Video: The Rise of Unix. The Seeds of its Fall. (DocDrop)

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In the beginning was the code, and the code was with the computer. But the code stayed with the computer. And if we changed the computer like for an upgrade or something then we had to rewrite all the code. And everyone agreed that this was wasteful. What we needed was a platform on which we can develop software. Capable of handling different hardware. But also not too expensive. Perhaps collectively managed and developed by

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a team of volunteers around the world? I wonder if such a thing is possible. The creation and emergence of the operating system Unix was one of those special moments in technology history. In this video, the rise and fragmentation of Unix. ## Beginnings In 1965, a few scientists at Bell Labs joined with peers from MIT and General Electric on a project called "Multiplexed Information and Computing Service", or Multics.

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The idea was to create this general-purpose utility for sharing time on a computer system. Computers were super expensive, so time-sharing operating systems were developed for multiple users to efficiently share computer resources. Over time these time-sharing systems matured into a communications tool connecting multiple users on the time share, with user public profiles and everything.

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General Electric then had a business selling time shares for their computer systems - and offered the Multics team the use of a GE 645 mainframe computer. Simulated with a 635 computer. Multics experimented with some interesting concepts. For instance, the idea of having arbitrary file names and directory structures - a virtual memory system. Virtual memory is where secondary storage like from a hard drive can

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be used like as if it were part of the main memory - the RAM. With this, the computer can handle more data than its RAM would otherwise physically allow it to handle. It was a massive improvement over existing file systems of the day and is still used today. The Multics team tried to bring together ideas like these - which previously were floating around but not implemented - into a single commercial product.

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## The End of Multics Looking back at it, they were probably trying to boil the ocean. Progress turned into a slog - too much money spent on too few people following too vague of a plan. Frustrated with the absence of a workable product, Bell Labs formally pulled out of the Multics project in 1969. Soon thereafter GE later decided to exit the computer industry entirely - selling the division to Honeywell.

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Despite this, a few scientists at the Bell Labs Computing Science Research Center - Ken Thompson, Dennis Ritchie, Rudd Canaday, Doug McIlroy, and J.F. Ossanna - continued working on the project. However, the end of Multics did mean losing the GE 635 computer that they had been working with up until then. Ken Thompson had written up this little space game for that computer called "Space Travel".

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Space Travel was an ambitious game that simulated the movement of the planets in the solar system and Pluto. The player can guide a ship through them and try to land on the planets ... and Pluto. A nice and mildly addicting game, but it cost $50-75 to play each time - per the cost of the computer timeshare. So when Thompson found a graphics-capable PDP-7 minicomputer

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that another department wasn't using, he decided in 1969 to rewrite the game for it. This turned out to be an ambitious project - more so since Thompson had to re-implement from scratch things like a debugging subsystem and a floating point arithmetic package. The work took some time and had been quite tedious - with the GE computer OS outputting paper tapes that had to be carried to the PDP-7.

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## A File System After finishing that, Thompson thought to then try implementing some ideas that he had been banding around with Dennis Ritchie and Canaday. They had been talking about a new type of file system for the GE 635 computer - sketching ideas for keeping files out of each other's hair. Now quite familiar with the PDP-7, he hacked out an implementation of this file system in a day or two. From there, Thompson and others added a series of simple utilities - copying,

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printing, deleting, and editing files. As well as a simple command interpreter - a shell - which was a program that ran other programs. Over time, the concept of the "file" coalesced. A file was an interface through which you can perform certain data operations like reading or writing. But the File System itself doesn't care what was actually in the file. In doing so, the concept abstracted away the differences between various computer hardwares.

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Now anyone on any device can make changes to a file - and this became one of Unix’s killer apps. In the summer of 1969, Ken Thompson's wife took their newborn son to see her parents, leaving Thompson with a lot of time. By the end of that summer, the whole thing had been rewritten into something separate from the original GECOS operating system this whole journey started on.

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They wouldn't have called it an operating system back then. Back then it was just seen as this convenient platform for developing software on. Some time next year 1970, team member Brian Kernighan suggested a new name for this system - "Unics" - as a "treacherous pun" on Multics. At some point, the spelling switched to "Unix". ## The Usefulness of Unix Unix on the PDP-7 offered a decent environment on which you can do programming.

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But the PDP-7 was an outdated minicomputer - first introduced back in 1964. Not to mention, it wasn't even theirs. So in 1970 they asked the company for a DEC PDP-11, which had then been recently introduced. Now, Thompson, Ritchie and the team have long been asking for money for a new computer but those requests were always rejected.

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This time, however, the request was granted. In part because the PDP-11 was a cheaper computer at just $65,000. And also in part the request now had a compelling pitch attached to it - to apply the file system for the use of creating and editing text files. Now with an actual use case, the request was eventually approved. Unix was rewritten for the PDP-11's low level assembly language, now with

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a text editor and a typesetting markup language called "roff". With this, the Unix operating system was offered to the Bell Labs Patent Department. The Patent Department chose to use Unix over the competing commercial product because Thompson and Ritchie quickly endowed "roff" with the ability to do line-numbered pages. What began with just three typists in the Patent Department became a popular homegrown product

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across the whole Bell Labs organization with multiple versions and its own support group. ## Unix Spreads Unix had only ever been intended as an internal tool for Bell Labs. However, it quickly escaped the laboratory and started spreading widely throughout the computing communities. Its unexpected popularity can be attributed to a few things. First, Unix was born on relatively humble hardware. Back then,

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the users of the hardware were not the same as those buying it. Programmers of the day had to make do with whatever the budget could afford. A standard Unix computer back then - usually a PDP-11/40 - cost about $50-150,000 in 1977 dollars depending on the memory configuration. Considering a graduate student cost about $10,000 back then it was a lot,

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but far cheaper than mainframes which might have cost a half million dollars at the minimum. Second, the Unix source code was written in an attractive, higher-level programming language called "C" - the first such OS like this. Dennis Ritchie had produced "C" from "B". Ken Thompson created "B" when he ported the Basic Combined Programming Language or BCPL by Martin Richards at MIT. It

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was far easier to program in C than in low-level machine assembly language. Because it was written in C, Unix was easy to port to different hardware architectures outside of the PDP minicomputer family. C also made Unix easier to modify and enhance. Third and most importantly, Unix did not cost an arm and a leg to acquire. AT&T and Bell Labs sold the Unix source code

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to nonprofits like universities for something like a few hundred dollars. This was in contrast to other software companies, which zealously guarded their programs’ source code. And even if users were able to see the code, they were not allowed to modify it. Not the case with Unix. ## The AT&T Consent Decree This behavior wasn't exactly out of Bell Labs' and AT&T's good heart.

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Back in 1956, AT&T settled an anti-trust lawsuit by the US government - the 1956 AT&T Consent Decree. The settlement decreed that in exchange for a legal monopoly on the US telephone system, AT&T would make available all of its inventions to the academic community at no charge, or license them for fair and reasonable terms. The Consent Decree also barred AT&T from entering the computer business - so a

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computer operating system like Unix was not commercially useful for them. Funny enough, the Consent Decree had already facilitated the spread of one ground-breaking electronics invention a few decades earlier - the transistor. And now it has done it for another. Whichever university asked for the Unix source code from AT&T had it … or more like had it thrown at them from out the window of a passing truck. Wary of violating the

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Decree, AT&T managers shied away from providing support to their licensees. Again, another piece of fortune because it encouraged university students with more cleverness and time than money to work together implementing the features they wanted. By the early 1970s, Unix had gone worldwide. University computers in Australia, the United Kingdom, Belgium, and the Netherlands were running it. ## Berkeley Unix

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In November 1973, Ken Thompson and Dennis Ritchie presented the first Unix paper at the Symposium on Operating Systems Principles at Purdue University. UC Berkeley Professor Bob Fabry was at the talk and obtained a copy. Since Unix then only ran on PDP minicomputers, several departments pooled their resources to get one. A few graduates and professors started working with it. And Ken Thompson himself

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joined Berkeley as a visiting professor in 1975 to help. He helped the team install the latest Unix version - Version 6 - on a newly acquired PDP 11/70 minicomputer. Two students in particular became quite familiar with this Unix - Chuck Haley and Bill Joy. They worked on finishing a Pascal implementation that Thompson started, which would allow Unix to support this higher level language.

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It turned out quite well, widely admired because of its excellent error handling. The Pascal implementation Thompson had apparently did not turn out error messages that were all that easy to understand. Haley and Joy also added a few utilities including a very capable wysiwyg text editor called "ex" for "EXtended". Ex later became "vim", a text editor that some people like.

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Word got around thanks to how well the Pascal compiler recovered from errors and how fast it compiled. People started requesting their own copies of the Berkeley variant of Unix. So early in 1977, Bill Joy put together 30 copies of what he called the "Berkeley Software Distribution" or BSD and sent them out for about $50 per tape. From there it

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got quite popular, which made good money for Joy since a tape cost like $10 each. A second version, "Second Berkeley Software Distribution" or 2BSD, quickly followed. Then in 1978, DEC introduced a new computer called the VAX-11/780, a 32-bit computer with more memory and compute power. AT&T released a version of their own UNIX/32V for it, but it did not support the VAX's virtual memory capabilities.

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This limited processing to the computer's physical memory, diminishing its power. In a game-changing move, Bill Joy and the Turkish grad student Ozalp Babaoglu added that virtual memory feature and shipped it in December 1979 as 3BSD. With this, Berkeley solidified its position as the coordinating gateway for new, leading edge Unix releases.

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## DARPA & the Internet BSD then took another big leap thanks to DARPA. Up until then, DARPA ran on a legacy mishmash of software written in different languages for different computers. In 1979, DARPA sought to consolidate to a single "universal computing environment" so they can share their software across the organization. They chose Unix to be that computing environment because of how it capably handled different hardware. In 1980, Fabry received an 18-month contract

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from DARPA to add some features to the 3BSD release of Unix. So he along with Bill Joy set up a new organization called the Computer Systems Research Group or CSRG for this. They had a small group of core programmers - the "steering committee" - coordinating a global network of volunteer contributors, working on the 4BSD or BSD Unix series.

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This new Unix had to support several of DARPA’s protocols including those for the Internet. For instance, 4.2BSD fully supported the Internet protocol stack TCP/IP and played a significant role in popularizing the Internet as we know it today. 4.2 was very popular. Over a thousand licenses were issued just a month after its official release in April 1983 - more than all of the other previous

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distributions combined. Momentum was accelerating. ## From Hobby to Industry Prior to that release though - in the summer of 1982 - Bill Joy announced that he would leave the CSRG to join Sun Microsystems as a full-cofounder. His work at BSD was earning him tens of thousands of dollars, but he felt the academic university atmosphere at Berkeley constrained efforts to grow. In his own words, "it needed to be a commercial activity".

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Sun Microsystems is famous for pioneering and popularizing the workstation computer which included - Unix OS with scientific/engineering applications, the Motorola 68000 microprocessor, and other off-the-shelf hardware. They later developed their own closed-source Unix variant for their hardware - SunOS, branched off from the 4.2BSD version of Unix.

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A single Sun workstation by itself could not match up with a mainframe or even a minicomputer. But these things were meant to be networked, and in doing so became immensely valuable. Sun in turn reaped the benefits to become one of the fastest growing companies in Silicon Valley. Sun quickly rose above, but they were far from the only company to commercialize Unix. For instance, we have the small, Berkeley-based software company Mt. Xinu. They

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sold a commercially licensed version of the BSD for the DEC Vax minicomputer. The interesting name fits well with its slogan, "We know Unix(TM) backwards and forwards". They handed out some pretty fun posters and calendars at events. Other notable Unix-based startups include Santa Cruz Operation, which sold Unix variants for x86 computers. And Onyx Systems,

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which marketed a variant of Unix for Zilog-based Personal Computers. Even Microsoft got into the fun with their Unix variant for 16-bit microcomputers called Xenix. And of course, we have Steve Jobs' workstation computer startup - NeXT. Founded in 1985, their operating system NeXTSTEP was derived from BSD, 4.3BSD Tahoe if I recall correctly.

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## Conclusion Unix pioneered these powerful concepts that helped make software the powerhouse industry it is today. Its early development and foundations came about through the efforts of people just interested in it, not really making money from it. But Bill Joy clearly said the quiet part out loud. As the community grew and its potential became more apparent, the work surrounding Unix needed to be a commercial activity.

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1983 marks the end of Unix's awkward growth years. A bounty of wealth laid seemingly ahead for the Unix industry - but who will reap its gains? The stage is set for the blood and fury of the Unix Wars.