SSD Multi-Bit Cell Storage Modes for Data Retention After EOL

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Solution Overview

Problem

Existing information processing apparatuses with SSDs using multi-bit cells face data retention issues and inability to guarantee data reading after power is cut off, particularly at end of life (EOL).

Innovation Solution

The apparatus employs a storage control unit that adjusts the threshold voltage variation width for multi-bit data storage, using a high-quality storage mode with a narrower voltage range for critical data areas and a normal mode for others, and includes a position information storage unit to manage data placement and retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multi-bit cells are used to increase SSD capacity, then storage capacity is improved, but data retention period is shortened

Engineering Contradiction:

Improvestorage capacityVSAvoiddata retention period

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The patent divides the storage space into specific areas with different threshold voltage variation widths. Critical data is stored in areas with narrower threshold voltage variation to ensure longer data retention, while non-critical data uses areas with wider variation that allow faster storage. This local differentiation resolves the contradiction by optimizing both capacity utilization and data retention for different data types.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the threshold voltage parameters dynamically based on data importance. By adjusting the threshold voltage variation width parameter - narrower for critical data and wider for non-critical data - the system achieves both high capacity utilization and extended data retention periods for important information stored in multi-bit cells.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If multi-bit cells are used to increase capacity, then storage capacity is improved, but data readability after EOL cannot be guaranteed

Engineering Contradiction:

Improvestorage capacityVSAvoiddata readability guarantee

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent creates specific areas with controlled threshold voltage characteristics where critical data is stored with narrower voltage variation. This local optimization ensures that even after EOL, data in these protected areas maintains readability, while the rest of the storage capacity continues to serve general purposes.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent prepares specific storage areas in advance with optimized threshold voltage parameters before data is written. By pre-configuring these areas with narrower voltage variation widths, the system creates a buffer against future degradation, ensuring data readability can be guaranteed for critical information even after the device reaches end of life.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If normal storage mode with wider threshold voltage variation is used, then storage speed is improved, but data retention is reduced

Engineering Contradiction:

Improvestorage speedVSAvoiddata retention period

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent implements different storage modes in different areas: normal storage mode with wider threshold voltage variation for non-critical data (faster storage), and high-quality storage mode with narrower variation for critical data (longer retention). This spatial differentiation resolves the speed-retention contradiction by allowing both modes to coexist optimally.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the storage system into multiple operational modes - normal storage mode for general data and high-quality storage mode for critical data. This segmentation allows the system to optimize for speed when appropriate and for retention when necessary, eliminating the need to choose one mode for all data.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces data corruption and ensures data readability for a certain period, even without power, by extending data retention and maintaining data integrity in critical areas.

Implementation Method 1

a storage process through which a variation width of a threshold voltage is changeable when the multi-bit data is stored in the multi-bit cell

Methodology Applied

Scientific EffectThreshold voltage variation: Capacitance

Data Source

PatentUS12614592B2Information processing apparatus and control method for storing multi-bit data with changeable variation width

Publication Date: 2026.04.28 LENOVO (SINGAPORE) PTE LTD

AI summary

An information processing apparatus includes: a solid state drive (SSD) configured with a multi-bit cell for storing multi-bit data in one memory cell and configured to include an electrically rewritable non-volatile storage unit; and a main control unit configured to execute processing based on data stored in the SSD. The SSD includes a storage control unit, which is a storage control unit configured to control access to the non-volatile storage unit, and configured to execute a storage process through which a variation width of a threshold voltage is changeable when the multi-bit data is stored in the multi-bit cell.