March 30, 1979 You use CP commands to communicate with the control program. CP commands
control the devices attached to your virtual machine and their
characteristics.
For example, if you want to allocate additional disk space for a work
area or if yOU want to increase the virtual address space assigned to
your virtual· machine, use the CP command DEFINE. CP takes care of the
space allocation for you and then allows your virtual machine to use it. Or if, for example, you are receiving printed output at your terminal
and do not want to be interrupted by messages from other VM/370 users,
you can use the CP command SET MSG OFF to refuse messages, since it is CP that handles communication among virtual machines. Using CP commands, you can also send messages to the VM/370 system
operator and to other users, modify the configuration of devices in your
virtual machine, and use the virtual machine input/output devices. CP coamands are available to all virtual machines using VM/370. You can
invoke these commands when you are in the virtual machine environment
using CMS (or some other operating system) in your virtual machine.
The CP commands and command privilege classes are listed in "Appendix
B: Summary of CP Commands". The CP Commands applicable to the average
user are discussed in detail in the The rest of the CP commands are discussed in However, since many CP commands are used with CMS commands, some of the CP commands you will use most frequently are
discussed in this publication, in the context of their usefulness for a CMS application. To aid you in distinguishing between CMS commands and CP commands, all CP commands used in examples in this publication are
prefaced with "Cpu. The CMS command language allows you to create, modify, and debug problem
or application programs and, in general, to manipulate data files. Many as language processors can be executed under CMS: the assembler, VS BASIC, as FORTRAN IV, as COBOL, and as PL/I Optimizing and Checkout
Compilers. In addition, the DOS/VS COBOL and DOS/VS PL/I program
Products are supported. You can find a comprehensive list of language
processors that can be executed under CMS and relevant publications in
the CMS executes the assembler and the compilers
when you invoke them with CMS commands. The ASSEMBLE command is used to
present examples in this publication; the supported compiler commands
are described in the appropriate DOS and as program product
documentation.
The EDIT command invokes the CMS editor so that you can create and modify files. The EXEC facilities allow you to execute procedures
consisting of CP and CMS commands; they also provide the conditional
execution capability of a macro language. The DEBUG command gives you
several program debugging subcommands. Other CMS commands allow you to read cards from a virtual card
reader, punch cards to a virtual card punch, and print records on a
virtual printer. Many commands are provided to help you manipulate your
virtual disks and files.
4 IBM VM/370 CMS User's Guide

Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-X18 You use the HELP command how to use CP commands and
explanations of CP and CMS when a brief explanation
sufficient, thereby avoiding
to a manual.
to display at your terminal information on CMS commands. subcommands, and EXECs, and
messages. You can issue the HELP command
of syntax, a parameter, or function is
interrupting your terminal session to refer Section 1. What it Means to Have a CMS Virtual Machine 4.1