HDD Host Memory Buffer Caching for Power-Loss Protection

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Solution Overview

Problem

Current hard disk drives (HDDs) require significant non-volatile memory for caching and journaling, leading to increased cost, complexity, and slower spin-up times due to reliance on rotational media for metadata access, and power loss protection involves costly and power-consuming non-volatile memory conversions.

Innovation Solution

HDDs are configured to directly cache data to a host memory buffer (HMB) via non-volatile memory express (NVMe) interfaces, utilizing remote direct memory access (RDMA) for power loss protection and eliminating the need for non-volatile memory within the HDD, allowing data to be securely erased by detachment from the host.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If HDD uses non-volatile memory for caching and journaling, then data protection against power loss is improved, but cost and device complexity increase

Engineering Contradiction:

Improvedata protection against power lossVSAvoidHDD memory configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the non-volatile memory caching and journaling functions from the HDD and relocates them to the host device's memory subsystem. The HDD controller is simplified to use only volatile memory for caching, while the host device assumes responsibility for maintaining protective copies of cached data, thereby reducing HDD complexity while preserving data protection capabilities.

Inventive Principle:

Principle #2Taking out (Extraction)

2Stability of the object's composition

If HDD uses rotational media for metadata storage, then data persistence is improved, but spin-up time and access speed worsen

Engineering Contradiction:

Improvemetadata persistenceVSAvoidspin-up time

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent segments the metadata storage function from the rotational media and places it in volatile memory within the HDD, with protective copying to the host device. This separation allows the rotational media to be used solely for bulk data storage while metadata operations occur in faster memory, eliminating the spin-up time penalty for metadata access while maintaining persistence through host-based protection.

Inventive Principle:

Principle #1Segmentation

3Reliability

If HDD includes non-volatile memory for cache, then power loss protection is improved, but cost and power consumption increase

Engineering Contradiction:

Improvepower loss protectionVSAvoidHDD power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the non-volatile memory power loss protection function from the HDD and transfers it to the host device. The HDD uses only volatile memory for caching, which consumes less power, while the host device provides power loss protection by maintaining protective copies of the cached data in its own non-volatile or protected memory resources.

Inventive Principle:

Principle #2Taking out (Extraction)

4Speed

If HDD uses volatile memory for caching, then speed and responsiveness are improved, but data loss risk on power failure increases

Engineering Contradiction:

Improvecache access speedVSAvoiddata protection

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent introduces the host device as an intermediary that provides power loss protection for the HDD's volatile cache. The host device monitors the volatile cache and maintains protective copies of cached data, allowing the HDD to use fast volatile memory for caching while the host acts as a safety net against power failures, thereby decoupling speed from reliability concerns.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12608156B2Hard disk drive direct metadata and data caching to host memory buffer via nonvolatile memory express

Publication Date: 2026.04.21 SEAGATE TECH LLC

AI summary

Described are data processing and storage systems, and methods for use therewith, that make use of a host memory buffer (HMB) partition of one or more host devices to directly cache at-risk data from one or more HMB-aware hard disk drives (HDDs) via remote direct memory access over nonvolatile memory express interfaces and protocols.