Abstract: A disk drive is disclosed employing an offset-nulling amplifier for detecting a back EMF voltage of a voice coil motor (VCM) in a velocity mode servo control system. The offset-nulling amplifier comprises a differential amplifier, an input stage for swapping the polarity of the input voltage at a periodic interval, and an output stage comprising a single-ended amplifier having an input switched at the periodic interval between the positive and negative outputs of the differential amplifier.

Abstract: A disk drive is disclosed for receiving a Self Monitoring Analysis and Reporting Technology (SMART) command from a host computer. The disk drive comprises a plurality of configuration parameters stored in a non-volatile manner for configuring at least one system when the disk drive is powered on. The SMART command comprises a command code comprising a predetermined value for identifying the command code as a SMART command and a sub command comprising one of a plurality of predetermine values identifying one of a plurality of SMART commands selected from the group consisting of enabling SMART diagnostics, reading diagnostic data, and transmitting setup data to the disk drive. The SMART command further comprises setup data for modifying the configuration parameters.

Abstract: A disk drive is disclosed that is responsive to standard disk-drive commands associated with disk-drive operations and to nonstandard disk-drive commands required for disk drive manufacture and quality testing. The disk drive includes a disk, a head actuated radially over the disk, and a disk control system. The disk control system responds to disk-drive commands and accesses data storage locations on the disk through the head. A serial ATA interface couples the disk control system to a host computer. The serial ATA interface is configured to transfer standard disk-drive commands from the host computer to the disk control system and is configured to not transfer nonstandard disk-drive commands from the host computer to the disk control system. The extracting means extracts a nonstandard disk-drive command that is embedded within a data block accessed using a standard disk-drive command and provides the extracted nonstandard disk-drive command to the disk control system.

Abstract: The invention may be embodied in a method for operating a disk drive in a mobile device to optimize power usage. The mobile device may be a hand held computing device such as a personal digital assistant (PDA) or a mobile terminal such as a cellular telephone. Immediately after responding to a disk access command, the disk drive is in first operating mode that consumes a relatively high level of power and may transition to a second operating mode that consumes a relatively low level of power. A transition from the second operating mode to the first operating mode consumes a transition quantity of power. A predictive technique tracks a user's usage pattern and adapts an operating mode transition time based on the usage pattern.

Abstract: A computer program embodied on a computer readable storage medium is disclosed for dependently adjusting at least three operating levels of a disk drive by dependently adjusting a plurality of disk drive parameters. The computer program receives control input from one or more sources, such as an end user, an environmental sensor, or the disk drive, wherein the control input for adjusting at least three operating levels of the disk drive in a dependent manner. In response to the control input, the computer program adjusts a plurality of parameter settings in the disk drive in a dependent manner. In one embodiment, the operating levels dependently adjusted by the control input comprise a performance level, a capacity level and a robustness level.

Abstract: A method and apparatus are disclosed for transmitting advertising information to a mobile terminal over a first connection during a synchronization session and storing the advertising information in a local memory of the mobile terminal. A rich text document is transmitted to the mobile terminal over a second connection, wherein the rich text document comprises conditional code comprising advertising display criteria including a first identifier for retrieving selected advertising information stored in the local memory of the mobile terminal and a second identifier for downloading the selected advertising information from the Internet.

Abstract: A distributed method of establishing a path in a multi-dimensional computer network comprising a plurality of nodes for transmitting isochronous data from a source node to a destination node is disclosed. A request packet is injected into the network, the request packet specifying a request to transmit the isochronous data from one of a plurality of source nodes. The request packet is routed to at least one the plurality of source nodes, and the source node determines whether it has sufficient resources to support transmitting the isochronous data. If the source node comprises sufficient resources to support transmitting the isochronous data, the source node reserves resources within the source node to support transmitting the isochronous data, and transmits an ack packet from the source node to a first neighboring node. The first neighboring node determines whether it has sufficient resources to support transmitting the isochronous data.

Abstract: A disk drive is disclosed comprising a plurality of disk surfaces and a plurality of respective heads actuated radially over the disk surfaces. Each disk surface comprises a plurality of tracks, each track comprising a plurality of data sectors and a plurality of embedded servo sectors, each embedded servo sector comprising a servo sync mark for synchronizing to the embedded servo sector. When the disk drive switches heads, a detection window for detecting the servo sync mark is opened early. An asynchronous gain control algorithm prevents a gain control system from diverging while reading an area of the disk surface preceding the servo sync mark, and a synchronous gain control algorithm maintains a proper gain of the read signal while reading the servo sync mark.

Abstract: The present invention relates to disk drive having a cache control system that generates scan results that permit response to a host command using existing cached data having a logical block address (LBA) range that overlaps a host command LBA range. The cache control system forms variable length segments of memory clusters in a cache memory for caching disk data in contiguous LBA ranges. The cached LBA ranges are scanned for segments having LBA ranges overlapping with an LBA range of a host command. The cache control system is effective in exploiting any existing overlapping cache data.

Abstract: A disk drive is disclosed comprising an interface for receiving a supply voltage from a host computer and control circuitry for controlling at least one operation of the disk drive. The supply voltage is applied to the windings of a multi-phase spindle motor in a commutation sequence during a normal operating mode, and a secondary voltage supplied by a center tap of the windings is used to power the control circuitry during the normal operating mode.

Abstract: The present invention may be regarded as a disk drive comprising a disk, a head, an actuator arm for actuating the head radially over the disk, and a voice coil motor (VCM) for rotating the actuator arm about a pivot, the VCM comprising a coil comprising a VCM resistance R. A back EMF voltage detector measures a back EMF voltage across the coil, and a current detector detects a current I flowing through the coil. An IR voltage detector, responsive to the current I detected by the current detector, detects an IR voltage proportional to the current I times the VCM resistance R. A voltage compensator substantially cancels the IR voltage from the measured back EMF voltage to generate a compensated back EMF voltage. A control voltage generator, responsive the compensated back EMF voltage, generates a control voltage applied to the coil to generate the current I flowing through the coil.

Abstract: The present invention is embodied in the disk drive having a cache control system that is configured to efficiently respond to host commands by forming variable length segments of memory clusters for caching disk data in contiguous ranges of logical block addresses without regard to the sequential order of the memory clusters. The cache control system has a tag memory usable only for defining the segments. The tag memory has a plurality of tag records pointing to cluster control blocks associated with the memory clusters for defining the segments. The tag memory may be accessed and updated by several state machines in the cache control system and by a microprocessor in the disk drive.

Abstract: A disk drive is disclosed wherein a write command is verified according to a rotational position optimization (RPO) algorithm rather than immediately after the write command to better optimize drive performance relative to mechanical latencies.

Abstract: The present invention may be regarded as a digital video recorder (DVR) comprising a storage device for storing an encrypted video program, a unique ID for interlocking the encrypted video program with the digital video recorder, and a cryptography facility. The cryptography facility comprises an encoder, responsive to the unique ID, for encrypting a plaintext video program into the encrypted video program stored on the storage device, and a decoder, responsive to the unique ID, for decrypting the encrypted video program stored on the storage device into the plaintext video program during playback.

Abstract: A disk drive is disclosed comprising a voice coil motor (VCM) driver including an H-bridge driver having a first sense resistor connected in series with a supply voltage and a second sense resistor connected in series with ground. First and second amplifiers amplify the voltages across the first and second sense resistors, wherein the output of the amplifiers drive respective first and second oscillators. A counter processes the frequency signals output by the oscillators to generate a digital representation of the current flowing through the voice coil of the VCM.

Abstract: A disk drive is disclosed comprising a voice coil motor (VCM) for actuating a head radially over a disk. A VCM driver comprises first and second transistors forming a common collector amplifier for sensing a current flowing through a voice coil of the VCM. The common collector amplifier improves the accuracy of the current sense measurement when the VCM is driven in a pulse width modulated (PWM) mode.

Abstract: A digital video recorder (DVR) is disclosed for storing a plaintext video program as an encrypted video program. The DVR comprises a random access storage (RAS) device for storing the encrypted video program in encrypted segments. The DVR further comprises a cryptography facility comprising an encoder for encrypting plaintext segments of the plaintext video program into the encrypted segments stored on the RAS device, and a decoder for randomly and independently decrypting the encrypted segments of the encrypted video program into plaintext segments during playback.

Abstract: A digital video recorder (DVR) is disclosed comprising a unique ID, a hard disk drive (HDD) for storing a plurality of encrypted video programs and an encrypted file system, the encrypted file system comprising a plurality of encrypted file system entries for decrypting the plurality of video programs. The DVR further comprises host circuitry for interfacing with the HDD, the host circuitry comprising a cryptography facility for encrypting plaintext file system entries into the encrypted file system entries stored on the HDD, and for decrypting the encrypted file system entries read from the HDD into plaintext file system entries. The cryptography facility comprises a pseudo-random sequence generator, responsive to the unique ID, for generating a pseudo-random sequence.

Abstract: A disk drive is disclosed comprising a semiconductor memory comprising a cache buffer having a plurality of segment pools, each segment pool comprising a plurality of cache segments, and each cache segment comprises 2k number of blocks where k is a predetermined integer for each segment pool. Host commands have a command size comprising a plurality of bits indicating a number of blocks of data associated with the host command. Each bit of the command size is mapped to a corresponding segment pool in order to allocate cache segments for the host commands.

Abstract: A disk drive is disclosed which links disk commands that access near sequential data sectors. The linked and non-linked disk commands are inserted into an input/output queue and selected for execution according to a rotational position optimization (RPO) algorithm. If an error occurs while executing a linked disk command, the disk commands are unlinked and at least one of the unlinked disk commands is executed. The residual unlinked disk commands are inserted back into the input/output queue for later execution in an order determined by the RPO algorithm.