SSD Data Compression and Adaptive ECC for Intra-Page Recovery

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Solution Overview

Problem

Solid-state drives (SSDs) face challenges in optimizing performance and reliability due to limitations in error correction mechanisms and data compression techniques, which affect the efficient use of memory space and error recovery capabilities.

Innovation Solution

The SSD employs dynamic data compression and adjustable error correcting code (ECC) strength, using a hardware-based compression engine and ECC algorithms to compress data below a threshold, storing compressed data with a known data pad for enhanced error detection and correction, and implements an XOR operation for intra-page recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If error correction mechanisms are strengthened to improve data reliability, then error recovery capability is improved, but memory space efficiency deteriorates

Engineering Contradiction:

Improveerror recovery capabilityVSAvoidmemory space efficiency

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent dynamically adjusts the ECC strength parameter based on the observed error rate in different memory regions. By changing the ECC parameter from fixed to variable, the system achieves both high reliability where needed and optimal space efficiency where error rates are low, directly resolving the contradiction between error recovery capability and memory space efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system transitions from static ECC configuration to dynamic ECC adjustment, where the error correction strength adapts in real-time based on memory region characteristics and observed error patterns. This dynamic approach allows the system to optimize both reliability and space efficiency simultaneously by applying appropriate ECC strength only where necessary

Inventive Principle:

Principle #15Dynamics

2Quantity of substance

If data compression is applied to improve memory space efficiency, then memory space efficiency is improved, but error detection and correction complexity increases

Engineering Contradiction:

Improvememory space efficiencyVSAvoiderror detection and correction complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent segments compressed data into smaller code word units, each protected by its own ECC check bytes. This segmentation allows error correction to be applied independently to each segment, reducing the overall complexity compared to applying ECC to the entire compressed data block, while still achieving high space efficiency through compression

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary error detection on compressed data before full correction is applied. By using known data pads and initial error detection mechanisms on the compressed data, the system can identify errors early and apply targeted correction, reducing the complexity of full error correction while maintaining space efficiency

Inventive Principle:

Principle #10Preliminary action

3Reliability

If stronger ECC is used to improve reliability, then error correction capability is improved, but power consumption increases

Engineering Contradiction:

Improveerror correction capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent dynamically changes the ECC strength parameter based on the actual error rate observed in different memory regions. By adjusting the ECC parameter to match the actual reliability needs, the system avoids the excessive power consumption that would result from uniformly applying strong ECC across all memory regions, thus resolving the contradiction between error correction capability and power consumption

Inventive Principle:

Principle #35Parameter changes

4Quantity of substance

If compression threshold is lowered to improve memory space efficiency, then memory space efficiency is improved, but write amplification increases

Engineering Contradiction:

Improvememory space efficiencyVSAvoidwrite amplification

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent applies different compression strategies to different data blocks based on their compressibility characteristics. By evaluating each block locally and applying compression only where it provides net benefit (improving space efficiency while keeping write amplification in check), the system resolves the contradiction between memory space efficiency and write amplification that arises from uniform compression threshold application

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8533550B2Method and system to improve the performance and/or reliability of a solid-state drive

Publication Date: 2013.09.10 SK HYNIX NAND PRODUCT SOLUTIONS CORP

AI summary

A method and system to improve the performance and/or reliability of a solid-state drive (SSD). In one embodiment of the invention, the SSD has logic compress a block of data to be stored in the SSD. If it is not possible to compress the block of data below the threshold, the SSD stores the block of data without any compression. If it is possible to compress the block of data below the threshold, the SSD compresses the block of data and stores the compressed data in the SSD. In one embodiment of the invention, the SSD has logic to dynamically adjust or select the strength of the error correcting code of the data that is stored in the SSD. In another embodiment of the invention, the SSD has logic to provide intra-page XOR protection of the data in the page.