Mission-Critical On-Board Software Using the Ada 95 Ravenscar Profile∗

This paper describes how GNAT Pro for ERC32 and the Ravenscar profile are suitable for designing and implementing complex on-board software using high-level tasking facilities. The static and simple tasking model defined by the Ravenscar profile allows for a streamlined implementation of the run-time system directly on top of bare machines. The reduced size and complexity of the run time, together with its configurability, makes it suitable for mission-critical space applications in which certification or reduced footprint is needed. Software reliability and predictability is also increased by excluding non-deterministic and non analysable tasking features. Product validation has been achieved by means of a comprehensive test suite intended to check compliance with the Ravenscar profile and Ada standards, and correct behaviour of specialised features and supplemental tools. Code coverage analysis is also part of the validation campaign, with the goal of achieving 100% statement coverage.

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