Flash Memory Driver Error Tracking and Block Retirement
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Solution Overview
Problem
Conventional flash memory systems fail to effectively manage and recover data from blocks with uncorrectable errors, often leading to data loss due to late detection of block degradation.
Innovation Solution
A device driver mechanism that tracks error history during read operations, changes read mode for data recovery, and proactively retires degraded blocks, allowing for early identification and management of unreliable blocks to prevent data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction codes are used to correct data errors, then data reliability is improved, but when errors exceed correction capability, data loss occurs without early detection
Solution Approach 1:
The patent applies preliminary action by proactively monitoring error patterns and retiring blocks before they become completely unreliable. The system performs preliminary error detection and block retirement actions before data loss occurs, rather than waiting for error correction to fail. This is achieved through continuous error rate monitoring and predictive block retirement mechanisms.
Solution Approach 2:
The patent implements feedback by continuously monitoring error rates and using this information to make real-time decisions about block retirement. The error monitoring system provides feedback to the memory management logic, which then adjusts block usage and retirement decisions based on the accumulated error data, creating a closed-loop system that prevents data loss.
2Quantity of substance
If blocks are retired only after error correction fails, then storage capacity is maximized, but data loss occurs because degradation is detected too late
Solution Approach 1:
The system performs preliminary retirement actions based on predicted block degradation trends. By analyzing error patterns and projecting future block reliability, the system retires blocks proactively before they fail completely, ensuring data safety while optimizing storage capacity utilization.
Solution Approach 2:
The patent applies beforehand cushioning by maintaining a reserve of healthy blocks and implementing predictive retirement mechanisms. This creates a buffer that allows the system to retire degraded blocks proactively without immediately impacting storage capacity, as replacement blocks are already available in the healthy pool.
3Reliability
If continuous monitoring of error patterns is implemented, then early detection of block degradation is achieved, but system complexity increases
Solution Approach 1:
The patent applies self-service by implementing error monitoring and block retirement logic that operates autonomously within the memory controller. The system monitors its own error patterns and makes automatic retirement decisions without requiring external intervention or complex external monitoring infrastructure, reducing overall system complexity.
Solution Approach 2:
The patent merges the error monitoring function with the existing error correction code logic and memory control functions. By integrating the monitoring and retirement decision-making into the existing memory management architecture rather than adding separate independent systems, the patent reduces overall system complexity while achieving reliable block degradation detection.
Data Source
AI summary
Apparatus and methods, such as those that read data from non-volatile integrated circuit memory devices, such as NAND flash. For example, disclosed techniques can be embodied in a device driver of an operating system. Errors are tracked during read operations. If sufficient errors are observed during read operations, the block is then retired when it is requested to be erased or a page of the block is to be written. One embodiment is a technique to recover data from uncorrectable errors. For example, a read mode can be changed to a more reliable read mode to attempt to recover data. One embodiment further returns data from the memory device regardless of whether the data was correctable by decoding of error correction code data or not.