International Business Machines Corporation

Richard George Hirko

Kochan Ju

Albert John Wallash

Ian L Sanders

Robert E Eaton

A method and apparatus is disclosed for recovering data with unstable low amplitude magnetorestrictive heads. After an error in data recovery is detected a technique is invoked that changes the bias current through the magnetoresistive head to the reverse direction in a predetermined manner. The method includes reversing the bias current direction, returning the bias current to its normal state and reading the data from the storage medium. Alternatively, the method includes reversing the bias current direction and reading the data when the bias current direction is reversed.

Method and apparatus for error recovery for unstable magnetorestrictive

A swap gate for ion-implanted contiguous disk bubble devices using folded minor loops is disclosed. The bubble device has a major loop, a folded minor loop and a swap element positioned between the major loop and the folded end of the minor loop. The swap element has a first portion for interchanging bubbles with the major loop, a second portion for receiving bubbles from a first region of the folded end of the minor loop, and a third portion for transferring bubbles from the first portion to a second region of the folded end of the minor loop. The folded end of the minor loop also has a third region positioned between the first and second regions to form two bubble storage locations. The bubble device has a conductor associated with the major loop and the first portion of the swap element to form a first transfer gate. The device also includes a second conductor associated with the folded minor loop and the second portion of the swap element to form a second transfer gate. The third portion of the swap element combines with the folded minor loop to form a merge element. In a preferred embodiment, the device has a quadruple period major loop which transfers a block of data into a single bit position on each of the minor loops.

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San Jose, CA, United States of America

Richard George Hirko