Method and system for separate data and media maintenance within direct access storage devices

• US 5,467,361 A
• Filed: 06/20/1994
• Issued: 11/14/1995
• Est. Priority Date: 06/20/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shipman, Lloyd R. Jr.
• Primary Examiner(s): Envall, Jr., Roy N.
• Assistant Examiner(s): BROWN, THOMAS
• Application Number:
  US08/263,895
• Time in Patent Office: 512 Days
• Field of Search: 371/37.1, 371/37.4, 371/40.1-40.4, 371/10.1, 371/10.2
• US Class Current: 714/755
• CPC Class Codes: G06F 11/1008 in individual solid state devices G06F11/1004 takes precedence
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence

Abstract

The present application may be utilized for enhanced maintenance of data stored on storage media within a data processing system storage subsystem. Data to be stored is first subdivided into multiple blocks and subblocks, segments or tracks. Each subdivision of data is then analyzed and appropriate logical Error Correction Codes (ECC) are calculated and inserted into the data at selected locations to permit certain data errors to be corrected by subsequent processing. Thereafter, the data and associated logical Error Correction Codes (ECC) are then coupled to a head/disk assembly within a storage subsystem. A physical Error Correction Code (ECC) logic circuit is then utilized to analyze the data and logical Error Correction Codes (ECC) and appropriate physical Error Correction Codes (ECC) are then calculated and inserted into the data at selected locations in response to the storage of the data and logical Error Correction Codes (ECC) within the storage media. Maintenance of the storage media and data may then be separately accomplished utilizing independent logical and physical Error Correction Code (ECC) circuits which operate separately upon the logical and physical Error Correction Codes (ECC) wherein media defects will not necessarily result in a loss of all data present within the defective media segment.

Claims

1. A method for enhanced maintenance of data stored on the storage media within a data processing system storage subsystem, said method comprising the steps of:

calculating and inserting a plurality of logical error correction codes based upon a content of said data at selected locations within said data prior to storage of said data;

during storage of said data and said plurality of logical error correction codes, calculating and inserting at selected locations within said data and said plurality of logical error correction codes a plurality of physical error correction codes, each of said plurality of said physical error correction codes based upon a content of both said data and said plurality of logical error correction codes; and

maintaining said data within said data processing system storage subsystem utilizing both said plurality of logical error correction codes and said plurality of physical error correction codes.

2. The method for enhanced maintenance of data stored on storage media within a data processing system storage subsystem according to claim 1, wherein said data processing system storage subsystem includes control circuitry and a head-disk assembly for storing blocks of data, each block of data comprised of a plurality of subblocks of data, and wherein said step of calculating and inserting a plurality of logical error correction codes based upon said content of data at selected locations within said data comprises the step of calculating and inserting a logical error correction code (ECC) within each subblock of data utilizing said control circuitry.

3. The method for enhanced maintenance of data stored on storage media within a data processing system storage subsystem according to claim 2, wherein said step of calculating and inserting at selected locations within said data and said plurality of logical error correction codes a plurality of physical error correction codes, each of said plurality of physical error correction codes based upon said content of both said data and said plurality of logical error correction codes comprises the step of calculating and inserting a physical error correction code (ECC) within each block of data during storage thereof utilizing said head-disk assembly.

4. A data processing system for permitting enhanced maintenance of data stored therein, said data processing system comprising:

a host processor;

a data storage subsystem, said data storage subsystem comprising;

a control circuit for calculating and inserting a plurality of logical error correction codes at selected locations within said data based upon a content of said data prior to storage thereof;

a storage device which includes storage media; and

a physical error correction code logic circuit for calculating and inserting at selected locations within said data and said plurality of logical error correction codes a plurality of physical error correction codes, each of said plurality of physical error correction codes based upon said content of both said data and said plurality of logical error correction codes in response to storage of said data and said plurality of logical error correction codes within said storage media.

5. The data processing system according to claim 4, wherein said storage device comprises a direct access storage device.

6. The data processing system according to claim 5, wherein said data storage subsystem includes a head-disk assembly.

7. The data processing system according to claim 4, wherein said data storage subsystem comprises means for storing blocks of data, each block of data comprising a plurality of subblocks and wherein said control circuit comprises means for calculating and inserting a logical error correction code within each subblock of data.

8. The data processing system according to claim 7, wherein said physical error correction code logic circuit comprises means for calculating and inserting at selected locations within said data and said plurality of logical error correction codes a plurality of physical error correction codes, each of said plurality of physical error correction codes based upon said data and said plurality of logical error correction codes comprises the step of calculating and inserting a physical error correction code within each block of data during storage thereof.

9. A data storage subsystem, said data storage subsystem comprising:

a control circuit for calculating and inserting a plurality of logical error correction codes at selected locations within said data based upon a content of said data prior to storage thereof;

a storage device which includes storage media; and

a physical error correction code logic circuit for calculating and inserting at selected locations within said data and said plurality of logical error correction codes a plurality of physical error correction codes, each of said plurality of physical error correction codes based upon said content of both said data and said plurality of logical error correction codes in response to storage of said data and said plurality of logical error correction codes within said storage media.

10. The data processing system according to claim 9, wherein said storage device comprises a direct access storage device.

11. The data processing system according to claim 10, wherein said data storage subsystem includes a head-disk assembly.

12. The data processing system according to claim 9, wherein said data storage subsystem comprises means for storing blocks of data, each block of data comprising a plurality of subblocks and wherein said control circuit comprises means for calculating and inserting a logical error correction code within each subblock of data.

13. The data processing system according to claim 12, wherein said physical error correction code logic circuit comprises means for calculating and inserting at selected locations within said data and said plurality of logical error correction codes a plurality of physical error correction codes, each of said plurality of physical error correction codes based upon said data and said plurality of logical error correction codes comprises the step of calculating and inserting a physical error correction code within each block of data during storage thereof.

14. A data processing program product, including instructions which implement specific operations and are stored as unique data structures on a computer readable media within a data processing system storage subsystem, for enhanced maintenance of data stored on storage media within said data processing system storage subsystem, said data processing program product comprising:

means, implemented by said instructions for calculating and inserting a plurality of logical error correction codes based upon a content of said data at selected locations within said data prior to storage of said data;

means, implemented by said instructions, for calculating and inserting at selected locations within said data and said plurality of logical error correction codes during storage of said data and said plurality of logical error correction codes a plurality of physical error correction codes, each of said plurality of physical error correction codes based upon a content of both said data and said plurality of logical error correction codes; and

means, implemented by said instructions for maintaining said data within said data processing system storage subsystem utilizing both said plurality of logical error correction codes and said plurality of physical error correction codes.