Compaq Computer Corporation, Inc.

Compaq Computer Coporation

John R Masters

Richard M Knox

Kevin F Clancy

James R Luttrall

Keith Pollock

A Rene Martinez

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.

Optical tape drive that performs direct read after write operations

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. In respective embodiments, the optical tape drive includes two head systems, four head systems, eight head systems, etc., where each head system includes one or more optical head units.

Optical tape drive that includes redundant optical heads to perform

A method of determining an object's position and associated apparatus provides positional information in a form that may be conveniently communicated to a computer to calculate the object's position. In a preferred embodiment, representatively incorporated in a computer keyboard, a method of determining an object's position includes forming an optical grid of reflected beacons and detecting an obstruction of the reflected beacons. The preferred embodiment apparatus utilizes a single light source and a single light sensor to detect an object's position in two dimensions.

Keyboard-compatible optical determination of object's position

A method of determining an object's position and associated apparatus provides positional information in a form that may be conveniently communicated to a computer to calculate the object's position. In a preferred embodiment, representatively incorporated in a computer keyboard, a method of determining an object's position includes forming an optical grid of reflected beacons and detecting an obstruction of the reflected beacons. The preferred embodiment apparatus utilizes a single light source to detect an object's position in two dimensions.

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Woodlands, TX, United States of America

John R Masters