Driving Recorder Storage Control for Power Loss Resilience
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Solution Overview
Problem
Unexpected power disconnections in driving recorders can lead to reading failures due to incomplete file allocation tables (FAT) in storage devices, particularly in FAT file systems used in storage devices like SD cards or hard drives, where data is scattered across non-consecutive clusters and not updated before power loss.
Innovation Solution
A control method and system that configures a storage device with a predetermined file allocation table (FAT) and directory entry, ensuring data is written in a way that maintains a complete FAT chain even during power disconnections, by pre-configuring data clusters and interleaving file storage based on bit rates to prevent random write phenomena and enhance writing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If data is written to scattered non-consecutive clusters in FAT file system, then storage flexibility is improved, but reading reliability deteriorates due to incomplete FAT chain during power disconnection
Solution Approach 1:
The patent applies preliminary action by pre-configuring the FAT chain structure before writing data. The system establishes a complete FAT chain mapping all data clusters in advance, ensuring that even if power disconnects during writing, the FAT structure remains intact and readable. This is achieved by maintaining FAT in DRAM and only updating storage device FAT when the complete chain is ready.
Solution Approach 2:
The patent implements beforehand cushioning by maintaining a complete FAT chain in DRAM as a buffer before committing to storage. This cushioning layer protects against power loss during writing, as the DRAM-held FAT chain can be recovered or re-synchronized after power restoration, preventing data loss or reading failures.
2Reliability
If FAT is updated frequently during writing process, then data consistency is improved, but writing performance deteriorates due to multiple update operations
Solution Approach 1:
The patent applies preliminary action by pre-establishing the complete FAT chain structure in DRAM before any data writing begins. This preliminary configuration includes all cluster assignments and FAT entries, eliminating the need for frequent FAT updates during the writing process and improving writing performance.
Solution Approach 2:
The patent implements continuity of useful action by maintaining the FAT chain continuously in DRAM throughout the writing process without interrupting data writes for FAT updates. The FAT chain remains active and accessible in DRAM, allowing continuous writing operations while maintaining data consistency through the persistent FAT structure.
3Productivity
If multiple files are written simultaneously to different clusters, then storage efficiency is improved, but FAT chain completeness deteriorates due to random write phenomena
Solution Approach 1:
The patent applies preliminary action by pre-configuring complete FAT chains for multiple files before simultaneous writing operations. Each file's FAT chain is established in advance in DRAM, ensuring that even with simultaneous random writes to different clusters, each file maintains its complete FAT chain structure and remains readable.
Data Source
AI summary
A control method for a storage device of a driving recorder includes: configuring a directory entry of a storage device according to a predetermined directory entry stored in a storage unit; configuring a file allocation table of the storage device according to a predetermined file allocation table stored in the storage unit; and controlling a controller to write data to the storage device according to the directory entry and the file allocation table. In one embodiment, entries of the predetermined file allocation table are interleaved to accommodate multiple files and still support a continuous write operation.