Magnetic Disk Cache Backup from Spindle-Motor Regeneration

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Solution Overview

Problem

Existing magnetic disk apparatuses face challenges in maintaining communication with host devices and ensuring data integrity during power loss, particularly when power is cut off, leading to potential data loss and inability to restart operations smoothly.

Innovation Solution

The apparatus incorporates a power supply monitoring circuit that maintains connection with external power supplies during power loss, utilizing regenerative energy from the spindle motor to generate power for a backup process, enabling data transfer to non-volatile memory and immediate reconnection upon power restoration, while transmitting status information to the host device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the magnetic disk apparatus disables communication with the host device during power loss protection, then data integrity is improved by ensuring complete backup of cache data, but communication availability deteriorates causing host device timeouts

Engineering Contradiction:

Improvedata integrityVSAvoidcommunication timeout

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The power supply is segmented into multiple independent sources: main power supply, auxiliary power supply, and regenerative power supply. This segmentation allows the system to maintain critical functions (communication and backup) using different power sources during power loss events, resolving the contradiction between data integrity and communication availability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The auxiliary power supply acts as an intermediary that bridges the gap between main power loss and complete system failure. It provides sufficient power to maintain communication with the host device while the backup process executes, preventing timeouts without compromising data integrity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the magnetic disk apparatus uses only regenerative energy from the spindle motor during power loss, then energy utilization is improved by converting motor deceleration energy, but power availability deteriorates due to insufficient energy for both backup and communication

Engineering Contradiction:

Improveregenerative energy utilizationVSAvoidavailable power

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

Multiple power sources (auxiliary power supply and regenerative power supply) are merged to create a combined power supply system. This merging provides sufficient total power to simultaneously execute the backup process and maintain communication with the host device during power loss events

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The auxiliary power supply is designed with multi-functionality to serve dual purposes: executing the backup process and maintaining communication with the host device. This universal power source resolves the contradiction between energy utilization and power availability

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Loss of information

If the magnetic disk apparatus maintains connection with the external power supply during power loss, then power monitoring capability is improved enabling detection of power restoration, but power consumption increases during the backup process

Engineering Contradiction:

Improvepower status informationVSAvoidpower consumption

Core Design Contradiction:

Loss of informationVSUse of energy by moving object

Solution Approach 1:

The power monitoring function operates at a minimal level during backup, consuming only the small amount of power already allocated for status monitoring. This partial operation maintains power restoration detection capability without significantly increasing overall power consumption during the critical backup process

Inventive Principle:

Principle #16Partial or excessive action

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

Ensures data integrity by saving cache data to non-volatile memory during power loss, allows immediate reconnection and communication with the host device, preventing timeouts, and facilitating smooth operation resumption.

Implementation Method 1

generate third power when supply of the first power is cut off, wherein the third power is generated based on regenerative energy generated by stoppage of the motor

Methodology Applied

Scientific EffectRegenerative energy: Electromagnetic Induction

Data Source

PatentUS12417037B1Magnetic disk apparatus and control method

Publication Date: 2025.09.16 KK TOSHIBA

AI summary

In a magnetic disk apparatus according to an embodiment, a power supply circuit generates second power from first power supplied by an external power supply, and generates third power when the first power is cut off. The third power is generated based on regenerative energy generated by stoppage of a motor. A controller writes data received from a host device to a magnetic disk via a cache area by the second power while the first power is supplied, and executes a backup process when the first power is cut off. The backup process is executed by disabling communication with the host device and saving content of the cache area to the first memory by the third power. A monitoring circuit keeps connection with the external power supply even when the first power is cut off. The controller enables communication with the host device when the first power is restored.