File Management Apparatus Buffer Cache Update Ordering
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Solution Overview
Problem
Existing file systems face challenges in maintaining consistency during power disconnections or storage device removals, especially when using APIs other than data writing, leading to potential data loss and system instability.
Innovation Solution
A file management apparatus that updates data, first meta-data, and second meta-data areas in a specific order based on the type of file operation, ensuring consistent recording across the file system, even during power disconnections or storage device removals, by employing a buffer cache with a defined flush order for each API operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a journaling file system is used to maintain consistency, then reliability is improved, but device complexity increases due to the need for extra backup information areas and restoration processing
Solution Approach 1:
The patent segments the file system into three distinct areas: data area, directory slot area, and cluster chain area. This segmentation allows each area to be updated independently in a specific order, maintaining consistency without requiring a complex journaling structure. The buffer cache is also segmented to track the update status of each area separately.
Solution Approach 2:
The patent applies preliminary action by updating the data area first before updating the meta-data areas (directory slot and cluster chain). This preliminary update ensures that if power is lost during the process, the most critical data is already persisted, and the system can recover more easily without needing complex journaling restoration procedures.
2Reliability
If meta-data recording is postponed to suppress damage during power disconnection, then reliability is improved, but productivity decreases due to delayed recording operations
Solution Approach 1:
The patent implements dynamic update ordering based on the type of file operation being performed. Different API operations (write, create, delete, etc.) trigger different update sequences and targets. This dynamic approach allows the system to optimize for reliability when needed while maintaining faster performance for operations where full consistency is less critical, thus balancing reliability and productivity.
Solution Approach 2:
The patent changes the parameter of update timing based on operation type and buffer cache status. Instead of a fixed postponement strategy, the system adjusts when and how meta-data is recorded based on whether the operation is a write, create, delete, or other file operation, allowing flexible optimization between consistency and performance.
3Ease of operation
If a fixed update order is used for all file operations, then ease of operation is improved, but adaptability decreases when using APIs other than data writing
Solution Approach 1:
The patent makes the update order dynamic by detecting the type of file operation API being used (write, create, delete, etc.). Each API type has its own optimized update sequence defined in the buffer cache. This allows the system to adapt to different operation types while maintaining a straightforward implementation through predefined patterns for each API category.
Solution Approach 2:
The patent creates a universal buffer cache structure that handles multiple types of file operations (write, create, delete, truncate, etc.) through a unified mechanism. The buffer cache universally tracks update status for all three areas (data, directory slot, cluster chain) and applies appropriate update sequences based on the operation type, making the system adaptable to various APIs while maintaining ease of operation.
Data Source
AI summary
A file management apparatus updates areas to be updated when a file operation is performed by collectively writing out buffer caches into a storage device for each of the areas according to a recording order corresponding to the type of the file operation.