Flash Memory Block Management Using Spare Good Block Table
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Solution Overview
Problem
Existing methods for managing Flash memory with multiple channels fail to properly utilize storage space, leading to inefficiencies and waste, as some blocks remain unused due to unstable characteristics of Multiple Level Cell (MLC) Flash memories.
Innovation Solution
A method for block management in Flash memory devices with multiple channels involves temporarily storing indices of good blocks in a spare good block table and dynamically updating it when bad blocks are detected, allowing for efficient replacement and management of blocks within meta blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MLC Flash memories are used to increase storage capacity and reduce cost, then storage density is improved, but reliability deteriorates due to unstable characteristics
Solution Approach 1:
The patent divides the Flash memory into multiple channels with separate block management for each channel. Blocks are organized into meta-blocks that can be independently managed, allowing reliable data access even when individual blocks fail due to MLC instability characteristics.
Solution Approach 2:
The patent changes the management parameter from traditional single-channel block management to multi-channel meta-block management. This allows the system to adapt to block failures by selecting alternative blocks from different channels, maintaining reliability while preserving the high capacity benefits of MLC.
2Reliability
If traditional block management mechanisms are used, then access control compliance is achieved, but storage space utilization deteriorates with some blocks never being utilized
Solution Approach 1:
The patent creates a cross-channel meta-block management system where blocks from different channels can be combined into functional meta-blocks. This universal approach allows any good block from any channel to be utilized, eliminating the waste of unused blocks while maintaining access control compliance through structured management.
Solution Approach 2:
The patent implements dynamic block management where the controller can adaptively select and replace blocks based on their actual status. When blocks become unavailable, the system dynamically reconfigures meta-blocks to use alternative blocks, ensuring continuous optimization of storage space utilization while maintaining compliance.
3Adaptability or versatility
If blocks are reserved for each channel separately, then channel independence is maintained, but storage space utilization deteriorates due to inability to share blocks across channels
Solution Approach 1:
The patent merges blocks from multiple independent channels into unified meta-blocks for data storage. This combining approach allows the system to maintain channel independence at the physical level while achieving cross-channel block sharing at the logical level, dramatically improving storage space utilization without sacrificing channel versatility.
Data Source
AI summary
A method for performing block management is provided. The method is applied to a controller of a Flash memory having multiple channels. The Flash memory includes a plurality of blocks respectively corresponding to the channels. The method includes: temporarily storing at least one index of at least one good block that is not grouped into any meta block into a spare good block table, where the good block is a block that is not determined as a bad block within the plurality of blocks; and when it is detected that a specific block corresponding to a specific channel within blocks currently grouped into meta blocks is a bad block, dynamically updating the spare good block table for use of block management. In particular, when needed, the good block is utilized for replacing a block grouped into a meta block. An associated memory device and a controller thereof are also provided.