X/Open

X/Open group (also known as the Open Group for Unix Systems<ref>Template:Cite news</ref><ref>Template:Cite book</ref> and incorporated in 1987 as X/Open Company, Ltd.<ref name=dgp>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=ial>Template:Cite book</ref>) was a consortium founded by several European UNIX systems manufacturers in 1984<ref name=dgp/><ref name=unixorghist>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> to identify and promote open standards in the field of information technology. More specifically, the original aim was to define a single specification for operating systems derived from UNIX, to increase the interoperability of applications and reduce the cost of porting software. Its original members were Bull, ICL, Siemens, Olivetti, and Nixdorf—a group sometimes referred to as BISON.<ref name=ausugn>Template:Cite magazine</ref> Philips and Ericsson joined in 1985,<ref name=ausugn/> at which point the name X/Open was adopted.

The group published its specifications as X/Open Portability Guide, starting with Issue 1 in 1985, and later as X/Open CAE Specification.

In 1987, X/Open was incorporated as X/Open Company, Ltd.<ref name=dgp/><ref name=ial/>

By March 1988, X/Open grew to 13 members: AT&T, Digital, Hewlett-Packard, Sun Microsystems, Unisys, NCR, Olivetti, Bull, Ericsson, Nixdorf, Philips, ICL, and Siemens.<ref>Template:Cite magazine</ref>

By 1990 the group had expanded to 21 members:<ref>Template:Cite journal Contains more on history of X/Open.</ref> in addition to the original five, Philips and Nokia from Europe; AT&T, Digital, Unisys, Hewlett-Packard, IBM, NCR, Sun, Prime Computer, Apollo Computer from North America; Fujitsu, Hitachi, and NEC from Japan; plus the Open Software Foundation and Unix International.

In October 1993, a planned transfer of UNIX trademark from Novell to X/Open was announced;<ref>Template:Cite newsgroup</ref> it was finalized in 2nd quarter of 1994.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

In 1994, X/Open published the Single UNIX Specification, which was drawn from XPG4 Base and other sources.<ref name=unixorgsus>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

In 1996, X/Open merged with the Open Software Foundation to form The Open Group.<ref name=unixorghist/><ref name=dgp/>

X/Open was also responsible for the XA protocol for heterogeneous distributed transaction processing, which was released in 1991.<ref>Template:Cite book</ref>

X/Open Portability Guide

X/Open published its specifications under the name X/Open Portability Guide (or XPG). Based on the AT&T System V Interface Definition,<ref>Template:Cite book</ref> the guide has a wider scope than POSIX, which is only concerned with direct operating system interfaces. The guide specifies a Common Application Environment (CAE) intended to allow portability of applications across operating systems. The primary aim was compatibility between different vendors' implementations of UNIX, though some vendors also implemented the standards on non-UNIX platforms.

Issue 1 of the guide covered basic operating system interfaces, the C language, COBOL, indexed sequential file access method (ISAM) and other parts<ref>Template:Cite book</ref> and was published in 1985.<ref name=bsi6>Template:Cite book</ref> Issue 2 followed in 1987,<ref name=bsi6/> and extended the coverage to include Internationalization, Terminal Interfaces, Inter-Process Communication, and the programming languages C, COBOL, FORTRAN, and Pascal, as well as data access interfaces for SQL and ISAM.<ref>Template:Cite magazine</ref> In many cases these were profiles of existing international standards. Issue 3 (XPG3) followed in 1989,<ref name=bsi6/> its primary focus being convergence with the POSIX operating system specifications; it added Window Manager, ADA Language and more.<ref>Template:Cite magazine</ref> Issue 4 (XPG4) was published in July 1992. The Single UNIX Specification was based on the XPG4 standard. The XPG3 and XPG4 standards define all aspects of the operating system, programming languages and protocols which compliant systems should have.

Multiple levels of compliance and corresponding labels were available, depending on the scope of the guide that was covered: Base and Plus; labels Component and Application are for SW components and applications that make use of the portability guide.<ref>Template:Cite magazine</ref>

Issue 1 was published as a single publication with multiple parts, Template:Isbn.

Issue 2 was published in multiple volumes:

• X/Open Portability Guide Volume 1: System V Specification Commands and Utilities, 1987, Template:Isbn
• X/Open Portability Guide Volume 2: System V Specification System Calls and Libraries, 1987, Template:Isbn
• X/Open Portability Guide Volume 3: System V Specification Supplementary Definitions, 1987, Template:Isbn
• X/Open Portability Guide Volume 4: Programming Languages, 1987, Template:Isbn
• X/Open Portability Guide Volume 5: Data Management, 1987, Template:Isbn

Issue 3 was published in multiple volumes:

• X/Open Portability Guide Volume 1: XSI Commands and Utilities, 1989, Template:Isbn
• X/Open Portability Guide Volume 2: XSI System Interface and Headers, 1989, Template:Isbn
• X/Open Portability Guide Volume 3: XSI Supplementary Definitions, 1989, Template:Isbn
• X/Open Portability Guide Volume 4: Programming Languages, 1988, Template:Isbn
• X/Open Portability Guide Volume 5: Data Management, 1988, Template:Isbn
• X/Open Portability Guide Volume 6: Window Management, 1988, Template:Isbn
• X/Open Portability Guide Volume 7: Networking Services, 1988, Template:Isbn

The XPG4 Base specification includes the following documents:

• System Interfaces and Headers (XSH), Issue 4, 1992, Template:ISBN, C202
• Commands and Utilities (XCU), Issue 4, 1992, Template:ISBN, C203
• System Interface Definitions (XBD), Issue 4, 1992, Template:ISBN, C204

The above three documents were published not under the label X/Open Portability Guide but rather as CAE Specification.<ref name=bsi6/> Nonetheless, the term X/Open Portability Guide, Issue 4 sees some use in reference to 1992 year of publication.<ref>Template:Cite book</ref><ref>Template:Cite book</ref>

Further X/Open publications under the label X/Open CAE Specification rather than X/Open Portability Guide:

• Distributed Transaction Processing: The XA Specification, December 1991, Template:Isbn<ref>Template:Cite book</ref>
• Systems Management: Management Protocol Profiles (XMPP), October 1993, Template:Isbn<ref>Template:Cite book</ref>
• X/Open DCE: Remote Procedure Call, August 1994, Template:Isbn<ref>Template:Cite book</ref>
• System Interface Definitions, Issue 4, Version 2, September 1994, Template:Isbn<ref>Template:Cite book</ref>
• System Interfaces and Headers, Issue 4, Version 2, September 1994, Template:Isbn<ref>Template:Cite book</ref>
• Commands and Utilities, Issue 4, Version 2, September 1994, Template:Isbn<ref>Template:Cite book</ref>
• Networking Services, Issue 4, September 1994, Template:Isbn<ref>Template:Cite book</ref>
• Data Management:SQL Call Level Interface (CLI), March 1995, Template:Isbn<ref>Template:Cite book</ref>
• File System Safe UCS Transformation Format (UTF-8), March 1995, Template:Isbn<ref>Template:Cite book</ref>
• Distributed Transaction Processing: The TX (Transaction Demarcation) Specification, April 1995, Template:Isbn<ref>Template:Cite book</ref>
• X.25 Programming Interface using XTI (XX25), November 1995, Template:Isbn<ref>Template:Cite book</ref>
• Distributed Transaction Processing: The TxRPC Specification, November 1995, Template:Isbn<ref>Template:Cite book</ref>
• Distributed Transaction Processing: The XATMI Specification, November 1995, Template:Isbn<ref>Template:Cite book</ref>
• Distributed Transaction Processing: The XCPI-C Specification Version 2, November 1995, Template:Isbn<ref>Template:Cite book</ref>
• X/Open Curses, Issue 4, 1995, Template:Isbn<ref>Template:Cite book</ref>
• X/Open Curses, Issue 4, Version 2, 1996, Template:Isbn<ref>Template:Cite book</ref>
• Data Management: Structured Query Language (SQL) Version 2, March 1996, Template:Isbn<ref>Template:Cite book</ref>
• And more.

See also

• Joint Inter-Domain Management

References

• Template:Cite newsgroup - Mentions X/Open; lists members and its efforts to define "a new standard interface to UNIX".
• C. B. Taylor. The X/OPEN group and the common application environment. ICL Technical Journal Vol 5(4) pp. 665–679, 1987.
• C. B. Taylor. X/Open - from Strength to Strength. ICL Technical Journal, Vol 7(3) pp. 565–583, 1991
• C. B. Taylor. X/Open and Open Systems. X/Open Company Limited, 1992. Template:ISBN

External links

• The Open Group, opengroup.org—resulted from merger of X/Open Company and Open Software Foundation
• What is UNIX?, unix.org
• X/Open Portability Guide, issue 1, 1985