Exabyte Corporation

Ecrix Corporation

Other

Tandberg Data As

Richard H McAuliffe

Thomas Edward Zaczek

Paul Newsome

Frederick G Munro

Michael A Blatchley

A data recording/recovery device () comprises a packet generator () for including recordable information into a packet (), the packet initially having a nominal run length limited (RLL) sequence if it were RLL encoded. A randomizer () uses a randomizer input value () to obtain a modified packet () which, when encoded, will at least partially have a different run length limited sequence than the nominal run length limited sequence. A write channel () records the modified packet () as a track packet at a destination physical location () on a storage medium (). The randomizer input value () used to obtain the modified packet () is related to a predetermined physical location on the storage medium. In one example embodiment the randomizer input value is related to the destination physical location on the storage medium.

Data randomization for rewriting in recording/reproduction apparatus

A method and system for monitoring and/or adjusting the positioning of a magnetic tape using central control packets that are recorded to the tape is presented. Central control packets are used for adjusting the timing of the read head signal over the tape, adapting the reel count to that of the drive at the time the tape was recorded, and monitoring filemarks for logical tape positioning.

Method and system for monitoring and adjusting tape position using control data packets

A method for detecting the location of falsely detected &ldquo;good&rdquo; data, or &ldquo;rogue&rdquo;, packets in a data buffer is presented. A segment-level CRC is generated over, and associated with, a buffer segment, and recorded along with the segment data onto a storage medium. During data recovery, only packets that pass a packet-level error detection test are allowed in the data buffer. Once a data segment is complete, a segment-level CRC test is performed over the recovered segment-level CRC and the entire recovered segment data. The segment contains a rogue packet if the segment-level CRC test fails. Reed-Solomon syndromes are generated and used to locate and optionally correct the rogue packets.

Rogue packet detection and correction method for data storage device

A method for logically rejecting previously recorded track residue from magnetic media is presented. A session ID unique to a given recording session is encoded into track packet error check and error correction codes but is not itself actually written to tape. During a data recovery session, a reference session ID for the original recording session is acquired by reconstructing the packet session ID from the first few track packets and verifying that a predetermined number of consecutive track packets have identical packet session IDs. Once the reference packet session ID is acquired, it is preloaded into error detection and correction hardware. When a residue track encoded with a previously recorded session ID is recovered by the tape drive track packet detection circuitry, it is inherently rejected because the error detection and correction hardware detects an error and it is therefore never allowed into the data buffer.

Method and apparatus for logically rejecting previously recorded track residue from magnetic media

A multi-level error correction technique for maintaining data integrity in a data recording/recovery device is presented. Data is stored in buffer packets in a segment of a data buffer before being recorded to a storage medium. Error correction codes are generated over a plurality of instances of a plurality of buffer packet patterns in the segment, and are recorded along with all of the buffer packets onto a storage medium. During data recovery from the storage medium, recovered error correction code packets are used to perform multi-level segment correction on the recovered data packets.

Multi-level error detection and correction technique for data storage recording device

A method and apparatus for reacquiring synchronization of a clock synchronization signal with a data signal in a non-tracking storage device is presented. A packet error detector detects errors in data packets from a data signal and generates a packet error status for each reconstructed packet. A read quality detector monitors the packet error status and determines whether the quality of the data signal is of an acceptable versus unacceptable read quality condition. The read quality condition is based on the number of consecutive packets in which an error is detected. Upon detection of an unacceptable read quality condition, the read channel is disabled and the clock synchronize signal is relocked to a known reference frequency. The read channel is then reenabled and the clock synchronization signal is relocked to the data signal.

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Boulder, CO, United States of America

Richard H McAuliffe