Single UNIX® Specification Frequently Asked Questions (FAQ Version 1.12)

Last Updated : Jun 8 2020: freq.ques,v 1.12

This is the Frequently Asked Questions file for the Single UNIX Specification. Its maintainer is Andrew Josey (ajosey at The Open Group ). Suggestions and contributions are always welcome.

This document can be found on the world wide web at http://www.opengroup.org/austin/papers/single_unix_faq.html.

UNIX® is a registered trademark of The Open Group in the USA and other countries.

The Open Group holds the definition of what a UNIX system is and its associated trademark in trust for the industry. The official web site for more information is http://www.unix.net.

This article includes answers to the following.


Q0. What is the Single UNIX Specification?
Q1. What is The Open Group Base Working Group ?
Q2. What is the Austin Group?
Q3. What is the latest version of the Single UNIX Specification?
Q4. Where can I read/download the Single UNIX Specification Version 4 from? Is there a book?
Q5. Where can I read/download earlier versions of the Single UNIX Specification from?
Q6. How do I become a participant in the Working Groups?

Q7. Does an operating system have to be derived from AT&T/SCO code to meet the Single UNIX Specification?
Q8. What about UNIX Certification?
Q9. Where can I get a UNIX License Plate from?
Q10. How do I get permission to excerpt materials from the standard for reuse in my product?
Q11. How do I add a question to this FAQ?


Q0. What is the Single UNIX Specification?

The Single UNIX Specification is a set of open, consensus specifications that define the requirements for a conformant UNIX system. The standardized programming environment provides a broad-based functional set of interfaces to support the porting of existing UNIX applications and the development of new applications. The environment also supports a rich set of tools for application development.

The Single UNIX Specification came into being when in 1994 Novell (who had acquired the UNIX systems business of AT&T/USL) decided to get out of that business. Rather than sell the business as a single entity, Novell transferred the rights to the UNIX trademark and the specification (that subsequently became the Single UNIX Specification) to The Open Group (at the time X/Open Company). Subsequently, it sold the source code and the product implementation (UNIXWARE) to SCO. The Open Group also owns the trademark UNIXWARE, transferred to them from SCO more recently.

Q1. What is The Open Group Base Working Group ?

The Open Group's Base Working Group is the group that has and continues to develop the technical specifications that make up the Single UNIX Specification. More information can be found at http://www.opengroup.org/platform/ . The Base Working Group is one of the three parties involved in the Austin Group that maintain the Base Specifications of the Single UNIX Specification Version 4, which are also IEEE Std 1003.1 (POSIX) and ISO/IEC 9945.

Q2. What is the Austin Group?

The Austin Common Standards Revision Group (CSRG) is a joint technical working group established to develop and maintain the core volumes of the Single UNIX Specification, which are also the POSIX 1003.1 standard and ISO/IEC 9945. Anyone wishing to participate in the Austin Group can do so. There are no fees for participation or membership. You may participate as an observer or as a contributor. You do not have to attend face-to-face meetings to participate, electronic participation is most welcome.

See http://www.opengroup.org/austin/ for more information.

See http://www.opengroup.org/austin/faq.html for the Austin Group FAQ.

Q3. What is the latest version of the Single UNIX Specification?

The latest version is the Single UNIX Specification Version 4 (2018 Edition). It consists of The Open Group Base Specifications Issue 7 and the X/Open Curses, Issue 7 specification.

The Single UNIX Specification uses The Open Group Base Specifications, Issue 7 documentation as its core. The documentation is structured as a single document, containing a number of volumes within it

Detailed information on the Single UNIX Specification, including accessing the version 4 specification in html is available at http://www.unix.org/version4/

Q4. Where can I read/download the Single UNIX Specification Version 4 from? Is there a book?

The html version of the latest version is available to read and download from: URL:http://www.unix.org/version4/, you need to register for a copy.

The complete specification in pdf format is available to members of The Open Group from The Open Group publications catalog. If you are working on standardization activities and need a copy to assist you in your work, please contact Andrew Josey directly, he can then add you as an individual affiliate member.

Ongoing draft specifications for future technical corrigenda are available online from the Austin Group web site at http://www.opengroup.org/austin/ . You need to be a member of the Austin Group. Information on how to join the group is on the web site.

URL:http://www.opengroup.org/austin/. (Austin Group Home Page)

Q5. Where can I read/download earlier versions of the Single UNIX Specification from?

The specifications that make up the original Single UNIX Specification (1994), the Single UNIX Specification Version 2 (1997), the Single UNIX Specification Version3 (2001-2004) and other related specifications can be download in pdf, and html where available, from The Open Group publications catalog at https://publications.opengroup.org/standards/unix.

Q6. How do I become a participant in the Working Groups?

To participate in the Austin Group just join the open mailing list. See http://www.opengroup.org/austin/lists.html for more information.

URL:http://www.opengroup.org/austin/lists.html. (How to Join the Austin Group)

If you want to join the Base Working Group please contact Andrew Josey for further information.

Q7. Does an operating system have to be derived from AT&T/SCO code to meet the Single UNIX Specification?

No. As the owner of the UNIX trademark, The Open Group has separated the UNIX trademark from any actual code stream itself, thus allowing multiple implementations. Since the introduction of the Single UNIX Specification, there has been a single, open, consensus specification that defines the requirements for a conformant UNIX system.

Q8. What about UNIX Certification?

There is a mark, or brand, that is used to identify those products that have been certified as conforming to the Single UNIX Specification, initially UNIX 93, followed subsequently by UNIX 95, UNIX 98, UNIX 03, and now UNIX V7. Information on the UNIX certification program which operates under The Open Group's Open Brand, can be found at http://www.opengroup.org/certification/idx/unix.html

The UNIX Certification Guide is available at http://www.opengroup.org/openbrand/.

The Practical Guide to the Open Brand is available at http://www.opengroup.org/openbrand/Certification_Guide/

The register of Certified Products is available at http://www.opengroup.org/openbrand/register/

Q9. Where can I get a UNIX License Plate from?

When in stock, the classic "Live Free or Die" license plates can be ordered from The Open Group shop at: http://shop.opengroup.org/n900.

A wall poster with the story of the history of the license plate can be downloaded from http://www.unix.net/Posters/

Q10. How do I get permission to excerpt materials from the standard for reuse in my product?

All queries regarding permission to reproduce sections of the standard should be sent to austin-group-permissions at The Open Group . Permission needs to be granted by both copyright holders, The IEEE and The Open Group.

Q11. How do I add a question to this FAQ?

Send the question (preferably with a proposed answer) to Andrew Josey.