While DFSMShsm has been writing the backup copy of a data set, an I/O error has occurred. An access method or hardware error message associated with this message has been found in the DFSMShsm job log SYSMSG data set. Message ARC1001I precedes this message, giving the data set name.

When this message text is considered because of a related ARC0734I message, and the data set backed up is in VSAM format, the reason code displayed in the associated ARC0734I message is the return code from DFSMShsm’s internal call to IDCAMS. For an explanation of these return codes, see z/OS DFSMS Access Method Services Commands