Single UNIX Specification

The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems, compliance with which is required to qualify for to use the "UNIX" trademark. The core specifications of the SUS are developed and maintained by the Austin Group, which is a joint working group of IEEE, ISO JTC 1 SC22 and The Open Group. If an operating system is submitted to The Open Group for certification, and passes conformance tests, then it is termed to be compliant with a UNIX standard such as UNIX 98 or UNIX 03.

Very few BSD and Linux-based operating systems are submitted for compliance with the Single UNIX Specification, although system developers generally aim for compliance with POSIX standards, which form the core of the Single UNIX Specification.

History

1980s: Motivation

The SUS emerged from a mid-1980s project to standardize operating system interfaces for software designed for variants of the Unix operating system. The need for standardization arose because enterprises using computers wanted to be able to develop programs that could be used on the computer systems of different manufacturers without reimplementing the programs. Unix was selected as the basis for a standard system interface partly because it was manufacturer-neutral.