Patent ID: 7050252

Claim:
A disk drive comprising: (a) a disk comprising a plurality of tracks, each track comprising a plurality of data sectors for storing user data; (b) a head actuated radially over the disk; (c) a marginal sector list; and (d) a disk controller for: receiving a read command from a host computer to read user data from a selected data sector; positioning the head over the selected data sector; reading the user data from the selected data sector; if a read error occurs: performing multiple retry operations by iteratively repositioning the head over the selected data sector and rereading the selected data sector in an attempt to recover the user data; if the number of retries required to recover the user data from the selected data sector exceeds a threshold, adding a sector identifier identifying the selected data sector to the marginal sector list; during an off-line scan, retrieving the sector identifier from the marginal sector list and verifying the selected data sector; and if the selected data sector fails the verification, relocating the selected data sector, adjusting a plurality of parameters of the disk drive during the iterative process of rereading the selected data sector; and adjusting the threshold relative to the adjusted parameter which enables the user data to be recovered from the selected data sector.