You can code CLOSE TYPE=T to temporarily close sequential data sets on magnetic tape and direct access volumes processed with BSAM. When you use TYPE=T, the DCB used to process the data set maintains its open status. You do not have to issue another OPEN macro to continue processing the same data set. CLOSE TYPE=T cannot be used in a SYNAD routine.

The TYPE=T parameter causes the system control program to process labels, modify some of the fields in the system control blocks for that data set, and reposition the volume (or current volume for multivolume data sets) in much the same way that the normal CLOSE macro does. When you code TYPE=T, you can specify that the volume is either to be positioned at the end of data (the LEAVE option) or to be repositioned at the beginning of data (the REREAD option). Magnetic tape volumes are repositioned either immediately before the first data record or immediately after the last data record. The presence of tape labels has no effect on repositioning.

When a DCB is shared among multiple tasks, only the task that opened the data set can close it unless TYPE=T is specified.

Figure 1, which assumes a sample data set containing 1000 blocks, shows the relationship between each positioning option and the point where you resume processing the data set after issuing the temporary close.

Figure 1. Record Processed when LEAVE or REREAD is Specified for CLOSE TYPE=T