Abstract: An apparatus and method for disk sector layout, formatting, reading and writing, is based on a flexible formatter microengine that is driven by parameter lists, which may include commands to dynamically download the microengine's writable control store during disk access operations. This reduces the intervention required by the local microprocessor to support exception handling, including defect management, thus decreasing total access time for typical disk access (format, write or read) operations. This also reduces or eliminates the area on the disk required for ID fields, thus increasing the storage capacity of disk drives controlled by the present invention. This also increases disk space utilization, thus increasing the storage capacity of a disk drive controlled by using the present invention. Additionally, the invention is based on ID fields that may contain redundant information for increased fault tolerance.

Abstract: A table driven method and apparatus for automatic split field processing in a disk drive system stores data representing the split fields after each servo mark of a frame. Each track of the disk drive system is divided up into frames or groups of sectors or equivalently servo marks, each frame comprising a predetermined number N of sectors and a predetermined number M of servo marks. Beginning from the INDEX mark, after every N sectors or equivalently M servo marks, the next sector must start after the next servo mark. The value N is a constant within each zone on a disk but can vary from zone to zone as the storage density changes. The information for each servo mark within a frame is stored in a frame table in the buffer memory. A starting address pointer and an ending address pointer are used to keep track of the starting and ending addresses, respectively, of the frame table. An address pointer is used to point to the current entry of interest in the frame table.

Abstract: An apparatus and method for disk-sector layout, formatting, reading and writing, is based on a flexible formatter microengine that is driven by parameter lists, which may include commands to dynamically down load the microengine's writable control store during disk access operations. This reduces the intervention required by the local microprocessor to support exception handling, including defect management, thus decreasing total access time for typical disk access (format, write or read) operations. This also reduces or eliminates the area on the disk required for ID fields, thus increasing the storage capacity of disk drives controlled by the present invention. This also increases disk space utilization, thus increasing the storage capacity of a disk drive controlled by using the present invention. Additionally, the invention is based on ID fields that may contain redundant information for increased fault tolerance.

Abstract: A method and apparatus for detecting the transfer of a wrong sector uses the LBA to ensure that a correct sector is transferred. The LBA may be appended to the sector data during a write operation and verified during a read operation. Preferably, the LBA is embedded into the CRC block during a write operation and used to detect the transfer of a wrong sector during a read operation. The LBA may be embedded within the CRC, before or after it is transmitted to a CRC Generator/Checker, by Exclusive-ORing the sector data or CRC data with the LBA. During a read operation, the incoming CRC is Exclusive-ORed with the expected LBA of the sector being read, thereby eliminating the LBA from the CRC data. The CRC data is then checked by the CRC Generator/Checker and an error is signalled if the CRC data does not match. Using the method and apparatus of the present invention, the LBA may also be embedded in the CRC during format and minimal latency operations.

Abstract: A test logic circuit for testing the functioning of an integrated circuit containing asynchronous logic and synchronous logic and state machines is provided with a comparison circuit that compares state numbers produced by one of the state machines to a defined target value. The comparison circuit asserts a signal when one of the state numbers is equal to the defined target value. Status latches are coupled to the comparison circuit and latch a status of the asynchronous logic in response to the assertion of the signal by the comparison circuit. The comparing of the state numbers to a defined target value by the comparison circuit in the test logic circuit allows the latching of the status of the asynchronous logic upon the state machine reaching the specified state, and thereby provides the speed necessary to determine the status of the asynchronous logic for a particular state of a state machine in the integrated circuit.