Hewlett-Packard Development Company, L.p.

Catharine Anne Maple

Jonathan Peter Buckingham

Paul Frederick Bartlett

Neil Thomas Hutchon

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

There is disclosed a method of accurately locating an append point along a length of linear tape data storage medium, comprising entering a search mode searching for an absolute code word quad set number, and having found the absolute code word quad set number, entering an interrupt mode for control of tape transport, followed by a write mode to write data at a data set containing the absolute code word quad set number.

Searching for append point in data storage device

A data reader is arranged to read data comprising user data and non-user data written across at least two channels of a data-holding medium, the data being arranged into a plurality of data items each containing user data and non-user data, with the non-user data holding information relating to the user data, including a header with information relating to the user data and header error detection information, and data items written across the channels at the same time being identified as a set of data items. The data reader has a read head for reading a respective channel of the data-holding medium to generate a data signal comprising the data items, and processing circuitry arranged to receive and process the data signals of a set of data items, including processing the header error detection information of each of the headers of the data items in the set to detect any of the headers which are in error, and also processing the headers to obtain information from a correct header to correct a header which is in error. Correcting the headers enables more of the data items to be recovered for use.

A data reader is arranged to read data comprising user data and non-user data written across at least two channels of 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 holding information relating to said user data, said data reader having a read head for reading a respective said 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 identify a set CCPset of said data items written at the same time onto different said channels. Identifying a set of data items written at the same time gives rise to the possibility of correcting header information for the data items in a set.

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Bristol, United Kingdom

Catharine Anne Maple