Changing the default DEFRAG processing of checkpointed data sets (OW20285)

When DEFRAG selects an extent for movement and the associated data set's FORMAT 1 DSCB in the VTOC has the DS1CPOIT flag set indicating that a checkpoint was taken while the data set was open, DEFRAG cannot relocate the data set extent. Message ADR211I is issued to indicate when this occurs. A patch byte is provided to allow an installation to change the default DEFRAG processing of checkpointed data set extents.

This function is affected by setting the flag at offset X'43' in ADRPATCH. The settings are listed below:

X'00': DFSMSdss functions normally as described above.
Any setting other than X'00': DEFRAG moves selected extents, even when the data set DS1CPOIT flag is set on. Message ADR252I is issued when the patch byte is set on to indicate that the installation is overriding normal DEFRAG processing.

To set the flag to on dynamically, use the SET PATCH command. To set the flag to on permanently, modify the sample JCL (see Sample JCL) as follows:

//SYSIN DD *
   NAME ADRDSSU ADRPATCH
   VER   43        00
   REP   43        FF