Storage Controller Command Length Estimation for Higher Random IOPS

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Solution Overview

Problem

Data storage devices, such as SD and microSD memory cards, face limitations in achieving the minimum random read and write performance specified by the 'A1' rating due to overhead from stop-transmission clean-up activities in open-ended commands, which impact input-output operations per second (IOPS).

Innovation Solution

Implementing command length estimation logic in the controller to restrict open-ended read/write commands to the length of previously-received commands, eliminating the need for stop-transmission clean-up activities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If open-ended read/write commands are used in data storage devices, then flexibility and adaptability are improved, but stop-transmission clean-up activities increase processing time and reduce IOPS performance

Engineering Contradiction:

Improvecommand flexibilityVSAvoidIOPS performance

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-determining the length of open-ended commands based on previously-received command lengths. The controller stores and reuses this length information to restrict subsequent open-ended commands, eliminating the need for stop-transmission clean-up activities and thereby improving IOPS performance while maintaining command flexibility

Inventive Principle:

Principle #10Preliminary action

2Reliability

If stop-transmission clean-up activities are performed for open-ended commands, then data integrity and reliability are ensured, but processing time increases and IOPS performance decreases

Engineering Contradiction:

Improvedata integrityVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary action by pre-restricting open-ended command lengths based on historical command patterns. This eliminates the need for time-consuming stop-transmission clean-up activities while maintaining data integrity through the use of previously-validated command length information stored in the controller

Inventive Principle:

Principle #10Preliminary action

3Productivity

If command length restriction based on previous commands is implemented, then IOPS performance is improved by eliminating clean-up activities, but device complexity increases

Engineering Contradiction:

ImproveIOPS performanceVSAvoidcontroller complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies copying by storing the length of previously-received commands and reusing this copied information to restrict subsequent open-ended command lengths. This simple copying mechanism eliminates complex clean-up activities and significantly improves IOPS performance with minimal increase in controller complexity

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent changes the parameter of command length from open-ended to restricted-based on previously-received command lengths. This parameter change eliminates the need for stop-transmission clean-up activities and improves IOPS performance while adding only minimal complexity for storing and retrieving length information

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250328487A1Data Storage Device and Method for Increasing Random Input-Output Operations Per Second (IOPS)

Publication Date: 2025.10.23 SANDISK TECHNOLOGIES LLC

AI summary

Data storage devices with an open-ended protocol can be limited in terms of input-output operations per second (IOPS) due to time spent on stop-transmission clean-up activities. A data storage device is disclosed that can increase IOPS by using command length estimation logic that stores/remembers the command length of a previous write/read command and restricts the next open-ended read/write command to the predicted/remembered length. This increases IOPS by eliminating a need to perform a stop-transmission clean-up activity.