公开(公告)号：JP2000132804A

公开(公告)日：2000-05-12

申请号：JP27595299

申请日：1999-09-29

Applicant: IBM

Inventor： SALO MICHAEL P ,  WALLASH ALBERT JOHN

IPC: G11B5/39 ,  G11B5/00 ,  G11B5/02 ,  G11B5/09 ,  G11B5/40 ,  G11B5/455

Abstract: PROBLEM TO BE SOLVED: To improve the magnetic stability of an MR head by writing the additional writing pulse having the specified polarity in the case the last writing pulse does not have the specified polarity after a group of writing pulses is written in. SOLUTION: A writing head polarity controller responds to a polarity signal, and the writing head is energized by one or plural additional pulses having the specified polarity when the polarity signal shows that the last writing pulse among a group of pulses does not have the specified polarity. The writing head is preferably energized by only one additional pulse. When the last writing pulse does not have the specified polarity, a pulse activating signal is outputted, and by this pulse activating signal, a writing driver is operated so that the writing head is energized by one or plural additional pulses having the specified polarity. Or, the writing head is energized by one or plural additional pulses having the specified polarity without considering the polarity of the last writing pulse.