What systems are registered UNIX systems?
The majority of commercial vendors have registered UNIX products.
See the product register
for the lists of registered products.
What is the Open Brand?
- The Open Brand is a mark awarded only when
a vendor guarantees (in a legal contract) that any
certified ("branded") product complies with the relevant
specification(s) and commits to maintaining that compliance.
More information on The Open Brand can
be obtained at http://www.opengroup.org/openbrand/
Why is the Open Brand valuable?
What is the difference between the XPG4 and the
What is the difference between Spec 1170 and the
Single UNIX Specification?
Is the Single UNIX Specification available on the world wide web?
What is the status of the UNIX Brand transfer?
What types of product can bear the UNIX
What is the difference between UNIX 93 , UNIX
95, UNIX 98 and UNIX 03?
What is a "Unix-like" operating system?
What are the requirements for the UNIX 95, UNIX 98 and UNIX 03 brands?
- Conformance with the Single UNIX
Specification for UNIX 95, the Single UNIX Specification Version 2 for UNIX 98, and the Single UNIX Specification Version 3 for UNIX 03.
Does The Open Group sell UNIX systems source code?
Does the sale of Novell's UNIX systems business
to SCO mean that The Open Group is no longer involved?
Some vendors say that they already have a licence
for the UNIX trade mark from Novell or USL, is this true?
notes on using the UNIX Trade mark]
If a vendor licenses source code from
SCO, why do they need a TMLA from The Open Group?
Can software carry the brand without hardware?
What is the UNIX trade mark fee structure?
Why do we need XPG4 Base when we have the
UNIX profile definition?
Can all my products use the UNIX trade mark?
What test suites do I need for UNIX system certification?
[Further information on testing and certification]
How will customers know UNIX Branded
products from older UNIX systems?
What are the usage guidelines for the UNIX trade
[Further notes on using the UNIX Trade mark]
Does the UNIX brand replace the XPG4 Base
Why is this the Open Brand so important?
How does the Common Desktop Environment( CDE )
relate to UNIX systems?
Will the UNIX Brand criteria allow Microsoft to
brand NT or others to brand proprietary environments?
Some trade mark attributions still say Novell (or
even AT&T or Bell Labs), which is correct?
[Further notes on using the UNIX Trade mark]
What are the test suites associated with the
- There is a growing portfolio of test
technology associated with the Open Brand. See
the testing web pages for the latest information.
What about POSIX conformance?
Many vendors claim it, are there tests?
The Open Group test suites can also run in POSIX modes for
customers who require to verify their POSIX conformance.
With the introduction of test suites for the Single UNIX
Specification, Version 2, The Open Group has the
only complete test coverage for ISO 9945-1:1996 (POSIX 1003.1-1996)
and ISO 9945-2:1993 (POSIX 1003.2-1992) available in the industry,
including test suites for POSIX Realtime, and POSIX Threads.
Some freely available test tools , including a complete
POSIX conformance test suite are available from the URL
For Version 3 of the Single UNIX Specification, the core volumes
of the specification replace POSIX 1003.1-1990 and its amendments,
and POSIX 1003.2-1992 and its amendments, with a revised standard
known as IEEE Std 1003.1-2001 (POSIX.1).
A certification program is being introduced for
the latest POSIX standard. See
for more information.
What about the Internet?
Is the Open Brand relevant to the Internet?
The UNIX 98 Server and UNIX 03 Server Product Standards include the platform independent
Internet Server product standard, including mandatory Java TM runtime environment and internet and intranet services.
These are defacto definitions of an open server platform for supporting
todays internet based services.
What about the Year 2000?
Y2K handling for interfaces within the Single UNIX Specification
for UNIX 98 is explicitly defined in Version 2 of that
specification, published in February 1997. A paper detailing the specific changes, and
recommended changes to UNIX 95 systems is available at
Test programs to check for rollover
handling on UNIX systems are available at the URL
UNIX 98 systems are required to process dates up to at least Jan 1st 2038,
please note that this is 38 years later than the last date
required by POSIX 1003.2-1992.
Vendors providing 64-bit based UNIX 98 systems, and supporting
64-bit time_t have reported their ability to process dates to the year 9999
What is in Version 3 of the Single UNIX Specification?
Version 3 of the Single UNIX Specification is now complete.
It aligns with ISO C99 and includes
updates for the latest POSIX standards. Further
information is available from
Further questions should be sent