Storage Technology Corporation

Fred C Eifert

Thai Nguyen

David A Lawson

Charles Allen Milligan

George A Rudeseal

David Grant Beal

Douglas Christian Hansen

Henry S Ludlam

David B Daniel

Shiba P Panda

Paul R Swiatek

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

It is difficult to read data from curved helical data tracks in a helical scan tape drive. Curved helical tracks can be caused by improper tape tension, tape damage, tape path misalignment, tape head offset between different head systems, and debris. The present invention solves the problem of recovering data from curved helical tracks by providing a table of different curve offset signals. Each curve offset signal represents a curve track profile of a typical curved track. The position of the helical read head reading a curved data track is controlled as a function of one of the curve offset signals such that the read head is positioned properly with respect to the helical data track to provide a proper read back signal. The curve offset signals are selected one at a time to control the position of the helical read head until the helical read head provides a proper read back signal.

Helical scan tape drive error recovery using track profile mapping

A disk storage system that writes multiple copies of records directed to user-specified volumes. A plurality of spaced apart control units interconnected by direct data links and a corresponding plurality of sets of recording means communicate over the direct data links when a write request is received by one control unit to cause one volume in each set of recording means to write a copy of the received record.

Data storage system for providing redundant copies of data on different

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Eaton, CO, United States of America

Fred C Eifert