Storage Controller Command Priority for Secure Deletion
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Solution Overview
Problem
Conventional overwrite-deletion methods for storage apparatuses, such as hard disk drives, are inefficient when dealing with large files, as they require repeated processes and high CPU load, and are complex to implement in systems with multiple OS configurations and mirroring systems.
Innovation Solution
A control apparatus and method that includes a receiving unit for deletion commands, a sending unit for overwrite data, and a control unit to manage command execution, allowing for priority processing and efficient data deletion by sector units without requiring consecutive memory regions, thus reducing CPU load and simplifying file management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional overwrite-deletion method is used with CPU generating pattern data, then data deletion security is improved, but CPU load increases significantly and processing efficiency deteriorates
Solution Approach 1:
The pattern data generation function is extracted from the CPU and transferred to the hard disk controller. The controller now independently generates overwrite patterns using its own resources, separating this computationally intensive task from the system CPU to improve overall processing efficiency while maintaining security requirements.
Solution Approach 2:
The hard disk controller performs self-service by autonomously generating overwrite patterns and executing the deletion process without requiring continuous CPU intervention. The controller manages its own deletion operations, reducing the burden on the system CPU and improving processing efficiency.
2Productivity
If overwrite-deletion is executed by hard disk controller using file management information, then CPU load is reduced, but system complexity increases due to extension of file management information
Solution Approach 1:
The solution uses standard, universally compatible file management information structures that can be applied across different operating systems and storage configurations. By avoiding proprietary extensions and using通用的 file management interfaces, the system achieves multi-functionality and broad applicability without increasing complexity.
3Productivity
If file management information is rewritten by hard disk controller, then overwrite-deletion processing is improved, but control operations become complicated in mirroring systems
Solution Approach 1:
In mirroring systems, the controller applies the same overwrite patterns to multiple disk copies simultaneously. Rather than managing complex differentiations between mirrored volumes, the system uses identical deletion operations across all copies, simplifying control while maintaining data integrity and security across the mirrored configuration.
4Reliability
If repeated overwrite processes are used for large files, then data deletion security is improved, but processing time increases and efficiency deteriorates
Solution Approach 1:
The controller prepares overwrite patterns in advance and buffers them in its internal memory before executing the deletion process. This preliminary preparation allows the actual overwrite operation to proceed efficiently without repeated CPU intervention, reducing processing time while maintaining the required number of overwrite passes for security.
Solution Approach 2:
The hard disk controller executes the overwrite-deletion process continuously without interruption or repeated setup phases. By maintaining continuous operation and avoiding repeated CPU involvement, the system reduces total processing time while ensuring the required number of overwrite passes are completed for secure deletion.
Data Source
AI summary
When a controller receives a new command from a main controller during overwrite-deletion processing for a specific storage apparatus, the received command is stored at least until completion of the overwrite-deletion processing when the received command is a command to the specific storage apparatus. Alternatively, progression of overwrite-deletion process is stored and priority processing of the received command is executed. On the other hand, when the received command is not a command to the specific storage apparatus, processing for the command is executed.