During offline and online processing, the commands BUILDIX, INIT,
INSPECT, INSTALL, REVAL, and REFORMAT issue the RESERVE macro to obtain
control of the device. After processing on the device finishes, the
DEQ macro is issued to release the device.
This procedure prevents other processors from accessing the volume,
but does not guarantee exclusive access to the volume from the same
processor.
When processing online, it is always possible that a particular
track will be concurrently updated. The following actions minimize
this impact:
BUILDIX or REFORMAT commands require additional serialization when
issued on systems sharing the same volume. This additional serialization
increases processing time by up to seven seconds per volume. If the
volume is not being shared by other systems, or the volume has been
varied offline to all other systems, then the serialization is not
needed and may be bypassed by using the JCL parameter PARM=NOSYSZ
on your EXEC statement. For example:
//stepname EXEC PGM=ICKDSF,PARM=NOSYSZ
Note: After any ICKDSF command modifies the volume label,
the VTOC, or the VTOC index, issue a MOUNT command from the processors
that share the volume.