History of C and UNIX.

• You should read chapter 1 of the book.
• Early development began in the late 1960s.
  • At Bell Labs, part of AT &T.
  • By Ken Thompson
  • Originally developed in assembly language.
  • The story goes he wanted to port a video game he had written on another system, and began developing utilities and tools...
  • He had been part of a previous OS project called Multics
  • He created a programming language (B) to assist in this process.
  • After several versions, Dennis Ritchie joined the project.
  • Ritchie began developing C as a tool for developing UNIX.
  • Wikipedia claims that Ritchie worked on porting UNIX to different platforms.
  • By 1973 the UNIX kernel was mostly written in C, with some portions in assembly or machine language.
  • Bottom pf page 2 "Like the UNIX operating system itself, C was designed by professional programmers for their own use."
• Further development
  • Early documentation was in the form of man pages.
    • And somewhat still is.
    • This meant the development of a typesetter.
    • troff
  • Presented at a symposium in 1973

    	        This led to requests for the system, but under a 1956 
    		consent decree in settlement of an antitrust case, the
    		Bell System (the parent organization of Bell Labs) was 
    		forbidden from entering any business other than 
    		"common carrier communications services", and was required 
    		to license any patents it had upon request. UNIX could not,
    		therefore, be turned into a product. Bell Labs instead 
    		shipped the system for the cost of media and shipping. 
    		Ken Thompson quietly began answering requests by shipping 
    		out tapes and disks, each accompanied by - according to 
    		legend - a note signed, "Love, Ken". 
    	     

  • In 1975 Thompson spent time at UC Berkeley.
    • Installed a version of UNIX
    • This was used for research and OS development.
    • They would release patches and utilities for UNIX (BSD)
    • This was based on the UNIX from Bell Labs, so this was UNIX.
  • At this time, AT&T released UNIX free to universities.
• The 1980s
  • Widely in use by academic computer science departments.
  • Started to be used by workstation companies like HP, IBM, DELL, SUN, ...
  • In 1982, a license could cost as little as $100
  • In 1983, the Bell system was broken up and AT&T started selling UNIX for real.
    • A UNIX license became much more expensive.
    • The system was "not as favorable for academic use as the older versions of Unix"
  • Enter the Richard Stallman and the Free Software Movement.
• Free Software Foundation (GNU)
  • With the breakup of AT&T and the restrictive license on UNIX, Richard Stallman became a strong advocate for free software.
  • He issued the Free Software Manifesto (later the GNU Manifesto.)
    • This defines GNU: Gnu's Not Unix
    • And the main goals of the FSF.
    • Read the last two paragraphs.
  • This lead to the development of GCC, which you know and love.
  • And many of the programs which you know and love.
• Linux
  • Linus Torvalds began developing a UNIX like kernel after taking an OS class.