GDSX Manual

DEVICE^HANDLER Example, Running and
Managing
Extended General Device Support (GDSX) Manual–134303
4-8
Running an Application Process
Enter:
PROCESS $GDS # -> INFO, DETAIL
The INFO, DETAIL command gives the same data as INFO, plus additional attribute
values.
Running an Application Process
The application terminals will be used for I/O with the example application. At the first
application terminal, log on and enter a WHO command to identify the terminal device
name. Suppose for this example that it is $TC1. Pause the TACL process with the
PAUSE command. Pausing the TACL process allows the application process to control
the terminal.
At the TACL terminal, use the Break key to interrupt the SCF process and return to the
TACL prompt. Start an application process, named $A1 in this example:
> RUN APPL /NAME $A1, OUT $GDS.#TC1, NOWAIT/
This process must be run after the GDSX process has been started, so that I/O from this
process can pass through GDSX. APPLS is designed so that it opens the specified OUT
file, sending a message to GDSE to open the application terminal $TC1. (A listing of
APPLS is in Appendix A.)
The application terminal should now show a prompt sent by the application process
through the GDSE process. The prompt contains the CPU number and PIN of the
application program. At the TACL terminal, from the TACL prompt (you may need to
press the Break key to interrupt SCF) enter:
> STATUS *, TERM
to verify this. Then pause the TACL process to allow SCF to regain control of the TACL
terminal. When you see the SCF prompt, enter:
-> STATUS
The command tells you that now there are two TSCODE (system) tasks, and one
USCODE (user) task, which is a DEVICE^HANDLER task. (Even though GDSE
contains a LINE^HANDLER procedure, in this DEVICE^HANDLER example the
LINE^HANDLER is never called by TSCODE. In Sections 6 and 7 the
LINE^HANDLER is demonstrated.)
Figure 4-3 illustrates the processing that occurred up to this point. The GDSX process,
named $GDS, performed its initialization processing and issued a READUPDATE on
$RECEIVE. Then the application program, named $A1, performed its initialization
processing and issued a call to OPEN $GDS.#TC1. $GDS received the open message
and in turn issued an OPEN $TC1, which was processed by the IOP.
Note. If you do not pause the TACL process, the application process will go into INSPECT.