Read Recovery Circuitry for Uncorrectable RAID Codeword Errors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional memory sub-systems face challenges in reducing read failures due to increasing erroneous bits, which consume more time and processing resources, and are affected by process variability leading to data throughput losses, as error correction techniques may not detect or correct all errors effectively.
Innovation Solution
Incorporating read recovery control circuitry that performs additional error detection and correction operations after initial error correction, using programmable recovery stages and discrete read voltages to adaptively manage error correction based on memory sub-system characteristics, such as lifecycle stage and wear leveling parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error correction techniques are used, then data retrieval is simplified, but the system fails to correct more than a threshold number of errors, reducing reliability
Solution Approach 1:
The error correction process is divided into multiple discrete read voltage stages. Each stage attempts to correct errors using a specific voltage level, and only proceeds to the next stage if errors persist. This segmentation allows the system to handle more errors than a single-stage system while maintaining manageable complexity through progressive refinement.
Solution Approach 2:
The system dynamically adjusts the read voltage based on the number of errors detected at each stage. By making the voltage selection adaptive rather than fixed, the system can optimize error correction for varying error conditions, improving reliability without requiring a completely different correction mechanism for each scenario.
2Reliability
If additional error detection and correction operations are performed, then data reliability improves, but data throughput decreases due to increased processing time
Solution Approach 1:
The error correction process operates in periodic stages, where each stage performs a specific correction function and then evaluates whether further correction is needed. This periodic structure allows the system to achieve high reliability through multiple correction attempts while minimizing unnecessary processing by stopping early when errors are successfully corrected, thus preserving throughput.
Solution Approach 2:
The system incorporates feedback from error detection at each voltage stage to determine whether to proceed to the next correction stage. This feedback mechanism ensures that additional correction operations are only performed when necessary, optimizing the balance between reliability improvement and throughput maintenance by avoiding redundant processing when errors are already corrected.
3Measurement precision
If discrete read voltages are used for adaptive error correction, then error correction accuracy improves, but device complexity increases
Solution Approach 1:
The system changes the voltage parameter in discrete steps to optimize error correction. By using a limited set of predefined voltage levels rather than continuous adjustment, the system achieves improved measurement precision for error detection while keeping the voltage control mechanism relatively simple and manageable through parameter discretization.
Data Source
AI summary
An apparatus includes an error correction component coupled to read recovery control circuitry. The error correction component can be configured to perform one or more initial error correction operations on codewords contained within a managed unit received thereto. The read recovery control circuitry can be configured to receive the error corrected codewords from the error correction component and determine whether codewords among the error corrected codewords contain an uncorrectable error. The read recovery control circuitry can be further configured to determine that a redundant array of independent disks (RAID) codeword included in the plurality of error corrected codewords contains the uncorrectable error, request that codewords among the error corrected codewords that contain the uncorrectable error are rewritten in response to the determination, and cause the plurality of error corrected codewords to be transferred to a host coupleable to the read recovery control circuitry.