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UNOS (operating system)
open-in-new
<h2 id="history">History</h2> <p>Jeff Goldberg created an experimental OS using only eventcounts for synchronization, that allowed a preemptive kernel, for a Charles River Data Systems (CRDS) <a href="/facts/PDP-11/9HkGUzFn">PDP-11</a>. CRDS hired Goldberg to create UNOS and began selling it in 1981.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>[<i>better source needed</i>] </p><p>UNOS was written for the <a href="/facts/Motorola_68000_series/jxd7VPlW">Motorola 68000 series</a> processors. While compatible with <a href="/facts/Version_7_Unix/ju5nRs7k">Version 7 Unix</a>, it is also an RTOS. CRDS supported it on the company's Universe 68 computers, as did <a href="/facts/Motorola/ztqczx68">Motorola</a>'s <a href="/facts/Versabus/wbApkELJ">Versabus</a> systems.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> CRDS's primary market was OEMs embedding the CRDS unit within a larger pile of hardware, often requiring better real-time response than Unix could deliver. </p><p>UNOS has a cleaner kernel interface than UNIX in 1981. There was e.g., a system call to obtain <a href="/facts/Ps_(Unix)/WWR5zQkC">ps</a> information instead of reading /dev/kmem. </p><p>UNOS required memory protection, with the 68000 using an MMU developed by CRDS; and only used Motorola MMUs after UNOS 7 on the <a href="/facts/Motorola_68020/LfHs3kMh">68020</a> (CRDS System CP20) (using the <a href="/facts/Motorola_68851/KKJaYrxY">MC68851</a> PMMU). </p><p>UNOS was written in the programming languages <a href="/facts/C_(programming_language)/Ky2No763">C</a> and <a href="/facts/Assembly_language/7XuV0cla">assembly language</a>, and supported <a href="/facts/Fortran/m1KqjcMU">Fortran</a>, <a href="/facts/COBOL/wVnhqs0k">COBOL</a>, <a href="/facts/Pascal_(programming_language)/b3yvp8bF">Pascal</a>, and <a href="/facts/Business_Basic/MeLNmqTr">Business Basic</a>. </p> <h2 id="limits">Limits</h2> <p>UNOS from CRDS never supported paged virtual memory<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> and multiprocessor support had not been built in from the start,<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> so the kernel remained mostly single-threaded on the few multiprocessor systems built.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> A UNOS variant enhanced by <a href="/facts/H._Berthold_AG/BfNypjma">H. Berthold AG</a> under the name vBertOS added demanded page loading and paged processes in 1984, but was given up in favor of <a href="/facts/SunOS/oWMcGLqc">SunOS</a> because of the missing GUI and the missing networking code in Spring 1985, when Berthold imported the first Sun to Europe. </p> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>"First DESKTOP Unix Box?". groups.google.com. Retrieved 2024-12-30. <a href="https://groups.google.com/g/alt.folklore.computers/c/M2sgLbnBn0Y" target="_blank">https://groups.google.com/g/alt.folklore.computers/c/M2sgLbnBn0Y</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>"Multics Significance". UNOS. Archived from the original on 2015-08-18. Retrieved August 15, 2015. <a href="https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html" target="_blank">https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Fiedler, Ryan (October 1983). "The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace". Byte. p. 132. Retrieved 30 January 2015. <a href="https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up" target="_blank">https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>"Multics Significance". UNOS. Archived from the original on 2015-08-18. Retrieved August 15, 2015. <a href="https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html" target="_blank">https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>"Multics Significance". UNOS. Archived from the original on 2015-08-18. Retrieved August 15, 2015. <a href="https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html" target="_blank">https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>"Multics Significance". UNOS. Archived from the original on 2015-08-18. Retrieved August 15, 2015. <a href="https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html" target="_blank">https://web.archive.org/web/20150818010925/http://ftp.stratus.com/vos/multics/tvv/signif.html</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> </ol>