GDSX (Extended General Device Support) Manual

Design and Development
Extended General Device Support (GDSX) Manual—529931-001
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User Tasks
Backup Task
If GDSX is run as a process pair, TSCODE creates a backup task (task 3) during
GDSX primary process initialization, which in turn creates a GDSX backup process
and checkpoints data to the backup process. There is only one backup task per GDSX
process, and it is always active after it is started.
UserInit Task
This task exists temporarily upon startup of a GDSX process.
Netmon Task
When the listener task receives a NETMON system message (CPU UP or CPU
DOWN), this task is created temporarily to oversee the creation of a DOWNCPU task
or the processing of an UPCPU system message.
DownCPU Task
This task exists temporarily during the processing of a DOWNCPU system message.
Open Task
During an open of a line or device this task creates a new DEVICE^HANDLER task or
LINE^HANDLER task and then is deleted.
ProcDel Task
The Process Deletion task is created temporarily to oversee the stopping, cleanup, and
deletion of another task that is to be stopped or abnormally ended (abended).
User Tasks
Following are descriptions of the different types of user tasks:
DEVICE^HANDLER Task
A DEVICE^HANDLER is a required, user-customized procedure typically used to
modify the communication of each thread between a requester and another file (often a
terminal). Running copies of DEVICE^HANDLER code are called DEVICE^HANDLER
tasks. These tasks are separate entities although they all use the same
DEVICE^HANDLER procedure code. DEVICE^HANDLER tasks are also called term
tasks.
In a GDSX application there is usually one DEVICE^HANDLER task created for each
terminal or device configured. A DEVICE^HANDLER task is created when a requester
process opens a dynamic SU through GDSX or when a preconfigured device or
subdevice is started.