Memory Sub-Block Relinking for Grown Bad Block Recovery
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Solution Overview
Problem
As memory block sizes increase in data storage devices, the number of memory blocks decreases, leading to reduced data allocation efficiency and speed, and when one sub-block of a memory block fails and/or is identified as a grown bad block, the entire memory block is lost, reducing the device's capacity.
Innovation Solution
A memory block relinking system identifies and salvages functional sub-blocks of grown bad blocks by executing operations to determine their viability, marking them as relinking candidates, and logically linking them with other sub-blocks to form metablocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the memory block size is increased to increase storage capacity, then the storage capacity is improved, but the number of memory blocks decreases leading to reduced data allocation efficiency and speed
Solution Approach 1:
The patent divides memory blocks into sub-blocks that can be independently managed, erased, and programmed. This segmentation allows the system to treat smaller functional units separately, improving data allocation efficiency and speed while maintaining overall storage capacity. The sub-block mode enables finer-grained control over memory resources.
Solution Approach 2:
The patent changes the operational parameters by introducing sub-block granularity, allowing the memory system to operate with both large block sizes for capacity and small sub-block sizes for efficiency. This parameter change enables the system to achieve both high storage capacity and high data allocation efficiency simultaneously.
2Productivity
If a memory block is divided into sub-blocks to improve data allocation efficiency, then the data allocation efficiency is improved, but when one sub-block fails the entire memory block is lost reducing capacity
Solution Approach 1:
The patent extracts the failed sub-block from the memory block and removes it from further operation. By taking out only the defective portion rather than the entire block, the system preserves the functional sub-blocks and maintains usable storage capacity. The failed sub-block is replaced with a spare sub-block.
Solution Approach 2:
The patent discards only the failed sub-block while recovering and continuing to use the functional sub-blocks. This selective discarding and recovery approach maximizes the utilization of good memory resources and prevents unnecessary loss of storage capacity.
3Reliability
If the entire memory block is marked as bad when one sub-block fails, then the reliability is maintained, but the storage capacity is reduced due to loss of functional sub-blocks
Solution Approach 1:
The patent segments the reliability management at the sub-block level rather than treating the entire memory block as a single reliability unit. This allows independent assessment and management of each sub-block's health status, enabling the system to maintain reliability for functional sub-blocks while isolating failed ones.
Solution Approach 2:
The patent changes the reliability management parameter from block-level to sub-block-level granularity. This parameter change enables more precise reliability control, where only the failed sub-block is marked as bad rather than the entire memory block, thereby preserving storage capacity while maintaining system reliability.
Data Source
AI summary
A data storage device includes a memory block relinking system. The memory block relinking system identifies memory blocks that have been identified as grown bad blocks. The memory block relinking system analyzes the memory blocks that have been identified as grown bad blocks to determine whether a sub-block of the memory block is salvageable. To determine whether the sub-block is salvageable, the memory block relinking system executes one or more operations on the sub-block. If the operation fails, the sub-block is retired. If the operation is successful, the memory block relinking system identifies the sub-block as a relinking candidate. The memory block relinking system logically links the sub-block that was identified as a relinking candidate with one or more other sub-blocks that were previously identified as relinking candidates to form a metablock.