Method and apparatus using multiple codes to increase storage capacity

• US 4,804,959 A
• Filed: 11/10/1987
• Issued: 02/14/1989
• Est. Priority Date: 11/10/1987
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Souther, Steven H., Makansi, Tarek, Melas, Constantin M., Patel, Arvind M.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/119,010
• Time in Patent Office: 462 Days
• Field of Search: 340/347 DD, 360/39, 360/40, 360/48, 341/50, 341/59, 341/61, 341/67
• US Class Current: 341/59
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence

Abstract

To increase storage capacity of a disk storage device, the recording surface of the device is partitioned into a plurality of concentric recording bands, data to be recorded on respective bands are encoded using different run-length-limited codes with the code rate of each band being higher than the adjacent inner band.

Claims

1. A method for increasing the effective storage capacity of a disk storage device, comprising the steps of:

(a) partitioning recording tracks of the device into a plurality of concentric recording bands, including a first band surrounded by an outer second band;

(b) providing a first encoder for encoding data in one run-length-limited code for recording on said first band;

(c) providing another encoder for encoding data for recording on said second band in another run-length-limited code having a higher code rate;

(d) providing a write driver operative at one clock frequency; and

(e) responsive to the track address designated in a disk write command, selectively connecting one of said encoders to the write driver for recording data at said one frequency on that band which includes said address;

(f) using a detector operative at said one clock frequency and one decoder, decoding data recorded in said first band;

(g) using said detector operative at said one clock frequency and another decoder, decoding data recorded in said second band; and

(h) responsive to the track address in a disk read command, selectively connecting one of the decoders to the detector for reading data at said one frequency on that band which includes the last mentioned address.

2. A method according to claim 1 wherein one of said first and second run-length-limited codes is a (1,7) code.

3. A method according to claim 1 wherein one of said first and second run-length-limited codes is a (2,7) code.

4. A method according to claim 1 wherein said first run-length-limited code is a (2,7) code and said second run-length-limited code is a (1,7) code.

5. A method for increasing the effective storage capacity of a disk storage device, comprising the steps of:

(a) partitioning recording tracks of the device into a plurality of concentric recording bands, including a first band surrounded by an outer second band;

(b) using a detector operative at one clock frequency and one decoder, decoding data recorded on said first band in a first run-length-limited code;

(c) using the same detector operative at said one frequency and another decoder, decoding data recorded on said second band in a second run-length-limited code having a higher code rate than said first run-length-limited code; and

(d) responsive to the track address designated in a disk read command, selectively connecting one of said decoders to the detector for reading data at said frequency on that band which includes said address.

6. A method for increasing the effective storage capacity of a disk storage device, comprising the steps of:

(a) partitioning recording tracks of the device into a plurality of concentric recording bands, including a first band surrounded by an outer second band;

(b) providing a first encoder for encoding data in one run-length-limited code for recording on said first band;

(c) providing another encoder for encoding data for recording on said second band in another run-length-limited code having a higher code rate;

(d) providing a write driver operative at a selected frequency; and

(e) responsive to the track address designated in a disk write command, selectively connecting one of said encoders to the write driver for recording data at said frequency on that band which includes said address.