US4464753A
Expired / Lapsed
US
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Two bit symbol SEC/DED code
Assignee: International Business Machines Corp
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Filing: 1981-12-30
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Granted: 1984-08-07
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Expires: 2001-12-30
Abstract
Abstract PCT No. PCT/US81/01767 Sec. 371 Date Dec. 30, 1981 Sec. 102(e) Date Dec. 30, 1981 PCT Filed Dec. 30, 1981 PCT Pub. No. WO83/02345 PCT Pub. Date Jul. 7, 1983.A modularized error correction apparatus for correcting package errors is provided by expanding an N bit single error correction, double error detection code to cover N packages of M bits each, so that the Exclusive-OR of all M bit single bit error syndromes in any given package results in a composite syndrome which is unique for each package. See FIG. 2 for the parity matrix H and the matching matrix M for the error correction code.
Inventors
- 👤 Chin L. Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:55
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/08; G06F11/10; G06F11/1008; G06F11/1012; G06F11/1028
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
164 words
In an error correction system having a single bit error correction code and double error detection code for a memory in which bits of memory data words are divided into N packages of M bits per package, modularized error correction apparatus for correcting package errors including: encoder means for encoding data words into code words in accordance with an N bit single error correction double error detection code that was expanded to cover N packages of M bits each so that the Exclusive-OR of all M single bit error syndromes in any given package N results in a composite syndrome which is unique for each package, decoder means including means comparing each single bit error syndrome with all possible single bit error syndromes and all possible composite syndromes to determine the location of any single bit error, any single package failure and to detect all double bit errors and all double package failures; and correction means for correcting errors located by said decoder means.
Claim 2
Dependent Claim
164 words
In an error correction system having a single bit error correction code and double error detection code for a memory in which bits of memory data words are divided into N packages of M bits per package, modularized error correction apparatus for correcting package errors including: encoder means for encoding data words into code words in accordance with an N bit single error correction double error detection code that was expanded to cover N packages of M bits each so that the Exclusive-OR of all M single bit error syndromes in any given package N results in a composite syndrome which is unique for each package, decoder means including means comparing each single bit error syndrome with all possible single bit error syndromes and all possible composite syndromes to determine the location of any single bit error, any single package failure and to detect all double bit errors and all double package failures; and correction means for correcting errors located by said decoder means.
Claim 3
Dependent Claim
18 words
The error correction apparatus of claim 1 with MR correction bits protecting MK data bits where: N=K+R K=R·(R-1)·(R-2)/3.
Claim 4
Dependent Claim
9 words
The error correction apparatus of claim 2 where M=2.
Claim 5
Dependent Claim
9 words
The error correction apparatus of claim 3 where K=8.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-07 | 1988-02-06 | 1988-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-07 | 1992-02-06 | 1992-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-07 | 1996-02-06 | 1996-08-07 | $7700.00 | Window Closed / Lapsed |