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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A disk drive system includes a disk drive controller system having separate head positioning and data transfer subsystems and supporting up to four disk drives, two of which may be removable and two of which may connect through a standard ST506 interface. The system provides a read and write protected cylinder for removably drive and a read only cylinder for removable drives which may store a unique serial number as well as other write protected data. Each removable disk drive may includes a register storing an identification code which may be used to control operation of the drive.

Abstract: A disk drive system includes a disk controller system having separate head positioning and data transfer subsystems and supporting up to four disk drives, two of which may be removable, portable drive units and two of which may connect through a standard ST506 interface. The removable disk drives incorporate a read and write protected data cylinder for storing information such as the maintenance history of the drive, and a read only cylinder for storing a unique serial number as well as other write protected data. The system also features a high capacity, high speed sector buffer which allows continuous transfers of data to or from noninterleaved sectors and supports concurrent disk and system accesses.

Abstract: A disk drive system includes a disk controller system having separate head positioning and data transfer subsystems and supporting up to four disk drives, two of which may be removable and two of which may connect through a standard ST506 interface. The system provides a read and write protected cylinder for removable drives, a read only cylinder for removable drives which may store a unique serial number as well as other write protected data, and a high capacity, high speed sector buffer which allows continuous transfers of data to or from noninterleaved sectors and supports concurrent disk and system accesses.The system provides communication between enhanced disk controllers and enhanced disk drives over a standard ST-506 interface whereby command and status signals greater in number than those normally transmitted over the dedicated lines of the ST-506 interface are communicated between the enhanced disk controller and enhanced disk drive.

Abstract: For use in an electronic printing system having a serial impact printer, apparatus is provided to accurately control the velocity of the print hammer during printing and provide accurately controlled impact energy, which is proportional to the character face area. The apparatus includes a servo feedback system where the primary driver for the print hammer is a moving coil in a magnetic field, and the velocity sensing required for the servo feedback loop is the back emf in the moving coil with the back emf being proportional to the hammer velocity.