Abstract: In a controller integrated circuit, which controls the operation of a peripheral storage device, a transfer monitoring circuit that facilitates the monitoring of successful transfers from outside the controller integrated circuit. The circuit includes a counter circuit that counts the number of successful transfers, a value storing register, a comparison circuit to compare the counter value to the value stored in the register and generate a result. The transfer monitoring circuit speeds up the operation of the controller integrated circuit especially during recovery from error conditions. The monitoring circuit also allows for a more optimal use of a look-ahead cache.

Abstract: In a controller integrated circuit, which controls the operation of a peripheral storage device, a transfer monitoring circuit that facilitates the monitoring of successful transfers from outside the controller integrated circuit. The circuit includes a counter circuit that counts the number of successful transfers, a value storing register, a comparison circuit to compare the counter value to the value stored in the register and generate a result. The transfer monitoring circuit speeds up the operation of the controller integrated circuit especially during recovery from error conditions. The monitoring circuit also allows for a more optimal use of a look-ahead cache.

Abstract: A method and apparatus for determining the position of a head with respect to a rotating magnetic disk within a disk data storage device using standard signals output from a head/drive assembly (HDA). Servo zone detect pulses are used to determine the position of the read/write head with respect to the servo cells. An index pulse determines the angular position of the head. A servo zone counter is incremented by one in response to a servo zone detect pulse. Accordingly, the servo zone counter maintains a unique value which is corresponds to each data wedge on a surface of the disk. A servo clock has a constant number of cycles between sectors. The servo clock is coupled to the clock input of a sector counter. A sector pulse is generated and the sector counter is reset to zero when the number of cycles counted indicates that the beginning of a sector is under the read/write head. A sector ID counter counts the number of sector pulses.