Seagate Technology Incorporated

Kenny Troy Coker

Edwin Scott Olds

Jack Allen Mobley

Mark David Hertz

Stephen R Cornaby

Philip T Mowery

Nigel Frank Misso

Mark Alan Heath

Carl Fred Adams

Jason Dale Gregg

Eldon Leroy Nelson

William John Raphael

Hans J Rodrigues De Miranda

Raymond Dean Nicholson

William J Hakel

Leonard D Doss

A unique system and method for ordering commands may reduce disc access latency while giving preference to pending commands. The method and system involves giving preference to pending commands in a set of priority queues. The method and system involve identifying a pending command and processing other non-pending commands in route to the pending command if performance will not be penalized in doing so. The method and system include a list of command node references referring to a list of sorted command nodes that are to be scheduled for processing.

Prioritizing commands in a data storage device

A parallel interface modem for simultaneous transfer of a plurality of parallel signals across a medium is disclosed. In a preferred embodiment, the parallel interface modem includes a modulation circuit for qualifying each of the plurality of parallel device interface signals for serial transmission. Each of the plurality of qualified signals substantially simultaneously accumulates at a summing junction responsive to the modulation circuit. A mixer communicating with the summing junction combines the plurality of accumulated qualified signals to provide a multi-frequency signal. A serial port connector communicating with the mixer simultaneously transmits the plurality of accumulated qualified parallel device interface signals over the medium. Additionally, the parallel interface modem includes a demodulation circuit communicating with the serial port connector demodulating each of a plurality of received signal forming a multi-frequency parallel device interface signal received from the medium.

Parallel interface transmission using a single multi-frequency composite signal

A disc drive with a control processor programmed with an execution time dependent command schedule optimization method to effect data throughput with a host device. The disc drive includes a head disc assembly executing commands scheduled by the control processor. The control processor selects and schedules a next optimum command from among commands analyzed by the control processor during a time the head disc assembly is executing a current command. The steps utilized by the control processor to select and schedule the next optimum command include executing a first command with the head disc assembly, determining a computation time for a second command, storing the computation time as a computation time estimate, and using the stored computation time estimate to determine the number of commands in a command queue for analysis to provide a level of command schedule optimization commensurate with the available time.

Execution time dependent command schedule optimization

Performing a cache only data transfer across a bus connecting a storage apparatus with a host concurrent with a period of bus availability while being incident within a time period for executing a connect host data transfer command. The time period for executing the connect host data transfer command is determined by a combination of a seek latency portion of the connect host data transfer command execution in combination with a rotation latency portion of the connect host data transfer command execution offset by a data transfer latency between the storage apparatus and the host in combination with an overhead time, wherein the overhead time is determined by a time for determining the time period for executing the connect host data transfer command in conjunction with a time for stopping an operation of the storage apparatus and transitioning to a new operation of the storage apparatus.

Cache memory transfer during a requested data retrieval operation

Method and apparatus for transferring data between a host device and a data storage device having a first memory space (such as a buffer) and a second memory space (such as magnetic discs). Data are stored on the discs in host-addressable data sectors. The data storage device is configured to operate in a local mode of operation and a nonlocal mode of operation. During the local mode, nonrequested user data are retrieved from the discs and placed into the buffer in anticipation of a future request for the nonrequested user data. During nonlocal mode, such nonrequested user data are not retrieved. An interface circuit monitors host data access patterns and dynamically switches between the nonlocal and local modes in relation to proximity of a data sector address of each most recently received read command to data sector addresses associated with previously received read commands.

Dynamic data access pattern detection in a block data storage device

Method and apparatus for transferring data between a host device and a data storage device having a first memory space and a second memory space. The host issues access commands to store and retrieve data. The device stores commands in the first memory space pending transfer to the second memory space. An interface circuit evaluates relative proximity of first and second sets of LBAs associated with pending first and second commands, and delays promotion of later pending commands in front of earlier pending commands during an overlap condition. If the overlap is caused by performance enhancing features (PEF) the PEFs are disabled so the commands can be scheduled for disc access. Indicators are set in the commands to signal that a PEF has caused the overlap and that PEF can be disabled. Values are added to indicators in the commands such that the PEFs can be modified and avoid overlaps.

Reducing delay of command completion due to overlap condition

Method and apparatus for transferring data between a host device and a data storage device having a first memory space and a second memory space. The first memory space employs a first command queue and a second command queue. The host issues access commands to store and retrieve data. The device stores commands in the first command queue and moves the commands to the second command queue. Write commands are removed from the first command queue and a message is sent to the host device to signal that the command has completed. Read and write commands are sorted at the second command queue for execution in an efficient order. Host transfer resources and disc transfer resources are utilized in such a way as to allow independent operation and to allow transfers using both sets of resources at once. More queue space is available for commands at the first command queue.

Data transfer performance through resource allocation

Apparatus and method for improving disc drive performance by compensating for head-to-head offsets when scheduling a plurality of pending access commands. A disc drive includes a plurality of recording surfaces on which a plurality of concentric data tracks are defined. A servo circuit performs seeks to move a plurality of heads from an initial track to a destination track. A positional offset between each of the plurality of heads is measured and applied to an estimated seek length to calculate a corrected seek length. A corrected seek time is calculated from a seek profile table in relation to corrected seek length. The corrected seek time is used by a control processor to schedule the access commands stored in the memory.

Performance in a data storage device using head-to-head offsets in access command scheduling

A unique system and method for ordering commands to reduce disc access latency while giving preference to pending commands. The method and system involves giving preference to pending commands in a set of priority queues. The method and system involve identifying a pending command and processing other non-pending commands in route to the pending command if performance will not be penalized in doing so. The method and system include a list of command node references referring to a list of sorted command nodes that are to be scheduled for processing.

An apparatus is described which reduces flow-induced disturbances of the head. A disc drive assembly is provided which includes a basedeck and top cover. A spindle motor mounted to the basedeck which rotates around a central axis; at least one magnetic storage disc mounted to the spindle motor for rotation around the central axis and an actuator arm assembly. The actuator arm assembly includes an actuator arm rotatably attached to a pivot axis and a suspension arm attached to a distal end of the actuator arm. A magnetic transducing head is attached to the suspension. The head is used to read and write data to the magnetic storage disc. Finally, a leading surface portion of the actuator arm utilizes several turbulence-reducing portions laterally recessed so as to guide an airflow to reduce a flow-induced disturbance acting on the transducing head.

Saw tooth actuator for a disc drive

A disc drive includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to said base and a device for moving the actuator assembly. The disc drive also includes at least one sensor for sensing disturbances to the disc drive. The disc drive has a system microprocessor in electrical communication with the sensor. In the event a read error is detected, a plurality of sets of corrective procedures are stored in the random access memory of the microprocessor. The system microprocessor executes the sets of corrective procedures in an order in response to the sensed disturbances input to the system microprocessor.

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Mustang, OK, United States of America

Kenny Troy Coker