Abstract: A helical scan tape recorder (30) comprises a rotatable scanner (84) and a transport system for transporting magnetic tape proximate the rotatable scanner in a manner so that information is recorded during a revolution of the scanner. A controller performs a pause routine (120) for pausing during a recording operation on tape. The pause routine, when executed, performs the steps of: determining a tape pause position reference value indicative of a pre-pause last recording position on the tape; recording an erase signal on the tape after the pre-pause last recording position; rewinding the tape; transporting the tape in a forward direction and obtaining a current tape position value; determining when the current tape position value reaches a predetermined value relative to the tape pause position reference value; and at beginning of a next revolution of the scanner, commencing recording of one or more post-pause stripes on the tape.

Abstract: A data recording/recovery device (20) comprises a packet generator (34) for including recordable information into a packet (44), the packet initially having a nominal run length limited (RLL) sequence if it were RLL encoded. A randomizer (38) uses a randomizer input value (50) to obtain a modified packet (46) which, when encoded, will at least partially have a different run length limited sequence than the nominal run length limited sequence. A write channel (40) records the modified packet (46) as a track packet at a destination physical location (42) on a storage medium (22). The randomizer input value (50) used to obtain the modified packet (46) 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.

Abstract: 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.

Abstract: A method for detecting the location of falsely detected “good” data, or “rogue”, 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.

Abstract: 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.

Abstract: 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.