In-Place LZO Decompression with Checkpoint Resume After Power Loss
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Solution Overview
Problem
During firmware updates, embedded devices can experience power failures, leading to interruptions in the decompression process, resulting in incomplete firmware images and the need for retransmission or additional storage, without the ability to resume decompression from the interrupted state.
Innovation Solution
A method where a computing system saves the internal algorithm state after each completed step of the decompression process, allowing the decompression to resume from the interrupted state upon power restoration, thereby completing the decompression process without requiring additional storage or starting over.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If in place decompression is used to speed up firmware transfer, then transfer time is reduced, but the input compressed image is overwritten during decompression making it impossible to resume after interruption
Solution Approach 1:
The decompression process is divided into multiple intervals with save points. The LZO decompressor saves its internal state at regular intervals during decompression, creating checkpoints that allow recovery without restarting the entire process. This segmentation enables both efficient in-place decompression and reliable resumption after interruptions.
Solution Approach 2:
The system performs preliminary actions by saving the decompressor state at predetermined intervals before potential interruptions can occur. These pre-saved states serve as recovery points, allowing the system to resume decompression from the last saved state rather than restarting from the beginning, thus maintaining both speed and reliability.
2Reliability
If additional storage is added to store the compressed image for later use, then decompression can be restarted, but storage size and cost increase
Solution Approach 1:
The patent merges the compressed image storage with the decompression output storage. By performing in-place decompression where the output is written to the same location as the input compressed data, the system eliminates the need for separate storage for the decompressed image. Combined with interval-based state saving, this allows resumption without additional storage capacity.
Solution Approach 2:
The system discards the compressed image data as it is decompressed in-place, recovering only the necessary decompressor state information at intervals. This approach recovers minimal essential data (the state snapshots) rather than preserving the entire compressed image, enabling resumption with negligible additional storage requirements.
3Manufacturing precision
If the decompression process starts at the beginning after an interruption, then completeness is ensured, but time is wasted re-decompressing already completed portions
Solution Approach 1:
The system performs preliminary state-saving actions at regular intervals during decompression. When an interruption occurs, these pre-saved states allow the system to resume from the last checkpoint rather than restarting, ensuring completeness while avoiding redundant work on already-decompressed portions and minimizing time loss.
Solution Approach 2:
The decompressor implements feedback by continuously monitoring its own state and saving progress at intervals. This self-awareness allows the system to determine exactly where to resume after an interruption, ensuring that no data is lost or duplicated while minimizing the time required to complete the decompression process.
4Quantity of substance
If decompression is performed without saving intermediate states, then memory usage is minimized, but the ability to resume after interruption is lost
Solution Approach 1:
The decompression process is segmented into intervals with periodic state saving. Instead of saving state continuously or at every step, the system saves at strategic intervals, significantly reducing memory usage compared to continuous saving while still providing adequate recovery points to minimize rework after interruptions.
Solution Approach 2:
The system applies partial action by saving only the essential decompressor state at intervals rather than maintaining complete decompression context throughout. This partial saving approach uses minimal additional memory while providing sufficient recovery capability to resume decompression without significant time loss.
Data Source
AI summary
A method includes inputting a compressed image in a computing system. The method also includes a process of decompressing another image over the compressed image by a processor. Power is restored to the process of decompressing the image in response to an interruption to the decompression process. The decompressed image is configured to override the inputted compressed image. The method also includes completing the process of decompressing the image over the inputted compressed image.