Abstract: A data reader arranged to read a data-holding medium 10 containing both user 30 and non-user 32, 34 data, said non-user data 32, 34 holding information relating to said user data 30, said data reader comprising at least one read head 12 arranged to read the data-holding medium 10 and generate a data signal 14 comprising user data and non-user data, said user data being arranged into a plurality of sets interspersed with said non-user data, said non-user data being arranged to identify said user data within said sets, processing circuitry 8 being arranged to receive and process said data signal 14 and obtain said user data 30 from said data signal 14 using said non-user data 32, 34 to identify said user data 30 within said data signal 14. The data reader is particularly suitable for use in tape drives, and/or in situations in which re-writes, and overwrites of data occur.

Abstract: A data reader is arranged to read data comprising user data 30 and non-user data 32, 34 written across at least two channels of a data-holding medium 10, said data being arranged into a plurality of data items 26 each 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 head 12 for reading a respective said channel of said data-holding medium 10 to generate a data signal comprising said data items, and processing circuitry 258, 280 arranged 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 dat

Abstract: A system for transferring data from a host computing system 10 to a magnetic tape cartridge 12. Data from the host computing system 10 is buffered in a burst buffer 14 before transfer to a logical formatter 16, where data is compressed and converted to a format suitable for storage on the magnetic tape cartridge 12. The logical formatter 16 arranges the data into ‘datasets. The datasets are written sequentially into a main buffer 24 and, as each row of a dataset is written into the main buffer 24, parity bytes (Reed-Solomon) are added.

Abstract: 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.