DCBptr

This is a pointer to a DFSMS Data Control Block. See DFSMS Macro Instructions for Data Sets.

Note:

In most cases, this will be a DCB opened by the calling application. It is possible to use a DCB (such as a STEPLIB DCB or the LINKLIB DCB) opened by the MVS™ system, but there may be some additional restrictions when this is done. See SB - Starting a session with a BLDL identifier for more information.
The fast data access service supports all data sets allocated in the extended addressing space (EAS) of an extended address volume (EAV).
The fast data access service supports the following dynamic allocation (DYNALLOC or SVC 99) options for all data sets: S99TIOEX(XTIOT), S99ACUCB (NOCAPTURE), and S99DSABA (DSAB above the line).