Traditionaly, it has been thought of as an Operating System, but that is really only partly correct today. Now, UNIX is really more of a family of Operating Systems, each designed with the same common goals in mind.
A UNIX system is typically one which adheres to POSIX standards, which are a standard specification for the interface and functionning of a given Operating System.
"The name POSIX was suggested by Richard Stallman. It is expected to be pronounced pahz-icks as in positive, not poh-six, or other variations. The pronounciation has been published in an attempt to promulgate a standardized way of referring to a standard operating system interface".
Many of the ideas of UNIX are now more than 30 years old. Why do we still use it then? The answer to this is non-trivial, but I hope it will be somewhat explained by these courses. Some brief reasons include:
UNIX is true multi-user and multi-processing
UNIX is robust and has been for a very long time
UNIX is mature
UNIX is intimately tied with C
UNIX provides a stable and mature development environment
UNIX allows something called a "File Abstraction" which enables abstracting away complicated interfaces and functions behind simple file interfaces
Many of the best UNIXes are free (not only as in freedom but as in no cost).
There have been many many players in the UNIX world since its inception, and an examination of its history is in order so that we can fully understand why it operates the way it does. However, lectures in UNIX history can become dull and tedious to all but the most astute UNIX-fan.
Thus, for this class, I will be experimenting with spending 45 minutes to an hour each day providing a glimpse at key sections of UNIX history rather than running through it all at once. This should allow us to get the necessary historical understanding of UNIX, yet also "dive right in" to working with UNIX so we can immediately start using what we learn.
The courses will largely be arranged by topics, and will loosely follow the books involved. I make no promises that everything in the books will be covered or that everything I cover will be in our books. We will cover what I feel a student would need in order to get a working UNIX system "up and running", which means that we will occassionally stray from the book. Bear in mind that you will always be able to re-read these classnotes online (provided that I can continue to afford my web-hosting).
