Abstract: A method is disclosed for writing product servo sectors to the disk of a disk drive by demodulating spiral tracks recorded on the disk. Each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. The high frequency signal is demodulated into a plurality of servo burst signals, and a position error signal is generated from the servo burst signals. A correlation between the position error signal and an off-track displacement of a head is calibrated, for example, by moving the head radially over the disk until the servo burst signals attain a first predetermined relationship, and then calibrating the correlation in response to the corresponding position error signal.

Abstract: A system and method for configuring and managing the connectivity of a broadband, cable modem network station to a network, including a state-driven network manager having a centralized error handling state and peripheral states for initialization, dynamic host configuration, configuration download, start simple-network-management, and an operational state. The operational state monitors for error and other messages communicated from other states and sends error messages to the centralized error-handling state and request messages to an operational support system interface management task. The error handling state receives error messages and requests error event logging from the operational support system interface management task. A change upstream-or-downstream channel task optimizes channel selection.

Abstract: A system architecture for a high speed serial bus compatible with the 1394 standard is disclosed. A transaction interface coordinates data packets received from or sent to a 1394 bus. A kernel/scheduler/dispatcher is used to allocate memory resources, and start a variety of tasks and services. The tasks and services vary depending on protocols used in a transport layer and application layer used in conjunction with the 1394 layers. The transaction interface uses information derived from the data packets received to form message control blocks, particular for each individual task, and places the control blocks into the proper task queue. The transaction interface forms a dispatcher message control block and places it into the scheduler/dispatcher queue to initiate the task. If there are no other message control blocks in the queue particular for the called task, the called task is immediately started. Otherwise, the message control block waits in the queue to eventually be operated on.

Abstract: A communications system uses a distributed architecture for allocating bandwidth to end units. In one embodiment, a Media Access Controller (MAC) processes packets received by a shared I/O port of a node. A fiber optic cable or other type of cable connects the I/O port to a plurality of end units, such as optical network units (ONUs). The ONUs request bandwidth allocations from the node and then wait to be granted access to the cable prior to transmitting their data. A Bandwidth Allocation Strategy (BAS) server (e.g., a CPU) in the node communicates with the various MACs and determines the bandwidth allocated to each ONU in response to requests by the ONUs for bandwidth. The BAS server accesses one or more algorithm processors for calculating the required access time (for a TDMA system) for each ONU allocation request.

Abstract: A system architecture for a high speed serial bus compatible with the 1394 standard is disclosed. A transaction interface coordinates data packets received from or sent to a 1394 bus. A kernel/scheduler/dispatcher is used to allocate memory resources, and start a variety of tasks and services. The tasks and services vary depending on protocols used in a transport layer and application layer used in conjunction with the 1394 layers. Each task operates according to a state machine progression. The transaction interface uses information derived from the data packets received to form message control blocks, particular for each individual task, and places the control blocks into the proper task queue. The transaction interface forms a dispatcher message control block and places it into the scheduler/dispatcher queue to initiate the task. If there are no other message control blocks in the queue particular for the called task, the called task is immediately started.

Abstract: A system architecture for a high speed serial bus compatible with the 1394 standard is disclosed. A transaction interface coordinates data packets received from or sent to a 1394 bus. A kernel/scheduler/dispatcher is used to allocate memory resources, and start a variety of tasks and services. The tasks and services vary depending on protocols used in a transport layer and application layer used in conjunction with the 1394 layers. Each task operates according to a state machine progression. The transaction interface accepts data information from the tasks and forms data packets for delivery to the 1394 bus. The data packets are initially sent via an associated hardware register, but if busy, the transaction interface polls for other available registers. In addition, all queued transactions are loaded into registers in the most expedient manner.

Abstract: Methods and apparatus for providing improved gain and bandwidth and robust damping of mechanical resonances for a servo control system by providing a collocated or nearly collocated feedback loop that operates in parallel with the ordinary feedback loop used for position or velocity feedback.