Storage Technology Corporation

Oracle America, Inc.

Oracle International Corporation

Keith Gary Boyer

Richard A Gill

Mark Hennecken

Steven Gregory Trabert

James C Cates

Jin Lu

John Paul Mantey

Roger D Hayes

Ronald Dean Gillingham

Robert G Brocko

Larry Blanchard

Thomas H Gohl

Michael Lawrence Leonhardt

Charles C Partee

Richard C Schneider

Robert D Thompson

Kenneth R Burns

Terry R Gottehrer

James William Wolf

Michael R Stephens

Kevin M Horn

Thomas G Liehe

Norman Lee Koren

Bernie R Marasco

Systems and methods that sense or obtain environmental conditions of a tape drive and dynamically apply voltage biases to tape head assembly elements based on the sensed/obtained environmental conditions to reduce tape stain accumulation and prolong tape head performance. Detection of different first and second sets of environmental conditions (e.g., in relation to temperatures, humidity levels, tape movement directions, etc.) may result in respective first and second voltage bias level sets being applied to respective first and second head assembly element sets. For instance, different first and second voltage bias level sets may be applied to the same head assembly elements (e.g., the first and second head assembly element sets may be the same), or the first and second voltage bias level sets may be applied to different head assembly elements (e.g., the first and second head assembly element sets may be at least partially different).

Dynamic reduction of tape stain accumulation on tape head assembly across multiple environments

A method of writing data to and reading data from a storage medium includes cycle slip detection and correction. An LDPC matrix includes a first area for cycle slip detection and correction. The first area satisfies a set of conditions such that a cycle slip at a particular position creates a pattern of parity check errors indicative of the position and polarity of the cycle slip. Writing user data to the storage medium includes encoding the user data with parity data according to the LDPC matrix. Reading the user data and the parity data from the storage medium includes decoding the user data and the parity data according to the LDPC matrix. Decoding includes, upon detecting a pattern of parity check errors indicative of the position and polarity of a detected cycle slip, correcting the detected cycle slip.

Cycle slip detection and correction

A parallel iterative decoding system interposed between a network interface and a block memory matrix receives encoded data and both stores the data in a First-In-First-Out ('FIFO') memory block and processes it through a timing recovery engine. The timing recovery engine delivers to an iterative decoder synchronized data samples and detects cycle slip. The iterative decoder thereafter performs a predetermined number of iterations to decode the data. Responsive to encoded data failing to converge after the predetermined number of iterations, the encoded data is communicated from the FIFO memory to an auxiliary decoder module. The auxiliary iterative error correction code decoder performs a second predetermined number of iterations to decode the data wherein the number of iterations performed by the auxiliary iterative error correction code decoder is greater than the primary iterative error correction code decoder. Converged data from the auxiliary decoder replaces otherwise null data stored in the block matrix memory.

Auxiliary path iterative decoding

An improved format is disclosed for storing a randomized data block in a storage device. The data block format includes a data field, an identifier (ID) field for storing an identifier that identifies data stored in the data field, and a randomizer seed field for storing a randomizer seed. An error check character generator generates an ID field error check character utilizing said identifier. The randomizer seed includes the ID field error check character.

Format for randomized data block in a storage device

A system and method for Reverse Error Correction Coding. The system includes a Constraint encoder, an Error Correction Code encoder, and a uniform interleaver. The Constraint encoder receives a source data stream and generates a first intermediate encoded data stream satisfying a first predetermined timing data constraint. The Error Correction Code encoder receives the first intermediate encoded data stream and generates a second intermediate encoded data stream having one or more Error Correction Code based elements. The uniform interleaver receives the second intermediate encoded data stream and generates a channel data stream having the one or more Error Correction Code based elements and satisfying a second predetermined timing data constraint.

System and method for reverse error correction coding

A Viterbi decoder is used to provide erasure information to a symbol based decoder. In a preferred embodiment, a Viterbi decoder is used to provide either minimum distance path metric information or path probability information, which is summed over a symbol window to derive erasure information for the symbol based decoder.

Soft viterbi Reed-Solomon decoder

In a tape drive for storing and retrieving information to and from a media, a system for optimizing write performance includes a tape head and a controller. The tape head may include a write element. The controller may be for optimizing write performance in response to at least one media information signal that is stored on a media cartridge.

System and method for read/write optimization

Servo tracks for magnetic tape storage are written using two opposite polarities, rather than the one polarity normally used in servo tracks. Timing continues to be performed using only pattern members of like polarity, due to physical restraints, but the use of two polarities allows additional information to be encoded in the pattern more efficiently.

Polarity encoded pattern for timing based servo

A drive and method of identifying write velocity during reading are provided. When a track is being read, the data signal is processed prior to determining the data stream to identify the velocity with which the track data were written. The read channel is adjusted based on the identified velocity to compensate for write channel transfer function variation.

Write velocity identification

In a magnetic recording device, a system and method for correcting errors in decoding a read data input signal. The system and method include multiple decoding channels, each channel processing the read data input signal and generating an output signal, where the output signal includes a data signal when no error is detected, and an error detection code when an error is detected. The system and method also include multiple error correction code (ECC) decoders, each decoder associated with and receiving the output signal of one of the channels and generating a corrected data signal when the received output signal is an error detection code and the error is correctable. The system and method further include a controller for selecting from the decoders one of the corrected data signals.

System and method for multi-channel decoding error correction

A tape drive for use with magnetic tapes includes a housing for receiving a magnetic tape having multiple parallel tracks, and a tape head for reading and writing the parallel tracks of the magnetic tape. A plurality of partial response maximum likelihood (PRML) equalization/detection channels are provided for processing the data signals to determine the data stream for each data signal. The plurality of PRML equalization/detection channels includes at least one PRML equalization/detection channel pre-assigned to each track. The plurality of PRML equalization/detection channels further includes at least one floating PRML equalization/detection channel dynamically assignable on an as-needed basis. The invention also contemplates an ASIC, a generic drive, and a PRML method.

Dynamically allocated parallel equalization and detection of a PRML read channel in a multi-channel drive

A method and system are provided for dynamically shortening a number of error correction codewords to correspond to an amount of user data to be recorded on a recording medium. The system and method determine in advance that the number of bytes of user data will only fill a portion of a codeword matrix, and automatically shortens the size of ECC word segments to match the actual user data fill. This allows an ECC interleave to be completed with only a partial fill of the matrix, thereby reducing the required number of recording passes and associated processing time.

Dynamic error correction code shortening

A tape drive and method of identifying write velocity during reading are provided. When a track is being read, a lead-in code of the data signal is processed prior to determining the data stream. The lead-in code identifies the velocity with which the track data were written. The equalization/detection channel is adjusted based on the identified velocity to compensate for write channel transfer function variation. The lead-in code is coded in a way that is reasonably immune to write channel transfer function variation such that the lead-in code is comprehended prior to adjusting the equalization/detection channel.

Write velocity identification in a PRML system

An asynchronous method for locating individual blocks of data in a tape drive, without having to read the blocks of data is provided. The invention comprises placing an ID mark adjacent to the data blocks and inter-block gaps on the tape. The ID mark contains a small amount of information about the next respective data block on the tape. The ID mark is encoded such that the same detection mechanism that detects the inter-block gap can also retrieve the ID mark information, without having to process the entire block of data associated with a particular ID mark. The ID mark is symmetrical such that it can be detected and decoded in the forward and backward direction, allowing the tape drive to find a desired block of data by searching either forward or backward, even when the magnetic tape uses a unidirectional data format.

Pre-block ID mark for multi-directional block location when using a unidirectional coding format

A method, apparatus, and computer instructions for writing data to a magnetic media. A first frequency is written on a first track on the magnetic media on a first track width. A second frequency is written on the first track in which a combination of the first frequency and the second frequency encodes a bit of data on the first track. An erase pattern is created on a second track on the magnetic media, the second track being adjacent to the first track in which the bit of data on the first track is readable by a tape drive system having a second track width wider than the track width of the first track.

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Broomfield, CO, United States of America

Keith Gary Boyer