Abstract: A target location for an actuator of a disk drive is determined for prepositioning the actuator before receiving a command from a host. The target location is determined based on at least one of a characteristic of the disk drive, recent command activity of the host, and information provided by the host. The actuator is moved toward the target location to preposition the actuator.

Abstract: A data storage device is disclosed comprising a non-volatile memory, such as a disk of a disk drive or a non-volatile semiconductor memory. First and second write commands are received from a host, and in response first and second write data are requested from the host. The first write data is stored in the non-volatile memory, and after storing the first write data, a first acknowledge is transmitted to the host to acknowledge completion of the first write command. After transmitting the first acknowledge, a third write command is received from the host. The second write data is stored in the non-volatile memory, and after storing the second write data, a second acknowledge is transmitted to the host acknowledging completion of the second write command. After transmitting the second acknowledge, third write data is requested from the host associated with the third write command.

Abstract: An embedded system with reduced susceptibility to single event upset effects. The system includes an instruction memory that can store at least one instruction set. The instruction memory utilizes a parity checking error-detection scheme. The system also includes a non-volatile memory that can store a copy of the at least one instruction set, and a data memory that can store at least one data sequence. The data memory utilizes an error correction coding (ECC) scheme. A controller, which is responsive to the instruction memory, the non-volatile memory, and the data memory, replaces the at least one instruction set in the instruction memory with the copy of the at least one instruction set from the non-volatile memory, if a parity error is detected in connection with the at least one instruction set in the instruction memory. The controller also operates in conjunction with the data memory to implement the ECC scheme.

Abstract: 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.

Abstract: A method and apparatus are provided for scheduling commands. A tentatively scheduled command is selected from a command queue for execution. An extended scheduling period, which represents a portion of a time between when a running command is completed and the tentatively scheduled command is scheduled to begin, is then determined. During the extended scheduling period, it is determined that a newly arriving command outperforms the tentatively scheduled command. As a result, the newly arriving command replaces the tentatively scheduled command.

Abstract: 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.

Abstract: A disc storage system having a host computer interface adapted to coupled to a host computer, a disc storage medium having a disc surface and a spindle motor coupled to the disc adapted to rotate the disc. The disc includes spare data regions and permanent data regions. A transducer is positioned for reading and writing data on the disc surface. The system further includes a controller adapted to write data on the spare data regions to thereby provide a non-volatile write cache.

Abstract: A method formats disc surfaces in a disc drive for storage of data in a group of tracks on the disc surfaces. The disc drive performs seek operations to seek among cylinders on the disc surfaces as a function of time according to an actual seek profile. An approximation of the actual seek profile is determined such that the actual seek profile falls within the approximation. The disc surfaces are formatted according to the approximation of the actual seek profile.

Abstract: A data storage system and method of scheduling commands in such a data storage system are provided in which commands are stored in a command sort queue and a scheduled command queue. Commands in the command sort queue are sorted and assigned a priority. Eventually, commands in the command sort queue are transferred to the scheduled command queue. Commands in the scheduled command queue are executed without further sorting. The desired queue depth or size of the scheduled command queue is determined as a function of both the queue depth of the command sort queue and a command execution rate value which is indicative of the rate at which commands in the scheduled command queue are executed. The desired queue depth may be dynamically determined using the queue depth of the command sort queue and the command execution rate value as inputs to a look-up table. The data storage system may include a small computer system interface (SCSI) disc (or “disk”) drive which executes commands from a host system.

Abstract: A method formats disc surfaces in a disc drive for storage of data in a group of tracks on the disc surfaces. The disc drive performs seek operations to seek among cylinders on the disc surfaces as a function of time according to an actual seek profile. An approximation of the actual seek profile is determined such that the actual seek profile falls within the approximation. The disc surfaces are formatted according to the approximation of the actual seek profile.

Abstract: An apparatus and associated method are disclosed for optimizing the data transfer performance of a disc drive in which user data is stored in data blocks arranged on tracks of at least one rotating disc. When a selected, uninterrupted amount of time passes since the most recently performed disc drive operation, the disc drive enters an idle mode and selectively evaluates the data blocks for uncorrected read errors. During the idle mode, at such time that a selected data block is found having an uncorrected error, a sequence of corrective operations are performed in an attempt to resolve the error and the selected data block is reallocated when at least selected one of the corrective actions are unsuccessful.

Abstract: A method formats disc surfaces in a disc drive for storage of data in a group of tracks on the disc surfaces. The disc drive performs seek operations to seek among cylinders on the disc surfaces as a function of time according to an actual seek profile. An approximation of the actual seek profile is determined such that the actual seek profile falls within the approximation. The disc surfaces are formatted according to the approximation of the actual seek profile.

Abstract: The present invention is a method for decreasing rotational latency in systems which include a data retrieval element and a rotating medium. The method requires that the rotating medium be divided into a plurality of discrete angular regions. For each discrete angular region, a number of cylinders that may be traversed by the data retrieval element during a single revolution of the medium is identified. A rotational latency assigned to each discrete angular region based on a current location of the retrieval element. A command queue array is searched for a command that addresses a location within a range of cylinders determined by the number of cylinders in the discrete angular region having the smallest rotational latency. Finally, the command addressing a location in the range of cylinders in the selected discrete angular region of the medium is executed.