US 5,848,438 AGranted

Memory mapping defect management technique for automatic track processing without ID field

AssigneeCirrus Logic, Inc.

InventorsSiamack Nemazie, John Schadegg

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Abstract

Defect management for automatic track processing without an ID field, processes defect information for a track on a magnetic media within a disk drive system. A system which uses any method of defect management including linear replacement, sector slipping, cylinder slipping or segment slipping, can be supported. A physical sector number for each sector is translated to a logical sector number relating to the order of data on a track. This translation of the physical sector number to a logical sector number for automatic track processing can be accomplished using any one of three methods: 1) a track defect table can be built in the buffer RAM; 2) the defect information can be written in the header of every sector; or 3) a system FIFO, located in the onboard logic, can be used to manage the defect list. The first and third methods support an ID.sub.-- less format wherein the data field does not contain a header subfield and information for sector identification is maintained by the disk drive system. In the second method, the header subfield comprises four defect records. In the third method, if there are more defect records for the track than will fit in the FIFO, then after initialization and loading the first and second banks of the FIFO by the drive microprocessor, the first and second banks are each loaded by the drive microprocessor while the other is being processed, in a ping-pong manner, until the track processing is complete. A defect record includes a physical sector number of the defective sector, an offset number and a flag indicating whether or not the defective sector has been slipped. The defect record may be either a fixed two byte entry or may be of a user defined number of bytes. Defect flags are automatically generated by the system for each defective sector.

Claims8

Dependent claims

In a data storage system having multiple media surfaces each having a plurality of concentric tracks subdivided into a plurality of sectors each having a predetermined sector organization without an identifier portion, wherein each of the plurality of concentric tracks includes repetitively occurring prerecorded servo sectors, each servo sector of the prerecorded servo sectors including cylinder and head numbers embedded therein and not within the plurality of sectors, and further wherein a cylinder is formed from a given location of tracks on different media surfaces, the data storage system comprising:

a. a retrieving circuit for retrieving a list of defect records for a current partition listing defective sectors, each defect record including a programmable number of bytes;
b. a selecting circuit coupled to the retrieving circuit for selecting a desired method of defect management;
c. a first mapping circuit coupled to the plurality of concentric tracks for mapping each physical sector of a plurality of physical sectors within the current partition to a respective logical sector of a plurality of logical sectors within the current partition, the plurality of physical sectors being mapped using the list of defect records and using the desired method of defect management, the plurality of logical sectors beginning from a first sector and continuing consecutively to a last sector, avoiding the defective sectors and utilizing spare sectors if the defective sectors are present in the current partition;
and
d. a second mapping circuit coupled to the first mapping circuit for mapping the defective sectors within the current partition to at least one further spare sector within a further partition using the desired method if a sector number of the defective sectors within the current partition exceeds a sector number of the spare sectors within the current partition.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/399,095Filed 3 Mar 1995 · continuation in part
Priority: 3 Mar 1994
Granted: 8 Dec 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G11B 20/1883
Error detection or correction; Testing , e.g. of drop-outs: methods for assignment of alternate areas for defective areas
G11B 20/1252
On discs: for discontinuous data, e.g. digital information signals or computer program data
G11B 20/1258
On discs: where blocks are arranged within multiple radial zones, e.g. Zone Bit Recording or Constant Density Recording discs, MCAV discs, MCLV discs
G11B 2020/1234
Sector, i.e. the minimal addressable physical data unit: wherein the sector is a headerless sector, i.e. it does not comprise an ID field