Editing CP/M-86 (section)

== {{anchor|Kanji}}History ==
Digital Research's CP/M-86 was originally announced to be released in November 1979, but was delayed repeatedly.<ref name="Paterson_2007_Design-DOS" /> When [[IBM]] contacted other companies to obtain components for the [[IBM PC]], the as-yet unreleased CP/M-86 was its first choice for an [[operating system]] because CP/M had the most applications at the time. Negotiations between Digital Research and IBM quickly deteriorated over IBM's [[non-disclosure agreement]] and its insistence on a one-time fee rather than DRI's usual [[royalties|royalty]] licensing plan.<ref name="Freiberger_1984_Fire" />
After discussions with [[Microsoft]], IBM decided to use [[86-DOS]] (QDOS), a CP/M-like operating system that Microsoft bought from [[Seattle Computer Products]] renaming it [[MS-DOS]]. Microsoft adapted it for the PC and licensed it to IBM. It was sold by IBM under the name of [[PC&nbsp;DOS]]. After learning about the deal, Digital Research founder [[Gary Kildall]] threatened to sue IBM for infringing DRI's [[intellectual property]], and IBM agreed to offer CP/M-86 as an alternative operating system on the PC to settle the claim. Most of the [[BIOS]] drivers for CP/M-86 for the IBM PC were written by [[Andy Johnson-Laird]].

[[File:Digital Research CP-M-86 for the IBM Personal Computer Version 1.0 720x400.png|thumb|Digital Research CP/M-86 for the IBM Personal Computer Version 1.0]]
The IBM PC was announced on 12 August 1981, and the first machines began shipping in October the same year, ahead of schedule. CP/M-86 was one of three operating systems available from IBM, with PC&nbsp;DOS and [[UCSD p-System]].<ref name="williams198201" /> Digital Research's adaptation of CP/M-86 for the IBM PC was released six months after PC&nbsp;DOS in spring 1982, and porting applications from CP/M-80 to either operating system was about equally difficult.<ref name="edlin19820607" /> In November 1981, Digital Research also released a version for the proprietary [[IBM Displaywriter]].<ref name="Digital_Research_1981_News" /><ref name="libes198112" />

{{anchor|CP/M-86/80|CP/M 8-16}}On some [[multiprocessing|dual-processor]] 8-bit/16-bit computers special versions of CP/M-86 could natively run CP/M-86 and CP/M-80 applications.<ref name="pournelle198403" /> A version for the [[DEC Rainbow]] was named CP/M-86/80, whereas the version for the {{ill|CompuPro System 816|sr|Compupro System 816}} was named CP/M&nbsp;8-16 (see also: [[MP/M&nbsp;8-16]]).<ref name="Kildall_1982_8-bit" /><ref name="Compupro816" /> The version of CP/M-86 for the 8085/8088-based [[Zenith Z-100]] supported running programs for both processors as well.

When PC clones came about, Microsoft licensed MS-DOS to other companies as well. Experts found that the two operating systems were technically comparable, with CP/M-86 having better [[memory management]] but DOS being faster. ''[[BYTE Magazine|BYTE]]'' speculated that Microsoft reserving [[Computer multitasking|multitasking]] for [[Xenix]] "appears to leave a big opening" for [[Concurrent CP/M-86]].<ref name="byte198207" />

On the IBM PC, however, at {{currency|amount=240|code=USD|fmt=gaps|linked=yes}} per copy for IBM's version, CP/M-86 sold poorly compared to the {{currency|amount=40|code=USD|fmt=gaps|linked=no}} PC&nbsp;DOS; one survey found that 96.3% of IBM PCs were ordered with DOS, compared to 3.4% with CP/M-86 or Concurrent CP/M-86.<ref name="pcommuniques198302" /> In mid-1982 [[Lifeboat Associates]], perhaps the largest CP/M software vendor, announced its support for DOS over CP/M-86 on the IBM PC.<ref name="pc19820607" /> ''BYTE'' warned that IBM, Microsoft, and Lifeboat's support for DOS "poses a serious threat to" CP/M-86,{{r|williams198201}} and [[Jerry Pournelle]] stated in the magazine that "it is clear that Digital Research made some terrible mistakes in the marketing".<ref name="pournelle198309" />

By early 1983 DRI began selling CP/M-86&nbsp;1.1 to end users for {{currency|amount=60|code=USD|fmt=gaps|linked=no}}.{{r|pcommuniques198302}} Advertisements called CP/M-86 a "terrific value", with "instant access to the largest collection of applications software in existence … hundreds of proven, professional software programs for every business and education need"; it also included [[Graphics System Extension]] (GSX), formerly {{currency|amount=75|code=USD|fmt=gaps|linked=no}}.<ref name="byte198306" /> In May 1983 the company announced that it would offer DOS versions of all of its languages and utilities. It stated that "obviously, PC&nbsp;DOS has made great market penetration on the IBM PC; we have to admit that", but claimed that "the fact that CP/M-86 has not done as well as DRI had hoped has nothing to do with our decision".<ref name="hughes198307" /> By early 1984 DRI gave free copies of Concurrent CP/M-86 to those who purchased two CP/M-86 applications as a limited time offer, and advertisements stated that the applications were [[self-booting disk]]s, which did not require loading CP/M-86 first.<ref name="1984-02" /> In January 1984, DRI also announced Kanji CP/M-86, a Japanese version of CP/M-86, for nine Japanese companies including [[Mitsubishi Electric Corporation]], [[Sanyo Electric Co. Ltd.]], [[Sord Computer Corp.]]<ref name="CW_1984_News" /><ref name="CW_1984_Kanji" /><ref name="Philippi_1984_DRI" /> In December 1984 [[Fujitsu]] announced a number of [[FM-16]]-based machines using Kanji CP/M-86.<ref name="CW_1984_22" /><ref name="Hiroshi_2006" />

CP/M-86 and DOS had very similar functionality, but were not compatible because the system calls for the same functions and [[program file]] formats were different, so two versions of the same software had to be produced and marketed to run under both operating systems. The command interface again had similar functionality but different syntax; where CP/M-86 (and CP/M) copied file <code>SOURCE</code> to <code>TARGET</code> with the command <code>[[Peripheral Interchange Program|PIP]] TARGET=SOURCE</code>, DOS used <code>COPY SOURCE TARGET</code>.

Initially MS-DOS and CP/M-86 also ran on computers not necessarily hardware-compatible with the IBM PC such as the [[Apricot Computers|Apricot]] and [[Sirius Systems Technology|Sirius]], the intention being that software would be independent of hardware by making standardised operating [[system call]]s to a version of the operating system custom tailored to the particular hardware. However, writers of software which required fast performance accessed the IBM PC hardware directly instead of going through the operating system, resulting in PC-specific software which performed better than other MS-DOS and CP/M-86 versions; for example, games would display fast by writing to video memory directly instead of suffering the delay of making a call to the operating system, which would then write to a hardware-dependent memory location. Non-PC-compatible computers were soon replaced by models with hardware which behaved identically to the PC's. A consequence of the universal adoption of detailed PC architecture was that no more than 640 kilobytes of memory were supported; early machines running MS-DOS and CP/M-86 did not suffer from this restriction, and some could make use of nearly one megabyte of RAM.