Disk compatibility
Data transfer between disks (with COPY-DISK or DUMP-DISK/RELOAD-DISK) is only possible if both disks have the same device type.
With disks of the same type but different sizes, data can only be transferred to the larger of the two. This means that some of the space on this larger disk will remain unused.
In mirrored-disk operation with RAID1 disks, if the device type is the same, data can also be transferred with COPY-DISK or DUMP-DISK/RELOAD-DISK between disks with and without mirroring.
MTC compatibility
Backup volumes (MTC) which has been created with a different FDDRL version from the one currently used can only be read by the latter version if the corresponding tape type (TAPE-DEVICE-TYPE) is supported by the other (older or newer) FDDRL version.
If the MTCs are administered by MAREN, they can only be used for restoration if the archive attribute CLOSE-INDICATOR=CLOSED is entered; for the reloading of older FDDRL saves, this indicator itself must be set (see chapter "Adjusting volume characteristics of earlier FDDRL versions").