A backup apparatus and method suitable for protecting the data volume in a computer system function by acquiring a base state snapshot and a sequential series of data volume snapshots, the apparatus concurrently generating succedent and precedent lists of snapshot differences which are used to create succedent and precedent backups respectively. The data volume is restored by overwriting the base state data with data blocks identified in one or more succedent backups. File recovery is accomplished by overwriting data from a current snapshot with one or more precedent backups.