To enter a CP command while the DOS/VS virtual machine is in operation, press the attention key (or its equivalent) twice, quickly,
to force aCP read. After entering the necessary CP commands, use the CP BEGIN cemmand to resume DOS/VS virtual machine execution. For example: If a DOS/VS PAUSE control statement requests the VM/370 cFerator tc Ferform some action, the user must enter the CP environment
to send a message to theVM/370 system operator. The following lines
represent a typical sequence on a typewriter terminal:
//PAUSE ASK OPERATOR TO ATTACH TAPE AS 284
! !CP msg op please attach scratch tape as 284
sleepTAPE 284 ATTACHED CP begin
TheSLEEP command locks the keyboard and places the virtual machine in a
dormant status to wait for any messages,.When the message appears
indicating the tape is attached, press the attention key once to return
toCP, and then issue the BEGIN command to resume virtual machine
execution. Because the //PAUSE message is still outstanding, press the RETURN key to continue DOS/VS execution.
In most cases during virtual machine operation, use the'CP function to
enterCP commands directly from the virtual machine environment. Users de not always have to press the attention key (or its equivalent) to
enter theCP environment. For example: If the virtual machine is
waiting for a read, a user can enter aCP command with the ICP function: #cp msg op please mount vo1240
The command line is processed byVM/370, and the virtual machine is
still waiting for a read. This methodmay be convenient for entering CP commands.
Note: Attimes CP commands cannot be entered with the ICP function. For exiiple: During the IPL procedure when DOS/VS is processing 1FL commands, the CCis used for these reads expect only three bytes of
data. Any additienal information onCP command lines is truncated. While DOS/VS is running in the virtual machine, a user can interrupt its
execution by using the attention key (or its equivalent) on the
terminal.When this key is pressed, the DOS/VS attention handler
responds with these messages:
AR1I60A READY FOR COMMUNICATIONS. AR When these messages appear, a user can enter attention commands. To
resume program execution, enter a null line. Normally, wait until the
attention has been processed before signaling another one. An exception
would be when canceling a dump.
92IBM VM/370 Operating Systems in a Virtual Machine
to force a
to send a message to the
represent a typical sequence on a typewriter terminal:
//
! !
sleep
The
dormant status to wait for any messages,.
indicating the tape is attached, press the attention key once to return
to
execution. Because the //
In most cases during virtual machine operation, use the
enter
enter the
waiting for a read, a user can enter a
The command line is processed by
still waiting for a read. This method
Note: At
data. Any additienal information on
execution by using the attention key (or its equivalent) on the
terminal.
responds with these messages:
AR
resume program execution, enter a null line. Normally, wait until the
attention has been processed before signaling another one. An exception
would be when canceling a dump.
92