Browse Prior Art Database

Programmable Logic Arrays to Capture Escapes

IP.com Disclosure Number: IPCOM000050975D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Bannon, RD: AUTHOR [+3]

Abstract

Escape is a phenomenon of multiple-bit hard errors occurring in high density storage units that are not being detected for a number of passes by the conventional (16, 22) error correcting codes (16-bit data, 22-bit data and check bits, Error Correcting Code (ECC), HSIAO code). Eventually the customer will log in the hard error. Here, logic is provided in conjunction with a high "Escape Detector" ECC code to add a high data integrity factor to a high density storage controller unit.

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Programmable Logic Arrays to Capture Escapes

Escape is a phenomenon of multiple-bit hard errors occurring in high density storage units that are not being detected for a number of passes by the conventional (16, 22) error correcting codes (16-bit data, 22-bit data and check bits, Error Correcting Code (ECC), HSIAO code). Eventually the customer will log in the hard error. Here, logic is provided in conjunction with a high "Escape Detector" ECC code to add a high data integrity factor to a high density storage controller unit.

Multiple-bit organized high density memory chips are generally available in 8nk X 8 or 8nk X 9 (where n is an integer) configurations. In order to implement 16, 6 SEC, DED ECC code (single error correct, double error detect ECC code), 8nk X 8 chips provide the low cost memory systems. The 16, 6 ECC code would normally be implemented on a machine, but because of (X8) granularity, 16, 8 ECC code to capture escapes, in addition to SEC and DED, is added to the logic. The (16, 6) HSIA0 code has 29 percent 3-bit Escape Detection, 37 percent 5-bit Escape Detection and 50 percent 7-bit Escape Detection. A 24-bit code shown below has 86 percent 3-bit Escape Detection, 88 percent 5-bit Escape Detection and 79 percent 7-bit Escape Detection. This code can be further fine-tuned to allow for a higher percentage detection. The H matrix for 16, 8 SEC, DED code is as follows: 001011000000100001101000 110010000000011010010100 000100000001100100100010 1010000...