Abstract: An optical tape drive that performs direct read after write (DRAW) operations with a plurality of optical heads, each capable of reading data from and writing data to an optical tape. The optical tape drive includes control apparatus that positions each of the optical heads at any position along the width of the optical tape, that controls each of the optical heads to either read or write data, and that receives and moves the optical tape in either one of two directions. The control apparatus performs bidirectional DRAW operations by reversing the direction of the tape and swapping the read/write functions of corresponding head units aligned with a same track. The optical tape drive may include as few as two optical heads, each operable independent of the other, so that the drive may read or write up to two tracks at a time. DRAW operations are performed on multiple tracks by increasing the number of optical head units.

Abstract: An optical tape drive including redundant optical heads to continue reading and writing data to an optical tape in the event of failure of one or more optical heads. The optical tape drive includes a plurality of optical heads, each capable of reading data from and writing data to an optical tape, detection logic that detects failure of any of the optical heads and control apparatus. The control apparatus positions each of the optical heads along the width of the optical tape, controls each of the optical heads to either read or write data, receives and moves the optical tape, detects failure of any of the optical heads and performs failure recovery by continuing to read and write data with remaining optical heads. The data throughput rate during failure recovery may be the same as the normal rate for some operations, such as direct read after write. Several different optical head configurations are contemplated.