Flash Memory Victim Block Selection for Merge Efficiency
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Solution Overview
Problem
Flash memory devices require an erase-before-program operation, which is time-consuming and inefficient, leading to the need for a method to effectively perform merge operations to manage valid and invalid data in data storage devices.
Innovation Solution
A data storage device with a controller that includes a victim block setup unit, which selects and manages victim blocks based on error counts to perform merge operations by copying valid data from a victim block to a merge block, optimizing data storage and retrieval processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If erase operation is performed on flash memory device, then data can be reprogrammed, but operation time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-selecting victim blocks based on error counts before the merge operation is needed. The victim block setup unit identifies and designates blocks with high error counts as victim blocks in advance, so that when a merge operation becomes necessary, the system can immediately proceed with data copying without delay. This pre-preparation significantly reduces the overall time required for data management operations.
Solution Approach 2:
The system implements self-service through automatic victim block selection and merge operation execution. The controller monitors error counts and automatically identifies victim blocks without external intervention. When valid data needs to be relocated, the system autonomously performs the merge operation by copying data from victim blocks to target blocks, eliminating the need for manual management and reducing operational delays.
2Reliability
If merge operation is delayed, then erase operation time is reduced, but data storage reliability decreases
Solution Approach 1:
The patent implements feedback mechanisms where the controller continuously monitors error counts in memory blocks and uses this information to dynamically select victim blocks. The victim block setup unit receives error count feedback and adjusts victim block selection accordingly. This feedback loop ensures that blocks with the highest error counts (and thus greatest risk to data reliability) are prioritized for merge operations, maintaining data reliability while optimizing operation efficiency.
Solution Approach 2:
The system changes parameters by selecting victim blocks based on error count thresholds and priorities. Instead of using fixed criteria for victim block selection, the system dynamically adjusts selection parameters based on current error counts, block usage patterns, and data importance. This parameter-based selection ensures that merge operations are performed on the most critical blocks first, maintaining reliability while improving overall efficiency.
Data Source
AI summary
A data storage device includes a nonvolatile memory device; and a controller suitable for controlling an operation of the nonvolatile memory device in response to a request from an external device, wherein the controller comprises a victim block setup unit suitable for setting a victim block for a merge operation based on an error count, which is detected when a read operation of the nonvolatile memory device is performed, and for storing information of the victim block for the merge operation, and wherein the controller converts the victim block into a free memory block during the merge operation and reuses the free memory block to store data.