System information

Section 1
CP/M Features and Facilities
1.1 Introduction
CP/M is a monitor control program for microcomputer system development that uses floppy
disks or Winchester hard disks for backup storage. Using a computer system based on the Intel
8080 microcomputer, CP/M provides an environment for program construction, storage, and
editing, along with assembly and program checkout facilities. CP/M can be easily altered to
execute with any computer configuration that uses a Zilog Z80 or an Intel 8080 Central
Processing Unit (CPU) and has at least 20K bytes of main memory with up to 16 disk drives. A
detailed discussion of the modifications required for any particular hardware environment is
given in Section 6. Although the standard Digital Research version operates on a single-density
Intel MDS 800, several different hardware manufacturers support their own input-output (I/O)
drivers for CP/M.
The CP/M monitor provides rapid access to programs through a comprehensive file management
package. The file subsystem supports a named file structure, allowing dynamic allocation of file
space as well as sequential and random file access. Using this file system, a large number of
programs can be stored in both source and machine executable form.
CP/M 2 is a high-performance, single console operating system that uses table-driven techniques
to allow field reconfiguration to match a wide variety of disk capacities. All fundamental file
restrictions are removed, maintaining upward compatibility from previous versions of release 1.
Features of CP/M 2 include field specification of one to sixteen logical drives, each containing
up to eight megabytes. Any particular file can reach the full drive size with the capability of
expanding to thirty-two megabytes in future releases. The directory size can be field-configured
to contain any reasonable number of entries, and each file is optionally tagged with Read-Only
and system attributes. Users of CP/M 2 are physically separated by user numbers, with facilities
for file copy operations from one user area to another. Powerful relative-record random access
functions are present in CP/M 2 that provide direct access to any of the 65536 records of an
eight-megabyte file.
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