Overlay Filesystem Storage Management for Embedded Systems
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Solution Overview
Problem
Current overlay filesystems inefficiently manage storage resources, particularly in embedded systems with limited volatile memory, as they copy unchanged files to the read/write overlay, leading to rapid memory fill-up during software updates and 'hot-patching' scenarios, limiting the number and size of changes that can be made.
Innovation Solution
Implementing a storage management controller that bypasses the package management system's file copy mechanism, writing new files to a temporary memory location and comparing them with existing files in the underlay or overlay filesystem, copying only changed files to the overlay filesystem, thereby avoiding redundancy and preserving volatile memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all files from package files are copied to the overlay filesystem during software updates, then the overlay filesystem contains all necessary files for updates, but volatile memory fills up rapidly limiting the number and size of changes
Solution Approach 1:
The patent extracts only the changed files from the package files and copies them to the overlay filesystem, rather than copying all files. The storage management controller compares package files with existing files in the underlay/overlay filesystem and selectively copies only those files that have been modified, thereby reducing volatile memory consumption while maintaining update completeness.
2Reliability
If unchanged files are copied to the overlay filesystem, then the overlay filesystem contains complete file versions, but storage redundancy increases and memory is wasted
Solution Approach 1:
The patent extracts and identifies only the changed files from package files through comparison with existing files in the underlay/overlay filesystem. By taking out only the necessary changed files and leaving unchanged files in the underlay filesystem, the system avoids storing redundant copies in the overlay filesystem, thereby preventing wasted volatile memory while maintaining complete file versions where needed.
3Reliability
If a traditional package management system copies all package files to the overlay filesystem, then all files are available for updates, but the process is inefficient and consumes excessive volatile memory
Solution Approach 1:
The patent extracts only the changed files from package files through comparison with existing files in the underlay/overlay filesystem. This selective extraction approach ensures that all necessary updated files are made available in the overlay filesystem while avoiding the inefficiency of copying unchanged files, thereby improving update efficiency and reducing volatile memory consumption.
Solution Approach 2:
The storage management controller performs self-service by automatically comparing package files with existing files in the underlay/overlay filesystem and autonomously determining which files need to be copied. This self-service mechanism eliminates the need for a traditional package management system to blindly copy all files, improving update efficiency through intelligent, automated file selection.
Data Source
AI summary
As a part of an embedded system environment, an overlay filesystem package manager obtains package files for a filesystem operation. the package files are stored in a temporary memory location. a composite layer presenting upper and lower filesystems of an overlay filesystem, is accessed to compare the package files with an associated files in the composite layer. When a difference is detected between a package file and an associated file, the package file is copied or moved to the upper filesystem. If the package file is not different from the associated file in the composite layer, it is not copied and deleted from the temporary memory location.