Defining the track group maps

Two track group maps are defined to JES2: the master track group map and the “badtrack” map defining those tracks specified as bad by JES2. Use the TGSPACE=(MAX=) parameter on the SPOOLDEF initialization statement to define the number of track groups in your JES2 complex. The maximum value is 132,649,472; however, the realistic limit is determined by your virtual storage limitations. The rounding factor is 16288.

Note: If the number of track groups you have allocated on each spool volume is not divisible by 8, there is a discrepancy between the maximum allocatable track groups and the sum of the allocated track groups plus the number of track groups available.

Use the $T SPOOLDEF command to modify the TGSPACE=(MAX=) parameter; therefore, you can increase the number of track groups as current system usage requires. In this manner, the operator can dynamically add spool volumes with the $S SPOOL command to a maximum of 253 spool volumes. Decreasing this value requires a JES2 cold start. (See Dynamic addition and deletion of SPOOL volumes and z/OS JES2 Commands for further information on this procedure.)