Coherent (operating system)

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Coherent
Coherent 4.2.10 i386 Boot.png
Log in
developer Mark Williams Company
License (s) Proprietary / Open Source since 2015
First publ. 1983
Current  version 4.2.10 ( 1995 )
ancestry Coherent
Architecture (s) x86
Others Development stopped

Coherent is a commercial Unixoid operating system from the Mark Williams Company and was one of the first Unixoid systems for IBM PC- compatible computers .

history

In 1983 the Mark Williams Company introduced the first version of Coherent as one of the first Unixoid systems for IBM PC-compatible computers. Coherent ran on most Intel-based PCs with 286 , 386 and 486 - processors , but like a "real" Unix , multitasking and multiple users could manage.

Coherent contained very good printed documentation of over 1,000 pages, consisting of tutorials for the most important Unix programs and a command reference ( manpages ). Coherent became known in 1990 with version 3.0, which was first marketed on a large scale. The special thing about Coherent 3.0 was that it was very inexpensive (under 100 DM in Germany ) and that it ran on 286 PCs , even though their processor only supported a segment-based memory management unit . It was up to ten times faster than the then common MS-DOS 3.1.

With Coherent 3.0 it was possible for the first time to run a high-performance Unix-like operating system on inexpensive hardware. Coherent contained, as it was for real Unix systems common to a C - compiler and the usual Unix development tools such as make or vi editor -CLONE. Thus, with Coherent, software could be developed at no additional cost that could normally be ported to real Unix systems without any problems. In Germany and other non-English speaking countries, however, it turned out to be a disadvantage that Coherent 3.0 had no localization . The keyboard layout, for example, was set to American keyboards.

With version 4.0, which appeared in May 1992, Coherent required a 386 PC as a minimum. The binary format now allowed programs larger than 64 kByte. For Coherent 4.0, there was a porting of the X Window System as a chargeable additional package .

Coherent is sometimes incorrectly referred to as "Coherent Unix". This is not correct. Coherent was based on the specifications of Unix Version 7, but without using Unix source code, neither from Bell Labs nor from BSD . The non-use of the source code was a development guideline set by the Mark Williams company, compliance with which, among other things. a. verified through visits to the company by Dennis Ritchie .
But even with the first, early Coherent versions for the system CBM 900 from Commodore , at least the compatibility with AT&T Unix System V SVR2 was advertised.

Much of the operating system was written by former students of the University of Waterloo : Tom Duff , Dave Conroy, Randall Howard, and Johann George. The development initially originated on the PDP-11/45 platform, but quickly switched to the emerging architectures Motorola 68000 and Zilog 8001/2 and Intel x86 , whereby the focus on the latter remained.

The Mark Williams Company went bankrupt in 1995 , the last published version of Coherent was version 4.2.10. There are many reasons for bankruptcy. One is that Coherent 4.0 has been overrun by Linux . Linux also required a 386, but it was free. Linux had TCP / IP network drivers, the X Window System, and many other software. In addition, Linux continued to develop rapidly, while MWC hardly provided any updates such as drivers for the latest hardware, which quickly left the system behind and annoyed many users.

In 2015, Coherent's sources were placed under an open source license and published.

history

version publication Systems supported
0.7.2 pre-release 1985 Zilog Z8000
0.7.3 1985
3.0 1989 80286 and 80386
3.1 1990
3.2 1991
4.0 May 1992 80386 and 80486
4.2 1994

Web links

Individual evidence

  1. ↑ a b Randall Howard: Dennis MacAlister Ritchie (1941-2011) - My Inspiration by a Great Man Who Quietly Shaped an Industry , report from January 1, 2012 on randalljhoward.com, viewed July 8, 2012 (English)
  2. ↑ Commodore C900 Announcement (English)
  3. ↑ Reaction to the sad news , posting by William Lederer on April 4, 1995 in the newsgroup alt.folklore.computers, on neil.franklin.ch, viewed July 8, 2012 (English)
  4. ↑ Coherent source code of the Mark Williams Company at nesssoftware.com (English)
  5. ↑ Commodore C900 on zimmers.net (English)
  6. ↑ Commodore C900 gallery
  7. ↑ Mark Williams Ships Coherent 3.1 , In: New Products , Dr. Dobb's Journal , February 1, 1991, accessed July 8, 2012