Hewlett-packard Development Company, L.p.

Hewlett Packard Enterprise Development LP

Hewlett-packard Company

Semtech Corporation

Andrew Hana

Gregory Keith Trezise

Jonathan Peter Buckingham

Robert Morling

Neil Thomas Hutchon

Christopher Huw Williams

Gregg Bernard Lesartre

Russ William Herrell

James Stephen Mason

Rafel Jibry

Nigel Ronald Evans

Jonah Edward Nuttgens

Shiraz Billimoria

Peter Arthur Walsh

John P Hardwick

Stephen Paul Langford

Robert Philip Morling

Dave Atkinson

Darren Edward Kent

Gregory Trezise

An OMA controller circuit utilizes a first ADC with an input coupled for receiving a residual error signal indicating a difference between a monitoring signal and a target data signal. A second ADC has an input coupled for receiving the target data signal. A first digital filter has an input coupled to an output of the first ADC, and a second digital filter has an input coupled to an output of the second ADC. A digital multiplier has a first input coupled to an output of the first digital filter and a second input coupled to an output of the second digital filter. An integrator has an input coupled to an output of the digital multiplier and an output providing an average error signal with sign and magnitude. The digital multiplier uses a four quadrant multiplier to perform a cross-correlation on the residual error and the target data signal.

Digital implementation of closed loop optical modulation amplitude controller for laser diode

A non-volatile memory (NVM) is to store data and a first password. The first password is to protect the data. A controller is to selectively enable interaction with the data based on authenticating the first password against a second password. A temporary region is to store the second password. The second password is discarded in response to a status change of the apparatus. The data, the first password, and the second password are resettable by the controller in response to a reset request to bypass the first password, such that the apparatus is restorable to an unused state without authenticating the first password.

Non-volatile memory to store resettable data

A memory module includes an error correction logic to provide data error protection for data stored in the memory module. The error correction logic is selectively controllable between an enabled state and a disabled state. Data stored in the memory module is without error protection provided by the memory module if the error correction logic is in the disabled state.

Memory module having error correction logic

A method and apparatus for data de-duplication is disclosed. Use de-duplication engine (DDE) divides data into regions. The DDE processes the regions in a serial fashion. The DDE clears its hash table before processing the first region. Each region is divided into a number of chunks. A hash is generated for each chunk in a region. When a hash for a chunk is not in a hash table, the hash is stored in the hash table and the chunk is stored on media. When the hash is a duplicate of a hash already in the table, the hash and chunk are discarded and a reference to the previously stored chunk is stored to the media. The DDE does not retain all the hashes from all the regions in the hash table at the same time. The DDE only retains the hashes for the current region being processed and N previous regions where N is a positive integer greater than zero.

Data duplication in tape drives

Data and a corresponding initial error correction code is written to a first portion of a memory device. Based on an error in the first data and the initial error correction code, the initial error correction code is modified.

Providing memory protection using a modified error correction code

Data storage and retrieval methods and apparatus are provided for facilitating data de-duplication for serial-access storage media such as tape. During data storage, input data is divided into a succession of chunks and, for each chunk, a corresponding data item is written to the storage media. The data item comprises the chunk data itself where it is the first occurrence of that data, and otherwise comprises a chunk-data identifier identifying that chunk of subject data. To facilitate reconstruction of the original data on read-back from the storage media a cache () is used together with a database (R), stored on the media, that includes for each duplicated chunk, the location of the corresponding chunk of subject data.

Data de-duplication for serial-access storage media

A technique includes compressing or decompressing data using a relative displacement of a location of a data pattern.

Compressing and decompressing data

A data processing apparatus comprises a monolithic integrated circuit having a data processor, a non-volatile memory storing at least one security code, and at least one interface at the boundary of the integrated circuit via which communication with the data processor can occur. Processing by the data processor of data received at the at least one interface is controlled by the at least one security code.

Data processing apparatus

A history buffer for use in adaptive lossless data compression comprises a plurality of memory locations. The memory locations are partitioned into two or more segments, each segment configured to detect a match sequence independently of the other segments. Control logic is provided for controlling the detection of match sequences between the two or more segments.

History buffer apparatus and method for adaptive lossless data compression

A method for performing adaptive lossless data compression using a buffer memory comprises the steps of receiving a plurality of first match signals (m() to m(n)), each first match signal indicating whether a byte of an input sequence matches a byte in a memory location of the buffer memory. A plurality of second match signals (mD() to mD(n)) are generated, wherein a second match signal (mD) is a delayed version of a corresponding first match signal (m). The second match signals (mD() to mD(n)) are used to detect a match sequence between the data bytes received in the input sequence and the data bytes stored in the content addressable memory, and the first match signals (m() to m(n)) used to predict whether the match sequence continues during a subsequent byte of the input sequence.

Method and apparatus for adaptive lossless data compression

A method of processing data comprising arranging data into a data group comprising a plurality of sub groups each said subgroup comprising a plurality of columns; for each column, determining at least one checksum data of said column; and for each column, storing the checksum data of that column within at least one said subgroup of the group, other than the subgroup to which said column belongs.

Data formatting in data storage

A data transfer device for transferring data to a removable data storage item. The data transfer device encrypts data to be stored using an encryption key, and additionally encrypts a copy of the encryption key using the encryption key. The data transfer device then stores the encrypted data and the encrypted encryption key to the removable data storage item.

Data transfer device

A block of user data is formatted by arranging the user data block into a byte array having plural rows and plural columns of bytes. An error correction code is applied to individual ones of the rows of bytes, such that each row has four code words.

DDS logical data grouping

A magnetic tape includes plural diagonal tracks, each storing a preamble sequence close to user data such that a transducer for reading the track reads the preamble sequence immediately before reading the user data. The preamble sequence is such that when the track is read by the transducer the preamble sequence has a power sequence with a power spectrum substantially equivalent to the power spectrum of the user data. An AGC circuit responds to the transducer.

Equalization preamble region in digital data storage (DDS) format

A method of encoding a digital data stream for writing to a digital storage (DDS) format tape data storage medium comprises writing a byte stream to a preamble region, immediately preceding a user data region. The byte stream has a power spectrum substantially similar to a power spectrum of the user data region. An automatic gain control circuit responds to the preamble data stream in a substantially similar fashion to its response to the user data stream.

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Bristol, United Kingdom

Andrew Hana