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CP/M, short for Control Program for Microcomputers, was a mass-market operating system created for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc. Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors. The combination of CP/M and S-100 bus computers loosely patterned on the MITS Altair was an early industry standard for microcomputers, and this computer platform was widely used in business through the late 1970s and into the mid-1980s. By greatly reducing the amount of programming required to install an application on a new manufacturer's computer, CP/M increased the market size for both hardware and software. The advent of (comparatively) low-cost microcomputers running CP/M was an important driver of software innovation as independent programmers and hackers bought them and shared their creations in user groups.〔(【引用サイトリンク】title=The Official Book for the Commodore 128 )〕 CP/M was displaced by MS-DOS soon after the 1982 introduction of the IBM PC. ==Hardware model== A minimal 8-bit CP/M system would contain the following components: * A computer terminal using the ASCII character set * An Intel 8080 (and later the 8085) or Zilog Z80 microprocessor * At least 16 kilobytes of RAM (beginning at address 0) * A means to bootstrap the first sector of the diskette * At least one floppy disk drive The only hardware system that CP/M, as sold by Digital Research, would support was the Intel 8080 Development System. Manufacturers of CP/M compatible systems customized portions of the operating system for their own combination of installed memory, disk drives, and console devices. CP/M would also run on systems based on the Zilog Z80 processor since the Z80 was compatible with 8080 code. While the Digital Research distributed core of CP/M (BDOS, CCP, core transient commands) did not use any of the Z80-specific instructions, many Z80 based systems used Z80 code in the system specific BIOS, and many applications were dedicated to Z80 based CP/M machines. On most machines the bootstrap was a minimal bootloader in ROM combined with some means of minimal bank switching or a means of injecting code on the bus (since the 8080 needs to see boot code at Address 0 for start-up, while CP/M needs RAM there); for others, this bootstrap had to be entered into memory using front panel controls each time the system was started. CP/M used the 7-bit ASCII set. The other 128 characters made possible by the 8-bit byte were not standardized. For example, one Kaypro used them for Greek characters, and Osborne machines used the 8th bit set to indicate an underlined character. WordStar used the 8th bit as an end-of-word marker. International CP/M systems most commonly used the ISO 646 norm for localized character sets, replacing certain ASCII characters with localized characters rather than adding them beyond the 7-bit boundary. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「CP/M」の詳細全文を読む スポンサード リンク
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