Editing CP/M (section)

=== Initial success ===
[[File:M Karte.JPG|thumb|Apple ''CP/M Card'' with manual]]

By September 1981, Digital Research had sold more than {{val|fmt=commas|250000}} CP/M licenses; ''[[InfoWorld]]'' stated that the actual market was likely larger because of sublicenses. Many different companies produced CP/M-based computers for many different markets; the magazine stated that "CP/M is well on its way to establishing itself as ''the'' small-computer operating system".{{r|hogan19810914state}} Even companies with proprietary operating systems, such as [[Heath/Zenith]] ([[HDOS]]), offered CP/M as an alternative for their 8080/Z80-based systems; by contrast, no comparable standard existed for computers based on the also popular [[6502]] CPU.<ref name=wilkinson19811019>{{cite journal | last=Wilkinson | first=Bill | date=October 19, 1981 | url=https://books.google.com/books?id=Gj0EAAAAMBAJ&pg=PA16 | title=Software interchangeability problems in the 6502 marketplace | journal=InfoWorld | publisher=IDG Publications | volume=3 | issue=22 | page=16 | via=Google Books | access-date=April 19, 2023 | archive-date=April 20, 2023 | archive-url=https://web.archive.org/web/20230420013852/https://books.google.com/books?id=Gj0EAAAAMBAJ&pg=PA16 | url-status=live }}</ref> They supported CP/M because of its large library of software. The [[Xerox 820]] ran the operating system because "where there are literally thousands of programs written for it, it would be unwise not to take advantage of it", Xerox said.<ref name="wise19820510"/> (Xerox included a [[Howard W. Sams]] CP/M manual as compensation for Digital Research's documentation, which ''InfoWorld'' described as atrocious,<ref name="meyer19820614"/> incomplete, incomprehensible, and poorly indexed.<ref name = "Infoworld 1981">{{cite journal | last = Hogan | first = Thom| title = Microsoft's Z80 SoftCard | journal = InfoWorld | volume = 3 | issue = 4 | pages =20–21 | publisher = Popular Computing| date = March 3, 1981| url = https://books.google.com/books?id=jT4EAAAAMBAJ&pg=PT14 | issn = 0199-6649}}</ref>) By 1984, [[Columbia University]] used the same [[source code]] to build [[Kermit (protocol)|Kermit]] binaries for more than a dozen different CP/M systems, plus two generic versions.<ref name="dacruz19840427"/> The operating system was described as a "[[software bus]]",<ref>{{cite book|title=CP/M - the Software Bus: A Programmer's Companion|first1=A.|last1=Clarke|first2=J. M.|last2=Eaton|first3=D. Powys Lybbe|last3=David|publisher=Sigma Press|date=October 26, 1983|isbn=978-0905104188 |url=https://archive.org/details/cpm-the-software-bus-a-programmers-companion-clarke-eaton-powys-lybbeacme-1/}}</ref><ref>{{cite web|url=https://retrotechnology.com/dri/d_dri_history.html|title=CP/M and Digital Research Inc. (DRI) History|first=Herbert R.|last=Johnson|date=July 30, 2014|access-date=2021-06-29 |archive-date=2021-06-29 |archive-url=https://web.archive.org/web/20210629071256/https://retrotechnology.com/dri/d_dri_history.html|url-status=live}}</ref> allowing multiple programs to interact with different hardware in a standardized way.<ref name="Swaine_1997_Entrepreneurship"/> Programs written for CP/M were typically portable among different machines, usually requiring only the specification of the [[escape sequence]]s for control of the [[computer terminal|screen]] and printer. This portability made CP/M popular, and much more software was written for CP/M than for operating systems that ran on only one brand of hardware. One restriction on portability was that certain programs used the extended [[instruction set]] of the Z80 processor and would not operate on an 8080 or 8085 processor. Another was graphics routines, especially in games and graphics programs, which were generally machine-specific as they used direct hardware access for speed, bypassing the OS and BIOS (this was also a common problem in early DOS machines).{{citation needed|date=August 2017|reason=Certainly a common problem for DOS programs, but CP/M programs typically were more configurable and thus less machine-specific. Therefore this needs to be sourced by a RS.}}

[[Bill Gates]] claimed that the [[Apple II]] with a [[Z-80 SoftCard]] was the single most-popular CP/M hardware platform.<ref name="bunnell19820203"/> Digital Research stated in 1982 that the operating system had been licensed for more than 450 types of computer systems.<ref name="libes198206">{{Cite magazine |last=Libes |first=Sol |date=June 1982 |title=Bytelines |url=https://archive.org/details/byte-magazine-1982-06/page/n440/mode/1up?view=theater |access-date=2025-03-17 |magazine=BYTE |pages=440–450}}</ref> Many different brands of machines ran the operating system, some notable examples being the [[Altair 8800]], the [[IMSAI 8080]], the [[Osborne 1]] and Kaypro [[luggable]]s, and [[MSX]] computers. The best-selling CP/M-capable system of all time was probably the [[Amstrad PCW]]. In the UK, CP/M was also available on [[Research Machines]] educational computers (with the CP/M source code published as an educational resource), and for the [[BBC Micro]] when equipped with a Z80 co-processor. Furthermore, it was available for the [[Amstrad CPC]] series, the [[Commodore 128]], [[TRS-80]], and later models of the [[ZX Spectrum]]. CP/M&nbsp;3 was also used on the NIAT, a custom handheld computer designed for [[A. C. Nielsen]]'s internal use with 1&nbsp;[[megabyte|MB]] of [[Solid-state drive|SSD]] memory.