Non-Volatile Memory Address Substitution for Disk Read Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing disk devices face challenges in managing information stored in non-volatile memory, particularly when correctable errors occur, leading to potential startup failures and difficulty in error analysis.
Innovation Solution
The disk device incorporates a non-volatile memory with an error correction circuit and a storage area that includes substitution areas, where correctable errors are corrected and associated with substitution information, allowing for the management of error-corrected data in separate redundant areas, and maintains address substitution information for efficient data retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction processing is performed on correctable errors in non-volatile memory, then read errors are reduced and reliability is improved, but device complexity increases due to the need for substitution areas and address substitution information management
Solution Approach 1:
The non-volatile memory is segmented into distinct functional areas: a first area for storing original information and a second area for storing corrected information. This segmentation allows the system to isolate error-prone operations from critical data storage, reducing read errors while maintaining a manageable structure through clear functional separation.
Solution Approach 2:
Address substitution information acts as an intermediary mechanism between the first area and second area. When correctable errors are detected, the system uses address substitution information to redirect reads from the erroneous first area to the corrected second area, resolving the contradiction by providing a mediation layer that reduces read errors without requiring complete structural redesign.
2Reliability
If substitution areas and address substitution information are implemented, then startup failures are prevented, but the quantity of information stored increases
Solution Approach 1:
Rather than implementing error correction mechanisms throughout the entire non-volatile memory, the patent applies correction functionality locally in a dedicated second area. This local quality approach prevents startup failures by concentrating correction resources where they are most needed, while avoiding the overhead of system-wide complexity.
Solution Approach 2:
The system performs preliminary error correction processing when writing to the first area, storing corrected versions in advance in the second area. This preliminary action ensures that if errors occur, corrected data is already available, preventing startup failures without requiring complex real-time correction mechanisms that would increase information overhead.
3Reliability
If correctable errors are managed with address substitution, then data integrity is improved, but ease of operation deteriorates due to complex address management
Solution Approach 1:
The error correction system operates autonomously through self-service mechanisms. When data is written to the first area, the error correction circuit automatically processes correctable errors and stores corrected versions in the second area. During reads, the controller automatically checks for correctable errors and uses address substitution information to retrieve corrected data without user intervention, maintaining data integrity while preserving ease of operation.
Solution Approach 2:
The system applies partial correction action by focusing only on correctable errors rather than attempting to handle all possible error types. This selective approach improves data integrity for the most common error cases while avoiding the complexity of comprehensive error management, thereby maintaining ease of operation for typical use cases.
Data Source
AI summary
According to one embodiment, a disk device includes a non-volatile memory and a controller for accessing the non-volatile memory. The non-volatile memory includes an error correction circuit and a storage area. The storage area includes first, second, and third areas. The first area comprises a plurality of error correction units. The controller stores information from a first error correction unit to the second area when the first error correction unit includes a bit that is a correctable error for the error correction processing by the error correction circuit, then creates or updates address substitution information in which an address of the first error correction unit is associated with an address at which the information from the first error correction unit was stored in the second area and then stores the address substitution information in the third area.