DFSMShsm uses a method for serializing the migration of a GDS data set that does not require locking the GDG base. This method overrides patches to the MCVT at offset X'4C3', bit 7 (......X.). If you want DFSMShsm to return to the previous serialization method, issue the following patch command:

PATCH .MCVT.+595 BITS(.....0..)

When this bit is off (0), the GDG base is locked if the patchable bit in the MCVT at offset X'4C3', bit 7 (......X.) is off (0). The base is not locked if the bit is on (1). If disabled, the new serialization method can be re-enabled with the following patch:

PATCH .MCVT.+595 BITS(.....1..)