CP/M

CP/M-80CP/M operating systemBDOSCP/M-68KCP/M PlusCP/M 2.2CCPCP/M BIOSPersonal CP/MCP/M file system
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, (or Control Program/Micro ) is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc.wikipedia
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Digital Research

DRDigital Research, Inc.Digital Initiatives
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, (or Control Program/Micro ) is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc.
Digital Research, Inc. (DR or DRI) was a company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser DOS, DOS Plus, DR DOS and GEM.

Gary Kildall

KnowledgeSetDorothy KildallComputer Connections: People, Places, and Events in the Evolution of the Personal Computer Industry
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, (or Control Program/Micro ) is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc.
Gary Arlen Kildall (May 19, 1942 – July 11, 1994) was an American computer scientist and microcomputer entrepreneur who created the CP/M operating system and founded Digital Research, Inc. (DRI).

Intel 8085

8085Intel 827580C85
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, (or Control Program/Micro ) is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc.
These processors could be used in computers running the CP/M operating system.

WordStar

MicroProMicroPro InternationalWordStar 4.0
WordStar used the 8th bit as an end-of-word marker.
It was published by MicroPro International, and written for the CP/M operating system but later ported to MS-DOS.

Kaypro

Kaypro IIKaypro ComputerKaypro 4
For example, one Kaypro used them for Greek characters, and Osborne machines used the 8th bit set to indicate an underlined character.
Kaypro produced a line of rugged, "luggable" CP/M-based computers sold with an extensive software bundle which supplanted its competitors and quickly became one of the top-selling personal computer lines of the early 1980s.

S-100 bus

S-100IEEE-696S100 bus
The combination of CP/M and S-100 bus computers was loosely patterned on the MITS Altair, an early standard in the microcomputer industry.
The S-100 bus formed the basis for homebrew computers whose builders (e.g., the Homebrew Computer Club) implemented drivers for CP/M and MP/M.

DOS

COM1AUX:LPT1
CP/M was displaced by DOS soon after the 1981 introduction of the IBM PC.
IBM PC DOS (and the separately sold MS-DOS) and its predecessor, 86-DOS, was based on Digital Research's CP/M—the dominant disk operating system for 8-bit Intel 8080 and Zilog Z80 microcomputers—but instead ran on Intel 8086 16-bit processors.

Intel 8080

8080i80808080A
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, (or Control Program/Micro ) is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc.
It became the engine of the Altair 8800, and subsequent S-100 bus personal computers, until it was replaced by the Z80 in this role, and was the original target CPU for CP/M operating systems developed by Gary Kildall.

BIOS

ROM BIOSSystem BIOSBasic Input/Output System
The name originates from the Basic Input/Output System used in the CP/M operating system in 1975.

Command-line interface

command linecommand-linecommand line interface
All CP/M commands had to be typed in on the command line. CP/M's command-line interface was patterned after the operating systems from Digital Equipment, such as RT-11 for the PDP-11 and OS/8 for the PDP-8.
Such access was primarily provided to users by computer terminals starting in the mid-1960s, and continued to be used throughout the 1970s and 1980s on VAX/VMS, Unix systems and personal computer systems including MS-DOS, CP/M and Apple DOS.

Filename extension

file extensionextensionfile extensions
On file systems of some mainframe systems such as CMS in VM, VMS, and of PC systems such as CP/M and derivative systems such as MS-DOS, the extension is a separate namespace from the filename.

PDP-11

LSI-11PDP-11/70DEC PDP-11
CP/M's command-line interface was patterned after the operating systems from Digital Equipment, such as RT-11 for the PDP-11 and OS/8 for the PDP-8.
Design features of PDP-11 operating systems, as well as other operating systems from Digital Equipment, influenced the design of other operating systems such as CP/M and hence also MS-DOS.

Microcomputer

microcomputersmicrocomputingmicro-computer
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, (or Control Program/Micro ) is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc.

Operating system

operating systemsOScomputer operating system
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, (or Control Program/Micro ) is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc.
One notable early disk operating system was CP/M, which was supported on many early microcomputers and was closely imitated by Microsoft's MS-DOS, which became widely popular as the operating system chosen for the IBM PC (IBM's version of it was called IBM DOS or PC DOS).

Dir (command)

DIRDIRECTORY DIR
The command is available in the command-line interface (CLI) of the operating systems DR CP/M, MP/M, Intel ISIS-II, iRMX 86, MetaComCo TRIPOS, DOS, IBM/Toshiba 4690 OS, IBM OS/2, Microsoft Windows, Singularity, ReactOS, AROS, and in the DCL command-line interface used on DEC VMS, RT-11 and RSX-11.

Drive letter assignment

drive letterload drivefloating drive
Each disk drive was identified by a drive letter, for example drive and drive.
The concept of drive letters, as used today, presumably owes its origins to IBM's VM family of operating systems, dating back to CP/CMS in 1967 (and its research predecessor CP-40), by way of Digital Research's (DRI) CP/M.

File Control Block

FCBDTAFCBs
The current size of a file was maintained in the file's File Control Block (FCB) by the operating system.
The FCB originates from CP/M and is also present in most variants of DOS, though only as a backwards compatibility measure in MS-DOS versions 2.0 and later.

Computer file

filefilescomputer files
In such systems, software employed other methods to track the exact byte count (e.g., CP/M used a special control character, Ctrl-Z, to signal the end of text files).

NEC V20

NEC V30V30V33
There were some programs which allowed 8080-based CP/M-80 programs to run on MS-DOS machines, notably V2080 CPMulator (later ZRUN) by Michael Day and 22nice from SYDEX.

Osborne Computer Corporation

OsborneOsborne Computer
For example, one Kaypro used them for Greek characters, and Osborne machines used the 8th bit set to indicate an underlined character.
It could survive being accidentally dropped and included a bundled software package that included the CP/M operating system, the BASIC programming language, the WordStar word processing package, and the SuperCalc spreadsheet program.

Peripheral Interchange Program

PIP
In the 1970s and 1980s Digital Research implemented PIP on CP/M and MP/M.

Text file

TXT.txttext
Determining the end of a text file therefore involved examining the last record of the file to locate the terminating control-Z.
In operating systems such as CP/M and MS-DOS, where the operating system does not keep track of the file size in bytes, the end of a text file is denoted by placing one or more special characters, known as an end-of-file marker, as padding after the last line in a text file.

ASCII

US-ASCIIAmerican Standard Code for Information InterchangeASCII code
For example, indicated an executable program file, and indicated a file containing ASCII text.
When Gary Kildall created CP/M he was inspired by some command line interface conventions used in DEC's RT-11.

8.3 filename

8.3short filename8.3 file naming
File names were specified as a string of up to eight characters, followed by a period, followed by a file name extension of up to three characters ("8.3" filename format).
Similar 8.3 file naming schemes have also existed on earlier CP/M, TRS-80, Atari, and some Data General and Digital Equipment Corporation minicomputer operating systems.

Ren (command)

RENAMEREN REN
The command is available in the operating systems Digital Research CP/M, MP/M, MetaComCo TRIPOS, DOS, IBM OS/2, Microsoft Windows, ReactOS, SymbOS, and DexOS.