Error control coding methods for memories with subline accesses
AssigneeInternational Business Machines Corporation
InventorsJunsheng Han, Luis A. Lastras-Montano, Michael R. Trombley
Life of this patent
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Abstract
A two-level error control protocol detects errors on the subline level and corrects errors using the codeword for the entire line. This enables a system to read small pieces of coded data and check for errors before accepting them, and in case errors are detected, the whole codeword is read for error correction.
Claims20
A method of error control for memories permitting subline accesses comprising the steps of:
- dividing a line of data into a plurality of sublines of data in memory;
- adding a first level of code to each of said plurality of sublines of data, said first level of code providing local protection for each of said plurality of sublines of data;
- adding a second level of code to the line of data, said second level of code providing global protection for said plurality of sulines of data;
- retrieving one or more sublines of data, wherein accessed sublines of data may be in different lines of data and multiple sublines may be concurrently retrieved;
- detecting errors in sublines of data using said first level of code;
- and
- correcting errors in sublines of data using said second level of code.
A memory system having a plurality lines of data, each composed of sublines of data protected using first and second level codes, comprising:
- access means for reading one or more sublines of data from memory along with redundant information for each accessed subline of data, wherein accessed sublines of data may be in different lines of data and multiple sublines may be concurrently accessed;
- error detecting means for detecting whether there is an error in a subline of data read from memory, and means responsive to an error detected by said error detecting means for reading additional sublines of data in the line of data together with shared redundant information;
- and
- error correcting means for attempting to correct an error detected by said detecting means using the private and shared redundant information as well as a value of the line read and reporting any errors detected and whether the errors are correctable or not.
A computer readable medium having recorded code which implements a method of error control for memories permitting subline accesses, said method comprising the steps of:
- dividing a line of data into a plurality of sublines of data in memory;
- adding a first level of code to each of said plurality of sublines of data, said first level of code providing local protection for each of said plurality of sublines of data;
- adding a second level of code to the line of data, said second level of code providing global protection for said plurality of sulines of data;
- retrieving one or more sublines of data, wherein accessed sublines of data may be in different lines of data and multiple sublines may be concurrently retrieved;
- detecting errors in sublines of data using said first level of code;
- and
- correcting errors in sublines of data using said second level of code.
Dependencies are inferred from the claim text.