Patent ID: 8015433

Claim:
A hybrid magnetic recording hard disk drive (HDD) comprising: a rotatable magnetic recording disk for the storage of user data from a host computer, the disk having a plurality of concentric data tracks, each data track including a plurality of contiguous physical sectors for the storage of user data, each sector having an associated logical block address (LBA), wherein all of the sectors in each data track have an associated LBA and none of the sectors are reserved as spare physical sectors to replace physical sectors that may become defective; a read/write head movable across the surface of the disk for writing user data to the sectors and reading user data from the sectors; a controller adapted for connection to the host computer for transferring user data between the host computer and the sectors on the disk in response to read and write commands from the host computer; volatile semiconductor memory connected to the controller for temporary storage of user data; and nonvolatile semiconductor memory connected to the controller; and wherein the controller comprises logic for executing method acts of: determining that a physical sector has become defective; assigning to the LBA for said defective sector a memory space in the nonvolatile semiconductor memory; maintaining a list of LBAs and their assigned nonvolatile semiconductor memory spaces for defective physical sectors (G-List); in response to a command from the host computer to write user data associated with a physical sector's LBA, checking the G-List to determine if the LBA for the physical sector to be written to is in the G-List; if the LBA for the physical sector to be written to is not in the G-List, then determining from the LBA for the physical sector to be written to the location on the disk of the physical sector to be written to, and writing the user data to said determined physical sector; and if the LBA for the physical sector to be written to is in the G-List, then determining from the G-List the assigned memory space in the nonvolatile semiconductor memory for the LBA for the physical sector to be written to and writing the user data to said determined assigned memory space.