Browse Prior Art Database

Code for Multitrack Error-Correction in Magnetic Tapes

IP.com Disclosure Number: IPCOM000036470D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Blaum, M: AUTHOR [+2]

Abstract

Disclosed is a code to be implemented in an 18-track magnetic tape. This code has 4 tracks carrying redundancy (the first two and the last two) while the central tracks carry the information (as in [1]).

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Code for Multitrack Error-Correction in Magnetic Tapes

Disclosed is a code to be implemented in an 18-track magnetic tape. This code has 4 tracks carrying redundancy (the first two and the last two) while the central tracks carry the information (as in [1]).

The code has the following error-correcting capability: two tracks in error, one track in error together with two erased tracks or four erased tracks. It turns out that this performance is optimal [2] and improves the performance of the code described in [1], which can only achieve this correction power in particular cases.

The idea of the new construction is similar to [1]. In this case, the cross-parity lines run across all the tracks. The four parity lines are as follows: 1. A vertical parity line. 2. A diagonal parity line

with slope 1. 3. A diagonal parity line with slope

-1. 4. A diagonal parity line with slope 1/2 (or

-1/2).

An easy description of the four lines is as a combination of a rook, two bishops and a knight.

Encoding and decoding procedures are fairly simple and similar to the ones in 1.

The code can be extended to families with greater error-correcting capability by taking more lines with different slopes.

References: 1 A. M. Patel, "Adaptive Cross Parity (AXP) Code for the IBM Magnetic Tape Subsystem," IBM Journal of Research

and Development, 29, 6, 546-562 (November 1985). 2 P. Piret and T. Krol, "MDS Convolutional Codes," IEEE Trans. on Information Theory, IT-29, 2, 224-233 (March

1983)....