IMA Module OS and Configuration Testing

Modern aircraft such as the Airbus A350 use Integrated Modular Avionics (IMA) to replace specialized controllers with powerful general-purpose platforms. Core Processing Input/Output Modules (CPIOMs) enable multiple safety-critical real-time applications of varying criticality levels, up to DAL-A, to run securely on the same hardware. They provide advanced time and space segregation, flexible I/O management, and standardized APIs, while reducing development, certification, testing, and maintenance costs through highly configurable system architectures.

Together with Airbus, Verified has developed a test bench, a test bed and a large collection of automated test procedures in order to perform extensive tests of the core CPIOMs, their configurations and the detailed interoperability and timing between API and I/Os.

With respect to normal operation testing, the tests focus on the availability and routing of all resources within the CPIOMs, especially the independence, correctness and timing of the routing and accessibility of up to some hundred thousand logical I/O signals, most of them mapped to specific locations in payloads of larger messages. These tests do not only check the main functionalities of the CPIOM but do also include the verification of the tool chain which is responsible to translate huge I/O configuration table inputs into setups of the CPIOM.

A second focus of the test suites is the robustness and stress testing of CPIOMs. The test bench includes fault-injection hardware which is controllable via automated tests such that external faults can be triggered in millisecond-precise timing and in synchronisation with application-specific API and I/O access. Furthermore, standard robustness tests for operating systems, like provoking stack overflows, trigger timing/scheduling violations and memory read/write access violations and check the operating system handling of such critical behaviour are included in the test suites.

This test setup was initially set up to gain confidence in the new CPIOM hard- and software for the new IMA hardware for the A380 family, but was later continued to be used to be able to perform detailed automated tests of the very complex configuration files for A380- and A350-family CPIOMs. These configurations change with extended application requirements and thus, configuration checks are a recurring activity.