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DEMO
Privileged Mode
Adds/deletes/lists terminals used for demonstrating System Debug.
Syntax
DEMO
DEMO LIST
DEMO ADD ldevs
DEMO DELETE ldevs
The DEMO command is used for giving demonstrations of System Debug. With
this command, the user is able to enslave up to 50 terminals. Each of
the enslaved terminals receives all input and output generated by System
Debug. Output generated by the CI through the use of the ":" command or
CIGETVAR and CIPUTVAR functions is not sent to the enslaved terminals.
Please read and heed the warnings listed in "Limitations, Restrictions."
Parameters
DEMO DEMO List the terminal LDEV's that currently are receiving
LIST System Debug I/O. Both command forms are identically
supported.
DEMO ADD This keyword tells System Debug to add the following
LDEVs to the list of terminals to receive a copy of all
System Debug I/O.
DEMO DELETE This keyword tells System Debug to remove the following
LDEVs from the list of terminals that receive a copy of
all System Debug I/O.
ldevs A list of terminal LDEV numbers (logical device
numbers), separated by blanks or commas. A note of
caution: remember that the LDEV numbers are interpreted
using the current input base for System Debug.
Examples
$nmdat > demo
No demonstration terminals are defined
$nmdat > demo add #200 #201 #205 #206
$nmdat > demo list
DEMO LDEVS (#): 200 201 205 206
First, check to see if any demonstration LDEVs have been specified.
Next, add four LDEVs to the list of terminals to receive a copy of DAT's
input and output stream. As soon as the DEMO ADD command is processed,
the indicated terminals begin receiving I/O. Finally, display the list of
demonstration terminals.
Limitations, Restrictions
A total of 50 demonstration LDEVs are supported.
The functionality is implemented with low-level I/O routines. I/O is
done directly to the LDEV. No attempt is made to lock or obtain ownership
of the LDEV before sending data to it. Nonpreemptive I/O is used when
sending data to the LDEVs. Therefore, if a read is pending at the LDEV
(For example, the CI prompt), System Debug blocks until the pending read
is satisfied. It is good practice to free up the LDEVs that will be used
during a demonstration by issuing the :RESTORE command at each terminal
(do not REPLY to the resulting tape request). This removes any pending
I/O from the LDEV. When the demonstration is finished, break out of the
RESTORE process and issue an ABORT command.
No validation of LDEV numbers is performed. If you give an ldev, then no
matter what the value is, System Debug tries to write to it!
The same LDEV may be specified more than once, in which case the LDEV is
sent a copy of any I/O for each occurrence in the list of LDEVs.
The Control-S/Control-Q/stop keys suspend output only for the master
terminal (that is, the one where the demonstration is being run). All of
the enslaved terminals continue to receive output as an uninterrupted
flow.
CAUTION The output format of all System Debug commands is subject to
change without notice. Programs that are developed to
postprocess System Debug output should not depend on the exact
format (spacing, alignment, number of lines, uppercase or
lowercase, or spelling) of any System Debug command output.