The UNIX Operating System

UNIX ® systems are ideal for providing services from a core group of computers to a heterogeneous group of clients. Based upon open standards and evolved from decades of practical application, there is no better choice for performance, reliability, and interoperability. UNIX gave rise to the Internet and the Web, as well as the C language, which is at the heart of virtually every component in a modern computer system.

The UNIX name, originally held by AT&T and the UNIX Systems Laboratories, was granted to the X/Open Group in 1995, which is now The Open Group. They developed the XPG and Single UNIX Specifications, to which certified commercial UNIX systems comply. Sun's Solaris Operating System is perhaps the dominant commercial UNIX implementation.

The GNU/Linux System

Linux® was developed by Linus Torvalds as an alternative to commercial UNIX. It provides the functionality of the UNIX kernel as free software. Together with The Free Software Foundation's GNU software, a complete UNIX-like system is now available for free under the terms of the GNU Copyleft license. XFree86 adds the X Window System, for which numerous utilities and desktop environments are available.

Commercial distributions that include Linux, the GNU components, XFree86, the Apache Web Server, and countless other free tools are available from several sources. A free version of Debian GNU/Linux can be downloaded from the Debian site, for the technically savvy with a broadband connection.

Free Software

A wealth of free software is available for UNIX-compatible systems. Most of this software runs on numerous other operating systems as well. The most comprehensive suite of packages is offered by The GNU Project. The GNU C Compiler and GNU Emacs probably support more platforms than any other body of software. GNOME is the GNU desktop, GTK+ is their toolkit for building GUI applications.

The Apache Software Foundation develops the Apache HTTP Server, and numerous Web tools such as the Xerces XML parser, the PHP server side scripting language, and the Tomcat Java servlet.

Another noteworthy piece of free software is Larry Wall's Perl, a powerful C-like scripting language, perhaps best known as the language of CGI scripts. Perl was the logical choice for this job, as the perl interpreter is available for a wide variety of operating systems, it is feature rich, and is freely distributed under the terms of Perl's Artistic License. It is an excellent choice for writing robust cross platform scripts. Perl is included in Mac OS X, and with Cygwin for Windows. A binary version is available for the legacy Mac platform at MacPerl .

• UNIX Home
• PASC (POSIX)
• Single UNIX Spec.
• GNU's Not Unix!
• The Open Group
• The XFree86 Project
• X.Org
• The Apache Software Foundation
• Linux Online
• Perl.com

• UNIX platforms
• Linux distributions
• Free Software
• The C Language
• Industry Standards

• UNIX Timeline
• GCC Compiler
• GNU Emacs Editor
• GNOME Desktop
• GTK+ X Toolkit
• Debian GNU/Linux
• More GNU Software
• The Jakarta Project
• Apache XML, Xerces
• Apache PHP
• MacPerl
• Mac OS X
• Cygwin