Flash Memory Controller ECC Length Adaptation
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Solution Overview
Problem
Flash memory controllers face inefficiencies in data access due to the increased ECC length, leading to reduced read speed and low encoding efficiency, especially when handling data tables smaller than the fixed chunk size, and the need to read entire chunks for decoding.
Innovation Solution
A flash memory controller that selects a specific encoding/decoding setting based on the erase count of blocks, allowing for varying ECC lengths, enabling the generation of encoded data with a suitable size for efficient writing and reading, thereby improving access efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC codes are used to increase ECC length for better error correction, then decoding capability is improved, but read speed decreases
Solution Approach 1:
The patent dynamically changes the ECC length parameter based on the erase count of flash memory blocks. For blocks with low erase counts, shorter ECC lengths are used to improve read speed. For blocks with high erase counts, longer ECC lengths are used to enhance error correction capability. This parameter adaptation resolves the contradiction by matching ECC strength to actual block conditions rather than using a fixed length for all blocks.
2Ease of manufacture
If fixed-size chunks are used for encoding, then encoding simplicity is maintained, but encoding efficiency decreases when data tables are smaller than chunk size
Solution Approach 1:
The patent introduces dynamic chunk sizing where the encoder adapts the chunk size based on the actual data size being encoded. When data tables are smaller than the traditional fixed chunk size, the encoder creates smaller chunks that match the data size, eliminating the need to pad and read unnecessary data. This dynamic adjustment maintains encoding simplicity while significantly improving encoding efficiency for variable-sized data.
3Reliability
If entire chunks are read for decoding, then decoding completeness is ensured, but decoding efficiency decreases for small data tables
Solution Approach 1:
The patent extracts only the necessary portion of data for decoding by using dynamic chunk sizing. Instead of reading entire fixed-size chunks, the system reads only the specific size needed for the data table being decoded. This extraction principle maintains decoding completeness for the actual data while eliminating the overhead of reading and processing unnecessary padding data, thereby improving decoding efficiency.
Data Source
AI summary
A method for accessing a flash memory module includes: selecting a block in the flash memory module; selecting a specific encoding/decoding setting from a plurality of sets of encoding/decoding settings at least according to an erase count of the block, wherein the plurality of sets of encoding/decoding settings include different error correction code (ECC) lengths, respectively; utilizing the specific encoding/decoding setting to encode a data to generate an encoded data; and writing the encoded data into the block.