Memory Subsystem Retention Latency Management

Solution Overview

Problem

Vehicle systems face data reliability issues due to varying retention latencies and external environmental factors, leading to performance degradation and potential data loss, as existing systems require multiple read operations with different trim settings, which decrease performance and increase the risk of data loss.

Innovation Solution

A memory subsystem that dynamically selects a type of programming based on retention latency by writing a timestamp representing the original write time and mapping it to optimized trim settings for reading data, and updates the timestamp for subsequent operations, ensuring data reliability and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple read operations with different trim settings are performed to handle varying retention latencies, then data reliability is improved, but system performance deteriorates and data loss risk increases

Engineering Contradiction:

Improvedata reliabilityVSAvoidsystem performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary classification of data based on retention latency characteristics during the write operation. Data is categorized into different retention latency groups (e.g., short-term, medium-term, long-term) and stored with corresponding metadata. When reading, the system retrieves data using the pre-determined trim setting associated with its retention latency group, eliminating the need for multiple read attempts and thereby improving performance while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the trim setting parameter based on the retention latency characteristics of the data. By changing the trim setting according to the data's retention latency classification, the system optimizes the read operation for each specific data type, achieving both high reliability and performance without requiring multiple read operations with different settings.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If multiple read operations with different trim settings are performed to handle varying retention latencies, then data reliability is improved, but the risk of data loss increases

Engineering Contradiction:

Improvedata reliabilityVSAvoiddata loss risk

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The system performs preliminary classification of data based on retention latency characteristics during the write operation. Data is categorized into different retention latency groups (e.g., short-term, medium-term, long-term) and stored with corresponding metadata. When reading, the system retrieves data using the pre-determined trim setting associated with its retention latency group, eliminating the need for multiple read attempts and thereby improving performance while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the write operation to determine the appropriate read operation. By storing retention latency metadata alongside the data, the system creates a feedback mechanism that guides the read operation selection, ensuring the correct trim setting is used from the start and preventing data loss that could occur with mismatched trim settings.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If data is stored without considering retention latency, then storage simplicity is maintained, but data reliability deteriorates under varying environmental conditions

Engineering Contradiction:

Improvestorage simplicityVSAvoiddata reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary classification of data based on retention latency characteristics during the write operation. Data is categorized into different retention latency groups (e.g., short-term, medium-term, long-term) and stored with corresponding metadata. When reading, the system retrieves data using the pre-determined trim setting associated with its retention latency group, eliminating the need for multiple read attempts and thereby improving performance while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system enables data to essentially self-identify its retention latency characteristics through automated classification during writing. The metadata stored with each data element contains the retention latency information, allowing the system to automatically select the appropriate read operation without manual intervention or complex external control, thus maintaining operational simplicity while improving reliability.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20240231695A1Managing retention latency for memory devices of vehicle systems

Publication Date: 2024.07.11 MICRON TECHNOLOGY INC

AI summary

Exemplary methods, apparatuses, and systems include a retention latency manager for controlling memory access operations in computing systems based on latency of a set of data bits. The retention latency manager receives a set of data bits from a host. The retention latency manager writes a time stamp. The retention latency manager writes the set of data bits to a location in memory. The retention latency manager computes a time difference between a current time and the time stamp. The retention latency manager selects a set of trim settings using the time difference. The retention latency manager reads the set of data bits from the first location in memory using the set of trim settings.