The requirement to support software partitioning is a recurring theme within high integrity real-time systems. The partition concept can be used to implement different 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 redundancy or re-configuration. Finally, the choice of a standard API can achieve partition re-use. This paper describes how an Ada95 compilation system that implements the Ravenscar Profile can be used to build a partitioned architecture in an Integrated Modular Avionics context.