UNIX

Operating system for digital computers, developed by Ken Thompson of Bell Laboratories in 1969. It was initially designed for a single user (the name was a pun on the earlier operating system Multics). The C language was subsequently developed specifically for UNIX, and the system was rewritten almost entirely in C; it was improved by the addition of multiprogramming and time-sharing capabilities and enhanced portability. UNIX is very popular in universities, where it is used mostly on scientific and engineering workstations, and it is used on most of the servers of Internet service providers. Because its modular construction allows it to be easily modified, it has been improved in many ways by academic and industrial institutions (see Linux).

A multiuser, multitasking operating system that is widely used as the master control program in workstations and servers. The Open Group holds the trademark for the UNIX name (spelled in upper case) on behalf of the industry and provides compliance certification to the UNIX standard (see Single UNIX Specification).

A myriad of commercial applications run on Unix servers, and most Web sites run under Unix. Over the years, there have been many different Unix versions, and, except for the PC world, where Windows dominates, almost every hardware vendor offers Unix either as its primary or secondary operating system. Sun was singularly instrumental in commercializing Unix with its Solaris OS (formerly SunOS), and HP, IBM, SCO and Digital (before it was acquired by Compaq) have also been major Unix promoters.

From the Telephone Company
Both Unix and the C programming language, which Unix is written in, were developed by AT&T. Unix and C were freely distributed to government and academic institutions, causing it to be ported to a wider variety of machine families than any other operating system. As a result, Unix became synonymous with "open systems." See AT&T.

Command Lines and GUIs
The Unix OS is made up of the kernel, file system and a shell, which is the command line interface with more than 600 commands for manipulating data and text. The major shells are the Bourne shell (original), C shell and Korn shell. Many commands are cryptic, but just as Windows hid the DOS prompt from users, the Motif GUI added a friendly image to Unix. Linux desktops offer various GUIs, and many pundits claim that Apple created the best GUI for Unix with its OS X operating system, which is Unix based. See Unix history, Mac OS X and Linux.

Unix Is Everywhere
Unix is widely used for mission critical applications, and its components are world class standards. The Internet runs on Unix protocols such as TCP/IP for network transfer and SMTP for e-mail. NFS provides file sharing, Kerberos provides network security, and X Window lets users execute programs remotely. See POSIX, BSD Unix, USENIX and UDI.

Versions of Unix that are compliant with The Open Group's UNIX specifications include Sun's Solaris, HP's HP-UX, IBM's AIX and z/OS and SCO's UnixWare. Mac OS X and Linux are also based on Unix. See Open Group, Solaris, HP-UX, AIX, z/OS, Mac OS X and Linux.

In the following illustrations, notice how many workstations and servers run Unix.

(operating system)

Unix - /yoo'niks/ (Or "UNIX", in the authors' words, "A weak pun on Multics") Plural "Unices". An interactive time-sharing operating system invented in 1969 by Ken Thompson after Bell Labs left the Multics project, originally so he could play games on his scavenged PDP-7. Dennis Ritchie, the inventor of C, is considered a co-author of the system.

The turning point in Unix's history came when it was reimplemented almost entirely in C during 1972 - 1974, making it the first source-portable OS. Unix subsequently underwent mutations and expansions at the hands of many different people, resulting in a uniquely flexible and developer-friendly environment.

By 1991, Unix had become the most widely used multi-user general-purpose operating system in the world. Many people consider this the most important victory yet of hackerdom over industry opposition (but see Unix weenie and Unix conspiracy for an opposing point of view).

Unix is now offered by many manufacturers and is the subject of an international standardisation effort Unix-like operating systems include AIX, A/UX, BSD, Debian, FreeBSD, GNU, HP-UX, Linux, NetBSD, NEXTSTEP, OpenBSD, OPENSTEP, OSF, POSIX, RISCiX, Solaris, SunOS, System V, Ultrix, USG Unix, Version 7, Xenix.

"Unix" or "UNIX"? Both seem roughly equally popular, perhaps with a historical bias toward the latter. "UNIX" is a registered trademark of The Open Group, however, since it is a name and not an acronym, "Unix" has been adopted in this dictionary except where a larger name includes it in upper case. Since the OS is case-sensitive and exists in many different versions, it is fitting that its name should reflect this.

The UNIX Reference Desk.

Spanish fire extinguisher.