Abstract: A method and apparatus for backing up files from a logical disk are described to a backup tape and restoring all or part of the files to the logical disk. Separate "backup" and "copy" buffers in the host processor's main memory are employed during a backup operation. Backup buffers hold data read from the logical disk during the sequential backup operation. Copy buffers hold data read from the logical disk prior to execution of a write operation to a portion of the disk not yet backed up. Data is stored on the backup tape in logical tape records containing either backup data or copied data. A full restoration of all files can be done in one read of the backup tape. A partial restoration of selected files can be done in two reads of the backup tape.