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title="UNIX-RT">UNIX-RT</a>)</span></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Unix variant with real-time operating system capabilities</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Not to be confused with <a href="/wiki/Penn_MERT" title="Penn MERT">Penn MERT</a>.</div> <div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Operating system</div> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox vevent"><caption class="infobox-title summary">Multi-Environment Real-Time</caption><tbody><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Programmer" title="Programmer">Developer</a></th><td class="infobox-data"><a href="/wiki/Bell_Labs" title="Bell Labs">Bell Labs</a><sup id="cite_ref-acm_1-0" class="reference"><a href="#cite_note-acm-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Programming_language" title="Programming language">Written in</a></th><td class="infobox-data"><a href="/wiki/C_(programming_language)" title="C (programming language)">C</a><sup id="cite_ref-bstj78_2-0" class="reference"><a href="#cite_note-bstj78-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">OS family</th><td class="infobox-data"><a href="/wiki/Unix-like" title="Unix-like">Unix-like</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Working state</th><td class="infobox-data">UNIX-RTR/3B21D version still in use.</td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Marketing target</th><td class="infobox-data"><a href="/wiki/Real-time_computing" title="Real-time computing">Real-time computing</a> applications</td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Available in</th><td class="infobox-data">English</td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Platforms</th><td class="infobox-data"><a href="/wiki/PDP-11" title="PDP-11">PDP-11</a>,<sup id="cite_ref-acm_1-1" class="reference"><a href="#cite_note-acm-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> <a href="/wiki/3B20D" class="mw-redirect" title="3B20D">3B20D</a>, <a href="/wiki/3B21D" class="mw-redirect" title="3B21D">3B21D</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Kernel_(operating_system)" title="Kernel (operating system)">Kernel</a> type</th><td class="infobox-data"><a href="/wiki/Microkernel" title="Microkernel">Microkernel</a><sup id="cite_ref-acm_1-2" class="reference"><a href="#cite_note-acm-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Real-time_operating_system" title="Real-time operating system">RTOS</a></td></tr></tbody></table> <p><b>Multi-Environment Real-Time</b> (<b>MERT</b>), later renamed <b>UNIX Real-Time</b> (<b>UNIX-RT</b>),<sup id="cite_ref-porting_3-0" class="reference"><a href="#cite_note-porting-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> is a hybrid <a href="/wiki/Time-sharing" title="Time-sharing">time-sharing</a> and <a href="/wiki/Real-time_operating_system" title="Real-time operating system">real-time operating system</a> developed in the 1970s at <a href="/wiki/Bell_Labs" title="Bell Labs">Bell Labs</a> for use in <a href="/wiki/Embedded_system" title="Embedded system">embedded</a> <a href="/wiki/Minicomputer" title="Minicomputer">minicomputers</a> (especially <a href="/wiki/PDP-11" title="PDP-11">PDP-11s</a>). A version named <b>Duplex Multi Environment Real Time</b> (<b>DMERT</b>) was the operating system for the <a href="/wiki/3B_series_computers" title="3B series computers">AT&T 3B20D</a> <a href="/wiki/Telephone_switching" class="mw-redirect" title="Telephone switching">telephone switching</a> minicomputer, designed for <a href="/wiki/High_availability" title="High availability">high availability</a>;<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-unix-rtr_6-0" class="reference"><a href="#cite_note-unix-rtr-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> DMERT was later renamed <b>Unix RTR</b> (Real-Time Reliable).<sup id="cite_ref-unix-rtr_6-1" class="reference"><a href="#cite_note-unix-rtr-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>A <i>generalization</i> of Bell Labs' time-sharing operating system <a href="/wiki/Unix" title="Unix">Unix</a>,<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> MERT featured a redesigned, modular <a href="/wiki/Kernel_(operating_system)" title="Kernel (operating system)">kernel</a> that was able to run Unix programs and privileged <a href="/wiki/Real-time_computing" title="Real-time computing">real-time computing</a> processes. These processes' data structures were isolated from other processes with <a href="/wiki/Message_passing" title="Message passing">message passing</a> being the preferred form of <a href="/wiki/Interprocess_communication" class="mw-redirect" title="Interprocess communication">interprocess communication</a> (IPC), although <a href="/wiki/Shared_memory" title="Shared memory">shared memory</a> was also implemented. MERT also had a custom <a href="/wiki/File_system" title="File system">file system</a> with special support for large, contiguous, statically sized files, as used in real-time <a href="/wiki/Database" title="Database">database</a> applications. The design of MERT was influenced by Dijkstra's <a href="/wiki/THE_multiprogramming_system" title="THE multiprogramming system">THE</a>, Hansen's <a href="/wiki/RC_4000_multiprogramming_system" title="RC 4000 multiprogramming system">Monitor</a>, and IBM's <a href="/wiki/CP-67" title="CP-67">CP-67</a>.<sup id="cite_ref-bstj78_2-1" class="reference"><a href="#cite_note-bstj78-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>The MERT operating system was a four-layer design, in decreasing order of <a href="/wiki/Protection_ring" title="Protection ring">protection</a>:<sup id="cite_ref-bstj78_2-2" class="reference"><a href="#cite_note-bstj78-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p> <ul><li>Kernel: resource allocation of memory, CPU time and <a href="/wiki/Hardware_interrupt" class="mw-redirect" title="Hardware interrupt">interrupts</a></li> <li>Kernel-mode processes including <a href="/wiki/Input/output" title="Input/output">input/output</a> (I/O) <a href="/wiki/Device_driver" title="Device driver">device drivers</a>, file manager, <a href="/wiki/Paging#History" class="mw-redirect" title="Paging">swap</a> manager, <i>root process</i> that connects the file manager to the disk (usually combined with the swap manager)</li> <li>Operating system supervisor</li> <li>User processes</li></ul> <p>The standard supervisor was MERT/UNIX, a Unix emulator with an extended <a href="/wiki/System_call" title="System call">system call</a> interface and <a href="/wiki/Unix_shell" title="Unix shell">shell</a> that enabled the use of MERT's custom IPC mechanisms, although an <a href="/wiki/RSX-11" title="RSX-11">RSX-11</a> emulator also existed.<sup id="cite_ref-bstj78_2-3" class="reference"><a href="#cite_note-bstj78-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Kernel_and_non-kernel_processes">Kernel and non-kernel processes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Multi-Environment_Real-Time&action=edit&section=1" title="Edit section: Kernel and non-kernel processes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>One interesting feature that DMERT – UNIX-RTR introduced was the notion of <i>kernel</i> processes. This is connected with its <a href="/wiki/Microkernel" title="Microkernel">microkernelish</a> architecture roots. In support, there is a separate command (<code>/bin/kpkill</code>) rather than (<code>/bin/kill</code>), that is used to send signals to kernel processes. It is likely there are two different system calls also (<code>kill(2)</code> and <code>kpkill(2)</code>, the first to end a user process and the second to end a kernel process). It is unknown how much of the normal userland <i>signaling</i> mechanism is in place in <code>/bin/kpkill</code>, assuming there is a system call for it, it is not known if one can send various signals or simply send one. Also unknown is whether the kernel process has a way of catching the signals that are delivered to it. It may be that the UNIX-RTR developers implemented an entire signal and messaging <a href="/wiki/Application_programming_interface" class="mw-redirect" title="Application programming interface">application programming interface</a> (API) for kernel processes. </p> <div class="mw-heading mw-heading2"><h2 id="File_system_bits">File system bits</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Multi-Environment_Real-Time&action=edit&section=2" title="Edit section: File system bits"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>If one has root on a UNIX-RTR system, they will surely soon find that their <code>ls -l</code> output is a bit different than expected. Namely, there are two completely new bits in the <code>drwxr-xr-x</code> field. They both take place in the first column, and are <code>C</code> (contiguous) and <code>x</code> (<a href="/wiki/Extent_(file_systems)" title="Extent (file systems)">extents</a>). Both of these have to do with contiguous data, however one may be to do with <a href="/wiki/Inode" title="Inode">inodes</a> and the other with non-metadata. </p><p>Example <code>ls -l</code>: </p> <div class="mw-highlight mw-highlight-lang-bash mw-content-ltr" dir="ltr"><pre><span></span><span class="w"> </span>drwxr-xr-x<span class="w"> </span>root<span class="w"> </span><span class="m">64</span><span class="w"> </span>Sun<span class="w"> </span>Dec<span class="w"> </span><span class="m">4</span><span class="w"> </span><span class="m">2003</span><span class="w"> </span>/cft <span class="w"> </span>xrwxr-xr-x<span class="w"> </span>root<span class="w"> </span><span class="m">64</span><span class="w"> </span>Mon<span class="w"> </span>Dec<span class="w"> </span><span class="m">11</span><span class="w"> </span><span class="m">2013</span><span class="w"> </span>/no5text <span class="w"> </span>Crwxr-xr-x<span class="w"> </span>root<span class="w"> </span><span class="m">256</span><span class="w"> </span>Tue<span class="w"> </span>Dec<span class="w"> </span><span class="m">12</span><span class="w"> </span><span class="m">2014</span><span class="w"> </span>/no5data </pre></div> <div class="mw-heading mw-heading2"><h2 id="Lucent_emulator_and_VCDX">Lucent emulator and VCDX</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Multi-Environment_Real-Time&action=edit&section=3" title="Edit section: Lucent emulator and VCDX"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>AT&T, then <a href="/wiki/Lucent" class="mw-redirect" title="Lucent">Lucent</a>, and now <a href="/wiki/Alcatel-Lucent" title="Alcatel-Lucent">Alcatel-Lucent</a>, are the vendor of the <a href="/wiki/SPARC" title="SPARC">SPARC</a>-based and <a href="/wiki/Solaris_(operating_system)" class="mw-redirect" title="Solaris (operating system)">Solaris</a>-OEM package ATT3bem (which lives on Solaris SPARC in /opt/ATT3bem). This is a full <a href="/wiki/3B21D" class="mw-redirect" title="3B21D">3B21D</a> emulator (known as the 3B21E, the system behind the Very Compact Digital eXchange, or VCDX) which is meant to provide a production environment to the Administrative Module (AM) portion of the <a href="/wiki/5ESS" class="mw-redirect" title="5ESS">5ESS</a> switch. There are parts of the 5ESS that are not part of the 3B21D microcomputer at all: SMs and CMs. Under the emulator the workstation is referred to as the 'AW' (Administrative Workstation). The emulator installs with Solaris 2.6/SPARC and also comes with Solstice <a href="/wiki/X.25" title="X.25">X.25</a> 9.1 (SUNWconn), formerly known as SunLink X.25. The reason for packaging the X.25 stack with the 3B21D emulator is because the Bell System, regional Bell operating companies, and ILECs still use X.25 networks for their most critical of systems (telephone switches may live on X.25 or Datakit VCS II, a similar network developed at Bell Labs, but they do not have TCP/IP stacks). </p><p>The AT&T/Alcatel-Lucent emulator is not an easy program to get working correctly, even if one manages to have an image from a pulled working 5ESS hard disk 'dd' output file. First, there are quite a few bugs the user must navigate around in the installation process. Once this is done, there is a configuration file which connects peripherals to emulated peripherals. But there is scant documentation on the CD which describes this. The name of this file is em_devmap for SS5s, and em_devmap.ultra for Ultra60s. </p><p>In addition, one of the bugs mentioned in the install process is a broken script to fdisk and image hard disks correctly: certain things need to be written to certain offsets, because the /opt/ATT3bem/bin/3bem process expects, or seems to need, these hard-coded locations. </p><p>The emulator runs on SPARCstation-5s and UltraSPARC-60s. It is likely that the 3B21D is emulated faster on a modern SPARC than a 3B21D microcomputer's processor actually runs as measured in MIPS. The most difficult thing about having the emulator is acquiring a DMERT/UNIX-RTR hdd image to actually run. The operating system for the 5ESS is restricted to a few people, employees and customers of the vendor, who either work on it or write the code for it. Having an image of a running system, which can be obtained on eBay, pulled from a working 3B21D, and imaged to a file or put into an Ultra60 or SPARCstation-5, provides the resources to attempt to run the UNIX-RTR system. </p><p>The uname -a output of the Bourne shell running UNIX-RTR (Real-time Reliable) is: </p> <div class="mw-highlight mw-highlight-lang-console mw-content-ltr" dir="ltr"><pre><span></span><span class="gp"> # </span>uname<span class="w"> </span>-a <span class="go"> <3B21D> <3B21D></span> </pre></div> <p>Though on 3B20D systems it will print 20 instead of 21, though 3B20Ds are rare, nowadays most non-VCDX 5ESSs are 3B21D hardware, not 3B20D (although they will run the software fine). The 3B20D uses the <a href="/wiki/Bellmac_32" title="Bellmac 32">WE32000</a> processor while the 21 uses the WE32100. There may be some other differences, as well. One thing unusual about the processor is the direction the stack grows: up. </p><p>Manual page for falloc (which may be responsible for Contiguous or eXtent file space allocation): </p> <pre> FALLOC(1) 5ESS UNIX FALLOC(1) NAME falloc - allocate a contiguous file SYNOPSIS falloc filename size DESCRIPTION A contiguous file of the specified filename is allocated to be of 'size' (512 byte) blocks. DIAGNOSTICS The command complains a needed directory is not searchable, the final directory is not writable, the file already exists or there is not enough space for the file. </pre> <p><br /> UNIX-RTR includes an atomic file swap command (atomsw, manual page below): </p> <pre> ATOMSW(1) 5ESS UNIX ATOMSW(1) NAME atomsw - Atomic switch files SYNOPSIS atomsw file1 file2 DESCRIPTION Atomic switch of two files. The contents, permissions, and owners of two files are switched in a single operation. In case of a system fault during the operation of this command, file2 will either have its original contents, permissions and owner, or will have file1's contents, permissions and owner. Thus, file2 is considered precious. File1 may be truncated in case of a system fault. RESTRICTIONS Both files must exist. Both files must reside on the same file system. Neither file may be a "special device" (for example, a TTY port). To enter this command from the craft shell, switching file "/tmp/abc" with file "/tmp/xyz", enter for MML: EXC:ENVIR:UPROC,FN="/bin/atomsw",ARGS="/tmp/abc"-"/tmp/xyz"; For PDS enter: EXC:ENVIR:UPROC,FN"/bin/atomsw",ARGS("/tmp/abc","/tmp/xyz")! NOTE File 1 may be lost during a system fault. FILES /bin/atomsw </pre> <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=Multi-Environment_Real-Time&action=edit&section=4" title="Edit section: References"><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"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-acm-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-acm_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-acm_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-acm_1-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><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 id="CITEREFBayerLycklama1975" class="citation conference cs1">Bayer, D. L.; Lycklama, H. (1975). <a rel="nofollow" class="external text" href="http://portal.acm.org/citation.cfm?id=806519"><i>MERT: a multi-environment real-time operating system</i></a>. Fifth ACM Symposium on Operating Systems Principles. Austin, Texas. <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/10.1145%2F800213.806519">10.1145/800213.806519</a></span><span class="reference-accessdate">. Retrieved <span class="nowrap">2008-08-18</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=MERT%3A+a+multi-environment+real-time+operating+system&rft.place=Austin%2C+Texas&rft.date=1975&rft_id=info%3Adoi%2F10.1145%2F800213.806519&rft.aulast=Bayer&rft.aufirst=D.+L.&rft.au=Lycklama%2C+H.&rft_id=http%3A%2F%2Fportal.acm.org%2Fcitation.cfm%3Fid%3D806519&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMulti-Environment+Real-Time" class="Z3988"></span></span> </li> <li id="cite_note-bstj78-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-bstj78_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-bstj78_2-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-bstj78_2-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-bstj78_2-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFLycklamaBayer1978" class="citation journal cs1">Lycklama, H.; Bayer, D. 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"The MERT Operating System". <i><a href="/wiki/Bell_System_Technical_Journal" class="mw-redirect" title="Bell System Technical Journal">Bell System Technical Journal</a></i>. <b>57</b> (6): <span class="nowrap">2049–</span>2086. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fj.1538-7305.1978.tb02142.x">10.1002/j.1538-7305.1978.tb02142.x</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:8711402">8711402</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Bell+System+Technical+Journal&rft.atitle=The+MERT+Operating+System&rft.volume=57&rft.issue=6&rft.pages=%3Cspan+class%3D%22nowrap%22%3E2049-%3C%2Fspan%3E2086&rft.date=1978-07%2F1978-08&rft_id=info%3Adoi%2F10.1002%2Fj.1538-7305.1978.tb02142.x&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A8711402%23id-name%3DS2CID&rft.aulast=Lycklama&rft.aufirst=H.&rft.au=Bayer%2C+D.+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMulti-Environment+Real-Time" class="Z3988"></span></span> </li> <li id="cite_note-porting-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-porting_3-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFBodenstabHoughtonKellemanRonkin1984" class="citation journal cs1">Bodenstab, D. 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"UNIX Operating System Porting Experiences". <i>AT&T Bell Laboratories Technical Journal</i>. <b>63</b> (8): <span class="nowrap">1769–</span>1790. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fj.1538-7305.1984.tb00064.x">10.1002/j.1538-7305.1984.tb00064.x</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:35326182">35326182</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=AT%26T+Bell+Laboratories+Technical+Journal&rft.atitle=UNIX+Operating+System+Porting+Experiences&rft.volume=63&rft.issue=8&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1769-%3C%2Fspan%3E1790&rft.date=1984&rft_id=info%3Adoi%2F10.1002%2Fj.1538-7305.1984.tb00064.x&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A35326182%23id-name%3DS2CID&rft.aulast=Bodenstab&rft.aufirst=D.+E.&rft.au=Houghton%2C+T.+F.&rft.au=Kelleman%2C+K.+A.&rft.au=Ronkin%2C+G.&rft.au=Schan%2C+E.+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMulti-Environment+Real-Time" class="Z3988"></span></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 id="CITEREFKaneAndersonMcCabe1983" class="citation journal cs1">Kane, J. 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E.; Campbell, J. H.; Dubman, M. R. (January 1983). "The 3B20D Processor & DMERT Operating System: DMERT Operating System". <i><a href="/wiki/Bell_System_Technical_Journal" class="mw-redirect" title="Bell System Technical Journal">Bell System Technical Journal</a></i>. <b>62</b> (1): <span class="nowrap">303–</span>322. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fj.1538-7305.1983.tb04397.x">10.1002/j.1538-7305.1983.tb04397.x</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:12901173">12901173</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Bell+System+Technical+Journal&rft.atitle=The+3B20D+Processor+%26+DMERT+Operating+System%3A+DMERT+Operating+System&rft.volume=62&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E303-%3C%2Fspan%3E322&rft.date=1983-01&rft_id=info%3Adoi%2F10.1002%2Fj.1538-7305.1983.tb04397.x&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A12901173%23id-name%3DS2CID&rft.aulast=Grzelakowski&rft.aufirst=M.+E.&rft.au=Campbell%2C+J.+H.&rft.au=Dubman%2C+M.+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMulti-Environment+Real-Time" class="Z3988"></span></span> </li> <li id="cite_note-unix-rtr-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-unix-rtr_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-unix-rtr_6-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFWallaceBarnes1984" class="citation journal cs1">Wallace, John J.; Barnes, Walter W. (August 1984). <a rel="nofollow" class="external text" href="http://www.computer.org/csdl/mags/co/1984/08/01659215.pdf">"Designing for Ultrahigh Availability: The Unix RTR Operating System"</a> <span class="cs1-format">(PDF)</span>. <i><a href="/wiki/IEEE_Computer" class="mw-redirect" title="IEEE Computer">IEEE Computer</a></i>. <b>17</b> (8). <a href="/wiki/IEEE" class="mw-redirect" title="IEEE">IEEE</a>: <span class="nowrap">31–</span>39. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FMC.1984.1659215">10.1109/MC.1984.1659215</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:17689432">17689432</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Computer&rft.atitle=Designing+for+Ultrahigh+Availability%3A+The+Unix+RTR+Operating+System&rft.volume=17&rft.issue=8&rft.pages=%3Cspan+class%3D%22nowrap%22%3E31-%3C%2Fspan%3E39&rft.date=1984-08&rft_id=info%3Adoi%2F10.1109%2FMC.1984.1659215&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A17689432%23id-name%3DS2CID&rft.aulast=Wallace&rft.aufirst=John+J.&rft.au=Barnes%2C+Walter+W.&rft_id=http%3A%2F%2Fwww.computer.org%2Fcsdl%2Fmags%2Fco%2F1984%2F08%2F01659215.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMulti-Environment+Real-Time" 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="CITEREFRitchie1977" class="citation conference cs1"><a href="/wiki/Dennis_Ritchie" title="Dennis Ritchie">Ritchie, Dennis M.</a> (1977). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20150205030215/http://cm.bell-labs.com/cm/cs/who/dmr/retro.html"><i>The Unix Time-sharing System: A retrospective</i></a>. Tenth Hawaii International Conference on the System Sciences. Archived from <a rel="nofollow" class="external text" href="http://cm.bell-labs.com/cm/cs/who/dmr/retro.html">the original</a> on 5 February 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=The+Unix+Time-sharing+System%3A+A+retrospective&rft.date=1977&rft.aulast=Ritchie&rft.aufirst=Dennis+M.&rft_id=http%3A%2F%2Fcm.bell-labs.com%2Fcm%2Fcs%2Fwho%2Fdmr%2Fretro.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMulti-Environment+Real-Time" class="Z3988"></span></span> </li> </ol></div></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 .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline 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title="UNIX/32V">UNIX/32V</a> (1979)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Internal</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/CB_UNIX" title="CB UNIX">CB UNIX</a> (c. 1975)</li> <li><a href="/wiki/PWB/UNIX" title="PWB/UNIX">PWB/UNIX</a> (1977)</li> <li><a class="mw-selflink selflink">MERT/DMERT/UNIX-RT</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Commercial</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/UNIX_System_III" title="UNIX System III">UNIX System III</a> (1982)</li> <li><a href="/wiki/UNIX_System_V" title="UNIX System V">UNIX System V</a> (1983)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">People</th><td class="navbox-list-with-group 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McMahon</a></li> <li><a href="/wiki/Joe_Ossanna" title="Joe Ossanna">Joe Ossanna</a></li> <li><a href="/wiki/Rob_Pike" title="Rob Pike">Rob Pike</a></li> <li><a href="/wiki/Dennis_Ritchie" title="Dennis Ritchie">Dennis Ritchie</a></li> <li><a href="/wiki/Ken_Thompson" title="Ken Thompson">Ken Thompson</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Companies</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/AT%26T_Computer_Systems" title="AT&T Computer Systems">AT&T Computer Systems</a></li> <li><a href="/wiki/Unix_System_Laboratories" title="Unix System Laboratories">Unix System Laboratories</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow hlist" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" 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</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/TRON_project" title="TRON project">TRON</a> support</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ITRON_project" title="ITRON project">ITRON project</a></li> <li><a href="/wiki/T-Kernel" title="T-Kernel">T-Kernel</a> <ul><li><a href="/wiki/Micro_T-Kernel" title="Micro T-Kernel">Micro T-Kernel</a></li> <li><a href="/wiki/T-Engine_Forum" title="T-Engine Forum">T-Engine Forum</a> (organization)</li> <li><a href="/wiki/T-License" title="T-License">T-License</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Partial</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/ECos" title="ECos">eCos</a>°</li> <li><i><a href="/wiki/RTEMS" title="RTEMS">RTEMS</a>°</i></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Capability-based_security" title="Capability-based security">Capability-based</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/EROS_(microkernel)" title="EROS (microkernel)">EROS</a></i>^°</li> <li><a href="/wiki/SeL4" class="mw-redirect" title="SeL4">seL4</a>^°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Java_virtual_machine" title="Java virtual machine">Java virtual machine</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><i><a href="/wiki/JavaOS#Chorus/Jazz" title="JavaOS">Chorus/Jazz</a></i>^ (<i><a href="/wiki/JavaOS" title="JavaOS">JavaOS</a></i> + <i><a href="/wiki/ChorusOS" title="ChorusOS">ChorusOS</a></i>^)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/DOS" title="DOS">DOS</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/Multiuser_DOS" title="Multiuser DOS">Multiuser DOS</a></i> <ul><li><i><a href="/wiki/Concurrent_DOS" class="mw-redirect" title="Concurrent DOS">Concurrent DOS</a></i></li> <li><i><a href="/wiki/FlexOS" title="FlexOS">FlexOS</a></i></li> <li><i><a href="/wiki/REAL/32" class="mw-redirect" title="REAL/32">REAL/32</a></i></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/L4_microkernel_family" title="L4 microkernel family">L4</a> kernel</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/L4Linux" title="L4Linux">L<sup>4</sup>Linux</a>^°</li> <li><a href="/wiki/PikeOS" title="PikeOS">PikeOS</a>^</li> <li><i><a href="/wiki/REX_OS" title="REX OS">REX OS</a></i>^</li> <li><a href="/wiki/Wombat_(operating_system)" title="Wombat (operating system)">Wombat</a>^°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Psion_(company)" title="Psion (company)">Psion</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/EKA2" title="EKA2">EKA2</a></i>^° kernel → <i><a href="/wiki/Symbian" title="Symbian">Symbian</a> OS</i>^°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Microsoft" title="Microsoft">Microsoft</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/ThreadX" title="ThreadX">ThreadX</a>^</li> <li><a href="/wiki/Windows_Embedded_Compact" class="mw-redirect" title="Windows Embedded Compact">Windows Embedded Compact</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/IBM" title="IBM">IBM</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/4680_OS" class="mw-redirect" title="4680 OS">4680 OS</a></i></li> <li><i><a href="/wiki/4690_Operating_System" title="4690 Operating System">4690 OS</a></i></li> <li><a href="/wiki/Transaction_Processing_Facility" title="Transaction Processing Facility">Transaction Processing Facility</a> (TPF)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Texas_Instruments" title="Texas Instruments">Texas Instruments</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><i><a href="/wiki/DSOS" title="DSOS">DSOS</a></i></li> <li><a href="/wiki/TI-RTOS#RTOS_kernel_overview" title="TI-RTOS">TI-RTOS Kernel</a>^°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Digital_Equipment_Corporation" title="Digital Equipment Corporation">DEC</a> <a href="/wiki/PDP-11" title="PDP-11">PDP-11</a> & <a href="/wiki/VAX" title="VAX">VAX</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/RSX-11" title="RSX-11">RSX-11</a></i></li> <li><i><a href="/wiki/RT-11" title="RT-11">RT-11</a></i></li> <li><i><a href="/wiki/VAXELN" title="VAXELN">VAXELN</a></i></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Low resource</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/ChibiOS/RT" title="ChibiOS/RT">ChibiOS/RT</a>^°</li> <li><a href="/wiki/Contiki" title="Contiki">Contiki</a>°</li> <li><a href="/wiki/ERIKA_Enterprise" title="ERIKA Enterprise">ERIKA Enterprise</a>°</li> <li>FunkOS°</li> <li><a href="/wiki/Apache_Mynewt" title="Apache Mynewt">Mynewt</a>°</li> <li><i><a href="/wiki/Nano-RK" title="Nano-RK">Nano-RK</a></i>°</li> <li><a href="/wiki/OpenComRTOS" title="OpenComRTOS">OpenComRTOS</a>^</li> <li><a href="/wiki/PX5_RTOS" title="PX5 RTOS">PX5 RTOS</a>^</li> <li><a href="/wiki/RT-Thread" title="RT-Thread">RT-Thread</a>° Nano</li> <li><a href="/wiki/RIOT_(operating_system)" title="RIOT (operating system)">RIOT</a>°</li> <li><a href="/wiki/RTEMS" title="RTEMS">RTEMS</a>°</li> <li><a href="/wiki/ThreadX" title="ThreadX">ThreadX</a>^</li> <li><a href="/wiki/Zephyr_(operating_system)" title="Zephyr (operating system)">Zephyr</a>^°</li></ul> </div></td></tr></tbody></table><div> <ul><li><i><a href="/wiki/BeRTOS" title="BeRTOS">BeRTOS</a></i>^°</li> <li><i><a href="/wiki/DioneOS" title="DioneOS">DioneOS</a></i></li> <li><a href="/wiki/Segger_Microcontroller_Systems" title="Segger Microcontroller Systems">embOS</a></li> <li><a href="/wiki/FreeRTOS" title="FreeRTOS">FreeRTOS</a>^°</li> <li><a href="/wiki/Micro-Controller_Operating_Systems" title="Micro-Controller Operating Systems">µC/OS</a>^°</li> <li><a href="/wiki/Green_Hills_Software#Real-time_operating_systems" title="Green Hills Software">µ-velOSity</a>^</li> <li><a href="/wiki/MQX" title="MQX">MQX</a>^</li> <li><a href="/wiki/OS-9" title="OS-9">OS-9</a> (<a href="/wiki/Microware" title="Microware">Microware</a>)</li> <li><a href="/wiki/Phantom_OS" title="Phantom OS">Phantom OS</a>^°</li> <li><i><a href="/wiki/PSOS_(real-time_operating_system)" title="PSOS (real-time operating system)">pSOS</a></i></li> <li><i><a href="/wiki/RMX_(operating_system)" title="RMX (operating system)">RMX</a></i></li> <li><a href="/wiki/RT-Thread" title="RT-Thread">RT-Thread</a>° Standard</li> <li><a href="/wiki/ScreenOS" title="ScreenOS">ScreenOS</a></li> <li><i><a href="/wiki/Sintran_III" title="Sintran III">Sintran III</a></i></li> <li><i><a href="/wiki/THEOS" title="THEOS">THEOS</a></i></li> <li><i><a href="/wiki/Thoth_(operating_system)" title="Thoth (operating system)">Thoth</a></i>^ → <i><a href="/wiki/Harmony_(operating_system)" title="Harmony (operating system)">Harmony</a></i>^</li> <li><a href="/wiki/Versatile_Real-Time_Executive" title="Versatile Real-Time Executive">VRTX</a>^</li> <li><a href="/wiki/VxWorks" title="VxWorks">VxWorks</a></li> <li><a href="/wiki/EulerOS" title="EulerOS">UniProton</a></li></ul></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Software_framework" title="Software framework">Frameworks</a>, <a href="/wiki/Software_development_kit" title="Software development kit">kits</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <li><a href="/wiki/Robot_Operating_System" title="Robot Operating System">Robot Operating System</a>° 2</li> <li><a href="/wiki/RTAI" title="RTAI">RTAI</a>°</li> <li><a href="/wiki/TI-RTOS" title="TI-RTOS">TI-RTOS</a>^°</li> <li><a href="/wiki/Xenomai" title="Xenomai">Xenomai</a>°</li> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Programmer" title="Programmer">Developers</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/Gordon_Bell_(QNX)" title="Gordon Bell (QNX)">Gordon Bell</a></li> <li><a href="/wiki/David_Cheriton" title="David Cheriton">David Cheriton</a></li> <li><a href="/wiki/Dave_Cutler" title="Dave Cutler">Dave Cutler</a></li> <li><a href="/wiki/Dan_Dodge" title="Dan Dodge">Dan Dodge</a></li> <li><a href="/wiki/Adam_Dunkels" title="Adam Dunkels">Adam Dunkels</a></li> <li><a href="/wiki/Ken_Sakamura" title="Ken Sakamura">Ken Sakamura</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><i>Italics</i> <b>= discontinued</b></li> <li><b>^ = <a href="/wiki/Microkernel" title="Microkernel">Microkernel</a></b></li> <li><b>° = <a href="/wiki/Open-source_software" title="Open-source software">Open-source software</a></b><br /><span class="noviewer" typeof="mw:File"><span title="List-Class article"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <b><a href="/wiki/Comparison_of_real-time_operating_systems" title="Comparison of real-time operating systems">Comparison</a></b> <span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <b><a href="/wiki/Category:Real-time_operating_systems" title="Category:Real-time operating systems">Category</a></b></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="Microkernels-nanokernels667" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="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:Microkernel" title="Template:Microkernel"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Microkernel" title="Template talk:Microkernel"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Microkernel" title="Special:EditPage/Template:Microkernel"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Microkernels-nanokernels667" style="font-size:114%;margin:0 4em"><a href="/wiki/Microkernel" title="Microkernel">Microkernels</a>-<a href="/wiki/Microkernel#Nanokernel" title="Microkernel">nanokernels</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Kernel_(operating_system)" title="Kernel (operating system)">Kernels</a></th><td class="navbox-list-with-group navbox-list navbox-odd" 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/L4_microkernel_family" title="L4 microkernel family">L4</a> family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/Eumel" title="Eumel">Eumel</a></i> → <i><a href="/wiki/L3_microkernel" class="mw-redirect" title="L3 microkernel">L3</a></i> → <a href="/wiki/L4_microkernel_family" title="L4 microkernel family">L4</a>°</li> <li><a href="/wiki/Open_Kernel_Labs" title="Open Kernel Labs">OKL4</a>°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Macintosh" class="mw-redirect" title="Macintosh">Macintosh</a> hosted</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/Mac_OS_nanokernel" title="Mac OS nanokernel">Mac OS nanokernel</a></i></li> <li><i><a href="/wiki/NuKernel" class="mw-redirect" title="NuKernel">NuKernel</a></i></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Psion_(company)" title="Psion (company)">Psion</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><i><a href="/wiki/EKA1" title="EKA1">EKA1</a></i> → <i><a href="/wiki/EKA2" title="EKA2">EKA2</a></i>^°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Amiga" title="Amiga">Amiga</a>-type</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/Exec_(Amiga)" title="Exec (Amiga)">Exec</a></i> <ul><li><a href="/wiki/Exec_(Amiga)#ExecSG" title="Exec (Amiga)">ExecSG</a></li></ul></li> <li><a href="/wiki/Quark_(kernel)" title="Quark (kernel)">Quark</a></li> <li><i><a href="/wiki/WarpOS" title="WarpOS">WarpOS</a></i></li></ul> </div></td></tr></tbody></table><div> <ul><li><i><a href="/wiki/Adaptive_Domain_Environment_for_Operating_Systems" title="Adaptive Domain Environment for Operating Systems">ADEOS</a></i>°</li> <li><i><a href="/wiki/EROS_(microkernel)" title="EROS (microkernel)">EROS</a></i>^°</li> <li><i><a href="/wiki/K42" title="K42">K42</a></i>°</li> <li>Little Kernel</li> <li><i><a href="/wiki/Mach_(kernel)" title="Mach (kernel)">Mach</a></i>° <ul><li><a href="/wiki/GNU_Mach" title="GNU Mach">GNU Mach</a>°</li></ul></li> <li><i><a href="/wiki/MicroEmpix" title="MicroEmpix">MicroEmpix</a></i></li> <li><a href="/wiki/Green_Hills_Software#Real-time_operating_systems" title="Green Hills Software">µ-velOSity</a>^</li> <li><i><a href="/wiki/Spring_(operating_system)#The_nucleus" title="Spring (operating system)">nucleus</a></i></li> <li>Off++ → Plan B</li> <li><i><a href="/wiki/Taligent#Pink_system" title="Taligent">Opus</a></i></li> <li><i><a href="/wiki/PowerUP_(accelerator)#PowerUP_software" title="PowerUP (accelerator)">PowerUP</a></i></li> <li><a href="/wiki/RTLinux" title="RTLinux">RTLinux</a>°</li> <li><a href="/wiki/TI-RTOS#RTOS_kernel_overview" title="TI-RTOS">TI-RTOS kernel</a>^°</li> <li><i><a href="/wiki/Vanguard_(microkernel)" title="Vanguard (microkernel)">Vanguard</a></i></li></ul></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Operating_system" title="Operating system">Operating<br />systems</a></th><td class="navbox-list-with-group navbox-list navbox-odd" 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/POSIX" title="POSIX">POSIX</a> support</th><td class="navbox-list-with-group navbox-list navbox-odd" 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/Unix-like" title="Unix-like">Unix-like</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <li><i><a href="/wiki/ARX_(operating_system)" title="ARX (operating system)">ARX</a></i></li> <li><a href="/wiki/GNU_Hurd" title="GNU Hurd">GNU Hurd</a>°</li> <li><i><a href="/wiki/Lites" title="Lites">Lites</a></i></li> <li><i><a href="/wiki/Meiko_Scientific#MeikOS" title="Meiko Scientific">MeikOS</a></i></li> <li><a href="/wiki/Minix" title="Minix">Minix</a>° <ul><li><a href="/wiki/Minix-vmd" class="mw-redirect" title="Minix-vmd">Minix-vmd</a>°</li> <li><a href="/wiki/Minix_3" title="Minix 3">Minix 3</a>°</li></ul></li> <li><i><a href="/wiki/MkLinux" title="MkLinux">MkLinux</a></i>°</li> <li><i><a class="mw-selflink selflink">Multi-Environment Real-Time</a></i>^ (<i>MERT</i> – <i>Unix-RT</i>)</li> <li><i><a href="/wiki/OS2000" title="OS2000">OS2000</a></i></li> <li><a href="/wiki/QNX" title="QNX">QNX</a>^</li> <li><a href="/wiki/Redox_(operating_system)" title="Redox (operating system)">Redox</a>°</li> <li><i><a href="/wiki/Spring_(operating_system)" title="Spring (operating system)">Spring</a></i></li> <li><a href="/wiki/Tinix" title="Tinix">Tinix</a></li> <li><i><a href="/wiki/UNICOS" title="UNICOS">UNICOS</a></i></li> <li><i><a href="/wiki/VSTa" title="VSTa">VSTa</a></i></li> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Partial</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/ChorusOS" title="ChorusOS">ChorusOS</a>^</i></li> <li><a href="/wiki/Integrity_(operating_system)" title="Integrity (operating system)">Integrity</a>^</li> <li><a href="/wiki/Nucleus_RTOS" title="Nucleus RTOS">Nucleus RTOS</a>^</li> <li><a href="/wiki/NuttX" title="NuttX">NuttX</a>^°</li> <li><a href="/wiki/Operating_System_Embedded" class="mw-redirect" title="Operating System Embedded">OSE</a>^</li> <li><a href="/wiki/RIOT_(operating_system)" title="RIOT (operating system)">RIOT</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/Capability-based_security" title="Capability-based security">Capability-based</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><i><a href="/wiki/GNOSIS" title="GNOSIS">GNOSIS</a></i> → <i><a href="/wiki/KeyKOS" title="KeyKOS">KeyKOS</a></i> → <i><a href="/wiki/EROS_(microkernel)" title="EROS (microkernel)">EROS</a></i> → CapROS</li> <li><i><a href="/wiki/Hydra_(operating_system)" title="Hydra (operating system)">Hydra</a></i></li> <li><a href="/wiki/L4_microkernel_family#High_assurance:_seL4" title="L4 microkernel family">seL4</a>^°</li> <li><i><a href="/wiki/Midori_(operating_system)" title="Midori (operating system)">Midori</a></i></li> <li><i><a href="/wiki/NLTSS" title="NLTSS">NLTSS</a></i></li> <li><i><a href="/wiki/HarmonyOS_NEXT" title="HarmonyOS NEXT">HarmonyOS NEXT</a> (<a href="/wiki/OpenHarmony" title="OpenHarmony">OpenHarmony</a>, <a href="/wiki/OpenHarmony#Oniro_OS" title="OpenHarmony">Oniro OS</a>)</i> → <i><a href="/wiki/HarmonyOS" title="HarmonyOS">HarmonyOS</a></i></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/L4_microkernel_family" title="L4 microkernel family">L4</a> kernel</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/L4Linux" title="L4Linux">L<sup>4</sup>Linux</a>^°</li> <li><a href="/wiki/PikeOS" title="PikeOS">PikeOS</a>^</li> <li><i><a href="/wiki/REX_OS" title="REX OS">REX OS</a></i>^</li> <li><a href="/wiki/Wombat_(operating_system)" title="Wombat (operating system)">Wombat</a>^°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Java_virtual_machine" title="Java virtual machine">Java virtual machine</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><i><a href="/wiki/JavaOS" title="JavaOS">JavaOS</a></i> (<i><a href="/wiki/JavaOS#Chorus/Jazz" title="JavaOS">Chorus/Jazz</a></i>^ integrates <i><a href="/wiki/ChorusOS" title="ChorusOS">ChorusOS</a></i>^)</li> <li><i><a href="/wiki/JX_(operating_system)" title="JX (operating system)">JX</a></i>°</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Macintosh" class="mw-redirect" title="Macintosh">Macintosh</a> hosted</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Unix-like13" scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Unix-like" title="Unix-like">Unix-like</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i><a href="/wiki/MachTen" title="MachTen">MachTen</a></i></li> <li><i><a href="/wiki/MacMach" title="MacMach">MacMach</a></i></li></ul> </div></td></tr></tbody></table><div> <ul><li><i><a href="/wiki/Copland_(operating_system)" title="Copland (operating system)">Copland</a></i></li> <li><i><a href="/wiki/Mac_OS_8#Mac_OS_8.6" title="Mac OS 8">Classic Mac OS</a></i> (<a href="/wiki/PowerPC" title="PowerPC">PowerPC</a> kernel)</li></ul></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Psion_(company)" title="Psion (company)">Psion</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <li><i><a href="/wiki/EPOC_(operating_system)" title="EPOC (operating system)">EPOC</a></i> → <i><a href="/wiki/Symbian" title="Symbian">Symbian</a> OS</i>^°</li> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Amiga" title="Amiga">Amiga</a>-type</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/AmigaOS" title="AmigaOS">AmigaOS</a></li> <li><a href="/wiki/AROS_Research_Operating_System" title="AROS Research Operating System">AROS</a>° <ul><li><a href="/wiki/AROS_Research_Operating_System#AspireOS" title="AROS Research Operating System">AspireOS</a>°</li> <li><a href="/wiki/AROS_Research_Operating_System#Broadway" title="AROS Research Operating System">Broadway</a>°</li> <li><a href="/wiki/AROS_Research_Operating_System#Icaros_Desktop" title="AROS Research Operating System">Icaros Desktop</a>°</li></ul></li> <li><a href="/wiki/MorphOS" title="MorphOS">MorphOS</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Microsoft" title="Microsoft">Microsoft</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/Singularity_(operating_system)" title="Singularity (operating system)">Singularity</a></li> <li><a href="/wiki/ThreadX" title="ThreadX">ThreadX</a>^</li> <li><i><a href="/wiki/Verve_(operating_system)" title="Verve (operating system)">Verve</a></i></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/AIM_alliance" title="AIM alliance">AIM alliance</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i>Pink</i> → <i><a href="/wiki/Taligent" title="Taligent">Taligent</a> OS</i> → <i><a href="/wiki/Workplace_OS" title="Workplace OS">Workplace OS</a></i></li></ul> </div></td></tr></tbody></table><div> <ul><li><i><a href="/wiki/Amoeba_(operating_system)" title="Amoeba (operating system)">Amoeba</a></i>°</li> <li><i><a href="/wiki/BeRTOS" title="BeRTOS">BeRTOS</a></i>^°</li> <li><a href="/wiki/ChibiOS/RT" title="ChibiOS/RT">ChibiOS/RT</a>^°</li> <li><a href="/wiki/FreeRTOS" title="FreeRTOS">FreeRTOS</a>^°</li> <li><a href="/wiki/HelenOS" title="HelenOS">HelenOS</a>°</li> <li><a href="/wiki/Micro-Controller_Operating_Systems" title="Micro-Controller Operating Systems">µC/OS</a>^°</li> <li><a href="/wiki/MQX" title="MQX">MQX</a>^</li> <li><a href="/wiki/OpenComRTOS" title="OpenComRTOS">OpenComRTOS</a>^</li> <li><a href="/wiki/Phantom_OS" title="Phantom OS">Phantom OS</a>^°</li> <li><i><a href="/wiki/RC_4000_multiprogramming_system" title="RC 4000 multiprogramming system">RC 4000</a></i></li> <li><a href="/wiki/SharpOS" title="SharpOS">SharpOS</a>°</li> <li><i><a href="/wiki/SPIN_(operating_system)" title="SPIN (operating system)">SPIN</a></i>°</li> <li><i><a href="/wiki/Thoth_(operating_system)" title="Thoth (operating system)">Thoth</a></i>^ → <i><a href="/wiki/Harmony_(operating_system)" title="Harmony (operating system)">Harmony</a></i>^ → <i><a href="/wiki/V_(operating_system)" title="V (operating system)">V</a></i></li> <li><a href="/wiki/Versatile_Real-Time_Executive" title="Versatile Real-Time Executive">VRTX</a>^</li></ul></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Software_framework" title="Software framework">Frameworks</a>, <a href="/wiki/Software_development_kit" title="Software development kit">kits</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <li><a href="/wiki/Cosmos_(operating_system)" title="Cosmos (operating system)">Cosmos</a>°</li> <li><a href="/wiki/Genode" title="Genode">Genode</a>°</li> <li><a href="/wiki/TI-RTOS" title="TI-RTOS">TI-RTOS</a>^°</li> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Programmer" title="Programmer">Developers</a></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/Gordon_Bell_(QNX)" title="Gordon Bell (QNX)">Gordon Bell</a></li> <li><a href="/wiki/Thomas_Bushnell" title="Thomas Bushnell">Thomas Bushnell</a></li> <li><a href="/wiki/David_Cheriton" title="David Cheriton">David Cheriton</a></li> <li><a href="/wiki/Dan_Dodge" title="Dan Dodge">Dan Dodge</a></li> <li><a href="/wiki/Per_Brinch_Hansen" title="Per Brinch Hansen">Per Brinch Hansen</a></li> <li><a href="/wiki/Gernot_Heiser" title="Gernot Heiser">Gernot Heiser</a></li> <li><a href="/wiki/Jochen_Liedtke" title="Jochen Liedtke">Jochen Liedtke</a></li> <li><a href="/wiki/James_G._Mitchell" title="James G. Mitchell">James G. Mitchell</a></li> <li><a href="/wiki/Ike_Nassi" title="Ike Nassi">Ike Nassi</a></li> <li><a href="/wiki/Richard_Rashid" title="Richard Rashid">Richard Rashid</a></li> <li><a href="/wiki/Andrew_S._Tanenbaum" title="Andrew S. Tanenbaum">Andrew S. Tanenbaum</a></li> <li><a href="/wiki/Avie_Tevanian" title="Avie Tevanian">Avie Tevanian</a></li> <li><a href="/wiki/William_Wulf" title="William Wulf">William Wulf</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><i>Italics</i> <b>= discontinued</b></li> <li><b>^ = <a href="/wiki/Real-time_operating_system" title="Real-time operating system">Real-time</a></b></li> <li><b>° = <a href="/wiki/Open-source_software" title="Open-source software">Open-source software</a></b><br /><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <b><a href="/wiki/Category:Microkernel-based_operating_systems" title="Category:Microkernel-based operating systems">Category: Microkernel-based operating systems</a></b> <span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <b><a href="/wiki/Category:Microkernels" title="Category:Microkernels">Category: Microkernels</a></b></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://auth.wikimedia.org/loginwiki/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Multi-Environment_Real-Time&oldid=1267081596">https://en.wikipedia.org/w/index.php?title=Multi-Environment_Real-Time&oldid=1267081596</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Real-time_operating_systems" title="Category:Real-time operating systems">Real-time operating systems</a></li><li><a href="/wiki/Category:Bell_Labs_Unices" title="Category:Bell Labs Unices">Bell Labs Unices</a></li><li><a href="/wiki/Category:Microkernel-based_operating_systems" title="Category:Microkernel-based operating systems">Microkernel-based operating systems</a></li><li><a href="/wiki/Category:Microkernels" title="Category:Microkernels">Microkernels</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_matches_Wikidata" title="Category:Short description matches Wikidata">Short description matches Wikidata</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 3 January 2025, at 14:26<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. 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