Digital Research's CP/M-86 was originally announced to be released in November 1979, but was delayed repeatedly. In May 1983 DRI announced that it would offer DOS versions of all of its languages and utilities. It stated that "obviously, PC 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". 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 disks, which did not require loading CP/M-86 first. 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. In December 1984
Fujitsu announced a number of
FM-16-based machines using Kanji CP/M-86. 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 SOURCE to TARGET with the command
PIP TARGET=SOURCE, DOS used COPY SOURCE TARGET. Initially MS-DOS and CP/M-86 also ran on computers not necessarily hardware-compatible with the IBM PC such as the
Apricot and
Sirius, the intention being that software would be independent of hardware by making standardised operating
system calls 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. == Reception ==