Unix was one of the most popular server operating systems, but its life has been marred by bitter legal battles
The developers wanted to play the game on a PDP-7, a minicomputer built by Digital Equipment Corp found in the corner of their building. But the game couldn’t be run run on more modern (and hence costly) equipment, as computing resource was a precious commodity back then.
By the summer of 1969 they had developed the new Unix OS that could run the computer game and in 1971 the first ever edition of Unix was released. A second edition of Unix arrived in December 1972 and was rewritten in the higher-level language C.
The Unix operating system first gained worldwide attention when it was presented formally at the 1973 Symposium on Operating Systems Principles, where Ritchie and Thompson delivered a paper.
However Bell Labs was forbidden under a legal ruling from the 1950s as acting as anything other than a communications carrier. It was also required to licence patents if asked.
This meant that Bell Labs could not commercially exploit the new OS. Instead Bell Labs shipped the system to organisations, just for the cost of media and shipping. Developer Ken Thompson also shipped out tapes and disks when it he received requests for the new OS.
Very soon a dedicated community appeared for the operating system and they all worked together to share resources.
What made Unix so popular was that the OS provided a hierarchical file system. This permitted what was then quite a revolutionary development – allowing for files to be placed in directories or folders, which in turn could be placed in other directories.
Essentially, Unix was elegantly designed, was simple to use, portable, and was graced with great timing, as it was able to jump aboard the computer revolution of the 1970s. Unix initially took root in academic circles, before it really hit the big time in the 1980s in the commercial world.
Four decades on, and Unix is still a heavily used OS, and its descendants number in the hundreds, including Mac OS.
Unix was born out Bell Labs, but went through many owners since then. When the US Department of Justice settled its second antitrust case against AT&T and broke up Bell System in 1983, it freed AT&T of the previous restriction that prevented it from exploiting Unix as a product.
AT&T promptly rushed to commercialize Unix System V, and nearly killed Unix in the process.
But things changed in the 1990s when Novell, who at the time specialised in proprietary network operating systems, acquired the rights to the original Unix source code when it purchased Unix System Laboratories from AT&T in June 1993.
Two year later in September 1995, Novell entered into an Asset Purchase Agreement (APA) with Unix vendor the Santa Cruz Operation. The APA transferred certain rights regarding Unix, and Novell’s UnixWare version of Unix, from Novell to Santa Cruz.
In 2000, Caldera Systems acquired the Server Software and Services divisions of Santa Cruz, as well as the UnixWare and OpenServer Unix technologies. Caldera Systems then became the legal successor to Santa Cruz for the purposes of the APA. A year later Caldera Systems changed its name to Caldera International in 2001 and then to The SCO Group (SCO) in 2002.
Unfortunately, the SCO Group then embarked on a highly controversial campaign in 2003 to force Linux users to pay them software license fees. SCO claimed that it was the owner of Unix, and it implied that it held the copyright for the original AT&T source code of Unix, and derivatives of that code.
SCO sued firms such as IBM, before Novell hit back saying that while it had transferred certain Unix assets to SCO’s predecessor (the Santa Cruz Operation), it had never transferred the copyrights upon which the IBM case hinged.
In August 2007, a judge ruled that Novell did indeed own the Unix source code, and both parties were about to head to court when SCO declared itself bankrupt thanks in part to the costs of the ongoing legal battles.
SCO appealed again, but this was rejected in 2011.
The current owner of the trademark Unix is The Open Group, an industry standards consortium.
The legacy of Unix lives on in other guises nowadays. Apple’s OS X for example is based on the Mach micro kernel and BSD 4.4.
Likewise Linux is a ‘Unix-like’ operating system developed by Linus Torvalds, and BSD is a Unix operating system that for legal reasons must also be called ‘Unix-like’.