Editing MP/M (section)

==MP/M platforms==
==={{anchor|MP/M I|1.0|1.1|MP/M II|2.0|2.1}}MP/M-80===
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The 8-bit system required a [[8080]] (or [[Z80]]) CPU and a minimum of 32&nbsp;[[Kilobyte|KB]] of [[Random Access Memory|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 [[Central processing unit|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&nbsp;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 II 2.0''' added file sharing capabilities in 1981,<ref name="DRI_MP/M-II_2.1_1982"/><ref name="MP/M_II_1981_UG"/><ref name="MP/M_II_1981_PG"/> '''MP/M II 2.1''' came with extended file locking in January 1982.<ref name="DRI_MP/M-II_2.1_1982"/>

Versions:
* MP/M 1.0 (1979)<ref name="MP/M_1981"/>
* MP/M 1.1<ref name="DRI_MP/M-II_2.1_1982"/> (January 1980)
* MP/M II 2.0 (July 1981,<ref name="MP/M_II_1981_UG"/><ref name="MP/M_II_1981_PG"/> added: file sharing)<ref name="DRI_MP/M-II_2.1_1982"/>
* MP/M II 2.1 (January 1982, added: extended file locking)<ref name="DRI_MP/M-II_2.1_1982"/>

==={{anchor|CCP/M|CCP/M-86}}MP/M-86===
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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.<ref name="DRI_1981_MP/M-86"/><ref name="MP/M_1981_UG"/><ref name="MP/M-86_1981_PG"/> Main developers of the system include Francis "Frank" R. Holsworth<!-- born 19??-09-04 https://amaus.net/static/S100/software/DRI/Digital%20Dialogue/03x04%20198408%20Digital%20Dialogue.pdf (using [[siglum]] FRH -->,<ref name="Wein_2002"/><ref name="Holsworth_2006"/> 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.<ref name="MP/M-86_2.1"/>

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<ref group="nb" name="NB_CCPM"/> (BDOS 3.0) in late 1982,<ref name="Kildall_1982_8-bit"/> which also added support for "virtual screens".<ref name="Kildall_1982_8-bit"/> [[Kathryn Strutynski]], the project manager for CP/M-86, continued as project manager for Concurrent CP/M-86. In December 1983,<ref name="DRI_1984_PCMODE"/> 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,<ref name="DRI_1984_CCPM31"/><!-- TBD. To be verified that this actually refers to CCP/M-86 3.1, not CCP/M-80 3.1. --> and the system was further developed into the [[MS-DOS]] compatible [[Concurrent DOS]] (BDOS 3.1 and higher).<ref name="DRI_1984_CDOS31"/> This in turn continued to evolve into [[FlexOS]] and [[Multiuser DOS]] and as such is still in use in some industrial applications.

Concurrent CP/M is often abbreviated '''CCP/M'''.<ref>
[https://www.computerhistory.org/collections/catalog/102762505 "CCP/M articles in the press"].
</ref>

{{See also|Multiuser DOS#Concurrent CP/M-86{{!}}Concurrent CP/M-86|Concurrent DOS}}

===MP/M 8-16===
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'''MP/M 8-16''' (sometimes also referred to as ''MP/M-8/16''<ref name="Kildall_1982_8-bit"/>) 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, along with multi-user, multi-tasking 8-bit MP/M operations<ref name="Kildall_1982_8-bit"/> running on the [[multi-processor]] {{ill|CompuPro System 816|sr|Compupro System 816}}.<ref name="Compupro816"/> Later on, this system was also able to run [[Concurrent DOS 3.1]].
{{SeeAlso|CP/M 8-16|CP/M-86/80|Concurrent CP/M-86/80}}

===MP/M-286===
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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.<ref name="Swaine_1982_MPM286"/> This was apparently never published "as is", but was further developed into [[Concurrent CP/M-286]],<ref name="Bidmead_1985_CCPM286"/> which seems to have formed the basis for the later [[Concurrent DOS 286]] in 1985<ref name="Bidmead_1985_CCPM286"/> and [[FlexOS 286]] in 1986.
{{SeeAlso|Concurrent CP/M-286|Concurrent DOS 286}}