Migration unload and fallback unload

Unloading an HDAM or HIDAM database in order to change the DL/I access method of the database to PHDAM or PHIDAM is called migration unload. The process of restoring HDAM or HIDAM databases that were migrated to PHDAM or PHIDAM is known as fallback. Unloading a PHDAM or PHIDAM database for fallback is called fallback unload.

FABHURG1 can be used for both purpose. FABHFSU can be used only for migration unload.