GDSX Manual

Extended General Device Support (GDSX) Manual–134303

6-1

LINE^HANDLER Example, Running

and Managing

The typical purpose of a DEVICE^HANDLER task is to modify the communication of

each thread between a requester and another file. The typical purpose of a

LINE^HANDLER is to allow each thread to use a shared resource without allowing the

threads to interfere with each other.

The GDSX program demonstrated in this section includes a LINE^HANDLER

procedure that manages communication of multiple requester processes with the same

resource, a terminal. (Sections 4 and 5 use the same program but do not call the

LINE^HANDLER procedure.) Figure 6-1 shows the environment for this example.

$A1, $A2, and $A3 are requester processes, each of which communicates

simultaneously with the same file (a terminal) by way of GDSX. T1, T2, and T3 are

DEVICE^HANDLER tasks, and LX is a LINE^HANDLER task.

This section of the tutorial requires three terminals designated the TACL terminal, the

SCF terminal, and the application terminal. It is assumed that the terminals will be

accessed by way of the TERMPROCESS IOP.

Figure 6-1. Environment of the LINE^HANDLER Example

$A1

$A2

$GDS

$TC1

$A2

D^H

IOCB

Queue

D^H L^H

CDT012