Interleaved Reed-Solomon Decoding for Memory Erasure Correction
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Solution Overview
Problem
Existing ECC techniques in memory devices are inefficient in correcting errors due to entire device failures or single row failures, leading to uncorrectable errors and increased costs due to the need for additional parity bits, especially in scenarios where parity symbols are used for metadata.
Innovation Solution
Implementing interleaved Reed-Solomon (IRS) decoding techniques that break down a single codeword into two sub-codewords, one with sufficient parity for random error correction and the other for erasure correction, leveraging knowledge of erasure locations to reduce decoding complexity and parity requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chipkill ECC techniques are used to correct entire device failures, then reliability is improved, but the number of parity bits required increases
Solution Approach 1:
The patent divides a single codeword into two sub-codewords, where the first sub-codeword handles random error correction and the second sub-codeword handles erasure correction. This segmentation allows each sub-codeword to be optimized for its specific error type, reducing the total parity bits needed compared to using a single comprehensive chipkill code
Solution Approach 2:
The patent applies different error correction strategies to different portions of the data based on local error characteristics. By identifying erasure locations and applying erasure correction specifically to those locations rather than treating all errors as random, the system reduces overall parity requirements while maintaining reliability
2Quantity of substance
If traditional ECC techniques are used that cannot detect entire device failures, then parity bit requirements are reduced, but uncorrectable errors increase
Solution Approach 1:
The patent performs preliminary identification of erasure locations before attempting correction. By first determining where erasures occur and then applying targeted erasure correction to those specific locations, the system ensures that device failures are detected and corrected without requiring the overhead of full chipkill encoding
Solution Approach 2:
The patent introduces an intermediary step of erasure location identification that bridges between simple ECC and full chipkill. This intermediary process allows the system to handle device failures effectively by focusing correction resources only where needed, rather than using comprehensive parity across all data
3Reliability
If comprehensive error correction is applied to all read operations, then reliability is improved, but decoding latency increases
Solution Approach 1:
The patent applies partial error correction by focusing only on identified erasure locations rather than attempting to correct all possible errors in the data. This selective approach reduces decoding complexity and latency while maintaining reliability for the specific failure modes addressed
Solution Approach 2:
By segmenting the correction process into random error handling and erasure error handling, the patent allows each segment to use optimized decoding algorithms appropriate to its error type, reducing overall decoding latency compared to a unified comprehensive correction approach
Data Source
AI summary
Provided is a memory system comprising a plurality of memory components. The ECC decoding is configured to construct first and second codewords from a single set of data within the plurality of memory components and perform error correction code (ECC) decoding on the first and second codewords received read from the plurality of memory components wherein the ECC decoding is configured to (i) detect random errors in the first received codeword and (ii) use data associated with the detected random errors to correct erasures in the second received codeword.