IBM Professional Series User Manual page 231

12. Search for a valid abbreviation or truncation of a CP
command.
For example, if you create a command module that has the
same name as a CMS nucleus-resident command, your
command module cannot be executed, since CMS locates the
nucleus-resident command first, and executes it. When a
user-written command has the same name as a CMS
command module abbreviation, certain error messages may
indicate the CMS command name, rather than the program
name.
You can enter CMS commands when you are running CMS
in your virtual machine, the terminal is idle, and the virtual
machine can accept input.
When CMS is processing a previously entered command, the
keyboard remains unlocked for additional command input.
Note that in these circumstances the command you enter is
stacked in the terminal input buffer and is not executed until
the command that is currently being executed completes. If
more commands are entered than CP can handle, a NOT
ACCEPTED message is displayed at the display terminal.
In addition to the commands listed in the figures that follow,
there are three commands called Immediate commands that
are handled in a different manner from the others. They
may be entered while another command is being executed,
and they are executed immediately. The Immediate
commands are:
• HT - Halt typing
• HX - Halt execution
RT - Resume typing
7-58 VM/PC Users Guide