GDSX (Extended General Device Support) Manual

Overview of GDSX
Extended General Device Support (GDSX) Manual—529931-001
1-11
Direct Terminal Access
example, if a GDSX application is designed to use SCF to preconfigure SUs T1 and T2
using devices $T1 and $T2, the following commands could be issued:
-> SCF
-> ADD SU $GDS.#T1
-> ADD SU $GDS.#T2
Note how the device names $T1 and $T2 become #T1 and #T2, respectively, when
combined with the GDSX process name in these commands. When GDSX receives
these commands, it derives the proper device names but does not open the files until
receiving an open message from Pathway/iTS.
Then, in the Pathway/iTS command interpreter, PATHCOM, you configure terminals to
be opened through GDSX. In this example, if a Pathway/iTS requester is to
communicate directly (without a LINE) with device $T2 through a GDSX process
named $GDS, the file name $GDS.#T2 is used in a series of PATHCOM commands:
= SET TERM TCP TCP-X
= SET TERM TYPE T16-6530:0
= SET TERM INITIAL LOGON-SCREEN
= SET TERM FILE $GDS.#T2
= ADD TERM TX-2
TERM TYPE specifies the type of terminal that the GDSX process is simulating for
Pathway/iTS.
A session or thread is established when you issue the PATHCOM command:
= START TERM TX-2
Then the TCP opens the file specified in the configuration commands, $GDS.#T2 in
this example. Within the GDSX process, TSCODE receives the open message,
derives the device name $T2 from the message, and opens the device. GDSX then
creates a DEVICE^HANDLER task to modify the communication of the thread, by
datastream conversion, for example. For the life of the requester’s open, the thread
exists from the TCP requester through $GDS to $T2.
The typical transaction flow in this environment is shown in Figure 1-5.
When a Pathway/iTS requester submits a request to GDSX, the request is picked up
by the DEVICE^HANDLER task associated with the requester, shown in Figure 1-6.
The task processes the request, and passes it to TSCODE, which passes it directly to
Figure 1-5. Direct Terminal Access Transaction Flow
TCP
TCP
Open
$GDS.#T2
Open $T2
VST005.vsd