Memory System Error Correction via Host-Card Segmentation
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Solution Overview
Problem
Conventional memory cards cannot correct data errors that can be corrected by a host apparatus's error correction circuit, leading to uncorrectable data errors during read operations.
Innovation Solution
A memory system with a code data generating section, an error correcting section, and an interface section that generates and uses code data to correct error bits in read data, allowing error correction even if the memory card's error correction capability is insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction processing is performed by the error correction circuit in the memory card, then data reliability is improved, but error correction capability is limited compared to the host apparatus
Solution Approach 1:
The error correction function is segmented between two locations: the memory card contains an error correction circuit for basic correction, while the host apparatus contains an error correction circuit for enhanced correction capability. This segmentation allows each component to have specialized error correction functions, with the host apparatus handling more complex error cases that the memory card's circuit cannot correct.
2Reliability
If uncorrectable data errors are not output from the memory card, then data integrity is maintained, but errors that could be corrected by the host apparatus are lost
Solution Approach 1:
Instead of the conventional approach where the memory card filters out uncorrectable errors, this invention inverts the logic by having the memory card output even data with uncorrectable errors. The memory card's error correction circuit identifies errors it cannot correct and outputs these along with error information, allowing the host apparatus to attempt correction with its more capable circuit.
3Adaptability or versatility
If the memory card outputs all read data including errors, then the host apparatus can perform additional error correction, but the memory card's error correction circuit becomes redundant
Solution Approach 1:
The memory card's error correction circuit performs partial error correction - it corrects errors within its capability and passes through data with errors it cannot correct. This partial action approach ensures that the host apparatus receives data that has been partially processed, reducing the host's correction burden while still allowing the host to handle cases beyond the memory card's capability.
Data Source
AI summary
A memory system includes code data generating section which generates code data based on write data. A nonvolatile semiconductor memory stores the write data and the code data for the write data and outputs read data and the code data for the read data. An error correcting section is configured to correct an error bit included in the read data using the read data and the code data for the read data, and outputs the read data which includes the error bit in accordance with a setting. An interface section receives the write data from outside of the memory system, and outputs the read data to outside of the memory system.