Suppressing SYNCDEV for alternate tapes during duplex migration

You can suppress SYNCDEV processing for alternate tapes during duplex migration. To do so, enter the following PATCH command:

PATCH .MCVT.+196 BITS(..1.....)

To reactivate SYNCDEV processing for alternate tapes, enter the following command:

PATCH .MCVT.+196 BITS(..0.....)

By default, SYNCDEV processing occurs for alternate tapes.

This patch is not suggested for earlier technology tape drives, such as the 3490 and 3590. However, using it with the 3592-J or Start of change 3592 End of change tape drives can improve performance.

This patch is ignored if your installation has specified that both the original and alternate tapes are to be marked full if the alternate tape volume encounters an error. You can specify this option through the ERRORALTERNATE(MARKFULL) subparameter of the SETSYS DUPLEX MIGRATION(Y) command.