Disk drive using PRML class IV sampling data detection with digital adaptive equalization

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner an improvement comprising a partial response, maximum likelihood data channel between the data transducer head and the sequencer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations, said analog read channel means including analog programmable filter/equalizer means for programmably adjusting its filtering/equalizing characteristics to the data transfer rate of each one of the plurality of data zones,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with a reference based upon a selected data zone during data write operations and in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone, and
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means tier controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the data transducer head and the sequencer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone,
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples, and
• wherein the analog read channel means includes a variable gain amplifier means, and further comprising an analog automatic gain loop means for determining a coarse gain setting of the variable gain amplifier means, and digital automatic gain vernier control means for generating and applying a gain vernier control to the analog automatic gain loop means in response to sensed amplitude of said quantized and filtered samples.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the data transducer head and the sequencer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with quantized samples during data read operations, the quantization clock generator means locking to unfiltered quantization samples during a timing acquisition submode during reading of a preamble field pattern within a read operation and locking to quantized and filtered samples during a timing tracking submode following timing acquisition submode,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone, and
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the sequencer and the data transducer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone,
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples, wherein the Viterbi detector means includes means for applying programmable reference levels for detecting and putting out the coded data from the quantized and filtered samples.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the data transducer head and the sequencer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone and including filter coefficient adaptation means for adapting filter coefficients by comparing data values recovered from quantized and filtered samples of a known text recorded in a said zone with data values of the known text and by adjusting the filter coefficients to improve correlation between the samples and the known text, and
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the data transducer head and the sequencer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone and including filter coefficient adaptation means for adapting coefficients for said FIR filter in real time based upon user data samples, and
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data blocks from and writing data blocks to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and wherein each block of data recorded in a track within a zone includes a header, and wherein the header includes a sync pattern for synchronizing a byte clock of the data sequencer, and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the data transducer head and the sequencer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with a reference based upon a selected data zone during data write operations and in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone,
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples,
• and sync pattern detection means connected to receive the quantized and filtered samples for detecting the sync pattern and for signaling the sequencer that the sync pattern has been found.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, wherein the concentric data tracks recorded at different data transfer rates are periodically interrupted by servo sectors recorded with head position information at a servo data rate asynchronous with the code data rate for the tracks and zones, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the data transducer head and the sequencer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone, wherein the programmable FIR filter is provided with servo coefficients during reading of the servo sectors by the data transducer head,
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples,
• and further comprising an asynchronous servo detector means for detecting said head position information from said quantized and filtered samples without phase locking of said quantization dock generator means to said samples, said head position information being provided to said embedded controller means.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel between the sequencer and the data transducer, the channel including:

• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization dock in phase lock with a reference based upon a selected data zone during data write operations and in phase lock with quantized samples during data read operations and including zero phase start means for restarting the quantization clock for each data read operation.
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone, and
• Viterbi detector means for detecting and putting out coded data from the quantized and filtered samples.

In a disk drive including a rotating disk having a data storage surface defining a plurality of data zones containing concentric data tracks recorded at different data transfer rates, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a partial response, maximum likelihood data channel, the channel including:

• encoder means connected to the sequencer for converting user data blocks into a predetermined code,
• precoder means for convening the predetermined code into class IV code,
• analog write driver means for supplying the class IV code to the data transducer head during data write operations,
• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with a reference based upon a selected data zone during data write operations and in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with filter coefficients selected for the said selected data zone,
• Viterbi detector means for detecting and putting out the class IV code from the filtered and quantized samples,
• postcoder means for converting the detected class IV code into detected predetermined code,
• decoder means for converting the detected predetermined code into user data and for supplying said user data to the sequencer and wherein the encoder means and the decoder means are included within a serializer-deserializer circuit.

In a disk drive including a rotating disk having a data storage surface defining a multiplicity of concentric data tracks which are periodically interrupted by servo sectors recorded with head position information at a servo data rate asynchronous with the code data rate for the tracks, a positionable data transducer head for reading data from and writing data to each data track, a head positioner for positioning the transducer over a selected data track, an interface for connecting the disk drive to an external host computer, a sequencer for controlling sequencing of data blocks between the disk surface and the interface and embedded controller means for controlling the interface, the sequencer and the head positioner, an improvement comprising a class IV partial response, maximum likelihood data channel, the channel including:

• encoder means connected to the sequencer for converting user data blocks into a predetermined 8/9ths code,
• precoder means for converting the 8/9ths code into class IV code,
• analog write driver means for supplying the class IV code to the data transducer head during data write operations,
• analog read channel means connected to the head for amplifying and conditioning analog signals during data read operations,
• quantization means for quantizing samples of the analog signals in accordance with a quantization clock,
• quantization clock generator means for generating the quantization clock in phase lock with a reference during data write operations and in phase lock with quantized samples during data read operations,
• programmable FIR filter means for filtering the quantized samples in accordance with selectable filter coefficients,
• Viterbi detector means for detecting and putting out the class IV code from the filtered and quantized samples,
• postcoder means for converting the detected class IV code into detected 8/9ths code,
• decoder means for converting the detected 8/9ths code into user data and for supplying said user data to the sequencer and wherein the programmable FIR filter is provided with servo coefficients during reading of the servo sectors, and
• asynchronous servo detector means for detecting said head position information from said quantized and filtered samples without phase locking of said quantization clock generator means to said samples, said head position information being provided to said embedded controller means.