SED Power Resumption via Filter Driver and Dummy SCSI Request

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Solution Overview

Problem

Self-Encrypting Drives (SEDs) can cause system freezing or crashing when transitioning from an operating system's power saving state due to conflicts with power resumption mechanisms, leading to constrained system functionality and user experience issues.

Innovation Solution

A method involving a storage lower filter driver and an extra external SCSI I/O queue is implemented to manage SED power saving transactions, using a dummy SCSI request to activate the internal SCSI queue during power resumption, thereby preventing system crashes and ensuring stable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If power saving mode is implemented in the operating system, then energy consumption is reduced, but system stability deteriorates due to SED freezing or crashing during power resumption

Engineering Contradiction:

Improveenergy consumptionVSAvoidsystem stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by inserting a dummy SCSI request into the internal SCSI queue during the power down transaction. This dummy request acts as a placeholder that ensures the internal SCSI queue is properly activated when the system resumes from power saving mode, preventing crashes before they can occur during resumption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a storage lower filter driver that mediates between the storage class driver and the SED. This filter driver manages the power saving transactions and coordinates the interaction between the operating system power management mechanisms and the SED, preventing direct conflicts that cause freezing or crashing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If SED power saving transactions are managed using existing storage stack mechanisms, then device complexity is reduced, but system reliability deteriorates due to overwhelming host adapter capability

Engineering Contradiction:

Improvedevice complexityVSAvoidsystem reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies segmentation by separating the SCSI queue into two distinct parts: an internal SCSI queue for normal operations and an external SCSI queue for power saving mode operations. This segmentation allows the host adapter to manage power saving transactions without overwhelming its capability, while maintaining system reliability through proper queue isolation and management.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9477489B1Software based self-encrypting drive (SED) sleep resuming method

Publication Date: 2016.10.25 DELL PROD LP

AI summary

A method that can stably and reliably resume SED from operating system power saving mode is disclosed. The solution comprises a storage lower filter driver and an extra external SCSI I/O queue. The storage lower filter driver is coupled to the storage class driver and configured to provide a SED power saving transaction in response to an operation system power function. An extra external SCSI queue and correspondingly a unique SCSI I/O queue state machine trigger mechanism are included in order to avoid overwhelming the capability of any particular host adapter. A dummy SCSI package is inserted into internal SCSI queue in last phase of operating system power down transaction so that internal SCSI queue can be activated during operation system power resuming.