Abstract: A Data Storage Device (DSD) includes at least one disk surface for storing data and a memory for storing a bitmap buffer. A segment of a disk surface is identified that includes at least one defect region, and a segment bitmap is generated for the segment indicating the at least one defect region within the segment. The segment bitmap is stored in the bitmap buffer.

Abstract: A disk drive including a disk storing a defect log including one or more defect records, wherein each of the defect records spans multiple words and comprises chunks which are word aligned, each chunk comprising one or more record fields, and a controller configured to read the defect records on a word basis. A method for performing a defect process on the disk drive including selecting a defect record from the defect log, selecting record fields in the selected defect record, reading the selected defect record on a word basis, and searching the selected record fields which are located in a same chunk of the selected record at a same time to determine when the selected defect record matches a target defect record.

Abstract: A disk drive including a disk storing a defect log including one or more defect records, wherein each of the defect records comprises record fields, and a controller configured to determine a match for a reference defect record by at least selecting one or more record fields of the reference defect record as search fields, setting the search fields in the reference defect record, generating a mask record comprising mask fields corresponding to the record fields, setting a first bit value for each bit in the mask fields corresponding to the search fields and a second bit value for each bit in the mask fields which do not correspond to the search fields, selecting a defect record from the defect log, generating an intermediate result by performing a first logic operation, and generating a matching result by performing a second logic operation.