Single Unix Specification

The Single UNIX Specification ( SUS) is the collective term for a family of standards for computer operating systems that allowed by their fulfillment are branded UNIX ®. The SUS is developed by The Austin Common Standards Revision Group and kept up to date, based on earlier work by the IEEE and The Open Group.


The SUS was created from a project mid-1980s, operating system interfaces for software that has been developed for variants of the UNIX operating system to standardize. The desire for standardization arose because computer -using companies wanted to develop programs that were run on the computer systems of different manufacturers. UNIX was chosen in part as the basis of a standardized system interfaces, as it was independent of the manufacturer. These standards were to IEEE 1003 ( also known as ISO / IEC 9945 ), or POSIX, which is roughly for Portable Operating System Interface for UNIX. This name was coined by Richard Stallman to create a name for the standards that you could also remember.

Prior to the Single UNIX Specification of the Open Group was not part of the official IEEE POSIX. The SUS, which was virtually equivalent, was the participation of several large manufacturers during the Unix wars becoming more popular because it was available for free, while the IEEE demanded substantial sums for access to the POSIX specification. Since 1998 the Austin Group, a united group, the combined standard, known as the Single UNIX Specification Version 3 to develop.

Flag for compliant systems

There are two official mark for SUS - compliant systems:

  • UNIX 98 - Registration for systems that satisfy version 2 of the SBS (partial compatibility )
  • UNIX 03 - Indicator for systems that meet the version 3 of the SUS ( full compatibility )

Older UNIX standards (expired):

  • UNIX93 ( to completion )
  • UNIX95 (compatibility acceptable for simpler software subsystems )

Operating Systems

Below is a list of operating systems whose manufacturers have paid the certification to the respective specification.


  • SCO OpenServer 5
  • NCR UNIX SVR4 (and possibly UNIX 95)
  • NEC UX/4800 (possibly UNIX 95)


  • HP -UX 11i V3 Release B.11.31 ago
  • SCO UnixWare 7.1.3
  • Solaris 2.5.1 ( withdrawn but not before more than a few dozen copies were delivered ) on the PowerPC Reference Platform
  • IBM z / OS 1.9


  • AIX 5L V5.2
  • Solaris 8 and 9 on 32- bit x86 and SPARC systems and on 64 -bit SPARC systems
  • Tru64 UNIX V5.1A and new


  • AIX 5L V5.2 with some updates, AIX 5L V5.3
  • HP- UX 11i V3 Release B.11.31
  • Mac OS X 10.5 on Intel systems
  • Solaris 10 on 32 - and 64- bit x86 and SPARC systems
  • IBM z / OS 1.9 *

* IBM announced on 28 September 2007 that z / OS 1.9 " better fulfill " the UNIX 03 specification will. What degree of compatibility was meant by this is unclear.

Linux and the SUS

Before the appearance of SUSv3 in December 2001, the high costs were frequently cited as a reason for a lack of certification of Linux distributors. Therefore, it was assured by the Open Group certification for a symbolic price. The certification process, actively helped with the Open Group members, was making good progress at the start, but was canceled due to irreconcilable differences between the Linux Standard Base and The Open Group, 2005. Linux is therefore until further SUSv3 not fully compliant.