The Evolution of the Unix Time-Sharing System (1984) [pdf]
OK, let&#x27;s take this in some more context:<p>&gt; To the Labs computing community as a whole, the problem was the increasing obviousness of the failure of Multics to deliver promptly any sort of usable system, let alone the panacea envisioned earlier.<p>What was Multics? One core animating idea of Multics was the &quot;Computer Utility&quot; concept, or centralized mainframe-based computing as a utility as reliable and available as water and power:<p><a href="https:&#x2F;&#x2F;multicians.org&#x2F;fjcc1.html" rel="nofollow noreferrer">https:&#x2F;&#x2F;multicians.org&#x2F;fjcc1.html</a><p>&gt; One of the overall design goals is to create a computing system which is capable of meeting almost all of the present and near-future requirements of a large computer utility. Such systems must run continuously and reliably 7 days a week, 24 hours a day in a way similar to telephone or power systems, and must be capable of meeting wide service demands: from multiple man-machine interaction to the sequential processing of absentee-user jobs; from the use of the system with dedicated languages and subsystems to the programming of the system itself; and from centralized bulk card, tape, and printer facilities to remotely located terminals. Such information processing and communication systems are believed to be essential for the future growth of computer use in business, in industry, in government and in scientific laboratories as well as stimulating applications which would be otherwise undone.<p>-- &quot;Introduction and Overview of the Multics System&quot;, F. J. Corbató (MIT) and V. A. Vyssotsky (Bell Labs)<p>This was an ambitious project and it took some time to achieve. Work on Multics started in 1965 and Multics was first used for paying customers in October of 1969, six months after Bell Labs dropped out and work on Unix began.<p><a href="https:&#x2F;&#x2F;multicians.org&#x2F;chrono.html" rel="nofollow noreferrer">https:&#x2F;&#x2F;multicians.org&#x2F;chrono.html</a><p>So did Multics deliver &quot;promptly&quot;? Probably not, but four years for an ambitious project isn&#x27;t so bad, and it took Unix six years (until 1975) to get to Sixth Edition, the first version of Research Unix used much outside of Bell Labs.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Version_6_Unix" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Version_6_Unix</a><p>My point is that Multics is given short shrift by this history, which is understandable because it&#x27;s about a completely different OS, but it&#x27;s painted as a failure that was stalled in development for an inordinate amount of time. It wasn&#x27;t a failure, as it was used commercially until 2000, and whether it was inordinately slow in coming is impossible to fairly judge because it was, in most respects, the first of its kind, in that it was the first &quot;complete&quot; OS with what we&#x27;d now consider the full complement of functionality.