Coherent (operating system)

Last updated
Coherent
Coherent.png
Coherent 4.2.10 installer screenshot.png
Coherent 4.2.10 installer
Developer Mark Williams Company
OS family Unix-like
Working stateDiscontinued
Source modelClosed source; open sourced in 2015
Initial release1980;44 years ago (1980)
Latest release 4.2.14 / 1994;30 years ago (1994)
Available in English
Platforms PDP-11, x86 (8088, 286, 386, 486), Motorola 68000, Zilog Z8000
Kernel type Monolithic
Default
user interface 		Command-line (KornShell)
License 2015: BSD-3-Clause [1]
Original: Proprietary
Coherent system startup and login prompt Coherent 4.2.10 i386 Boot.png
Coherent system startup and login prompt
Viewing the root directory and system information Coherent 4.2.10 i386 Root Directory.png
Viewing the root directory and system information

Coherent is a clone of the Unix operating system for IBM PC compatibles and other microcomputers, developed and sold by the now-defunct Mark Williams Company (MWC). Historically, the operating system was a proprietary product, but it became open source in 2015, released under the BSD-3-Clause license. [1]

Contents

Development

Coherent was not Unix; the Mark Williams Company had no rights to either the Unix trademark or the AT&T/Bell Labs source code. In the early years of its existence, MWC received a visit from an AT&T delegation looking to determine whether MWC was infringing on AT&T Unix property. The delegation included Dennis Ritchie, who concluded that "it was very hard to believe that Coherent and its basic applications were not created without considerable study of the OS code and details of its applications." However, he also stated that: [2]

[...] looking at various corners [for peculiarities, bugs, etc. that I knew about in the Unix distributions of the time] I couldn't find anything that was copied. It might have been that some parts were written with [AT&T] source nearby, but at least the effort had been made to rewrite. If it came to it, I could never honestly testify [...] that what they generated was irreproducible from the manual.

Much of the operating system was written by alumni from the University of Waterloo: Tom Duff, Dave Conroy, Randall Howard, Johann George, and Trevor John Thompson. Significant contributions were also made by people such as Nigel Bree (from Auckland, New Zealand), the later author of Ghost. [3]

Versions

Coherent was originally written for the PDP-11 range of minicomputers in 1980, then ported to various early 1980s microcomputer systems including IBM PC compatibles and machines based on the Zilog Z8000 and Motorola 68000. Initially sold to OEMs, starting 1983 it was available on the consumer market from MWC directly. [4] At this point, Coherent 2.3 offered roughly the functionality of Version 7 Unix on PC hardware, including the nroff formatter but not the BSD extensions offered by competing Unix/clone vendors; compared to its competitors, it was a small system distributed on only seven double-sided floppy disks, costing only US$500 for a license. [4]

BYTE in 1984 called Coherent a "highly compatible UNIX Version 7 lookalike". [5] In 1985 it criticized the difficulty of installation, but stated that "as a UNIX clone, Coherent is amazingly complete ... it should be easy to port programs ... the price of $495 is a bargain". [6] Early 1990s reviews of Coherent pointed out that the system was much smaller than other contemporary Unix offerings, as well as less expensive at US$99.95, but lacking in functionality [7] and software support. [8] PC Magazine called Coherent 3.0 a "time capsule" that captured the state of Unix in the late 1970s, without support for mice, LANs or SCSI disks, good for learning basic Unix programming but not for business automation. [7] A review in the AUUG's newsletter was more positive, favorably comparing Coherent to MKS Toolkit, Minix and Xenix, and suggesting it might fill a niche as a low-end training platform. [9]

Coherent was able to run on most Intel-based PCs with Intel 8088, 286, 386, and 486 processors. Coherent version 3 for Intel-based PCs required at least a 286, Coherent version 4 for Intel-based PCs required at least a 386. Like a true Unix, Coherent was able to multitask and support multiple users. From version 4, released 1992, [10] Coherent also had support for X11 and MGR windowing systems.[ citation needed ]

Later versions of Coherent (version 4 and higher) supported features common in modern Unix-like systems, including a version of MicroEMACS, access to FAT16 file systems,[ citation needed ] an optimizing [ citation needed ] C compiler, and a modified version of Taylor UUCP.[ citation needed ] The final releases of Coherent also fully supported the iBCS COFF binary standard,[ citation needed ] which allowed binary compatibility with SCO Unix applications, including WordPerfect, Lotus 1-2-3, and several Microsoft applications including QuickBASIC, Microsoft Word, and MultiPlan. The last 386 versions supported virtual memory, but not demand paging.

A Zilog Z8000 port of Coherent was also used by the canceled Commodore 900 system. [11]

In 1983, NCSC (a subsidiary of Nixdorf) announced a port of Coherent to IBM mainframes, in the form of a Unix compatibility subsystem for IBM's DOS/VS and DOS/VSE and Nixdorf's Edos/VS and Edos/VSE operating systems, known as Programmer Work Station/VSE-Advanced Functions, or PWS/VSE-AF for short. [12]

The Mark Williams Company closed in 1995. [13]

On January 3, 2015, Coherent sources were released under the BSD-3-Clause license. [1]

Coherent1.jpg

See also

Related Research Articles

<span class="mw-page-title-main">IBM Personal Computer</span> Personal computer model released in 1981

The IBM Personal Computer is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a team of engineers and designers directed by William C. Lowe and Philip Don Estridge in Boca Raton, Florida.

i386 32-bit microprocessor by Intel

The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors and were the central processing unit (CPU) of many workstations and high-end personal computers of the time.

<span class="mw-page-title-main">Minix</span> Unix-like operating system

MINIX is a Unix-like operating system based on a microkernel architecture. Since version 2.0, it has been Portable Operating System Interface (POSIX) compliant.

Clean-room design is the method of copying a design by reverse engineering and then recreating it without infringing any of the copyrights associated with the original design. Clean-room design is useful as a defense against copyright infringement because it relies on independent creation. However, because independent invention is not a defense against patents, clean-room designs typically cannot be used to circumvent patent restrictions.

<span class="mw-page-title-main">Xenix</span> Discontinued Unix version published by Microsoft

Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and eventually replaced it with SCO UNIX.

<span class="mw-page-title-main">Zilog Z8000</span> 16-bit microprocessor

The Z8000 is a 16-bit microprocessor introduced by Zilog in early 1979. The architecture was designed by Bernard Peuto while the logic and physical implementation was done by Masatoshi Shima, assisted by a small group of people. In contrast to most designs of the era, the Z8000 did not use microcode which allowed it to be implemented in only 17,500 transistors.

<span class="mw-page-title-main">UNIX System V</span> Early commercial UNIX operating system

Unix System V is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, and 4. System V Release 4 (SVR4) was commercially the most successful version, being the result of an effort, marketed as Unix System Unification, which solicited the collaboration of the major Unix vendors. It was the source of several common commercial Unix features. System V is sometimes abbreviated to SysV.

The Z80000 is Zilog's 32-bit processor, first released in 1986. It is essentially a 32-bit expansion of its 16-bit predecessor, the Zilog Z8000. It includes multiprocessing capability, a six-stage instruction pipeline, and a 256-byte cache. Its memory addressing system can access 4 gigabytes of RAM. It can execute code written for the Z8000, but is not compatible with the Z80.

BSD/OS is a discontinued proprietary version of the BSD operating system developed by Berkeley Software Design, Inc. (BSDi).

The Commodore 900 was a prototype microcomputer originally intended for business computing and, later, as an affordable UNIX workstation. It was to replace the aging PET/CBM families of personal computers that had found success in Europe as business machines. The project was initiated in 1983 by Commodore systems engineers Frank W. Hughes, Robert Russell, and Shiraz Shivji.

The MIPS Magnum was a line of computer workstations designed by MIPS Computer Systems, Inc. and based on the MIPS series of RISC microprocessors. The first Magnum was released in March, 1990, and production of various models continued until 1993 when SGI bought MIPS Technologies. SGI cancelled the MIPS Magnum line to promote their own workstations including the entry-level SGI Indy.

<span class="mw-page-title-main">Nixdorf Computer</span> German computer company

Nixdorf Computer AG was a West German computer company founded by Heinz Nixdorf in 1952. Headquartered in Paderborn, Germany, it became the fourth largest computer company in Europe, and a worldwide specialist in banking and point-of-sale systems.

<span class="mw-page-title-main">Venix</span> Version of the Unix operating system for low-end computers

Venix is a discontinued version of the Unix operating system for low-end computers, developed by VenturCom, a "company that specialises in the skinniest implementations of Unix".

Interactive Systems Corporation was a US-based software company and the first vendor of the Unix operating system outside AT&T, operating from Santa Monica, California. It was founded in 1977 by Peter G. Weiner, a RAND Corporation researcher who had previously founded the Yale University computer science department and had been the Ph.D. advisor to Brian Kernighan, one of Unix's developers at AT&T. Weiner was joined by Heinz Lycklama, also a veteran of AT&T and previously the author of a Version 6 Unix port to the LSI-11 computer.

SINIX is a discontinued variant of the Unix operating system from Siemens Nixdorf Informationssysteme. SINIX supersedes SIRM OS and Pyramid Technology's DC/OSx. Following X/Open's acceptance that its requirements for the use of the UNIX trademark were met, version 5.44 and subsequent releases were published as Reliant UNIX by Fujitsu Siemens Computers.

A source-to-source translator, source-to-source compiler, transcompiler, or transpiler is a type of translator that takes the source code of a program written in a programming language as its input and produces an equivalent source code in the same or a different programming language. A source-to-source translator converts between programming languages that operate at approximately the same level of abstraction, while a traditional compiler translates from a higher level programming language to a lower level programming language. For example, a source-to-source translator may perform a translation of a program from Python to JavaScript, while a traditional compiler translates from a language like C to assembly or Java to bytecode. An automatic parallelizing compiler will frequently take in a high level language program as an input and then transform the code and annotate it with parallel code annotations or language constructs.

<span class="mw-page-title-main">Microport Systems</span>

Microport Systems (1985–2002) was a software development group that pioneered a new approach towards software ports that dramatically reduced development costs and, consequently, the price charged for UNIX. Microport created the first ports of AT&T's UNIX System V for the IBM 286 and 386 personal computers, as well as IBM's PS/2 systems. Microport was critical to enabling the Free Software Foundation (FSF) to port its GNU C compiler (gcc) and associated utilities, onto the x86 architecture by donating a complete 386 development system to the Richard Stallman-led group. Microport also played a key role in Kevin Mitnick's first arrest, after he broke into the internal computer networks of both Microport and The Santa Cruz Operation.

RM Nimbus was a range of personal computers from British company Research Machines sold from 1985 until the early 1990s, after which the designation Nimbus was discontinued. The first of these computers, the RM Nimbus PC-186, was not IBM PC compatible, but its successors the PC-286 and PC-386 were. RM computers were predominantly sold to schools and colleges in the United Kingdom for use as LAN workstations in classrooms.

Edos is a discontinued operating system based upon IBM's original mainframe DOS. The name stood for extended disk operating system. It was later purchased by the West German computer company Nixdorf, who renamed it to NIDOS.

References

  1. 1 2 3 "Mark Williams Company Sources". Archived from the original on 2015-01-06. Retrieved 2021-06-18.
  2. ↑ Dennis Ritchie (April 10, 1998). "Re: Coherent". Newsgroup:  alt.folklore.computers. Usenet:   352DC4B7.3030@bell-labs.com.
  3. ↑ "Preface". COHERENT manual. Mark Williams Company. 1994.
  4. 1 2 Hannotte, Dean (12 June 1984). "A Good Buy on UNIX". PC Mag. pp. 250–254.
  5. ↑ Phraner, Ralph A. (Fall 1984). "The Future of Unix on the IBM PC". BYTE. pp. 59–64.
  6. ↑ Rochkind, Marc J. (Fall 1985). "Pick, Coherent, and THEOS". BYTE. p. 231. Retrieved 19 March 2016.
  7. 1 2 Christian, Kaare (11 December 1990). "Coherent: Unix power for $99". PC Magazine. p. 50.
  8. ↑ Dryden, Patrick (23 April 1990). "PC Users Get Alternative to Unix". InfoWorld. p. 40.
  9. ↑ Dikian, Jack (1991). "Good Things Still Come in Small Packages". Australian UNIX Systems User Group Newsletter. 12 (1): 21–22.
  10. ↑ "In brief". Computerworld. 8 June 1992. p. 51.
  11. ↑ "From the news desk". InfoWorld. 6 April 1984. p. 9.
  12. ↑ "Nixdorf unwraps Unix-compatible T/S for IBM", Computerworld, vol. 27, no. 37, IDG Enterprise, p. 4, 12 September 1983, ISSN   0010-4841
  13. ↑ Closing Announcement
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.