System information

control character: Nonprinting character combination. CP/M interprets some control characters
as simple commands such as line editing functions. To enter a control character, hold down the
CONTROL key and strike the specified character key.
Control Program for Microcomputers: See CP/M.
CP/M: Control Program for Microcomputers. An operating system that manages computer
resources and provides a standard systems interface to software written for a large variety of
microprocessor-based computer systems.
CP/M 1.4 compatibility: For a CP/M 2 system to be able to read correctly single-density disks
produced under a CP/M 1.4 system, the extent mask must be zero and the block size 1K. This is
because under CP/M 2 an FCB may contain more than one extent. The number of extents that
may be contained by an FCB is EXM + 1. The issue is of CP/M 1.4 compatibility also concerns
random file I/O. To perform random file I/O under CP/M 1.4, you must maintain an FCB for
each extent of the file. This scheme is upward compatible with CP/M 2 for files not exceeding
512K bytes, the largest file size supported under CP/M 1.4. If you wish to implement random I/O
for files larger than 512K bytes under CP/M 2, you must use the random read and random write
functions, BDOS functions 33, 34, and 36. In this case, only one FCB is used, and if CP/M 1.4
compatiblity is required, the program must use the return version number function, BDOS
Function 12, to determine which method to employ.
CP/M prompt: Characters that indicate that CP/M is ready to execute your next command. The
CP/M prompt consists of an upper-case letter, A-P, followed by a > character; for example, A>.
The letter designates which drive is currently logged in as the default drive. CP/M will search
this drive for the command file specified, unless the command is a built-in command or prefaced
by a select drive command: for example, B:STAT.
CP/NET: Digital Research network operating system enabling microcomputers to obtain access
to common resources via a network. CP/NET consists of MP/M masters and CP/M slaves with a
network interface between them.
CSV: See checksum vector.
cursor: One-character symbol that can appear anywhere on the console screen. The cursor
indicates the position where the next keystroke at the console will have an effect.
data file: File containing information that will be processed by a program.
deblocking: See blocking & deblocking algorithm.
default: Currently selected disk drive and user number. Any command that does not specify a
disk drive or a user number references the default disk drive and user number. When CP/M is
first invoked, the default disk drive is drive A, and the default user number is 0.
Appendix H : Glossary CP/M Operating System Manual
H-6