SUBTSKS

The SUBTSKS system initialization parameter specifies the number of task control blocks (TCBs) you want CICS to use for running tasks in concurrent mode.

SUBTSKS={0|1}
Specifies whether there is to be a concurrent mode TCB so that CICS can perform management functions as system subtasks.
0
If you specify 0 (the default), CICS runs under the following two TCBs:
  • The quasi-reentrant mode TCB. CICS runs all user applications under this TCB.
  • The resource-owning mode TCB. CICS runs tasks that open and close files under this TCB.
1
If you specify 1, CICS runs under the two TCBs listed previously, and uses an additional TCB, a concurrent mode TCB, to perform system subtasking.