EXPDT and RETPD: Specifying a tape expiration date or a retention period

Explanation: EXPDT(ccyyddd ) and RETPD(nnnn) are mutually exclusive, optional parameters specifying either an expiration date or a retention period for the alternate tape volume. The date is placed in the tape label but has no relation to when DFSMShsm will remove the tape from its inventory. The alternate tape is deleted by DFSMShsm at the same time the original is deleted.

It is important for you to understand that specifying an expiration date for the alternate tape volume that would cause the alternate tape volume to return to scratch before the original tape volume returns to scratch can result in data loss. For example, consider the following scenario:

Tape 1 is an original volume that has Tape 2 as its alternate volume.
Tape 2 is returned to scratch by the Tape Management System because the specified expiration date is reached. Tape 2 is now known to the Tape Management System as a scratch tape; however, DFSMShsm regards this tape as a valid alternate of Tape 1. (The expiration date does not relate to when the tape is removed from the DFSMShsm inventory.)
Tape 2 is now mounted in response to a scratch request from either DFSMShsm or another user request. After it has been written to, Tape 2 is not a valid alternate for Tape 1 anymore because it has been overwritten; however, DFSMShsm still considers Tape 2 a valid alternate of Tape 1. This, in itself, poses a problem if the alternate tape is needed, but the potential for problems continues.
Tape 1 is now returned to scratch by the ARCTVEXT exit, which also results in Tape 2 being returned to scratch. Now, Tape 2 is again a scratch volume and the data written to Tape 2 after its return to scratch the first time can be overwritten again if mounted in response to a scratch request.

EXPDT is an optional parameter that specifies a different expiration date (other than 1999365) for the alternate tape volume. The date is checked for validity, and the entire command is rejected if the test fails. Date limits for ccyyddd are from the current date to 31 December 2155.

Values for ccyyddd of 1999365 and 1999366 are recognized as “never expire” dates. Values of 1998000 and 1999000 are recognized as meaningful to certain tape management systems.

RETPD is an optional parameter that sets the expiration date by specifying a retention period. The valid range is 0–9999. RETPD is converted to an expiration date and is processed as described under EXPDT.

Defaults: None.

Table 1 shows all of the conditions for each tape volume processed by DFSMShsm. If the tape data set exit (ARCTDEXT) is in effect, DFSMShsm invokes the exit after processing any of the conditions shown in Table 1 and puts the date specified by the exit on the tape being copied.

Table 1. DFSMShsm Processing by Condition
Conditions				DFSMShsm...
Is an expiration date specified in the INDATASET record?	Is an expiration date specified on the TAPECOPY command?	Is the SETSYS TAPESECURITY (EXPIRATION) command in effect?	Is an expiration date specified for the original volume?	DFSMShsm...
no	no	no	no	Does not protect the alternate volume with an expiration date.
no	no	no	yes	Uses its default date of 1999365.
no	no	yes	no
no	no	yes	yes
no	yes	no	no	Uses the expiration date specified on the TAPECOPY command.
no	yes	no	yes
no	yes	yes	no
no	yes	yes	yes
yes	no	no	no	Uses the expiration date specified in the INDATASET record.
yes	no	no	yes
yes	no	yes	no
yes	no	yes	yes
yes	yes	no	no
yes	yes	no	yes
yes	yes	yes	no
yes	yes	yes	yes