Data Storage Power Cycle Management via Fast Page Segmentation

Solution Overview

Problem

Existing data storage systems using non-volatile media struggle to maintain data integrity during power transitions, as hold-up capacitors can only sustain operation until they discharge below a minimum voltage, leading to incomplete data writes and potential data loss.

Innovation Solution

A data storage system with a power monitor module that detects host power loss, interrupts the unit controller, and configures a memory controller to write only fast pages of a multi-level cell NAND flash device, skipping slow pages to reduce write time and power consumption, ensuring data is stored in a non-volatile memory array before power depletion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hold-up capacitors are used to maintain power during transitions, then data storage system can operate during power failure, but write time exceeds available hold-up time and data integrity is compromised

Engineering Contradiction:

Improvedata integrityVSAvoidwrite time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the flash memory pages into fast pages and slow pages based on their write characteristics. By identifying and writing only to fast pages during power failure recovery, the system reduces the total write time to within the hold-up capacitor's available energy window, thereby ensuring data integrity without requiring complete writing of all pages.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs partial action by writing only to the subset of fast pages rather than all pages in the flash memory array. This partial writing approach is sufficient to maintain data integrity for critical information while staying within the time and energy constraints imposed by the hold-up capacitor, avoiding the need to complete excessive writing operations.

Inventive Principle:

Principle #16Partial or excessive action

2Reliability

If all pages are written during power recovery, then complete data storage is achieved, but power consumption exceeds hold-up capacitor capacity

Engineering Contradiction:

Improvedata integrityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the flash memory pages into fast pages and slow pages based on their write characteristics. By identifying and writing only to fast pages during power failure recovery, the system reduces the total write time to within the hold-up capacitor's available energy window, thereby ensuring data integrity without requiring complete writing of all pages.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs partial action by writing only to the subset of fast pages rather than all pages in the flash memory array. This partial writing approach is sufficient to maintain data integrity for critical information while staying within the time and energy constraints imposed by the hold-up capacitor, avoiding the need to complete excessive writing operations.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If standard write operations are performed during power exceptions, then data is stored, but bit-error rates increase due to incomplete writes

Engineering Contradiction:

Improvedata integrityVSAvoidbit-error rate

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the flash memory pages into fast pages and slow pages based on their write characteristics. By identifying and writing only to fast pages during power failure recovery, the system reduces the total write time to within the hold-up capacitor's available energy window, thereby ensuring data integrity without requiring complete writing of all pages.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system accepts that slow pages may not be fully written during power exceptions and treats them as disposable or recoverable. The fast pages serve as the reliable, short-living storage medium for critical data during power exceptions, ensuring that at least some data is preserved with low error rates even if complete writing is not achieved.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 write time by up to 40%, minimizes hold-up power requirements, and enhances data integrity by writing exclusively to fast pages, which have lower bit-error rates, thereby ensuring reliable storage of in-flight data and system control memory contents during power exceptions.

Implementation Method 1

providing a power monitor module for detecting a loss of host power

Methodology Applied

Scientific EffectVoltage detection: Electric Field

Implementation Method 2

writing only fast pages of a multi-level cell NAND flash device

Methodology Applied

Scientific EffectElectrical charge storage: Capacitance

Data Source

PatentUS8792273B2Data storage system with power cycle management and method of operation thereof

Publication Date: 2014.07.29 SANDISK TECHNOLOGIES LLC

AI summary

A method of operation of a data storage system includes: providing a power monitor module for detecting a loss of host power; interrupting a unit controller by the power monitor module; configuring a memory controller by the unit controller; and writing a non-volatile memory array for storing in-flight data and contents of a system control random access memory in a multi-level cell NAND flash device in response to detecting the loss of the host power.