Figure 1 shows the syntax for the RPROGRAM keyword.

INCLUDE (reblockable program include list)

Specifies a list of program names whose data sets will be reblockable.

EXCLUDE (reblockable program exclude list)

Specifies a list of program names whose data sets will not be reblockable.

Many data sets currently on tape have block sizes that are efficient for tape, but inefficient for DASD. For example, 32 760 is a commonly used block size for tape data sets. However, 32 760 is greater than half a track of 3390 DASD and would result in poor track use. Fortunately, most programs have no restrictions on block size. In the DFSMS environment you can eliminate the use of hard coded block size and allow DFSMS to choose the optimum block size with system determined block size.

If the user's DD statement has a BLKSIZE value that exceeds 32 760 when writing, that data set cannot be redirected to DASD. If the system determined the block size and it exceeds 32 760, the system will determine a smaller block size if the data set is redirected to DASD.

GFTAVMA calculates tracks required using the device type specified by the DASDDEV keyword and the data set's block size and block count.

If you specify RPROGRAM, GFTAVMA models designated programs as reblockable. If GFTAVMA considers a program to be reblockable, any data sets created by that program and allocated to DASD are modelled as having optimum block sizes that use DASD tracks more efficiently.