A data recovery method from thermal asperities
Original Publication Date: 1999-Dec-01
Included in the Prior Art Database: 2003-Jun-18
TA(Thermal Asperity) is well known as one of the predominant hard failure mechanism of HDD(Hard Disk Drive) which utilizes MR and or GMR heads. This technical disclosure reveals a data recovery method from TA without any hardware change to the HDD. When MR/GMR read element flies on a TA, the interference between them causes short term temperature rise on the element and disturbs read back signal in a certain decay. So if TA can be removed by some means, the data can be read without error. On the other hand it is well known phenomena that a write element of HDD head protrudes from the ABS(air bearing slider) surface when write current is applied. This means that while writing data on a track, the write element flies lower than MR/GMR read element and have more chance to hook thermal asperities existing on the disk surface. This means that this phenomena can remove the TA on the disk. i.e. When encountered with TA, repeat write operation on healthy sector on the same track and let the write head protruded and hook TA, then read the errored sector and secure the data. Followings are the typical algorithm samples for this method.