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
shellTo execute a program:
1program.COM
shellFile 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.
