Physical data saving involves the saving of all occupied blocks of a volume. FDDRL physically saves and restores the contents of whole disks in their physical order. All the data on a disk to be saved, including the volume labels, is transferred block by block in the same physical order onto other volumes, from where it can be restored if necessary.
The occupancy information of a disk (VTOC area) is determined using the F5 labels of the disk. FDDRL is able to identify that the F5 labels are not consistent in relation to the DMS catalog, for example, in the event that a pubset was not exported correctly. In this case, the disk is saved without using the occupancy information, or in other words, the disk is saved in its entirety.
If, for example, a disk has to be restored, it is not necessary to initialize the alternate disk with the desired VSN (volume serial number) beforehand. The alternate disk can be put into operation with the original VSN immediately after the FDDRL run.
FDDRL also retains the physical concatenations on a bootable disk, with the result that the copy can likewise be booted.
FDDRL cannot be used to save or restore individual files or to reorganize disks. These operations require software products for logical data saving such as “HSMS” (see the “HSMS” manual [6]) or “ARCHIVE” (see the “ARCHIVE” manual [1]). Alternatively BS2000 supports logical saving to so-called Snapsets at command level (see the “Introductory Guide to Systems Support” [5]).
FDDRL saves the (occupied) blocks of the disks in ascending order without knowing their file assignment.