System Debug Reference Manual (32650-90888)

118 Chapter4
System Debug Command Specifications :-Exit
DIS
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.
DIS
Disassembles a single NM or CM assembly instruction, based on the current mode.
Syntax
DIS nmword [ virtaddr ]