Abstract: A disk drive has a channel circuit for demodulating data sectors and servo sectors stored on a rotating medium to provide data-sector data and servo-sector data. The channel circuit transmits the data-sector data and servo-sector data to a disk controller circuit in an order which is different than the order in which they are stored on a rotating medium to allow for demodulation latency while maintaining real-time updates of embedded servo information.

Abstract: A printed circuit board assembly (PCBA) includes first and second integrated-circuit terminals and first and second connector terminals. A first transmission line transmits a data signal and a second transmission line transmits a clocking signal. The PCBA includes integrated circuitry comprising first and second pads, a first digital circuit for propagating the data signal through the first pad and a second digital circuit for propagating the clocking signal through the second pad. The first transmission line includes a first integrated-circuit conductive path including a first series-connected integrated circuit resistive element and a first printed-circuit conductive path. The second transmission line includes a second integrated-circuit conductive path including a second integrated-circuit resistive element and a second printed-circuit conductive path.

Abstract: A disk drive has a unified bus forming a signal path for transmitting register data, user data and servo sectors. The unified bus is connected between a channel circuit and a disk controller circuit. The channel circuit has an output stream engine which responds to and provides control signals to multiplex data on the unified bus at various times between demodulated user data, servo sector data and register data.

Abstract: This disclosure describes a snooping coherency protocol for a multiprocessor network wherein every processor has its own private cache and bus interface means and the network is connected via a common system bus. Each processor has its own cache directory and image directory that duplicate each other non-atomically. The snooping protocol utilizes the duality of directories coupled with the non-atomicity of directory updates to maximize processor-cache availability and minimize processor-cache access times thus supporting high performance architectures.