Hewlett-Packard Development Company, L.p.

Hewlett-Packard Company

Hewlett Packard Enterprise Development LP

Jonathan Peter Buckingham

Catharine Anne Maple

Andrew Hana

Neil Thomas Hutchon

Liqun Chen

Gregory Keith Trezise

Paul Frederick Bartlett

Christopher Huw Williams

Peter Thomas Camble

Simon Pelly

Rafel Jibry

Simon Kai-Ying Shiu

Shiraz Billimoria

Robert Morling

Peter Arthur Walsh

Joseph S Ficara

Jorge Antonio Sved

John William Drew

Hendrik Radon

Laura Loredo

Darren Edward Kent

Dave Atkinson

Storing and retrieving ciphertext in data storage can include determining a first ciphertext value for a first data chunk to be saved to a client-server data storage system using an encrypted chunk hash value associated with the first data chunk as an initial value, and storing the first data chunk on a server in the client-server data storage system in response to determining that the first ciphertext value is a unique ciphertext value. Also, storing and retrieving ciphertext in data storage can include decrypting a ciphertext value for a second data chunk received from a client in the client-server data storage system and based on an encrypted chunk hash value associated with the second data chunk, and sending the second data chunk to the client in response to determining that the decrypted ciphertext value corresponds to an original data chunk saved to the server by the client.

Storing and retrieving ciphertext in data storage

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 method and apparatus for writing data to a tape is disclosed. A plurality of data segments are written onto a tape simultaneously. Any data segments written to the tape that needs to be rewritten are identified. Each data segment that needs to be re-written is accumulated. The accumulated data segments are written to tape when a full set of data segments have been accumulated. The re-written data segments each have a first field in a header that designates itself and a second field in the header that designates a second re-written data segment.

Writing data to a tape

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 data transfer device for transferring data to a removable data storage item. The data transfer device receives content data to be stored to the removable data storage item, encrypts the content data using an encryption key, and transforms at least one of predetermined reference data and the encryption key. The data transfer device also encrypts the transformed predetermined reference data using the encryption key or encrypts the predetermined reference data using the transformed encryption key, and then stores the encrypted content data and the encrypted transformed/predetermined reference data to the removable data storage item.

Data transfer device

A method and apparatus for writing data to a tape is disclosed. A plurality of data tracks are written onto a tape simultaneously. Any data tracks written to the tape that needs to be rewritten are identified. Each re-write unit that contains a data track that needs to be re-written is accumulated. The accumulated rewrite units are written to tape when a full set of rewrite units have been accumulated.

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 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.

A data transfer device for storing data to a removable data storage item, wherein data are received as records and encrypted by the data transfer device prior to storage. The data transfer device encrypts a first portion of the records using a first encryption key and a second portion of the records using a second encryption key. The encrypted records are then stored to the removable data storage item as a plurality of data blocks, each data block comprising one or more encrypted records, wherein records in a respective data block are encrypted using only a respective one of the encryption keys.

A data transfer system comprising a host device and a data transfer device. The host device generates an encryption key based upon information unique to a removable data storage item onto which data are to be stored. The encryption key is then delivered by the host device to the data transfer device. Data to be stored are encrypted by the data transfer device using the encryption key.

Data transfer system encrypting data with information unique to a removable data storage item

A data reader is arranged to read data from a data-holding medium, said data being arranged into a plurality of data items each containing user data and non-user data, with said non-user data including one or more synchronisation fields. The data reader has a read head for reading a channel of said data-holding medium to generate a data signal comprising said data items, and processing circuitry arranged to receive and process said data signals to detect synchronisation fields, including qualifying the detection of the synchronisation fields to tolerate one or more errors in those synchronisation fields. This means that the synchronisation fields can be detected more reliably, so that more of the user data is recovered.

Data storage

A linear tape data storage device comprises a read head and a write head; a tape transport mechanism for transporting the linear tape data storage medium across the read head and the write head, the device being operated according to a predefined tape format; a DRAM buffer memory for storing data received during a write or a read operation; and error protection means configured to protect said data from soft errors generated by said buffer memory wherein the protection means comprises means for checking parity generated within the tape format itself. In the preferred embodiment the tape format used is the Linear Tape Open (LTO) format.

Method and apparatus for protecting against errors occurring in data storage device buffers

A data reader is arranged to read data comprising user dataand non-user datawritten across at least two channels of a data-holding medium, said data being arranged into a plurality of data itemseach containing user data and non-user data, with said non-user data holding information relating to said user data, including write pass number information, and data items written across the said channels at the same time being identified as a set of data items, said data reader holding a current write pass number and having a read headfor reading a respective said channel of said data-holding mediumto generate a data signal comprising said data items, and processing circuitryarranged to receive and process said data signals of a set of data items, including processing said write pass number information of each of said data items in said set, and causing updating of said current write pass number held by said data reader on the basis of the write pass number information of said data items in said set.

Write pass error detection

Data from a host computer is buffered, transferred to a logical formatter, compressed and converted to a format suitable for storage on a magnetic tape before being arranged and written sequentially into a main buffer where parity bytes are added as each row of a dataset is written. A physical formatter takes the data sequentially from the main buffer and writes them as codeword quadsets in plural tape tracks. A determination of whether each codeword quadset is acceptably recorded is made by evaluating each codeword quadset for header and codeword quadset pair errors and combining the evaluations.

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Bristol, United Kingdom

Jonathan Peter Buckingham