05/12/2021

031 – UNIX operating system – 1969

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I wanted to separate data from programs,
because data and instructions are very different. Ken Thompson

Bell Labs worked with MIT and GE on Project MAC, Project on Maths and Computation, and in 1965 co-developed MULTICS, the multiplexed information and computing service.  But Bell concluded that the MULTICS project had grown too complex, diverted into artificial intelligence.  Bell adopted GE’s operating system GECOS for itsl use.

Ken Thompson, Dennis Ritchie, Brian Kernighan, M D McIlroy, and J F Ossanna were among the last of the Bell team to work on MULTICS and were unimpressed by GECOS.  They decided to design their own OS, retaining the multi-user environment that MULTICS had created.

1969 Working on the PDP-7, Thompson and Ritchie created an OS with a multi-tasking yet single-user approach.  It had hierarchical files, utility files, device files – all operating via a command-line interpreter.  This was intended to be a developer’s tool.  Peter Neumann named it the UNICS, Uniplexed Information and Computing System; when this operating system became multi-user it was renamed UNIX.

UNIX expressed the main items of an OS in a kernel of just 11,000 lines of code in assembly language.  This kernel drove a whole series of utilities; twenty years on Windows NT 3.1 had over 5m lines!

A 1958 consent decree forbade AT&T from entering the computer business; it licensed UNIX to universities and commercial operators.

C Programming language also emerged from work on UNIX at Bell Labs.  It was named C simply because it followed on from a version B!  In 1978 Brian Kernighan and Dennis Ritchie published a book to define C.  The language became so useful that in 1972/3 UNIX was rewritten in the C programming language; 10,000 of the lines of code were changed into the high-level language rather than machine code.  This made it portable, requiring little work to port it from platform to platform.  It soon became the preferred OS for work stations, servers and mobile devices.

1974 Bob Fabry at UCB acquired ARPA funding to improve UNIX.  He created the Computer Systems Research Group and from 1977 released versions of Berkeley UNIX or BSD.  Berkeley Software Distribution was preferred by educational users; Bill Joy used it to develop Sun OS.

1983 AT&T’s antitrust case was resolved and the Bell organisation broken up.  AT&T launched UNIX System V as a commercial product.  This almost killed the OS, though System V spawned Microsoft Xenix and SCO UNIX.

A number of initiatives sought to ensure UNIX was open software.  In 1982 Richard Stallman launched the GNU Project and eight years later Open Software Foundation released OSF/1, a UNIX version based on Mach and BSD.

1991 A group of UCB developers founded Berkeley Software Design Inc to create UNIX for the Intel platform.

This was the same year that Linus Torvalds was moved to develop the Linux version.

AT&T sold on its UNIX rights to Novell who unsuccessfully tried to combat Microsoft Windows NT with UnixWare.  The rights were subsequently passed on to the X/Open Consortium.

2005 Based on UNIX System V, Sun’s Solaris software was released as open source.  So now UNIX in most of its forms was securely open source software.  Today the Open Group, an industry standards operation, officially owns the UNIX trademark.

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