Abstract: An improved backup system for computer networks provides simplified operation, reduced utilization of computer system resources, and increased recovery potential in the events of information loss. At each backup time interval, the computer system sends all files created or modified since the time stamp to the backup system. The file stream flowing from the computer system to the backup system contains metadata at the boundaries of each file. Once all files are received from the computer system, the backup system produces a new full backup tape by merging the present backup tape with the newly received files, replacing each file on the presently existing tape that was modified with the newer version of that file. The resulting backup tape contains substantially the same set of files that would result from a full backup, or, if desired, a higher level backup.