Documentation of Operating Systems and Developers

Unix Open Group

Open Group resulted from the association of X/Open Company Ltd. and Open Source Foundation in 1996. It is a neutral, international Consortium with more than 200 members. The IT DialTone initiative worries about to guarantee that the Internet remains open in the core to save the worldwide security and reliability. Open Group cooperated in the field of research and development in open technologies and specifications to guarantee the compatibility to commercial products by individual tests and new proceedings.

UNIX is a registered trademark of Open Group since 1994.
The nine sponsors of Open Group are Digital Equipment Corporation, Hewlett Packard, Siemens Nixdorf, Fujitsu Limited Inc., Hitachi Limited, IBM Corporation, NCR Corporation, Novell Inc. and Sun Microsystems Inc. Open Group certifies the UNIX system variants of manufacturers, whether this are UNIX 95 respectively UNIX 98 compatible. Per default included are Java VM support, 64-bit code, CDE GUI, conformal Threads, network support, standard protocols and services.

Unix family

As 1965 was, the 3rd generation of the calculating machines with integrated circuits in use were, at first offline multi program program operating systems (e.g. IBM system/360) are used. This generation was later replaced by improved online time-sharing operating systems. Important tasks were the automated batch processing of jobs in the spooler which replaced the batch based systems as of 1969. One of the first Time-sharing representative was CTTS from the MIT, which was reprogrammed together with Bell Labs and general Electric to MULTICS. MULTICS was built up to complexly and programmed in the language PL/1 so it was given up later. Ken Thompson developed in 1971 (Bell Labs) an assembler version slimmed down of MULTICS, which was named first UNICS (1969) and later UNIX (plural is Unices). Dennis Ritchie pleased UNIX, but only not the assembler programming. Thompson developed from BCPL (a simplification of CPL) the programming language B which was reprogrammed of Ritchie to the language C. Thompson and Ritchie then programmed together UNIX newly in C in 1974.

The mother company of Bell Labs, AT&T was not allowed to get in into the computer business because of monopoly regulations, at first the source code of UNIX was distributed free of charge because of this. For the derivatives another name had to be used as UNIX because of the protected trademark. After a restructuring this changed and AT&T offered the UNIX System III as of 1981 itself. UNIX was developed further by Bell Laboratorien and Westerns Electric and achieved increasing popularity by his high customization ability on microcomputers of the upper performance category. It had more than 200 console commands and extensive utility programs in C. With the high portability programs are portable to different calculating machine types like m86k architecture without many modifications.

In meanwhile the Berkeley university and DARPA had accepted the UNIX concept and it fundamentally changed and separated in 1978 to BSD-UNIX. BSD-UNIX supports unlike the AT&T-UNIX paging, TCP/IP and a huge number of standard software tools. The POSIX standard was created to prevent the split up of this two UNIX variants. But IBM, DEC and HP thought, AT&T would come off with it too well and founded a own standard named OSF. After that AT&T also answered with a standard UI of its own. The companies finally decided to develop a UNIX version of their own for himself.

A. Tanenbaum criticized the increasing complexity of UNIX and designed a UNIX derivative of his own named MINIX in 1984 which can be used as a teaching system. Inspired by Minix the student Linus Torvalds developed an operating system of his own as of August 1991. He programmed from scratch the Kernel, later with strongly growing number of programmers an extensive operating environment with the name Linux. By the more than 30 years constant further development operating systems related to UNIX can count on high technological progress as well as the proved performance, stability and security. Different companies have created a own UNIX related operating system according to her needs. These are Solaris of Sun Microsystems, HP-UX of Hewlett-Packard, AIX of IBM and Tru64 UNIX (formerly digital UNIX of DEC) of Compaq.



Characteristics
Things in common can be stated at all UNIX versions and derivatives. These are listed in detail followingly but do not have to apply to all varations in the full range.

- File structure, device files, mount points
- Absolute multi tasking
- Absolute multi user abilities
- Portability to other platforms
- Many (portable) UNIX programs
- Common library files for application software (shared, static)
- Microkernel
- CLI (Command Line Interface) with a very high number of programs
- The high technical stand of the operating system design, the network implementation
- High support by companies, the Internet Community for further development, bug fixes
- Several operation interfaces (CDE, OpenLook, KDE, Gnome, FVWM 95 )
- High market share in science, research, development and education area
- Support by software manufacturers or external support companies
- High configuring, individual depending on the field of application

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