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Encyclopedia > Single Unix Specification

The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name "Unix". The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. A computer is a machine capable of undergoing complex calculations. ... In computing, an operating system (aka, OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... Wikibooks has more about this subject: Guide to UNIX Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ... The Austin Group or the Austin Common Standards Revision Group is a joint technical working group formed to develop and maintain a common revision of POSIX.1 and parts of the Single UNIX Specification. ... The Institute of Electrical and Electronics Engineers or IEEE (pronounced as eye-triple-ee) is an international non-profit, professional organization incorporated in the State of New York, United States. ... The Open Group is a vendor- and technology- neutral industry consortium with a vision of Boundaryless Information Flow that will enable access to integrated information within and between enterprises based on open standards and global interoperability. ...

Contents


History

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. These standards became IEEE 1003 (also registered as ISO/IEC 9945), or POSIX, which loosely stands for Portable Operating System Interface. The 1980s decade refers to the years from 1980 to 1989, inclusive. ... In computing, an operating system (aka, OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... In general usage, an interface is the point, area, or surface along which two substances or other qualitatively different things meet; it is also used metaphorically for the juncture between items. ... Logo of the International Organization for Standardization The International Organization for Standardization (ISO or iso) is an international standard-setting body composed of representatives from national standards bodies. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... POSIX is the collective name of a family of related standards specified by the IEEE to define the application program interface (API) for software designed to run on variants of the Unix OS. They are formally designated as IEEE 1003 and the international standard name is ISO/IEC 9945. ...


Previously, The Open Group's Single UNIX Specification was separate from the official IEEE POSIX. The near-equivalent SUS became more popular with the involvement of several major vendors in the wake of the Unix wars because it was available for free, whereas the IEEE charged a substantial fee for access to the POSIX specification. Beginning in 1998 a joint working group known as the Austin Group, began to develop the combined standard that would be known as the Single UNIX Specification Version 3. The Unix wars were the struggles between vendors of the Unix computer operating system in the late 1980s and early 1990s to set the standard for Unix henceforth. ... 1998 (MCMXCVIII) is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ... Wikipedia does not have an article with this exact name. ... The Austin Group or the Austin Common Standards Revision Group is a joint technical working group formed to develop and maintain a common revision of POSIX.1 and parts of the Single UNIX Specification. ...


Specification

The user and software interfaces to the OS are specified in four main sections:

  • Base Definitions - a list of definitions and conventions used in the specifications and a list of C header files which must be provided by compliant systems.
  • Shell and Utilities - a list of utilities and a description of the shell, sh.
  • System Interfaces - a list of available C system calls which must be provided.
  • Rationale - the explanation behind the standard.

The standard user command line and scripting interface is the Bourne Shell. Other user-level programs, services and utilities include awk, echo, ed, and numerous (hundreds) others. Required program-level services include basic I/O (file, computer terminal, and network) services. The C Programming Language, Brian Kernighan and Dennis Ritchie, the original edition that served for many years as an informal specification of the language The C programming language is a standardized imperative computer programming language developed in the early 1970s by Dennis Ritchie for use on the Unix operating system. ... The Bourne shell, or sh, was the default Unix shell of Unix Version 7, and replaced the Thompson shell, whose executable file had the same name, sh. ... The Bourne shell, or sh, was the default Unix shell of Unix Version 7, and replaced the Thompson shell, whose executable file had the same name, sh. ... AWK is a general purpose computer language that is designed for processing text based data, either in files or data streams. ... Echo may refer to: Echo (mythology), a nymph from Greek mythology. ... The correct title of this article is ed. ... This article is about the computer interface. ... A file in a computer system is a stream (sequence) of bits stored as a single unit, typically in a file system on disk or magnetic tape. ... A computer terminal is an electronic or electromechanical hardware device used for entering data into, and displaying data from, a computer or a computing system. ... A computer network is a system for communication between computers. ...


A test suite accompanies the standard. It is called PCTS or the Posix Certification Test Suite.


Note that a system need not include source code derived in any way from AT&T Unix to meet the specification. For instance, IBM OS/390, now z/OS, qualifies as a "Unix" despite no code in common. Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ... International Business Machines Corporation (IBM, or colloquially, Big Blue) NYSE: IBM (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, NY, USA. The company manufactures and sells computer hardware, software, and consulting services. ... OS/390 is an IBM operating system for the System/370 and System/390 IBM mainframe computers. ... z/OS Welcome Screen seen through a terminal emulator The title of this article begins with a capital letter due to technical limitations. ...


Marks for compliant systems

There are two official marks for conforming systems:

  • UNIX 98 - the mark for systems conforming to version 2 of the SUS
  • UNIX 03 - the mark for systems conforming to version 3 of the SUS

Linux and the SUS

Linus Torvalds designed Linux to be as POSIX conforming as possible. First, this was a lot of guess-work, because he purchased a printout of the standard some time after starting on Linux. He is also said to have based his system call behavior on man pages from other systems. Linus Benedict Torvalds (born December 28, 1969 in Helsinki, Finland) is a Finnish software engineer best known for initiating the development of Linux. ... Almost all substantial UNIX and Unix-like operating systems have extensive documentation available as an electronic manual, split into multiple sections called man pages (short for manual pages and based on the command used to display them). ...


Most Linux vendors do not go to the expense of certifying a given version of their distribution as meeting the SUS. Furthermore, the content of a typical Linux distribution changes so fast that recertification would be required far more often than would be financially viable. A Linux distribution is a Unix-like operating system comprising the Linux kernel, the GNU operating system (or most of it), other assorted free software/open-source software, and possibly proprietary software. ...


For Linux systems, several common extensions and complementary de facto standards are provided by the Linux Standard Base. Tux is the official Linux mascot. ... The Linux Standard Base, or LSB, is a joint project by several Linux distributions under the organizational structure of The Free Standards Group to standardize the internal structure of Linux-based operating systems. ...


BSD and the SUS

No freely available BSD system was registered as SUS compliant, for the same reasons as Linux. However, FreeBSD seems to be more up to date than other BSDs (and in some cases Linux) relating to the SUS. FreeBSD is a Unix-like free software operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through 386BSD and 4. ...


See also

The Unix wars were the struggles between vendors of the Unix computer operating system in the late 1980s and early 1990s to set the standard for Unix henceforth. ... In the Linux operating system, the Native POSIX Thread Library (NPTL) is a software feature that enables the Linux kernel to run programs written to use POSIX-style threads very efficiently. ... Almost all substantial UNIX and Unix-like operating systems (*nix) have extensive documentation known as man pages (short for manual pages). The Unix command used to display them is man. ... Open systems are computer systems that provide either interoperability, portability, or freedom from proprietary standards, depending on your perspective. ... Open Standards are publicly available specifications for achieving a specific task. ...

External links


  Results from FactBites:
 
The Single UNIX Specification, Version 3 - Overview (562 words)
The core of the Single UNIX Specification, Version 3, collectively known as the Base Specifications, was developed, and is maintained, by a joint working group of members of the IEEE Portable Applications Standards Committee, members of The Open Group, and members of ISO/IEC Joint Technical Committee 1.
The approach to specification development was one of ``write once, adopt everywhere'', with the resulting set of specifications being approved as IEEE Std 1003.1-2001 (POSIX), ISO/IEC 9945:2002 (parts 1 to 4), and The Open Group Base Specifications, Issue 6.
Specifically, the scope of this work excluded doing any ``new'' work, but rather collecting into a single document what had been spread across a number of documents, and presenting it in what had been proven in practice to be a more effective way.
Single UNIX Specification - Wikipedia, the free encyclopedia (638 words)
The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name "Unix".
Unix was selected as the basis for a standard system interface partly because it was manufacturer-neutral.
The near-equivalent SUS became more popular with the involvement of several major vendors in the wake of the Unix wars because it was available for free, whereas the IEEE charged a substantial fee for access to the POSIX specification.
  More results at FactBites »

 

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