"You need Unix-level performance and reliability. You don't have a Unix-level budget." — Microsoft's advertisement (2003)

Unix is one of the oldest operating system, originally written in assembly in 1969 by Dennis Ritchie and Ken Thompson at Bell Labs. Later Unix was rewritten in C (its native language) for portability in 1972. Unix is the most portable and reliable operating system.

By the way, UNIX© is not the same as Unix. UNIX© (all capital letters) is a trademark while Unix (a proper name) is a philosophy. Considering the latter, BSD and Linux are not UNIX©. They are UNIX© clones, but nonetheless they are considered Unix. If you are confused, you are not alone.

Several vendors have registered versions of UNIX©. They are Tru64 Unix, IBM AIX, SCO UnixWare, SGI IRIX and Sun Solaris.

At the same time, there are several Unix clones like BSD and Linux. For those who work with Windows and do not want to handle a separate installation, Cygwin is handy with its Unix-like environment.

About 90% of the internet relies on a variation of the Unix operating system (normally either Linux or BSD), with the Apache web server. For example, this web site is hosted by Netfirms, running on FreeBSD, with Apache, SSI, Perl, PHP, MySQL and Sendmail with FormMail. If you are new to these technologies and would like to try them, go to Apache Friends where you can download everything in one file.

Most code from the various distributions of Linux and BSD, Apache, PHP, the MySQL database, and the Mozilla web browser are open source. Support the open source community. One way you can do this is by supporting the Open Source Education Foundation.

Installing Unix (or Unix Clones):

Unfortunately I have no experience installing Tru64 Unix, IBM AIX, SCO UnixWare, SGI IRIX or Sun Solaris. I have experience installing BSD and Linux though.

Some of the information mentioned in this page was taken from the developerWorks site.