Write-Protect Hardware Acceleration for SSD Command Overlaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid state devices (SSDs) face inefficiencies when handling command overlaps, particularly in managing write-protected ranges and read-overlaps, leading to increased firmware overhead and complex flow management.
Innovation Solution
The firmware monitors the overlap table instead of both read and write-protected commands, allowing the controller to process read commands normally and pass write overlaps into the data path, reducing monitoring to when the data path clears the overlap table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the firmware monitors both overlap read commands and write protected overlapped write commands, then command processing correctness is maintained, but firmware overhead increases and complexity increases
Solution Approach 1:
The patent divides the monitoring function into two parts: the firmware monitors the overlap table for read command overlaps, while the data path hardware monitors write command overlaps with write protect ranges. This segmentation reduces firmware overhead by transferring write overlap monitoring to hardware.
Solution Approach 2:
The patent introduces an intermediary structure (the overlap table) that stores write command information, allowing both firmware and data path to monitor overlaps without direct firmware intervention in every write operation. The data path uses this table to detect write overlaps hardware-efficiently.
2Measurement precision
If the firmware monitors both read and write protected commands, then overlap detection accuracy is maintained, but processing time increases
Solution Approach 1:
The patent replaces the mechanical firmware monitoring process with a hardware-based data path monitoring mechanism. The data path hardware automatically checks write commands against the overlap table and prevents writes to protected ranges without firmware intervention, reducing processing time while maintaining accuracy.
Solution Approach 2:
The patent performs preliminary action by pre-populating the overlap table with write command information before read commands arrive. This allows the system to quickly detect overlaps without real-time firmware analysis, reducing processing time for read commands.
3Reliability
If write commands are passed to the exception queue for write protect overlaps, then write protect integrity is maintained, but command processing efficiency decreases
Solution Approach 1:
Instead of the traditional approach where write protect violations are handled as exceptions, the patent inverts the flow by having the data path hardware proactively detect and handle write protect overlaps before they become firmware exceptions. This allows most write protect cases to be handled efficiently in hardware, with only true errors reaching the exception queue.
Data Source
AI summary
Instead of the firmware (FW) monitoring for both an overlap read command and a write protected (WP) overlapped write command, the FW can monitor the overlap table only. The controller will receive a read command or an overlap read command. If the command is not an overlap read command, then the controller will process the command normally. If the command is an overlap read command, then the controller will look for the write command that is being overlapped. When passing the write overlap of write protect (WP) into the data path instead of the exception queue, the FW is limited to monitoring the overlap table. As such, when the WP command is completed the entry is removed by the data path. As a result, the FW can limit monitoring to when the data path clears the overlap table.