wiki/Digital_Visual_Interface" title="Digital Visual Interface">DVI</a></li> <li><a href="/wiki/VGA_connector" title="VGA connector">VGA</a></li></ul> </div></td></tr></tbody></table><div></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/History_of_computing_hardware" title="History of computing hardware">History of computing hardware</a></li> <li><a href="/wiki/History_of_computing_hardware_(1960s%E2%80%93present)" title="History of computing hardware (1960s–present)">History of computing hardware (1960s–present)</a></li> <li><a href="/wiki/List_of_pioneers_in_computer_science" title="List of pioneers in computer science">List of pioneers in computer science</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Primary_computer_data_storage_technologies126" style="padding:3px"><table class="nowraplinks mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Primary_storage_technologies" title="Template:Primary storage technologies"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Primary_storage_technologies" title="Template talk:Primary storage technologies"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Primary_storage_technologies" title="Special:EditPage/Template:Primary storage technologies"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Primary_computer_data_storage_technologies126" style="font-size:114%;margin:0 4em"><a class="mw-selflink-fragment" href="#Primary_storage">Primary computer data storage</a> technologies</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Volatile_memory" title="Volatile memory">Volatile memory</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%">Current</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/Dynamic_random-access_memory" title="Dynamic random-access memory">DRAM</a> <ul><li>e.g., <a href="/wiki/DDR_SDRAM" title="DDR SDRAM">DDR SDRAM</a></li></ul></li> <li><a href="/wiki/Static_random-access_memory" title="Static random-access memory">SRAM</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Future</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/Z-RAM" title="Z-RAM">Z-RAM</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Historical</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/Delay-line_memory" title="Delay-line memory">Delay-line memory</a></li> <li><a href="/wiki/Selectron_tube" title="Selectron tube">Selectron tube</a></li> <li><a href="/wiki/Williams_tube" title="Williams tube">Williams tube</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/Non-volatile_memory" title="Non-volatile memory">Non-volatile memory</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%">Current</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/Resistive_random-access_memory" title="Resistive random-access memory">RRAM</a> ( <a href="/wiki/3D_XPoint" title="3D XPoint">3D XPoint</a> )</li> <li><a href="/wiki/EEPROM" title="EEPROM">EAROM</a></li> <li><a href="/wiki/EEPROM" title="EEPROM">EEPROM</a></li> <li><a href="/wiki/EPROM" title="EPROM">EPROM</a></li> <li><a href="/wiki/Flash_memory" title="Flash memory">Flash memory</a></li> <li><a href="/wiki/Programmable_read-only_memory" class="mw-redirect" title="Programmable read-only memory">PROM</a></li> <li><a href="/wiki/Read-only_memory" title="Read-only memory">ROM</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Future</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/Ferroelectric_RAM" title="Ferroelectric RAM">FeRAM</a></li> <li><a href="/wiki/Magnetoresistive_random-access_memory" class="mw-redirect" title="Magnetoresistive random-access memory">MRAM</a></li> <li><a href="/wiki/Nano-RAM" title="Nano-RAM">NRAM</a></li> <li><a href="/wiki/Phase-change_memory" title="Phase-change memory">PRAM</a></li> <li><a href="/wiki/SONOS" title="SONOS">SONOS</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Historical</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/Bubble_memory" title="Bubble memory">Bubble memory</a></li> <li><a href="/wiki/Drum_memory" title="Drum memory">Drum memory</a></li> <li><a href="/wiki/Magnetic-core_memory" title="Magnetic-core memory">Magnetic-core memory</a></li> <li><a href="/wiki/Twistor_memory" title="Twistor memory">Twistor memory</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r1038841319">.mw-parser-output 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