Mobile Handset Update Agent Interruption Detection
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Solution Overview
Problem
Mobile handsets face challenges in updating firmware and software due to limited memory space, making it difficult to determine where an update was interrupted, especially in FLASH-based devices where writing status information is time-consuming and costly.
Innovation Solution
An update agent capable of executing multiple transform passes in a fault-tolerant mode, using special signatures like CRC and MD5 hash values to determine the point of interruption and resume updates efficiently, employing a set of decision maker banks to identify interrupted transforms and initiate recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If status information is saved frequently in FLASH memory to track update progress, then update interruption detection capability is improved, but update time and operational cost increase due to the expensive FLASH write operation
Solution Approach 1:
The update process is divided into multiple transform passes, each processing a subset of memory banks. Special signatures are placed at specific segments (last updated banks) to track progress without requiring continuous status writes. This segmentation allows the system to detect interruption points efficiently by only checking signature matches at segment boundaries rather than maintaining continuous status information.
Solution Approach 2:
Special signatures are pre-placed in the FLASH memory at specific locations (last updated banks) before the update process begins. These signatures serve as predetermined markers that enable rapid interruption detection without requiring any write operations during the update. The preliminary placement of these signatures eliminates the need for frequent status writes during the update process.
2Reliability
If multiple transform passes are used to update firmware/software, then update completeness and reliability are improved, but difficulty in determining which pass to resume from increases
Solution Approach 1:
Special signatures act as intermediary markers between the multiple transform passes. Each signature is associated with a specific pass and memory bank, serving as a mediator that indicates whether that pass was completed. The update agent uses these signatures as intermediaries to determine which pass to resume from, simplifying the complexity of tracking progress across multiple passes without requiring complex state management.
3Productivity
If individual bits of FLASH memory can be written, then status information update efficiency is improved, but FLASH memory write capability must be changed which is not feasible
Solution Approach 1:
Instead of writing status information directly to FLASH memory, the system creates a copy of the expected signature and compares it with the actual signature read from FLASH. This copying approach allows status tracking without requiring actual write operations to individual bits. The comparison of copied data (signatures) provides the necessary status information while respecting the FLASH write constraints.
Data Source
AI summary
A mobile handset with a fault tolerant update agent employs an efficient interruption point detection technique to recover from interruptions during the update of firmware or software. In one embodiment, the update agent updates firmware and/or software employing a plurality of transforms, each transform employing one pass or a subset of one pass to execute, each pass associated with its own bank order and with its own decision maker bank (for recovery following a fault, such as power failure). The devices and method disclosed are applicable to other electronic devices such as, for example, personal digital assistants (PDAs), personal computers (PCs), pagers, and the like.