Section 1. Introduction and General Concepts
Virtual :1achine Facility/370 (VM/370) is a system contr::>l program (SCP) that controls "virtual machines." A virtual machine is the functional of a real machine, but where the real machine has lights to
show and buttons and switches on the real system console to
control it, the virtual machine has a virtual system c::>nsole to display
status a command language to start operations and contr::>l them. The virtual system console is your terminal; there are three command which correspond roughly to the four comp::>nents of the system: • :ontrol (CP) controls the resources of the real machine;
that is, the physical machine in your computer room. The CP commands
are described in for • The Remote Spooling Communications Subsystem (RSCS) is a subsystem
designed to supervise transmission of files across a teleprocessing
network controlled by CPo For information about RSCS, see the RgmQtg • Ihe :onv?rsational Monitor System (CMS; is a conversational operating svstem designed to run under CPo All of the CMS commands for general use, the subcommands and that you can use in the environment, are described in this publication. • The Interactive Problem Control System (IPCS) provides and installation support personnel analvsis and management facilities, including problem
cceation, problem tracking, and CP abend dump analysis. IP:S the CMS command environment; for details, see system
problem
report
runs in E[cept for IPCS, each of the components of a unique
"command environment" which must be active in order for a command to be
acceoteJ. For CMS users, the two basic conmand environments are the CP environment and the eMS command environment. By default, CP are acceptable input in the CMS command environment; if you enteL a :P command, it is executed by CP, but control returns to the CMS environment.
The eMS Environment The :MS command language allows you to create, modify, debug, and, in
general, a system of files. JS/VS Assembler and many as/vs ana DOS/VSE Language processors
can be executed under eMS. For example, the OS VS BASIC, FORTRAN IV and PL/T compilers, as well as the DOS FL/I and caSOL compilers, can execute under CMS. You can find a complete list of
language processors that can be executed under CMS in the CMS invokes the assembler and the compilers when you
issue the appropriate eMS commands. The ASSEMBLE command is described
in this manual; the supported compiler commands ace described in the program product publications.
section 1. Introduction and General Concepts

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 disks and files. The CMS commands are described in "Section 2. CKS Commands."
A special set of CMS commands becomes available to you when you issue
the command:
set aos on
These called CMS/DOS commands, simulate various functions of
the Pisk Operating System (DOS) in your eMS virtual machine. When the CMS/DOS environment is active, the CMS/DOS commands are an integral part
of the CMS command language; they are listed alphabetically among the
other commands in "Section 2. CMS Commands."
The EDIT command places your virtual machine in the EDIT subcommand
environment. In this environment you can use the editor to create
and modify files. In the EDIT subcommand environnent, you can place
your virtual machine in either of two modes, edit moda or input mode.
Edit mode lets you modify a file; input mode lets you create or add to a
file. The subcommands available to you in the EDIT subcommand
environment are described in "Section 3. EDIT Subcomlllands and Macros." The DEBUG command places your virtual machine in the DEBUG subcommand
environment. In this environment you can issue commands to display
registers and storage, specify breakpoints (address instruction stops), display the contents of control words, and so on. The DEBUG subcommands
are described in "Section 4. DEBUG Subcommands." The EXEC command executes CMS command procedures, called EXEC files. You can create EXEC files consisting of CMS and CP commands and EXEC control statements. The EXEC facility also has a symbolic capability; by
manipulating variable symbols within an EXEC file, you can control the execution of the procedure. These procedures are usually created in the
edit environment. The EXEC control statements, variable symbols, and
built-in functions are described in "Section 5. EXEC Control Statements. " You can use the CMS assembler language macros when you write
assembler language programs to execute in the CMS environment.
Descriptions of these macros are contained in "Section 6. CMS Macro Instructions."
Entering CMS Commands
A eMS command consists of a command name, usually followed by one or
more positional operands and, in many cases, by an option list. CMS commands and EDIT and DEBUG subcommands described in this publication
are shown in the format:
r I command name L- [operands ••• ] [(options ••• [)]]
1 I --' You must use one or more blanks to separate each entry in the command
line unless otherwise indicated. For an explanation of the special
symbols used to describe the command syntax, see "Notational
Conventions."
2 IBM I!M/370 eMS 11...",..._" •• 0. ......... V Reference