Data storage device attenuating thermal decay effect on fly height measurement

摘要

A data storage device is disclosed comprising a head actuated over a disk. A first spacing pattern is written to the disk and a second spacing pattern is written to the disk different from the first spacing pattern. A first fly height measurement (FHM1_1) is generated by reading the first spacing pattern and a first fly height measurement (FHM2_1) is generated by reading the second spacing pattern. After an interval, a second fly height measurement (FHM1_2) is generated by reading the first spacing pattern and a second fly height measurement (FHM2_2) is generated by reading the second spacing pattern. A change in the fly height of the head is estimated based on:
(ΔFHM2−B·ΔFHM1)/(A−B)
where ΔFHM1 represents a difference between FHM1_1 and FHM1_2, ΔFHM2 represents a difference between FHM2_1 and FHM2_2, and A and B are constants.

主权项

1. A data storage device comprising:
a disk; a head; and control circuitry configured to:
write a first spacing pattern to the disk;write a second spacing pattern to the disk different from the first spacing pattern;generate a first fly height measurement (FHM1—1) by reading the first spacing pattern and generate a first fly height measurement (FHM2—1) by reading the second spacing pattern;after an interval, generate a second fly height measurement (FHM1—2) by reading the first spacing pattern and generate a second fly height measurement (FHM2—2) by reading the second spacing pattern; andestimate a change in the fly height of the head based on:
(ΔFHM2−B·ΔFHM1)/(A−B)where:
ΔFHM1 represents a difference between FHM1—1 and FHM1—2; ΔFHM2 represents a difference between FHM2—1 and FHM2—2; and A and B are constants.