Data disk defect handling using relocation ID fields

• US 4,914,529 A
• Filed: 07/18/1988
• Issued: 04/03/1990
• Est. Priority Date: 07/18/1988
• Status: Expired due to Term

• Current Assignee: Western Digital Corporation
• Original Assignee: Western Digital Corporation
• Inventors: Bonke, Carl
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US07/220,552
• Time in Patent Office: 624 Days
• Field of Search: 369/54, 369/58, 369/59, 360/31, 360/39, 360/48, 360/49, 360/53, 360/63, 324/212
• US Class Current: 360/48
• CPC Class Codes: G11B 20/1883 Methods for assignment of alternate areas for defective areas
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers

Abstract

The invention provides a method and format for storing a relocation identification block within the data field of a sector having a defect. The relocation identification block provides an address for a replacement sector to be used for data which cannot be stored in the unusable sector.

Claims

1. A method for data relocation due to disk media defects comprising providing:

an alternate storage sector having an identification field;

asserting a bad block bit and a mapped flag bit in the ID field of the defective sector;

storing an alternate ID field corresponding to the alternate sector in the data field of the defective sector only if the sector is defective;

reading the bad block bit during data transfer;

reading the alternate sector ID from the data field;

completing data transfer from the current track;

seeking to the alternate sector defined by the alternate ID present in the data field; and

reading the data stored in the alternate sector.

2. A record with a data format for sectors of a disk track comprising:

a first ID field including a definition byte having a bad block bit and a mapped flag bit;

a data field for normal data storage located within the sector defined by the first identification field;

a second identification field having identical format with the first identification field, the second identification field stored in the data field of the sector when a media defect is present in the data field.