POSIX

POSIX is the collective name of a family of related standards specified by the IEEE to define the application program interface (API) for software designed to run on variants of the Unix OS. They are formally designated as IEEE 1003 and the international standard name is ISO/IEC 9945. The standards emerged from a project, begun circa 1985. The term POSIX was suggested by Richard Stallman in response to an IEEE request for a memorable name. It is a near acronym for Portable Operating System Interface, with the X signifying the Unix heritage of the API.

Related Topics:
Standard - IEEE - Application program interface - Unix - OS - ISO - IEC - 1985 - Richard Stallman - Acronym

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POSIX specifies the user and software interfaces to the OS in some 15

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different documents. The standard user command line and scripting interface is the

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Korn shell. Other user-level programs, services and utilities include awk, echo, ed, and hundreds of others. Required program-level services include basic I/O (file, terminal, and network) services. POSIX also defines a standard threading library API which is very popular, and is supported by most modern operating systems.

Related Topics:
Korn shell - Awk - Echo - Ed - I/O - File - Terminal - Network - Threading

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A test suite for POSIX accompanies the standard. It is called PCTS or the Posix Conformance Test Suite.

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Since the IEEE charges very high rates for POSIX documentation and does not allow on-line publication of the standards, there has been a tendency toward the "Single UNIX Specification" standard, which is open, accepts input from anyone, and is freely available on the Internet. Beginning in 1998 a joint working group, the Austin Group, began to develop a combined standard that would be known as the Single UNIX Specification Version 3.

Related Topics:
Single UNIX Specification - Internet - 1998 - Austin Group

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Although used mainly for Unix systems, the POSIX standard can apply to any operating system. For example, Microsoft Windows NT complies with the real-time part of the POSIX specification. Windows can also be enhanced to include more POSIX compatibility by installing "Windows Services for Unix" or Cygwin.

Related Topics:
Unix - Microsoft - Windows NT - Real-time - Cygwin

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For Linux-based operating systems, several common extensions and complementary de facto-standards are provided by the Linux Standard Base. These are unlikely to be followed by other Unix-like systems which adhere to long established standards, except in cases where the Linux Standard Base itself already adheres to those standards.

Related Topics:
Linux - De facto - Linux Standard Base - Unix-like

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