All operating systems (OSs) in this category support POSIX standards fully. The main standard defining what constitutes a Unix OS is POSIX, an acronym for: Portable Operating System Interface for UniX. Much like TRON, POSIX is not a body of computer code that is compiled and run on some processor. Rather, it is a set of standards (IEEE 1003.1): interfaces, design guidelines, software design specifications, defining (for creating) the computer code that will become language interfaces between an OS kernel and its programs, to give compatibility when moving programs between compatible systems. POSIX is made mostly of features from BSD Unix and Unix System V. Much like Open Source software, all POSIX standards are copyrighted (by the Institute of Electrical and Electronics Engineers, Inc., IEEE; new versions have joint copyright by IEEE and Open Group), but available for use by software developers anywhere in the world for free. Thus the OS architecture based on POSIX is an open architecture that invites and welcomes cloning and interoperability. Unix is a highly developed, mature, very stable, complex, and very powerful family of OSs for computers for running data processing and telephone systems. It provides multi-tasking, and multi-user abilities that let multiple programs run on one computer simultaneously, and let multiple users use one computer simultaneously; Unix systems can be servers, clients, and/or both, at once, all at the same time, as needed. On this page, links are arranged in three groups and levels: 1) Top group: issues spanning multiple unrelated Unix OSs. 2) Middle group: types or classes of OS, or OSs for which there are more than one instance of an OS of this name/type, an OS family. 3) Bottom group: specific Unix OSs.
All operating systems (OSs) in this category support POSIX standards fully.
A/UX (from Apple Unix) was Apple Computer's implementation of the Unix operating system for some of their Macintosh computers. The latest versions of A/UX run on the Macintosh II, Quadra and Centris series of machines. A/UX was first released in 1988, with the final version (3.1.1) released in 1995. A/UX requires a 68k Mac with an FPU and a paged memory management unit (PMMU).
Information and services available regarding administration of Unix and similar operating systems.
This sub-category is strictly for how-to documents and walk-throughs. If you''re submitting another type of document, please take the time to find another category it would fit under.

AIX

Information specific to the IBM AIX operating system. AIX is an award winning OS that supports features not found in other forms of Unix. Besides extensive commercial product offering from many vendors, AIX has a strong following in the free software community.

BSD

This is a general category for Unix operating systems (OSs) of the BSD variety. BSD = Berkeley Software Distribution, which is one of the two main trunks of the Unix tree. The early Internet was based mainly on BSD software, and a large fraction of today's Internet runs on such. All the main BSD variants (BSD/OS, FreeBSD, NetBSD, OpenBSD) have monolithic architectures.
To this category, please submit links that apply only to all BSD operating systems, to BSD generally, or which fit no other BSD category. Submit links for specific BSD variants to their specific categories.
OS: Unix: Documentation contains sites with documentation on using Unix or Unix-like operating systems, as well as the internal structure of Unix and Unix-like operating systems.
Please submit only general Unix documentation, and documentation on Unix distributions without their own sub-category.

Sites documenting Unix administration should be submitted to Operating Systems: Unix: Administration.

Sites documenting the Linux operating system should be submitted to Operating Systems: Linux.

The IRIX operating system is the Silicon Graphics version of UNIX.
This category contains sites relating to software that allows the Macintosh to run as a Unix machine. There are many flavors of Unix. While Unix-like, Linux-related sites perform the same functions and should be posted to Computers/Systems/Macintosh/Software/Linux.
MINIX is a family of Unix/POSIX compliant, small, microkernel operating systems (OSs). All versions include source code. MINIX has a strong presence in computer education. MINIX 1 originated to teach college level computer science. MINIX 1 and 2 were used only for education, and by hobbyists. MINIX 1 had a more restrictive license. MINIX 2 and 3 are free, open source, with a BSD-like license. MINIX 3 is the first version intended for more than education. It is optimized for reliability: it is flexible, secure, and self-healing, it keeps running even during software faults; almost everything, including drivers, runs in user space. Over 400 programs are ported to it.

SCO

SCO is an acronym for The Santa Cruz Operation, Inc., the old name for this firm. In 2001, Caldera Systems, Inc., bought the OS division, the majority, of SCO, Inc. The Caldera-based firm now does business as (d/b/a) The SCO Group. The remainder of the original SCO, Inc., is now d/b/a Tarantella, Inc. The SCO Group develops and sells these Linux and Unix operating systems: Linux (OpenLinux), Unix (OpenServer, OpenUnix, UnixWare). In 1995, SCO, Inc., bought the rights to the AT&T UNIX(tm) trademark and intellectual property from Novell, Inc. This is now owned by The SCO Group.
Please submit only FAQs and tutorials that have good original content. Sites that are just link farms should not be submitted unless the annotations are excellent.
Shells are interactive, programmable command interpreters for Unix and GNU-Linux operating systems (OSs). They have text-only interfaces, have some of the properties of programming languages, and are often used for remote access to systems through telnet or SSH client programs.
Please submit only sites related to using Unix or GNU-Linux shells, and ports of such shells to other operating systems (OSs).

Submit shell scripting links to: Computers/Software/Operating_Systems/Unix/Shell/Scripting.

Submit shell script archives to: Computers/Software/Operating_Systems/Unix/Shell/Scripting/Script_Libraries.

This category lists web sites and pages which have software that is written or optimized to work with or on Unix operating systems in some way.
This is the category for Sun Microsystems' Solaris 2.x operating system (also known as SunOS 5.x).
Please submit sites that have a significant portion of the content dedicated to the Solaris (or SunOS) operating system. General UNIX system administration sites should be submitted to Computers/Software/Operating_Systems/Unix/Administration.
Compaq Tru64 Unix. Before Compaq bought Digital it was called Digital Unix (DU). Before that it was called OSF1 or DEC OSF/1 AXP. Earlier Unix product from Digital (DEC) was Ultrix. OSF1 was a new system, not derived from Ultrix.
Groups of Unix users that get together regularly to network, associate, help and teach each other, and learn to use Unix and associated programs more effectively.
Ports of Unix utilities to the common Microsoft Windows operating system (OS). Many are very powerful.
To this category, please submit only links for ports of Unix utilities to the common Microsoft Windows operating system (OS).