Rewrite with embedded reassign for data recovery from marginally defective data sites on a data storage device
AssigneeWestern Digital Technologies, Inc.
InventorMark R. Schibilla
Life of this patent
Estimating the term…
Abstract
A method for recovering data from marginally defective data sites on a disk drive surface. If a user data site is determined to be marginally defective during a read operation, a read error recovery procedure is performed on the marginally defective data site. The read error recovery procedure begins by conditionally reassigning data from the marginally defective data site to a spare data site. Next, the data from the marginally defective data site is rewritten to the marginally defective data site. If the data rewrite operation is successful, the method ends. If the data rewrite operation fails, the conditionally reassigned data from the marginally defective data site is reassigned to the spare data site.
Claims17
A method for operating a disk drive, including recovering data from a marginally defective data site on a disk surface, wherein the hard disk drive employs a vector reassignment method to reassign data from defective data sites to spare data sites, the method comprising the steps of:
- determining the data site to be a marginally defective data site characterized by an increased recoverable error frequency as determined by a predefined performance threshold;
- first writing the block of data to a spare data site within a pool of spare data sites to create a conditional reassignment of the marginally defective data site when the predefined performance threshold is exceeded;
- then determining whether the marginally defective data site is a defective data site based upon an unsuccessful recovery operation;
- and
- if the marginally defective data site is a defective data site, then:
- marking the marginally defective data site as a defective data site;
- adding the defective data site to a list of defective data sites;
- updating a vector reassignment table to cross-reference the defective data site to the spare data site to finalize the reassignment.
In a disk drive, a method for recovering data from a marginally defective data site on a disk surface, the method comprising the steps of:
- providing a pool of spare data sites;
- providing a read error recovery procedure, the read error recovery procedure comprising a plurality of recovery steps;
- reading a data block from a user data site and, if an error occurs while reading the data block:
- executing the read error recovery procedure to recover the data block;
- determining that the user data site is marginally defective based upon an increased recoverable error frequency in the user data site which exceeds a predefined performance threshold;
- conditionally reassigning the data block to a conditionally reassigned spare data site within the pool of spare data sites;
- writing a copy of the data block to the conditionally reassigned spare data site;
- writing the data block in the user data site;
- performing a predetermined subset of the plurality of recovery steps to recover the data block;
- and
- if the data block is not recovered within the predetermined subset, then:
- reassigning the data block to the conditionally reassigned spare data site to finalize the reassignment.
Dependencies are inferred from the claim text.