Chapter 1, History and Standards

• What is an operating system?
  • CSCI 125: A program that manages the resources of the computer.
• What are these resources?
• Name some operating systems.
• Can you give a principle difference between linux and windows?
• What constitutes an operating system?
  • More later, but
    • A kernel or operating system proper
      • The program that is the operating system
      • Scheduler or process management
      • Memory manager
      • Disk/storage manager
      • Network management
    • The kernel along with all of the utilities
      • Editors
      • Web browsers
      • Compilers
      • Text based user interface
      • Graphical user interface
      • Solitaire
• Bell Labs
  • AT&T once had a monopoly on the phone system
    • If you had phone service, it was from AT&T
    • This allowed them to install the phone system (wires) and make a profit.
    • No problem for cities, real problem for remote locations
    • Think miles of wire per phone in some sections of the country
  • AT&T had a research lab
    • This was more common before the 80's
    • These were huge private research complexes
    • Think IBM's TJ Watson Labs in NY
    • Bell Labs conducted primary research
      • Papers, patents, Nobel Prizes.
      • A quick look at the wikipedia page tells us quite a story.
    • Bell Labs has had many computer scientists working for them
      • Bjarne Stroustrup (C++)
      • Brian Kernighan (AWK, C, ...)
      • Denis Ritchie (C)
      • John Hopcroft (Data structures)
      • Ken Thompson(unix)
      • And MANY others.
• A brief history of unix
  • Developed at Bell labs in the late 60's by Ken Thompson and others.
  • C was developed at the same time by Denis Ritchie (and others)
    • Up until this time, most OSs were written in assembly
    • This made porting to new hardware extremely difficult.
  • Since C and UNIX were developed in parallel,
    • The Application Programming Interface or API was written in C as well.
    • This is how programmers interact with the operating system.
  • In 1974 Ritchie and Thompson presented a paper in the Communications of the ACM about UNIX.
    • Many institutions requested copies of the software
    • But AT&T did not have permission to do anything but phones
    • So they licensed the software to educational institutions for a very low price (~$100)
    • And MANY research projects began working on UNIX.
  • By 1977 UNIX was running on many sites
  • BSD
    • Ken Thompson spent an academic year at Berkeley
    • He worked with many students on Unix projects.
    • BSD or Berkeley Software Distribution, became an offshoot of UNIX
    • AT&T still owned the unix source code
    • But BSD provided many different additions/improvements to the code.
  • Workstations and UNIX growth
    • In the 80's companies like IBM (AIX) Dec (ULTRIX) Sun (SunOS), HP (HPUX) and others licensed unix code
    • Then produced their own versions
    • BSD continued
    • SCO, Minix and others arrived
    • This led to a divergence of UNIX especially the API
    • This led to the creation of POSIX (Portable Operating System Interface ) standards
  • In 1982 the Bell system was broken up
    • AT&T lost the monopoly on the phone system
    • But gained the right to sell software.
    • And they did.
    • This drove Richard Stallman, among others insane.
  • Stallman, Free Software and GNU
    • Software should be free (like speech, not like beer)
    • GNU - Gnu's Not Unix
      • An attempt to create a free open source version of unix
      • GCC, GDB, emacs, ....
• Linux
  • Minux is Tanenbaum's response to unix source code shut down.
  • But he charged for it.
  • Using GNU utilities and MINUX Linus Torvalds created Linux
  • An expansion of an OS project
  • Free as in open source
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