Parity Storage Element Selection for Flash Memory Error Management
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Solution Overview
Problem
As storage density increases in data storage devices like flash memory, cells become more susceptible to disturbances, leading to errors due to factors such as cell damage, charge leakage, and temperature effects, necessitating effective parity data management to recover data.
Innovation Solution
A method and system for parity storage management, where a storage element with a higher error rate is selected as a parity storage element to store parity data for other elements, reducing the likelihood of errors by minimizing frequent read operations on the weakest cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If storage density is increased to improve storage capacity, then storage capacity is improved, but error rate increases due to cell susceptibility to disturbances
Solution Approach 1:
The storage system is segmented into data storage elements and a separate parity storage element. This segmentation allows the parity element to specifically handle error correction for the data elements, addressing the increased error rate caused by higher storage density while maintaining the improved storage capacity.
Solution Approach 2:
Parity data serves as an intermediary mechanism between the data storage elements and the error correction process. The parity element mediates the recovery of data when errors occur in data elements, enabling the system to maintain reliability despite increased error rates from higher density storage.
2Reliability
If frequent read operations are performed on storage elements to detect errors, then error detection capability is improved, but endurance deteriorates due to additional wear on storage cells
Solution Approach 1:
Parity data is pre-calculated and stored alongside the data elements during the write operation. This preliminary action enables error detection and correction without requiring additional read operations on the data elements themselves, thus improving error detection capability while preserving endurance.
3Reliability
If the weakest storage element is used for parity data storage, then system reliability is improved by protecting stronger elements from read disturbances, but the weakest element suffers from reduced lifespan
Solution Approach 1:
The weakest storage element, which would normally be most susceptible to errors and reduce system reliability, is strategically assigned to store parity data. This converts its weakness into a benefit: it is read less frequently (only when error correction is needed), thereby reducing read disturbances to the stronger data elements and improving overall system reliability. The parity element's frequent writes are acceptable since parity data changes less often than active data.
Data Source
AI summary
Apparatuses, systems, methods, and computer program products are disclosed for parity storage management. A system includes a plurality of storage elements. A system includes a controller that selects a parity storage element from a plurality of storage elements. A parity storage element has an error rate higher than other elements of a plurality of storage elements, and the parity storage element stores parity data for the plurality of storage elements.