Building partitioned architectures based on the Ravenscar profile

The requirement to support software partitioning is a recurring theme within High Integrity and Safety Critical systems. The partition concept is used to implement differing access protection levels for applications of varying criticality levels executing on the same processor. Partitions can also be used in fault tolerant systems that require high availability, redundancy or dynamic re-configuration.The Ravenscar Profile was a major output of the 8th International Real-Time Ada Workshop. The profile defines a subset of the Ada95 tasking constructs that matches the requirements of Safety Critical, High Integrity and Hard Real-Time systems by eliminating constructs with high overhead or non-deterministic behavior (semantically or temporally) whilst retaining those elements that form the basic building blocks for constructing analyzable and deterministic real-time software.This paper describes how a COTS Ada95 compilation system that implements the Ravenscar Profile can be used in the implementation of a partitioned architecture in an Integrated Modular Avionics context based on the ARINC 653 Application Executive (APEX) standard.