GDSX (Extended General Device Support) Manual

Extended General Device Support (GDSX) Manual—529931-001
Glossary-1
Glossary
active task. An existing task that was started and is now executing, or ready to execute, or
waiting for a resource.
backup task. A system task that processes activities related to fault-tolerant functioning.
This task is created only if GDSX is run as a process pair.
converted. An application that has been modified to use an extended feature of the D-
series operating system. TSCODE assumes that USCODE is converted only if
d^plus^enabled of the CONTROLFLAGS configuration parameter is set to 1. A
converted process may or may not be converted with respect to high PIN use.
C-series service routine. A C-series-compatible service routine that can be called on either
a D-series system or a C-series system.
D^H. See DEVICE^HANDLER.
DCB. Device control block. A DCB is the internal representation of an SU object, used to
manage communication between a DEVICE^HANDLER task and a file.
DEVICE^HANDLER. A USCODE 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. DEVICE^HANDLER
is abbreviated D^H in figures. DEVICE^HANDLER tasks are also called term tasks.
dispatch. To wake up and execute a task.
dynamic SU. An SU object not configured through SCF, but created when an external
process opens a file through GDSX. Contrast with preconfigured SU object.
FCB. File control block. Each file opened within GDSX, with the exception of $RECEIVE, is
assigned an FCB that is used to manage the file.
GDSX. Extended General Device Support. A nonprivileged, multitasking process that is
typically used to handle datastream conversion and data communications-related
functions for a business application.
inactive task. A task that is stopped.
in-queue file. A $RECEIVE-like file used by a LINE^HANDLER task to pick up intertask
messages from DEVICE^HANDLER tasks.
IOCB. Input/output control block. TSCODE allocates an IOCB to manage each outstanding
nowait I/O.
IOP. Input/output process. Generally, a communications subsystem that handles the lower
levels of protocol for I/O.