Abstract: A cartridge library (30) comprises a library frame; at least one drive (60); a cartridge magazine (52); a transport mechanism (54) configured to transport the cartridge between the magazine and the drive; and an entry/exit port. The cartridge magazine comprises at least one cell configured to accommodate a cartridge of information storage media. The entry/exit port (200) is configured to permit selective passage of the cartridge between an exterior of the frame and the at least one cell, the passage being through an aperture provided in the frame. The entry exit port (200) comprises an entry/exit port handle (210) and a cartridge caddy (220). The entry/exit port handle (210) is configured both for selective closure of the aperture and selective translation with respect to the frame for opening the aperture. The cartridge caddy (220), to which the handle (210) is attached, is configured to carry the cartridge out of the at least one cell and through the aperture upon translation of the handle (210).

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 and apparatus for varying track recording speed to maximize host-to-tape data transfer rates is presented. Variable data transfer rates of host systems and networks are accommodated by continually adjusting the tape speed to match the tape drive to the host's actual transfer rate. jThe speed of the tape is adjusted according to both the level of data present in the tape drive data buffer and whether the current mode of the drive is write mode or read mode. In the preferred embodiment, when the tape speed is accelerated or decelerated while writing a number of data track pairs to tape, a predetermined number of dummy track pairs are first written to tape at the current speed. On the next write head phase after the speed is increased or decreased as appropriate while the read heads are over the track, a predetermined number of dummy track pairs followed by more data track pairs are written to the tape at the new speed.

Abstract: A method and apparatus for varying track recording speed to maximize host-to-tape data transfer rates is presented. Variable data transfer rates of host systems and networks are accommodated by continually adjusting the tape speed to match the tape drive to the host's actual transfer rate. The speed of the tape is adjusted according to both the level of data present in the tape drive data buffer and whether the current mode of the drive is write mode or read mode. In the preferred embodiment, when the tape speed is accelerated or decelerated while writing a number of data track pairs to tape, a predetermined number of dummy track pairs are first written to tape at the current speed. On the next write head phase after the speed is increased or decreased as appropriate while the read heads are over the track, a predetermined number of dummy track pairs followed by more data track pairs are written to the tape at the new speed.

Abstract: A method for rewriting track packets that fail a check-after-write test onto a track of a storage medium is presented. Local packet address information is included in the track packet itself to allow track packets to be written to the storage medium in any addressing order. This allows a single packet to be rewritten along a later track among other track packets that are being recorded for the first time, thereby reducing rewrite track overhead and eliminating the requirement for a lengthy backhitching sequence.

Abstract: 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.

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 varying track recording speed to maximize host-to-tape data transfer rates is presented. Variable data transfer rates of host systems and networks are accommodated by continually adjusting the tape speed to match the tape drive to the host's actual transfer rate. jThe speed of the tape is adjusted according to both the level of data present in the tape drive data buffer and whether the current mode of the drive is write mode or read mode. In the preferred embodiment, when the tape speed is accelerated or decelerated while writing a number of data track pairs to tape, a predetermined number of dummy track pairs are first written to tape at the current speed. On the next write head phase after the speed is increased or decreased as appropriate while the read heads are over the track, a predetermined number of dummy track pairs followed by more data track pairs are written to the tape at the new speed.

Abstract: A method and apparatus for varying track recording speed to maximize host-to-tape data transfer rates is presented. Variable data transfer rates of host systems and networks are accommodated by continually adjusting the tape speed to match the tape drive to the host's actual transfer rate. The speed of the tape is adjusted according to both the level of data present in the tape drive data buffer and whether the current mode of the drive is write mode or read mode. In the preferred embodiment, when the tape speed is accelerated or decelerated while writing a number of data track pairs to tape, a predetermined number of dummy track pairs are first written to tape at the current speed. On the next write head phase after the speed is increased or decreased as appropriate while the read heads are over the track, a predetermined number of dummy track pairs followed by more data track pairs are written to the tape at the new speed.

Abstract: Disclosed is a means for synthesizing many different antenna patterns with different beamwidths and elliptical symmetries, being derived from a common data set corresponding to a planar cut or slice of an arbitrary antenna pattern which is stored in an addressable memory such as a programmable read only memory (PROM). A pattern surface or envelope is modeled by an algorithm which takes generated azimuth and elevation values simulating a desired scanning motion from which a memory address is produced according to a predetermined mathematical relationship including factors which determine the degree of ellipticity as well as the beamwidth relative to the stored planar cut of the arbitrary antenna pattern.