GDSX Manual

Design and Development
Extended General Device Support (GDSX) Manual–134303
2-59
MAXIOCBS
TSCODE allocates an IOCB pool from extended memory. (See iocb^template in the
DCCBDECS file in Appendix C.) The size in bytes of the IOCB pool is calculated as
follows:
IOCB pool size = $LEN(IOCB^TEMPLATE) * MAXIOCBS
MAXIOCBS
This static parameter specifies the maximum number of nowait I/O operations that can
be outstanding at one time.
MAXITC
This static parameter specifies the maximum number of DEVICE^HANDLER tasks that
communicate with each other by ITC messages. If LINE^HANDLER tasks are to be
created, TSCODE increases the MAXITC value assigned by you to accommodate other
needed ITC files.
To calculate the actual number for MAXITC, TSCODE first chooses the minimum value
between the value you supply and 1,020. This is expressed by the following equation:
Minimum value = $MIN(MAXITC, 1020)
Then TSCODE chooses the maximum value between the MAXITC number from the
above equation and a number derived from MAXTASKS and MAXLINES, as expressed
in the following equation:
Actual value = $MAX((MAXTASKS - MAXLINES), minimum value))
MAXLDCBPOOL
This static parameter can be used to override the calculation of the logical device control
block (LDCB) 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 MAXLDCBPOOL, or by
assigning a value to the internal parameter name in the
USER^INIT^CONFIG^PARAMS user exit. TSCODE will use the user-specified
setting unless it is determined that the pool size would be insufficient, in which case
TSCODE will use the value that it calculated.
Internal DEFINE Name CONFIG^PARAMS Name Default Value Range
maxiocbs maximum^iocbs 128 I/Os 128–2047 I/Os
Internal DEFINE Name CONFIG^PARAMS Name Default Value Range
maxitc max^itc 0 0–1020 tasks
Internal DEFINE
Name
CONFIG^PARAMS
Name Default Value Range
maxldcbpoolsize maxldcbpool^size (see following
equation)
Up to 131,064 bytes