Sector translation layer for hard disk drives

A method of maintaining a sector translation layer in a hard disk drive, comprising the steps of:

• receiving at the hard disk drive a write command that has a logical block address, wherein the hard disk drive comprises a write head, a plurality of sectors in a plurality of tracks of a memory, a sector map, a translation map, the sector map has a plurality of flags, and each flag in the sector map corresponds to a respective one of the sectors and indicates whether the respective one of the sectors contains valid data or is free;
• copying a portion less than all of the sector map from a solid-state memory to a cache based on a current position of the write head and an angular speed capability of a voice coil motor that moves the write head relative to how fast the flags of one of the tracks can be copied from the solid-state memory to the cache;
• selecting one or more of the sectors from the sector map in the cache that are marked as free and are temporally proximate to the write head based on the angular speed capability of the voice coil motor and a rotational speed of the memory;
• writing new data associated with the write command in the one or more sectors selected;
• and
• updating the sector map in the cache according to the sectors where the new data was written.

An apparatus comprising:

• an interface circuit configured to process a plurality of read/write operations to/from a memory, wherein the memory comprises a write head and a plurality of sectors in a plurality of tracks;
• and
• a control circuit comprising a cache and a solid-state memory, wherein the solid-state memory is configured to store a sector map and a translation map, the sector map has a plurality of flags, and the control circuit is configured to
• receive a write command that has a logical block address,
• copy a portion less than all of the sector map from the solid-state memory to the cache based on a current position of the write head and an angular speed capability of a voice coil motor that moves the write head relative to how fast the flags of one of the tracks can be copied from the solid-state memory to the cache,
• select one or more of the sectors from the sector map in the cache that are marked as free and are temporally proximate to the write head based on the angular speed capability of the voice coil motor and a rotational speed of the memory,
• write new data associated with the write command in the one or more sectors selected, and
• update the sector map in the cache according to the sectors where the new data was written, wherein each flag in the sector map corresponds to a respective one of the sectors and indicates whether the respective one of the sectors contains valid data or is free.