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History of UNIX a short version

History of UNIX a short version. CSCI 333 August 31, 2011. Before UNIX. In the 40’s and 50’s, all computers were “personal computers” That is, one person signed up for an hour of computing time In the 60’s, batch systems with punched cards were the way of life. Multics.

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History of UNIX a short version

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  1. History of UNIXa short version CSCI 333 August 31, 2011

  2. Before UNIX • In the 40’s and 50’s, all computers were “personal computers” • That is, one person signed up for an hour of computing time • In the 60’s, batch systems with punched cards were the way of life

  3. Multics • In 1965, a collaborative project by GE, MIT and AT&T • Goal: Create an operating system to “show that general-purpose, multi-user, timesharing systems were viable.” • Name: Multics (Multiplexed Information and Computing Services)

  4. Multics • In 1969, frustrated by slow progress, AT&T pulled out of the project • Ken Thompson, of AT&T, needed something interesting to do • He took over an unused DEC PDP-7 (minicomputer) and pursued some of the Multics ideas on his own (most of which were shot down by AT&T)

  5. Ken Thompson • The code was written using assembly language • It was much simpler than Multics • It was good at running programs • Another researcher at Bell Labs jokingly referred to it as UNICS (Uniplexed Information and Computing Services)

  6. Dennis Ritchie • In 1970, Thompson along with Dennis Ritchie and others, rewrote UNIX for a new PDP-11 (this was the dominant minicomputer in the 70’s...it had 24K RAM, 12K of which for UNIX…it only cost a mere $65,000) • More tools were added, such as a shell, editor, assembler, utilities like rm, cat, and cp

  7. B • In 1972, Thompson wrote B, a very simple programming language • He got it going on the PDP-7 because Fortran wouldn’t work for him • He wanted to re-write UNIX in a high-level language

  8. C • In 1972, Ritchie used the PDP-11 to add types to B • Initially, it was called NB, “New B” • Then, he wrote the compiler • The C programming language was born • C was designed to be simple and portable

  9. Re-writing UNIX • In 1973, Thompson re-wrote UNIX using C • Operating systems written in assembly language consisted of hardware-dependent code • An operating system written in a high-level language, such as C, allowed it to be portable • The kernel consisted of 10,000 lines of code • Many features of other O.S. kernels were left out of the UNIX kernel (e.g., the command language ran as a user process)

  10. The spread of UNIX • In 1974, Ritchie and Thompson published a paper about UNIX • Many universities were interested • AT&T licensed UNIX for a modest fee • Releases were distributed as C source code • By 1977, more than 500 sites (125 universities) were running UNIX

  11. BSD • Graduate students at the University of California Berkeley began making significant enhancements to the source code • In 1978, they released 30 copies of their Berkeley Software Distribution (BSD): • Easy to switch between programs • Longer filenames (255 vs. 14) • Easy to connect UNIX machines to LANs

  12. Versions / Flavors of UNIX • Under agreement with AT&T, organizations could release minor updates without renegotiating contract • DEC and Sun adopted the Berkeley UNIX • Data General, IBM, HP, and Silicon Graphics were among those that adopted the AT&T (“standard”) System V • In 1980, Microsoft developed XENIX • In the early 90s, Linux and Solaris were created

  13. Different versions of UNIX • To find out what you are responsible for knowing about UNIX versions on Exam #1, click on the link below: • Exam #1 Outline • IEEE Portable Operating System Interface (POSIX) is an attempt to standardize UNIX (among other things)

  14. Pioneers of computing…today

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