Patent Number: 6,169,639

Title: Unipolar last write for improved magnetic stability

Abstract: A method, devices, and an article of manufacture for reducing magnetic instability in a magnetoresistive read head of a combined read-write head after writing data onto a magnetic storage medium. The last write pulse polarity that results in the least amount of magnetic instability in the read head is determined, and is referred to as the designated polarity. Then, after a set of write pulses is written, it is determined whether the last write pulse has the designated polarity. If the last write pulse does not have the designated polarity, then an additional write pulse with the designated polarity is written. Thus, the last write pulse before a read always has the designated polarity, thereby reducing the magnetic instability of the read head, and consequently improving read head performance.

Inventors: Salo; Michael Paul (San Jose, CA), Wallash; Albert John (Morgan Hill, CA)

Assignee: International Business Machines Corporation

International Classification: G11B 5/09 (20060101); G11B 5/00 (20060101); G11B 005/09 ()

Expiration Date: 01/02/2018