Storage Device Firmware Failure Recovery via Watchdog Timer

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Solution Overview

Problem

Storage devices can become non-functional and enter a 'brick state' due to firmware failures, leading to data compromise and requiring costly replacement.

Innovation Solution

Incorporating a failure detector module and a recovery module within the storage device's controller, which identifies firmware failures and recovers the device by updating the boot address and loading recovery firmware to perform phased recovery actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If firmware is used to control storage device operations, then device functionality and data processing capability are improved, but firmware failures can cause the device to enter a non-detectable brick state

Engineering Contradiction:

Improvedata processing capabilityVSAvoidfirmware stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a watchdog timer that continuously monitors firmware execution before failures can occur. The timer is preset to detect missing periodic signals within a specific time window, allowing the system to proactively identify and respond to firmware failures before they cause complete device failure or data loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent establishes a feedback mechanism where the firmware thread sends periodic signals to the watchdog timer, and the timer provides feedback by detecting when these signals are missing. This closed-loop feedback system enables continuous monitoring of firmware health and automatic detection of execution failures, allowing the system to respond appropriately to maintain reliability.

Inventive Principle:

Principle #23Feedback

2Device complexity

If the storage device enters a brick state due to firmware failure, then device complexity is reduced to a non-functional state, but data recovery becomes impossible

Engineering Contradiction:

Improvedevice stateVSAvoiddata recovery

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent stores recovery firmware in advance within the storage device's memory, prepared beforehand for potential firmware failures. When a failure is detected via the watchdog timer, the system can immediately switch to this pre-stored recovery firmware without requiring external intervention, enabling data recovery before complete device failure occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful brick state into a recoverable condition by implementing a dual-firmware system. The failure detection mechanism transforms what would be a catastrophic failure into a controlled recovery event, where the system can switch to recovery firmware and restore functionality, thereby converting the potential loss into an opportunity for recovery.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If multiple power cycle attempts are performed to revive the storage device, then ease of operation is maintained by allowing host intervention, but time is lost during repeated failed recovery attempts

Engineering Contradiction:

Improvehost intervention capabilityVSAvoidrecovery time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent implements self-service recovery capability where the storage device automatically detects firmware failures through the watchdog timer and executes recovery procedures using stored recovery firmware without requiring host intervention. This autonomous self-recovery mechanism eliminates the time-consuming cycle of host-powered retries and significantly reduces recovery time while maintaining operational simplicity.

Inventive Principle:

Principle #25Self-service

4Productivity

If the firmware operates in a multi-threaded multi-core environment, then device functionality and processing speed are improved, but deadlocks between firmware modules can cause execution failure

Engineering Contradiction:

Improveprocessing speedVSAvoidfirmware execution stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a watchdog timer that provides continuous feedback on firmware thread execution status. Each firmware thread in the multi-threaded multi-core environment sends periodic signals to the watchdog timer, enabling real-time monitoring of all threads and cores. This feedback mechanism detects deadlocks and execution failures across multiple threads and cores, allowing the system to identify and recover from synchronization issues that would otherwise cause complete firmware failure.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250165345A1Method for detecting and recovering an inoperable drive

Publication Date: 2025.05.22 SANDISK TECHNOLOGIES LLC

AI summary

A storage device may recover from a firmware failure that places the storage device in an undetectable state. The storage device includes a memory device to store recovery firmware. A storage device controller includes a failure detector module that may identify the firmware failure when a periodic signal is not received by the failure detector module from a firmware thread, when the failure detector module determines that an initialization counter value is greater than an initialization threshold, or when the failure detector module receives a notification of a predefined number of power cycle events occurring with a given time frame. Upon identifying the firmware failure, the failure detector module updates a boot address. A recovery module May obtain recovery firmware from the memory device, based on the boot address, to recover the storage device in a recovery mode, and perform phased recovery actions to restart the storage device.