Memory Management Circuit Garbage Collection Optimization
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Solution Overview
Problem
In rewritable non-volatile memory systems, the traditional garbage collection method often fails to effectively identify and utilize physical erasing units with valid data, leading to reduced availability of physical erasing units and impaired writing performance.
Innovation Solution
A memory management method that records the valid data count of each physical erasing unit and identifies units within a specific range, allowing for the selection of appropriate units for garbage collection operations to optimize data redistribution and extend memory lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional garbage collection selects physical erasing units with the least valid data, then available physical erasing units are released, but physical erasing units with partial valid data are not selected causing reduced writing performance
Solution Approach 1:
The patent changes the selection parameter from 'least valid data count' to 'valid data count within predetermined range'. This parameter change allows physical erasing units with partial valid data to be selected for garbage collection, improving writing performance while maintaining sufficient availability of erasable units.
Solution Approach 2:
The patent introduces dynamic adjustment of the predetermined range based on the distribution of valid data counts across physical erasing units. When many units have similar valid data counts, the range is adjusted to include units that would otherwise not be selected, dynamically optimizing garbage collection effectiveness.
2Productivity
If physical erasing units with partial valid data are selected for garbage collection, then writing performance improves, but the complexity of selecting appropriate units increases
Solution Approach 1:
The patent performs preliminary actions by maintaining a distribution table that pre-calculates and stores the distribution of valid data counts across all physical erasing units. This preliminary information allows the controller to quickly determine the predetermined range without complex real-time analysis during garbage collection operations.
Solution Approach 2:
The patent introduces a distribution table as an intermediary data structure that mediates between the raw valid data counts and the garbage collection selection process. This intermediary simplifies the selection logic by providing pre-processed statistical information about the distribution of valid data.
Data Source
AI summary
A memory management method, and a memory control circuit unit and a memory storage apparatus using the same are provided. The method includes recording a valid data count of each physical erasing unit, and identifying a plurality of first physical erasing units, wherein the valid data count of each first physical erasing unit is between a first predetermined value and a second predetermined value. The method also includes selecting a physical erasing unit from the first physical erasing units for performing a garbage collection operation if the number of the first physical erasing units meets a predetermined condition.