CP/M, short for Control Program for Microcomputers, is an early operating system created by Gary Kildall of Digital Research, Inc. in 1974. It was designed for Intel 8080/85-based microcomputers and became widely popular in the late 1970s and early 1980s. CP/M played a crucial role in the evolution of personal computing and significantly influenced the development of MS-DOS, also known as PC-DOS.
Historical Context
Early Development
CP/M was designed to abstract the hardware specifics of microcomputers, thus providing a standard operating environment. This operating system was initially tailored for the Intel 8080/85 microprocessors, which were among the first microprocessors used in earlier personal computing devices.
Commercial Success
By offering a standardized operating framework, CP/M allowed software developers to write applications that could run on a variety of hardware platforms. This interoperability made it highly popular among early computer manufacturers and users.
Influence on DOS
When IBM was developing its first personal computer (PC), it originally considered using CP/M but eventually opted for Microsoft’s MS-DOS. Nevertheless, MS-DOS was heavily influenced by CP/M, borrowing many commands and design elements.
Key Features
Command-Line Interface
CP/M featured a command-line interface (CLI), where users could interact with the system by typing specific commands. Common commands included DIR for listing files, COPY for copying files, and ERA for erasing files.
File System
CP/M used a simple file allocation table (FAT) file system, which organized files on storage devices such as floppy disks.
Modularity
CP/M consisted of three main components:
- BIOS (Basic Input/Output System): Responsible for hardware interfacing.
- BDOS (Basic Disk Operating System): Handled the file system and input/output operations.
- CCP (Console Command Processor): Interpreted and executed user commands.
Examples and Usage
Writing and Executing Programs
Users could write assembly language programs using the standard CP/M assembler. These programs could then be assembled, linked, and executed within the CP/M environment. For example, to assemble a program:
1ASM program.ASM
To execute a program:
1program.COM
File Management
Managing files in CP/M involved straightforward commands. For example:
- To list files:
DIR - To copy a file:
COPY A:FILE1.TXT B:FILE2.TXT - To delete a file:
ERA FILE.TXT
Applicability and Legacy
Personal Computing
CP/M was the de facto standard for microcomputer operating systems before the rise of IBM-compatible PCs. It was instrumental in the early days of software development and distribution.
Influence on Modern Systems
Many concepts and command structures from CP/M have persisted in modern operating systems, particularly in the command-line interfaces of UNIX-like systems and Windows PowerShell.
Comparisons and Related Terms
CP/M vs. MS-DOS
While CP/M and MS-DOS have similar command structures, MS-DOS introduced a more sophisticated file system and better support for hard drives. MS-DOS eventually became more widely adopted due to its association with IBM PCs.
Concurrent CP/M
Concurrent CP/M was a version of CP/M that supported multi-tasking, allowing users to run multiple applications simultaneously.
FAQs
What does CP/M stand for?
Who developed CP/M?
Why was CP/M influential?
References
- Kildall, Gary. “CP/M Operating System Manual,” Digital Research, Inc., 1976.
- Freiberger, Paul, and Michael Swaine. “Fire in the Valley: The Making of the Personal Computer,” McGraw-Hill, 1984.
- Ceruzzi, Paul E. “A History of Modern Computing,” MIT Press, 1998.
Summary
CP/M was a pioneering operating system that established a new paradigm for microcomputer software development and execution. It enabled a standardized computing environment for a variety of early personal computers and laid the foundation for subsequent operating systems, notably MS-DOS. CP/M’s influence is still evident in modern computing, underscoring its historical significance in the evolution of personal computing.
