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|Developer||Digital Research, Inc. / Tom Rolander|
|Source model||Originally closed source, meanwhile open source|
|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 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 Intel 8086, and appeared as MP/M-86 2.0 in September 1981. Known revisions of MP/M-86 2.0 were dated 1981-09-25 and 1981-10-05. There also was a MP/M-86 2.1 dated 1982-07-20.
MP/M-86 2.x absorbed some of the technology of CP/M-86 1.1 (BDOS 2.2) to become Concurrent CP/M-86 3.0 (BDOS 3.0) in 1982/1983. 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 1984-02-21, 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.
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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 a MP/M server with multiple CP/NET clients (named requesters) running CP/M.
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. A version 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 2001-09-12, the free distribution license was refreshed and expanded by Lineo, who had meanwhile become the owner of those Digital Research assets, on 2001-10-19.
- Digital Research (July 1981) . MP/M - Multi-Programming Monitor Control Program - User's Guide (PDF) (4 ed.). Pacific Grove, CA, USA: Digital Research. Archived (PDF) from the original 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
- Information Technology Corporate Histories Collection
- 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.
- Shustek, Len (2016-08-02). "In His Own Words: Gary Kildall". Remarkable People. Computer History Museum.
- 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.
- 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 (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.
- Digital Research (1981). MP/M II Operating System - Programmer's Guide (PDF) (1 ed.). Pacific Grove, CA, USA: Digital Research. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
- Digital Research (March 1981) . MP/M - Multi-Programming Monitor Control Program - User's Guide (PDF) (3 ed.). Digital Research. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
- 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 (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
- Digital Research (September 1981). MP/M-86 Operating System - Programmer's Guide (PDF) (1 ed.). Pacific Grove, CA, USA: Digital Research. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
- 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.
- Digital Research (1984). "Concurrent CP/M ships early in response to team effort". Digital Dialogue - Employee Newsletter of Digital Research Inc. 3 (1): 1. Archived (PDF) from the original on 2017-01-04. Retrieved 2017-01-04.
- Digital Research (May 1984). "Concurrent DOS bridges PC DOS, CP/M". Digital Research News - For Digital Research Users Everywhere. 4 (2): 3.
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.
- MP/M II, MP/M II Operating System User's Guide
- 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 2016-11-25. Retrieved 2016-11-25.
- Olmstead, Tim (1997-08-10). "CP/M Web site needs a host". comp.os.cpm. Retrieved 2018-09-09.
- Olmstead, Tim (1997-08-28). "ANNOUNCE: Caldera CP/M site is now up". comp.os.cpm. Retrieved 2018-09-09. 
- "License Agreement". Caldera, Inc. 1997-08-28. Archived from the original on 2015-09-24.   
- "Tim Olmstead". 2001-09-12.
- Sparks, Bryan W. (2001-10-19). Chaudry, Gaby, ed. "License agreement for the CP/M material presented on this site". Lineo, Inc. Archived from the original on 2015-09-14.
[…] 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 […]
- Chaudry, Gaby (ed.). "The Unofficial CP/M Web Site". Archived from the original on 2016-02-03.
- Gasperson, Tina (2001-11-26). "CP/M collection is back online with an Open Source licence - Walk down memory lane". The Register. Archived from the original on 2017-09-01.
- Swaine, Michael (2004-06-01). "CP/M and DRM". Dr. Dobb's Journal. Retrieved 2018-09-09.