A recording element or a reproducing element in a head generates heat that
decomposes lubricating agent adhered to a slider surface near the
recording/reproducing element of the head. This decomposed lubricating
agent leads to corrosion of the magnetic layer and the like of the
magnetic disk. The lubricating agent undergoes volume expansion due to
this corrosion, creating a protrusion on the magnetic disk surface to
which the lubricating agent is adhered. The magnetic disk surface to which
the lubricating agent is adhered comes into contact with the magnetic
head, leading to friction with the protective layer, the magnetic layer,
and the like. In the worst case, this can lead to secondary errors where
data recorded on the magnetic layer is erased. To prevent such secondary
errors, the present invention provides a hard disk drive including:
a magnetic disk to which is applied a first lubricating agent formed as
##STR1##
(where p=0 or an integer of at least 1, q=0 or an integer of at least 1,
and X=1-5); and
a mechanism for supplying a second lubricating agent to the magnetic disk
having an average molecular weight of no more than 2,400 and no less than
600 and formed as
HOCH.sub.2 CF.sub.2 (OC.sub.2 F.sub.4).sub.p (OCF.sub.2).sub.q OCF.sub.2
CH.sub.2 OH
(where p=0 or an integer of at least 1 and q=0 or an integer of at least
1).
