Editing CP/M (section)

=== Displacement by MS-DOS ===

By the early 1980s an estimated 2000 CP/M applications existed.{{r|magid1982junjul}} Many expected that it would be the standard operating system for 16-bit computers.<ref name="pournelle198403"/> In 1980 IBM approached Digital Research, at [[Bill Gates]]' suggestion,<ref name="Isaacson_2014"/> to license a forthcoming version of CP/M for its new product, the IBM Personal Computer. Upon the failure to obtain a signed [[non-disclosure agreement]], the talks failed, and IBM instead contracted with Microsoft to provide an operating system.<ref name="Bellis_2010"/>

Many of the basic concepts and mechanisms of early versions of MS-DOS resemble those of CP/M. Internals like file-handling data structures are identical, and both refer to disk drives with a letter (<code>A:</code>, <code>B:</code>, etc.). MS-DOS's main innovation was its [[File Allocation Table|FAT]] file system. This similarity made it easier to port popular CP/M software like [[WordStar]] and [[dBase]]. However, CP/M's concept of separate user areas for files on the same disk was never ported to MS-DOS. Since MS-DOS has access to more memory (as few IBM PCs were sold with less than 64&nbsp;KB of memory, while CP/M can run in 16&nbsp;KB if necessary), more commands are built into the [[command.com|command-line shell]], making MS-DOS somewhat faster and easier to use on floppy-based computers.

Although one of the first peripherals for the IBM PC was the Baby Blue card, a SoftCard-like [[expansion card]] that lets the PC run 8-bit CP/M software like WordStar not yet available for it,<ref name="magid1982junjul"/> and ''BYTE'' in 1982 described MS-DOS and CP/M as [[David and Goliath]], the magazine stated that MS-DOS was "much more user-friendly, faster, with many more advantages, and fewer disadvantages".{{r|libes198206}} ''InfoWorld'' stated in 1984 that efforts to introduce CP/M to the home market had been largely unsuccessful and most CP/M software was too expensive for home users.<ref name="Mace_1984"/> In 1986 the magazine stated that Kaypro had stopped production of 8-bit CP/M-based models to concentrate on sales of MS-DOS compatible systems, long after most other vendors had ceased production of new equipment and software for CP/M.<ref name="Groth_1986"/> CP/M rapidly lost market share as the microcomputing market moved to the IBM-compatible platform, and never regained its former popularity. ''[[Byte (magazine)|Byte]]'' magazine, one of the leading industry magazines for microcomputers, essentially ceased covering CP/M products within a few years of the introduction of the IBM PC. For example, in 1983 there were still a few advertisements for S-100 boards and articles on CP/M software, but by 1987 these were no longer found in the magazine.

Later versions of CP/M-86 made significant strides in performance and usability and were made compatible with MS-DOS. To reflect this compatibility the name was changed, and CP/M-86 became [[DOS Plus]], which in turn became [[DR-DOS]].