Defect Table-Based Sector Management for Downgrade Memory
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Solution Overview
Problem
Downgrade memory chips with defect memory cells are not utilized efficiently due to conventional controllers marking entire blocks as defective, leading to reduced usable memory space and performance.
Innovation Solution
A data storage device and method that generates a defect table to identify and avoid defect sectors in downgrade memory, allowing data to be written to remaining functional sectors, thereby increasing usable memory space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional controller marks an entire block as defective due to a few defect memory cells, then data storage reliability is improved, but usable memory space is reduced
Solution Approach 1:
The patent segments the memory block into individual sectors instead of treating the entire block as a single unit. The controller identifies and marks only the specific defective sectors while leaving other sectors in the same block available for data storage. This segmentation allows selective avoidance of defect areas while maximizing usable space.
Solution Approach 2:
The patent applies local quality by differentiating the status of individual sectors within a block. Instead of uniformly marking the entire block as defective, the controller assigns different quality statuses to different sectors - defective sectors are marked and avoided, while non-defective sectors remain available for normal data storage operations.
2Reliability
If a conventional controller avoids storing data in blocks with defect memory cells, then data read errors are reduced, but memory performance is degraded
Solution Approach 1:
The controller segments the memory space into usable and unusable sectors at the sector level rather than blocking entire blocks. This allows the memory system to maintain high performance by utilizing all non-defective sectors while ensuring data read accuracy by avoiding only the specific defective sectors.
3Reliability
If a conventional controller marks entire blocks as defective, then data storage safety is improved, but capacity utilization is reduced
Solution Approach 1:
The patent implements local quality by marking only the specific defective sectors within a block rather than the entire block. This approach maintains data storage safety by ensuring that data is never written to defective sectors, while simultaneously improving capacity utilization by making all non-defective sectors available for data storage.
Data Source
AI summary
The invention provides a data storage device. In one embodiment, the data storage device is coupled to a host, and comprises a downgrade memory and a controller. The downgrade memory comprises a plurality of blocks, wherein each of the blocks comprises a plurality of pages, each of the pages comprises a plurality of sectors, and some of the sectors are defect sectors. The controller generates a defect table for recording a plurality of defect addresses of the defect sectors in the blocks, receives a plurality of data sectors to be written to the downgrade memory from the host, determines a plurality of first physical sector addresses for storing the data sectors according to the defect table, and sends write commands to the downgrade memory to direct the downgrade memory to write the data sectors to the downgrade memory according to the first physical sector addresses.