Method for reducing adjacent track interference effects in a data storage system
A system and method is disclosed for improved operation of a data storage device such as a hard disk drive. The overhead for data rewriting may be reduced by the periodic remapping of logical block addresses to avoid excessive adjacent track interference effects on data blocks having lower data writing rates. It may employ the indirection system to remap data “hot spots” to new locations neighboring on spare data blocks. In circumstances where it is not possible to write data next to spare data blocks, the active LBA may be periodically moved after a predefined number of write operations.
1. A method for reducing adjacent track interference effects in a data storage system, comprising the steps of:
configuring the data storage system with:
a hard drive data storage device comprising a rotating data storage medium, wherein the data storage medium comprises a multiplicity of data tracks, and wherein each data track comprises a multiplicity of data blocks;
a write head for storing data in data blocks;
a read head for reading data from the data blocks written by the write head; and
storage for an array of write cycle counters, comprising one counter for each data block; and
executing an algorithm for writing data to the data blocks comprising the steps of:
initializing the write cycle counters to zero;
receiving a data block to be written to the data storage device at a first data block location;
incrementing the write cycle counter for the first data block location by one;
comparing the value of the write cycle counter of the first data block location to a predetermined maximum adjacent track interference (ATI) limit count, wherein:
if the write cycle counter of the first data block location exceeds the predetermined maximum ATI limit count, then:
locating a second data block location on the data storage device;
writing the data to the second data block location; and
resetting the write cycle counters of the first and second data block locations; and
returning to the receiving a data block to be written step.
2. The method of claim 1 , wherein the step of locating a second data block location on the data storage device comprises locating a data block location with at least one adjacent spare data block.
3. The method of claim 1 , wherein the predetermined maximum ATI limit count is set to a value substantially less than the number of ATI events which would induce substantial ATI effects on an adjacent data block.
4. The method of claim 1 , wherein the predetermined maximum ATI limit count is no larger than 200.
5. The method of claim 1 , wherein the predetermined maximum ATI limit count is no larger than 50.
6. The method of claim 1 , wherein the predetermined maximum ATI limit count is no larger than 10.
7. A method for reducing adjacent track interference effects in a data storage system, comprising the steps of:
configuring the data storage system with:
a hard drive data storage device comprising a rotating data storage medium, wherein the data storage medium comprises a multiplicity of data tracks, and wherein each data track comprises a multiplicity of data blocks;
a write head for storing data in data blocks;
a read head for reading data from the data blocks written by the write head; and
storage for an array of write cycle counters, comprising one counter for each data block; and
executing an algorithm for writing data to data blocks comprising the steps of:
initializing the write cycle counters to zero;
receiving a data block to be written to the data storage device at a first data block location;
incrementing the write cycle counter for the first data block location by one;
comparing the value of the write cycle counter of the first data block location to a predetermined maximum adjacent track interference (ATI) limit count, wherein the predetermined maximum ATI limit count is set to a value substantially less than the number of ATI events which would induce substantial ATI effects on a data block, and wherein:
if the write cycle counter of the first data block location exceeds the predetermined maximum ATI limit count, then:
locating a second data block location on the data storage device, wherein the step of locating a second data block location on the data storage device comprises locating a data block location with at least one adjacent spare data block;
writing the data to the second data block location; and
resetting the write cycle counter of the second data block location; and
returning to the receiving a data block to be written step.
8. The method of claim 7 , wherein the predetermined maximum ATI limit count is no larger than 200.
9. The method of claim 7 , wherein the predetermined maximum ATI limit count is no larger than 50.
10. The method of claim 7 , wherein the predetermined maximum ATI limit count is no larger than 10.