International Business Machines Corporation

Satoshi Tohji

Tomoaki Kimura

Glen Alan Jaquette

Hiroshi Itagaki

Kazuhiro Tsuruta

Eiji Ogura

Kenji Nakamura

Terue Watanabe

Hirokazu Nakayama

Paul Merrill Greco

Hironobu Nagura

Norikazu Kobayashi

A storage device in which file data is divided into multiple blocks for storage on a recording medium is provided. The storage device includes an additional data storing section for storing additional data to be recorded on the recording medium in association with the data to be written, a position determining section for determining recording positions on the recording medium where the blocks should be respectively written, based on the additional data, and a block writing section for writing the respective blocks on the recording positions on the recording medium determined by the recording position determining section. The additional data this defines a gap length between blocks of recorded data. During a read operation, if the gap length does not comport with the additional data, then an error is assumed.

Water marking in a data interval gap

A storage device in which file data is divided into multiple blocks for storage on a recording medium. The storage device includes an additional data storing section for storing additional data to be recorded on the recording medium in association with the data to be written, a position determining section for determining recording positions on the recording medium where the blocks should be respectively written, based on the additional data, and a block writing section for writing the respective blocks on the recording positions on the recording medium determined by the recording position determining section. The additional data thus defines a gap length between blocks of recorded data. During a read operation, if the gap length does not comport with the additional data, then an error is assumed.

An object of the present invention is to embed information while making effective use of a recording area at the time of recording data. To this end, a controller in a tape drive includes: a storage unit which stores information desired to be embedded; an acquisition unit which acquires the information stored in the storage unit; a writing unit which repeatedly writes a CQ set determined on the basis of the acquired information the number of times determined on the basis of this information; a reading unit which reads data in which information is embedded; and an identification unit which identifies information embedded in the read data, and which determines whether or not the read data can be used and the like, in comparison with this information and the information stored in the storage unit.

Device for embedding information into data

Backspacing over data to overwrite the data as recorded on magnetic tape is provided logically, rather than by causing a magnetic tape to drive to backhitch. The data is written to the magnetic tape as it was before it was logically changed in order to insure that the data is preserved on tape. Recovery of the data is from a succeeding data set which logically invalidates the original data by a superseding identifier. Control logic arranges data transactions for writing to magnetic tape as data sets; and, in response to backspace and overwrite commands, or when transactions are accumulated into a succeeding data set, rewrites the original transaction adjusted in accordance with the commands as a superseding data set downstream from the original transaction, logically invalidating the original transaction by setting a superseding identifier in the superseding data set(s).

Writing to magnetic tape with backhitchless backspacing and data set invalidation

A method and system for rewriting data on a tape when an error occurs during an initial write operation. When the initial write error occurs, the data is rewritten at a location that is a pre-defined block gap distance from the last valid write location on the tape. By measuring the length of the pre-defined block gap distance, the cause or causes of the write error or errors are known. Thus, the pre-defined block gap not only ensures that the data is not re-written in a no-write zone of the tape, due to the zone known to be error prone, but a historical record of past write errors is logged based on the length of the block gaps.

Growing community of inventors

Yamato, Japan

Satoshi Tohji