DIGITAL RESEARCH(r) CP/M Plus TM (CP/M Version 3) Operating ...

Section 4
CP/M 3 Command Concepts
As we discussed in Section 1, a CP/M 3 command line consists of a command
keyword, an optional command tall, and a carriage return keystroke. This section
describes the two kinds of programs the command keyword can identify, and tells
how CP/M 3 searches for a program file on a disk. This section also tells how to
execute multiple CP/M 3 commands, and how to reset the disk system.
4.1 Two Kinds of Commands
A command keyword identifies a program that resides either in memory as part of
CP/M 3, or on a disk as a program file. Commands that identify programs in memory
are called built-in commands. Commands that identify program files on a disk
are called transient utility commands.
CP/M 3 has six built-in commands and over twenty transient utility commands.
You can add utilities to your system by purchasing various CP/M 3-compatible application
programs. If you are an experienced programmer, you can also write your
own utilities that operate with CP/M 3.
4.2 Built-in Commands
Built-in commands are part of CP/M 3 and are always available for your use
regardless of which disk you have in which drive. Built-in commands reside in memory
as a part of CP/M 3 and therefore execute more quickly than the transient
utilities.
Some built-in commands have options that require support from a related transient
utility. The related transient has the same name as the built-in and has a filetype of
COM. This type of transient utility is loaded only when a built-in command line
contains options that cannot be performed by the built-in command.
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