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|Developer||Digital Research, Inc. / Tom Rolander, Gary Kildall, Frank Holsworth|
|Source model||Originally closed source, since open sourced|
|Latest release||2.1 / 1982|
|Platforms||8080, 8085, Z80, 8086, 80286|
|Kernel type||Monolithic kernel|
|Default user interface||Command-line interface|
|License||Originally proprietary, now BSD-like|
|Preceded by||CP/M, CP/M-86|
|Succeeded by||Concurrent CP/M, Concurrent CP/M-86|
MP/M (Multi-Programming Monitor Control Program) is a discontinued multi-user version of the CP/M operating system, created by Digital Research developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each using a separate terminal.
MP/M was a fairly advanced operating system for its era, at least on microcomputers. It included a priority-scheduled multitasking kernel (before such a name was used, the kernel was referred to as the nucleus) with memory protection, concurrent input/output (XIOS) and support for spooling and queueing. It also allowed for each user to run multiple programs, and switch between them.
The 8-bit system required a 8080 (or Z80) CPU and a minimum of 32 KB of RAM to run, but this left little memory for user applications. In order to support reasonable setups, MP/M allowed for memory to be switched in and out of the machine's "real memory" area. So for instance a program might be loaded into a "bank" of RAM that was not addressable by the CPU, and when it was time for the program to run that bank of RAM would be "switched" to appear in low memory (typically the lower 32 or 48 KB) and thus become visible to the OS. This technique, known as bank switching was subsequently added to the single user version of CP/M with version 3.0.
One of the primary uses of MP/M, perhaps to the surprise of DRI, was as a "power user" version of CP/M for a single user. The ability to run several programs at the same time and address large amounts of memory made the system worth the extra price.
- MP/M 1.0 (1979)
- MP/M 1.1 (January 1980)
- MP/M II 2.0 (July 1981, added: file sharing)
- MP/M II 2.1 (January 1982, added: extended file locking)
Like CP/M, MP/M was eventually ported to the 16-bit Intel 8086, and appeared as MP/M-86 2.0 in September 1981. Main developers of the system include Francis "Frank" R. Holsworth, later a director of marketing at Digital Research. Known revisions of MP/M-86 2.0 were dated 25 September 1981 and 5 October 1981. There also was an MP/M-86 2.1 dated 20 July 1982.
MP/M-86 2.1 absorbed some of the technology of CP/M-86 1.1 (BDOS 2.2) to become Concurrent CP/M-86 3.0[nb 1] (BDOS 3.0) in late 1982, which also added support for "virtual screens". In December 1983, a DOS emulator named PC-MODE became available as an optional module for Concurrent CP/M-86 3.1 (BDOS 3.1), shipping on 21 February 1984, and the system was further developed into the MS-DOS compatible Concurrent DOS (BDOS 3.1 and higher). This in turn continued to evolve into FlexOS and Multiuser DOS and as such is still in use in some industrial applications.
MP/M 8-16 (sometimes also referred to as MP/M-8/16) was CompuPro's name for a combination of the multi-user 16-bit MP/M-86 to perform single-user, single-stream CP/M functions, alongside with multi-user, multi-tasking 8-bit MP/M operations running on the multi-processor CompuPro System 816. Later on, this system was also able to run Concurrent DOS 3.1.
In 1982, Digital Research announced plans to develop MP/M-286 to take advantage of the 16-bit Intel 80286's new memory management and protection features to run existing MP/M-86 and CP/M-86 applications. This was apparently never published "as is", but was further developed into Concurrent CP/M-286, which seems to have formed the basis for the later Concurrent DOS 286 in 1985 and FlexOS 286 in 1986.
CP/NET, CP/NOS, MP/NET and MP/NOS
In the early 1980s Digital Research also developed a networking software named CP/NET used to connect an MP/M server with multiple CP/NET clients (named requesters) running CP/M. It was originally developed by Tom Rolander.
MP/NET was an MP/M system with networking allowing the MP/M system to function as both requester and server with CP/M requesters.
The CP/NET clients could also be run in a diskless configuration with the system stored in ROM, then named CP/NOS (with NOS for Network Operating System). Similar, MP/NOS contained MP/M without local disk facilities. Like CP/NOS, MP/NOS performed the disk functions through the network.
The system allowed to share files and printers and send electronic messages.
- NIOS – Network I/O System
- SNIOS – Slave Network I/O System
- NDOS – Network Disk Operating System
CP/NET existed in versions 1.0, 1.1 and 1.2 in versions for 8080 and Z80 processors. CP/NET-86 for 8086 was available as well.
Caldera permitted the redistribution and modification of all original Digital Research files, including source code, related to the CP/M and MP/M families through Tim Olmstead's "The Unofficial CP/M Web site" since 1997. After Olmstead's death on 12 September 2001, the free distribution license was refreshed and expanded by Lineo, who had meanwhile become the owner of those Digital Research assets, on 19 October 2001.
- Since there was apparently no 8-bit version of Concurrent CP/M, the 16-bit version Concurrent CP/M-86 was also referred to simply as Concurrent CP/M.[clarification needed]
- . Information Technology Corporate Histories Collection. Computer History Museum http://www.computerhistory.org/corphist/view.php?s=events&id=1816. Missing or empty
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- Kildall, Gary Arlen (2016-08-02) . Kildall, Scott; Kildall, Kristin (eds.). Computer Connections: People, Places, and Events in the Evolution of the Personal Computer Industry (Manuscript, part 1). Kildall Family. Retrieved 2016-11-17.
- Wein, Josef "Joe" (2002). "Gary Kildall in England". Archived from the original on 2019-04-03. Retrieved 2019-04-03.
- Holsworth, Francis "Frank" R. (2006-02-01). "Video: Frank Holsworth, developer" (interview). Information Technology Corporate Histories Collection. Computer History Museum. ID 102770341. ITCHP 44403c1a3fd53. Lot Number X7847.2017. Archived from the original on 2019-04-03. Retrieved 2019-04-04. 
- Digital Research (July 1981) . MP/M - Multi-Programming Monitor Control Program - User's Guide (PDF) (4 ed.). Pacific Grove, CA, USA: Digital Research. Archived from the original (PDF) on 2017-01-04. Retrieved 2017-01-04.
- Digital Research (1979-08-09). "MP/M 1.0 - A Multi-Programming Monitor Control Program for Microcomputer System Development - FUNCTIONAL SPECIFICATION" (PDF) (internal specification). Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
- Evans, Harold; Buckland, Gail; Lefer, David (2004). They Made America: From the Steam Engine to the Search Engine: Two Centuries of Innovators. Little, Brown and Co. ISBN 978-0-316-27766-2.
- Digital Research (January 1982), MP/M II Operating System Release 2.1 Release Notes, Pacific Grove, CA, USA: Digital Research, retrieved 2017-01-04  
- Digital Research (August 1981). MP/M II Operating System - User's Guide (PDF) (1 ed.). Pacific Grove, CA, USA: Digital Research. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
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- Digital Research (October 1981) [September 1981]. MP/M-86 Operating System - System Guide (PDF) (corrected 1st ed.). Pacific Grove, CA, USA: Digital Research. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
- Digital Research (1981-09-25). MP/M-86 Operating System - User's Guide (PDF) (1 ed.). Pacific Grove, CA, USA: Digital Research. Archived from the original (PDF) on 2017-01-04. Retrieved 2017-01-04.
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- "MP/M-86 2.1 disk contents". Retrieved 2020-01-07.
- Kildall, Gary Arlen (1982-09-16). "Running 8-bit software on dual-processor computers" (PDF). Electronic Design: 157. Archived (PDF) from the original on 2017-08-19. Retrieved 2017-08-19.
- Digital Research (1984). "PC-Mode bridges CP/M and PC DOS". Digital Dialogue - Employee Newsletter of Digital Research Inc. 3 (1): 3. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-03.
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[…] "Concurrent DOS Release 3.1 is rapidly gaining momentum and support from a wide range of microcomputer manufacturers," Wandryk said. "Some 60 hardware companies have licensed the product since it was released in early March." […]
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[…] Digital Research is producing an operating system for the 286. MP/M-286 will take advantage of the processor's memory management and protection and virtual memory support. Digital Research is promising "complete" compatibility with its MP/M-86 and CP/M-86 for the 8086 processor. Intel is supplying Digital Research with the hardware to develop and test MP/M-286. […]
- Bidmead, Christopher H. (2006-05-09) [1985-03-25]. "Surviving Big Blue". Doctor Who. Which Computer?. Archived from the original on 2020-01-07. Retrieved 2020-01-07.
[…] Paul Bailey of Digital Research keenly promotes this approach; it is his company that is supplying ICL and others with Concurrent Dos-286. This chameleon operating system allows ICL and other 80286 manufacturers to build machines that will be able to cope with all the existing body of IBM-PC software -- and at the same time promise multi-tasking, windowing and true concurrency, three features that together allow a single micro to do several things at once. […] Although no firm announcements have been made, it seems certain that by the end of the year ACT will be offering a Concurrent CP/M 286 machine to fuel its drive into the corporate market. But by this time it will have to contend with IBM's own 80286 office micro, the PC/AT. […] IBM also have a software product in the offing that could pull the rug out from under the Concurrent contenders. Some 180K in size, TopView is a program for IBM PC's and AT's that beefs up the operating system to provide windowing facilities for existing 'well behaved' standard packages. […]
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- Kildall, Gary Arlen (June 1981). "CP/M: A Family of 8-and 16-Bit Operating Systems". BYTE. Retrieved 2018-09-09.
- CP/NET - Network Operating System - Reference Manual (5 ed.). Digital Research. November 1982 . Archived from the original on 2016-11-24. Retrieved 2016-11-25.
- Olmstead, Tim (1997-08-10). "CP/M Web site needs a host". Newsgroup: comp.os.cpm. Archived from the original on 2017-09-01. Retrieved 2018-09-09.
- Olmstead, Tim (1997-08-29). "ANNOUNCE: Caldera CP/M site is now up". Newsgroup: comp.os.cpm. Archived from the original on 2017-09-01. Retrieved 2018-09-09. 
- "License Agreement". Caldera, Inc. 1997-08-28. Archived from the original on 2018-09-08. Retrieved 2018-09-09.CS1 maint: bot: original URL status unknown (link)  
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- Sparks, Bryan Wayne (2001-10-19). Chaudry, Gabriele "Gaby" (ed.). "License agreement for the CP/M material presented on this site". Lineo, Inc. Archived from the original on 2018-09-08. Retrieved 2018-09-09.
[…] Let this email represent a right to use, distribute, modify, enhance and otherwise make available in a nonexclusive manner the CP/M technology as part of the "Unofficial CP/M Web Site" with its maintainers, developers and community. I further state that as Chairman and CEO of Lineo, Inc. that I have the right to do offer such a license. […] Bryan Sparks […]CS1 maint: bot: original URL status unknown (link)
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