ARINC850 850 System Level Guidance for Data Loading LRU Target Systems

This document provides LRU Target System manufacturers, airframe manufacturers, and others with principles, concepts, and guidance for the design of data loading targets and complex data loading target systems. The mechanisms described in this paper apply to federated LRUs and complex platforms, such as airborne servers and data loading of IMA systems.

The document guides data loading system design for Target Systems:

• How to avoid common pitfalls during the system/software design architectural design phase 
• Specific considerations to actively decide on in early conceptual design phases 
• Increase of useability and robustness for the end-user and maintainer of data loading targets 

This document focuses on reaching common design objectives for Target System data loading systems and circumventing repeatedly occurring issues rooted in system design.

Commonly desired design objectives include:

• Architectural choices – Simplify the upload process of LRU Target Systems of the same type
• Reducing incorrect failure behaviors: a “bricked” LRU Target System after transfer interruption
• Performance: Optimized load times using commonly known design tradeoffs

Operational constraints to be avoided are:

• Unexpected operational behavior
• Not fully realized performance and violation of expected load times
• Corrupted or inconsistent states of installation
• The inability to reload/recover LRU target systems after upload failures