A copy procedure detects qualified data objects in a body of source data, and
copies
the source data to a target storage unit except for unqualified data objects, which
are replaced with a prescribed bit pattern. Following completion of the backup,
a record is prepared indicating that all data objects exist in the specified target
storage, regardless of whether each data object was replaced with a predetermined
bit pattern rather than being physically written to the specified target storage.
This process may be repeated in order to perform data reclamation, effectively
removing user files no longer qualifying for backup.