Optical tape drive that performs direct read after write operations

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. For example, four independent head units may be included to perform DRAW on two tracks at a time, eight head units to perform DRAW on four tracks at a time, etc. Furthermore, each head system may include multiple head units organized into an array for aligning with different tracks.