Memory Write Ordering by Compression Ratio for Nonvolatile Storage

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Solution Overview

Problem

In nonvolatile memory systems, the inefficiency in writing compressed data due to varying data sizes leads to increased unwritten areas, requiring large buffer memories and higher costs, and existing methods to manage compression ratios are not effective in optimizing storage capacity utilization.

Innovation Solution

The memory system estimates the compression ratio of write data using entropy information linked to the write command and determines the execution order of write commands based on this estimation, allowing for efficient data fitting within the write unit without the need for a large buffer memory, by rearranging data and executing commands out of order.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If data compression is applied to increase storage capacity, then storage efficiency is improved, but data size varies leading to increased unwritten areas and requiring larger buffer memories

Engineering Contradiction:

Improvestorage capacityVSAvoidbuffer memory capacity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The system performs preliminary compression ratio estimation using entropy information before actual data writing. This allows the memory controller to pre-determine the execution order of write commands and allocate buffer memory efficiently, avoiding the need for large buffer capacities to handle variable compression outcomes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the execution order of write commands based on real-time compression ratio estimates. By reordering commands according to estimated compression outcomes, the system optimizes buffer memory utilization and eliminates wasted unwritten areas without requiring additional buffer capacity.

Inventive Principle:

Principle #15Dynamics

2Reliability

If write commands are executed in order to maintain data integrity, then reliability is improved, but storage capacity utilization decreases due to unwritten areas from variable compression sizes

Engineering Contradiction:

Improvedata integrityVSAvoidstorage capacity utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary compression ratio estimation and execution order determination before actual writing. This allows the system to plan the optimal writing sequence that maximizes storage utilization while ensuring data integrity through controlled execution based on pre-calculated compression outcomes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses entropy information as feedback to estimate compression ratios and adjust write command execution order. This feedback mechanism enables the system to optimize storage capacity utilization while maintaining data integrity by making informed decisions about command execution sequencing.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11218163B2Memory system and information processing system

Publication Date: 2022.01.04 KIOXIA CORP

AI summary

A memory system includes a nonvolatile memory, an interface circuit, and a controller configured to upon receipt of a plurality of write commands for storing write data in the nonvolatile memory via the interface circuit, acquire compression-ratio information about the write data associated with each write command, determine a compression ratio of each write data based on the acquired compression-ratio information, and determine an execution order of the write commands based on the determined compression ratio.