GDSX Manual

Design and Development
Extended General Device Support (GDSX) Manual–134303
2-64
MAXTCBPOOL
TSCODE uses system tasks that each require a TCB: a monitor task, a listener task, a
backup task if GDSX is running as a process pair, and six other kinds of system tasks.
Therefore, when allocating the TCB pool, TSCODE adds five to MAXTASKS to handle
all the system tasks. However, as more than five system tasks could be active
simultaneously, it is a good idea to set MAXTASKS a little higher than the number of
DEVICE^HANDLER and LINE^HANDLER tasks needed, because if TSCODE
determines that all TCBs are in use, it does not allow a new task to be created.
MAXTCBPOOL
This static parameter can be used to override the calculation of TCB pool space done
automatically by TSCODE during process initialization. In general, you should not
need to set this parameter.
The size that TSCODE calculates for the pool can be overridden by using a TACL
PARAM command to assign a value to the external name MAXTCBPOOL, or by
assigning a value to the internal parameter name in the
USER^INIT^CONFIG^PARAMS user exit. TSCODE uses the user-specified setting
unless it is determined that the pool size would be insufficient, in which case TSCODE
uses the value that it calculated.
If the pool size specified by this parameter is too large (more than 131,064 bytes), or if
the size causes the running total calculated for control block pools, the extended buffer
pool, and the extended message pool to exceed 16,777,216 bytes, an error message is
sent to the home terminal, and the GDSX process stops with abend error 020. The
configuration error message is:
10002 maxTCBpool or previous pools too large.
TSCODE allocates the TCB pool from extended memory. (See tcb^template in the
DCCBDECS file in Appendix C.) The size in bytes of the TCB pool is calculated as
follows:
TCB pool size = $LEN(TCB^TEMPLATE) * (MAXTASKS + 5)
MAXTERMS
This static parameter specifies the maximum number of subdevices (SUs) that can be
active simultaneously within a GDSX process. This number should include those SUs
preconfigured with SCF as well as those configured dynamically. As each device to be
opened by GDSX is assigned a DCB control block, this parameter determines how many
device control blocks to allocate.
Internal DEFINE
Name
CONFIG^PARAMS
Name Default Value Range
maxtcbpoolsize maxtcbpool^size (see following
equation)
Up to 131,064 bytes
Internal DEFINE Name CONFIG^PARAMS Name Default Value Range
maxterms maximum^terms 32 SUs 2–1128 SUs