Patent US3768071A successfully refreshed from Google Patents.
US3768071A
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US
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Compensation for defective storage positions
Assignee: International Business Machines Corp
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Filing: 1972-01-24
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Granted: 1973-10-23
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Expires: 1992-01-24
Abstract
Abstract In order to save in a storage the storage elements for the redundancy bits which are required when using an error correction code, the following method is employed. Apart from the storage elements for the data bits and the appertaining parity bit, only one additional storage element is provided per storage location. For error detection, a word to be stored is read immediately after having been stored. If an error is detected, the word to be stored is inverted, marked as an inverted word in the additional storage element and stored in this form. When the word is read later on, it is again inverted by virtue of the marking in the additional storage element to retrieve the original correct information supplied. If not more than one storage element is defective per storage location, error detection is carried out by means of a simple parity check. In the case of several defective storage elements the word to be stored is compared with the word read.
Inventors
- 👤 G Knauft
- 👤 F Koederitz
- 👤 P Skuin
- 👤 E Vogt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:53
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
84 words
A method of operating a storage for program-controlled electronic data processors, said storage containing defective storage elements, comprising the steps of: placing a word to be stored in the storage; reading the word immediately after it is stored and producing an error indication if the read word contains an error; inverting the read word in case of an error indication and marking the word as an inverted word; placing the marked inverted word in storage; inverting the marked inverted word during subsequent retrieval thereof.
Claim 2
Independent Claim
84 words
A method of operating a storage for program-controlled electronic data processors, said storage containing defective storage elements, comprising the steps of: placing a word to be stored in the storage; reading the word immediately after it is stored and producing an error indication if the read word contains an error; inverting the read word in case of an error indication and marking the word as an inverted word; placing the marked inverted word in storage; inverting the marked inverted word during subsequent retrieval thereof.
Claim 3
Dependent Claim
50 words
A method according to claim 1, comprIsing the steps of: reading the marked inverted word immediately after it is stored and producing a second error indication if the read marked inverted word contains an error; and interrupting the program of the data processor in case of a second error indication.
Claim 4
Dependent Claim
21 words
A method according to claim 1 wherein each word is examined for single bit errors by means of a parity check.
Claim 5
Independent Claim
172 words
A system for operating a storage for program-controlled electronic data processors, said storage containing defective storage elements, each storage element being operable to store both a word and a marking bit, comprising: input means for placing a word to be stored in a storage element of the storage; means coupled to said storage for reading the word immediately after it is stored; means operable concurrently with said reading means for producing an error indication if the read word contains an error; inverting means responsive to said error indication for inverting the word read by said reading means and for producing a marking bit to mark the word as an inverted word; means for placing the inverted word and the marking bit in said storage element: means operable in the absence of a said error indication for replacing the word read by said error detection means in said storage element without modification of said word, and output means responsive to said marking bit for inverting the marked inverted word during subsequent retrieval thereof.
Claim 6
Independent Claim
172 words
A system for operating a storage for program-controlled electronic data processors, said storage containing defective storage elements, each storage element being operable to store both a word and a marking bit, comprising: input means for placing a word to be stored in a storage element of the storage; means coupled to said storage for reading the word immediately after it is stored; means operable concurrently with said reading means for producing an error indication if the read word contains an error; inverting means responsive to said error indication for inverting the word read by said reading means and for producing a marking bit to mark the word as an inverted word; means for placing the inverted word and the marking bit in said storage element: means operable in the absence of a said error indication for replacing the word read by said error detection means in said storage element without modification of said word, and output means responsive to said marking bit for inverting the marked inverted word during subsequent retrieval thereof.
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |