Storage Technology Corporation

Shiba P Panda

Thai Nguyen

Robert O Wyman

Patrick K Wong

Fred C Eifert

David A Lawson

Track positioning of a scanning tape head in a helical tape system may be adversely affected by relative offsets between elements in read element pairs and in write element pairs accessing synchronization patterns. Compensating for variations in the position of read and write elements accessing a given pair of data channels is accomplished by using the relative offset of the first detected synchronization patterns in each pair of data channels as a measure of the relative locations of write elements producing the synchronization patterns and read elements accessing the synchronization patterns. This relative offset is then used to correct subsequent synchronization pattern readings taken from the data channel pair.

Helical scan tape track following

A method and system for controlling position of a tape head relative to a tape includes sensing the servo track of a tape with servo read elements of the tape head. A position error signal is then generated for each servo read element. indicative of a position of the servo read element relative to the servo track. The position error signal from each servo read element is then determined to be either an unexpected or an expected position error signal. A position error signal is unexpected when at least one measured parameter based on a function of movement of the position of the servo read element relative to the servo track is greater than a predetermined threshold limit and is expected when the at least one measured parameter is lesser than the predetermined threshold limit. A position error signal for each unexpected position error signal is then predicted based on a function of the expected position error signals from the other servo read elements and historical behavior of the unexpected position error signal. A feedback signal is then compiled as a function of the expected position error signals and the predicted position error signals. The tape head is then positioned as a function of the feedback signal.

Adaptive filter for redundant sensor sampled magnetic tape drive control system

Tape drives and methods for reading/writing on first and second surfaces of a tape include a pair of read/write heads for reading/writing on the surfaces at the same time in synchronism as the tape moves across the heads. A controller determines if the heads are reading corresponding portions of the surfaces of the tape at the same time. The controller also determines if the heads are moving to corresponding portions of the surfaces of the tape in the same time period. The controller further determines if the heads are moving to corresponding tracks on the surfaces of the tape at the same time.

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Shiba P Panda