After Multics' cancellation in March of 1969, essentially no department was allowed to buy a computer powerful enough to continue Multics research. Sam Morgan became the department head of computing science research at Bell Labs in 1967, well into the Multics program. He was present during the cancellation of Multics and the birth of Unix.
There was an announcement, a formal announcement that the work was stopping, that we were [devoting] no more effort to [Multics], and that we were simply out of it. I believe it had to be done that way because ... unless there is a definite statement that you are not going to work on a project anymore, why, some people will continue to work on it. That's the way... research goes. Folk from day to day do their own thing. And so there was a clear announcement that the work was over...It was simply... using up effort and was not... advancing and showed no promise of... turning into a user useful thing.
A number of factors contributed to AT&T's decision to not buy any more computers powerful enough to run Multics. As Sam Morgan was able to recount about the removal of service computing from all technical organizations in Bell Labs in the middle of 1969:
... service computing at all Bell Labs locations ... merged into a single division under a man named Phil Thayer... All the comp centers were put under unified management and for a year and a half I was both Director of Service Computing at Murray Hill and Whippany, and Director of Computing Science Research. ... It just wasn't reasonable ... for a research organization also to try to manage a stable computing center. So anyhow, having a separate computing service organization was long overdue. [The separate computing organization] was started in the middle of 1969. And this was another impetus I think toward the development of an operating system for small machines, namely Unix, that went on in computing science research. Because once the comp center machines were moved out from under the research aegis, we had in research had our own machines, and management would not buy big DEC PDP 10's and so we had to do something on minicomputers. And that was another impetus toward Thompson and Richie in the Unix direction. Anyway, that's, that's kind of the history of things.
Many scientists did not understand, or did not want to understand, that AT&T was out of computers. Thompson in particular recalls, "There was no explicit policy that we weren't going to get back into the computer business"
Thompson and Ritchie began work on a Multics like file system because they enjoyed using Multics, as didmost of the scientists, and wanted to continue research. Sam Morgan felt that scientists liked Multics because "[Multics] was fun. You could develop software, you could do all sort of things with it. It just wasn't ... cost effective." Because the writers of Unix liked the type of environment Multics provided, when Unix was developed, it "turned out to be a much simpler, more cost effective environment which provided users with the pleasures of... the same kind of sandbox," the best of both worlds. Thompson and Ritchie were determined to find a computer to continue Multics-like research. What they found was an aging DEC PDP-7, the only system available. It had a very limited memory but at least they could implement a file system.
The PDP-7 in question was specially equipped for fancy graphics work being done by Bill Minkey. It belonged to department 13, headed by Joseph Condon, an electrical engineer who worked on current flow. Condon's group wasn't using the computer, and Ken Thompson and Dennis Ritchie were fooling around with it. They even programmed a famous computer game, "Space Travel". Sam Morgan noted "that Ken Thompson had a space war game that he played for a while when he was looking for something to replace Multics."
When asked how Thompson and Ritchie were using a computer not in their department, Condon said, "I don't know." In fact, Condon had become the head of the department that owned the PDP-7 after Thompson and Ritchie began borrowing the machine. Thompson explains how it happened:
It was another department that owned it, and when it would break, it would be a hassle over who maintained it, and we didn't maintain it because we couldn't get our department to pay for maintenance. There was... no money ...[and] they just didn't want us to do this. ... this department that owned the machine ... wanted to throw it away, but [we wanted] to keep it, on their space and maintain it for [ourselves]. That was a precarious situation, and that persisted. Then when it became clear that these machines were nearing the end of their life, we ... tried to get them officially ours, which failed, our manager wouldn't pick up these machines, at zero cost, you know, they didn't want...the cost of the space.
When Thompson realized that the PDP-7 was not powerful enough to implement a file system that could offer some of the advantages of Multics he initially programmed a bare-bones file system. The file system was then put on a PDP-10. Using this enhanced capability, Thompson and the others slowly added tools that helped them monitor what the file system was doing. Thompson devoted a month apiece to the shell, editor, assembler, and other software tools. When asked when he realized that a new operating system was being born, Thompson replied,
... in the summer of '69, it was totally rewritten in a form that looked like an operating system, with tools that were sort of known, you know, assembler, editor, and shell -- if not maintaining itself, right on the verge of maintaining itself, to totally sever the GECOS connection.
It was this point that the epic birth of UNIX became a reality. After the OS was implemented in assembly language it was dubbed UNIX as a play on Multics; MULTI- being many and UNI- being one.
The file system on the PDP-7 was created in assembly language. As noted above, Thompson realized that for an operating system to be useful it needed to be created in a high-level programming language by which it could be ported to any system. Thompson initially began programming a Fortran compiler, but changed his mind and created a very simple language called B. Ritchie improved upon B and renamed the language C. UNIX was written in C and could be ported to any computer.
Because of its portability, Unix could now be tried on a larger machine. The only trouble was finding a machine around the size of Multics and a department head to purchase it. Thompson was able to recall the process.
... we started on a set of proposals for getting a new machine,...... So what would happen was that we would take these proposals for these machines and do all the research on them and get the vendors in and waste everybody's time, and get these proposals up and they'd be thought about our management for a extended periods of time and they'd say 'no' for some funny reason, you know, never for a real one (unclear) computing anymore. There were several, really several, of these big rounds of trying to get a vendor and a machine and, to get....to do this work. Most of it was carried on by Osanna and me, and the interference type people. Ultimately what happened was um we found a PDP-11, it was in fact not announced yet, but it was right on the edge of being announced. ...Osanna and I put together a proposal to buy a PDP-11 to do ... research in text processing, (unclear) and document preparation, ... it was the first of the goals that were specific, ... The other ones were...we wanted to play with computers and operating systems, and they were unspecific, and the our management went off and thought about it, and rejected it again. But in the meantime going up and down the hierarchy a sister department, 122, psychology research, came over and said 'well we'll fund it out of our area,' embarrassed the hell out of our management. And they bought it, gave it to us, and...They just had Insight, and inspiration and unfortunately our management didn't.... our management was suffering from wounds from the Multics days.
Eventually, Lee McMahon, one of the four members of the Unix machine proposal group, the only one who belonged to another department, convinced his own department head to fund a machine.
Meanwhile, Joe Osanna convinced the Bell Labs patent office that Unix would be a worthwhile investment as a text processing system. Use of Unix started in the patent office of Bell Labs, but by 1972 there were a number of non-research organizations at Bell Labs that were beginning to use Unix for software development. Morgan recalls the importance of text processing in the establishment of Unix.
[Space Travel] was fun but the, the first real application of the file system that became Unix was a text processing system. And this was kind of the merging of file system work and work that folks had been interested in for a long time, text processing...
People were interested in text editing and formatting and you could do this on a small computer... if you had an operating system that involved easy handling of files and... time sharing, ... people could access and use each other's files. The Unix file system and the text editing and formatting work kind of came together...
[A text processing system] was a system the Labs was willing to buy a machine for. When this, the proposal was first made that we should buy a machine for text processing it was presented to me because I had to sign the purchase order.
Though in afterthought Morgan admits to the merits of text processing, he had this defense to his initial rejection:
[T]he pitch was not really that two of Morgan's MTS, having been thrown out of Morgan's office (I exaggerate here, but having been thrown out of Morgan's office), trot down the hall to Matthew's and say, 'Morgan doesn't love us what can you do for us?' They came in through McMahon's director ...The people who originally made the proposition to me were Osanna, Thompson and McMahon, who were working together.
Morgan admits to his underestimation of the proposals but, acting as a department head, his responsibility was to rely on what he knew, which wasn't much about text processing.
I didn't understand at the time the innovative nature of the Unix file system, and we had done text processing work in the past and I didn't see that we were, that any great research advance was being made. It sounded as if people wanted to provide a service or something with a typing pool. So the first proposal to buy a, I guess it was a PDP1120 I turned down...As I said the first time that Thompson and company asked for a computer they asked for a DEC PDP10 and they were told no on that. It was simply too big and you are not going to do operating system research for a big computer just after Multics has been turned off. The second time they asked, they wanted a PDP-1120 and I said, 'I am not convinced yet, I want to see more of what you say you are going to do with your text processing system.'
In any event, his philosophy followed a somewhat lax path.
I didn't stomp on them, but neither did I sign their order and they found somebody else, another director to sign the order, and the third time they came around they wanted an 11/45 and by that time they had a perfectly plausible and defensible story. So they got selective enthusiasm used on them but not too violently or with too short of a time scale. If it is going to be good it will prove itself.
One of Morgan's problems with accepting the proposals was in dealing with his own management and the bureaucracy in the upper levels of Bell Labs.
well I guess I had some difficulty in sorting out the signal from the noise. I was quite well aware that my bosses wouldn't approve the purchase of a really large computer to support any surreptitious continuation of the Multics effort. And I was I think willing to wait for the initial shouting to die down, and I figured that if there was a research component involved in the text processing work that it would appear in due course. And indeed it did.
Being a manager, Morgan had rules of management to follow.
The management principles here are that you hire bright people and you introduce them to the environment, and you give them general directions as to what sort of thing is wanted, and you give them lots of freedom. Doesn't mean you always necessarily give them all the money that they want. ...You exercise selective enthusiasm over what they do. And if you mistakenly discourage or fail to respond to something that later on turns out to be good, if it is really a strong idea it will come back...
To Morgan, his decision and the effects of his decision were a natural process, and there was nothing to regret.
I have never been in an organization that had enough money, or enough hiring slots, or enough office or land space to do everything that we would like to do. So one provides some back pressure. And in the case of the transition from Multics to Unix, the Multics faucet had to be turned off reasonably hard. It was a part of turning off, I mean it was a management decision that this was going to be turned off. And part of turning it off was not immediately buying hardware on which Multics could be continued. In retrospect, Thompson and Ritchie and other people did find partly through their own efforts and partly by looking for a director that was willing to buy a small amount of hardware, did find machines on which they could work. And in due course when it was clear to everybody around the research area that Unix was going to go somewhere and needed to be supported, they have had the machines that they wanted. They simply went to the director of the other person in the trio. And I didn't think there was anything wrong with this or unreasonable about it.
There was a reasonable justification for the way things eventually worked out.
Max Matthews was a person who collected little computers anyway, and it may be that he had more money at the time than I did. We have certain plant budgets. Anyway, I didn't think that there was anything out of the way about this and I didn't feel that somebody was criticizing my judgment. Max was perhaps in a better position to support the machine, or I don't know what. But anyway it didn't seem unusual to me, and now that I recall McMahon reported to me for a long time. He transferred from Max's organization into mine not too long after this particular incident. But at the time he was a department head for Max Matthews. So he added his voice to the desires that the other fellows had and so Max bought the first computer. But there was nothing, there was nothing particularly unusual about this. And since it would have been a little more unusual if people entirely from one center had gone to a different director and said, 'Can you support this?' In which case, I am sure that Max would have come to me and said, 'Look, two of your guys have come to me and have said, will I buy them a computer? If a computer is going be bought, you ought to buy it. Let's discuss whether it should be bought or not.' The reason it didn't happen that way was that one of Max's department heads was in this story.
In Morgan's view, Matthews' department was a better choice for supporting the funding of a new machine than his own.
I was told, 'Look, Max Matthews can support this.' He was the other director. And why could he support it? He could support it because he was interested in text processing. He was doing, ... he was in behavioral sciences and psychology, and he had people who were working on text processing, and in fact one of the folk who was, came in with the proposition for the 11/20 that I turned down.
Fraught with difficulties, the search for a machine came to a successful end. Though Thompson and his fellow Unix programmers eventually obtained a PDP-11/45, the PDP7, the machine that was too small, was integral in the way Unix developed. Had the PDP-7 not been available, history might have been different.