Hewlett-Packard Development Company, L.p.

Robert Morling

Andrew Hana

Rafel Jibry

Nigel Ronald Evans

Stephen V Deckers

Peter Arthur Walsh

Jonathan Peter Buckingham

Gregory Keith Trezise

Russell Ian Monk

Neil Thomas Hutchon

Christopher Huw Williams

John P Hardwick

Darren Edward Kent

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

Multi-rate oversampling of analog signals in storage devices is described. A method of processing an analog signal derived from a storage medium in a storage device includes: filtering the analog signal with an anti-alias filter having a fixed cut-off frequency related to a target sampling rate; sampling the analog signal using an over-sampling rate of a plurality of over-sampling rates provided by a variable-rate analog-to-digital converter (ADC) to produce an over-sampled digital signal; and filtering the over-sampled digital signal using a decimation filter of a plurality of decimation filters provided by a digital signal processor (DSP) to produce a digital signal having the target sampling rate.

Multi-rate oversampling of analog signals in storage devices

A tape drive apparatus is for a tape medium having a magnetic segment for magnetically transducing information and an identification segment carrying a medium identification pattern and a segment identification pattern. The tape drive apparatus has a data transfer apparatus configured to transfer data between the tape medium and the tape drive apparatus, a reader configured to read a signal representative of the identification segment, a detector configured to detect the segment identification pattern in the signal, and a decoder configured to decode the medium identification pattern in response to the detection of the segment identification pattern.

Apparatus for a medium having a medium identification pattern and a segment identification pattern

A tape medium has an identification segment located on a transparent leader segment of the tape medium for optical detection of the segment identification pattern. The segment identification pattern and the medium identification pattern have a predefined spatial relationship, enabling photo-optical detection of the segment identification pattern and reading of the medium identification pattern. The medium identification pattern carries various medium identification information, such as tape manufacturer, tape serial number and a tape medium property.

Medium for use in a tape drive apparatus having identification segment and a segment identification pattern

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 tape drive apparatus has at least one rotary head for reading/writing a track. The track has a number of fragments and each fragment has an identifier. The tape drive apparatus has a position indicator apparatus for providing a signal that indicates a rotational position of the head. The combination of the signal and the identifier unequivocally identifies a fragment within the fragments of a track. This has the advantage that non-unique identifiers can be used for the fragments of a track.

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Bristol, United Kingdom

Robert Morling