Specifying and implementing object managers in Ada

An outline of a formalism for writing specifications of synchronisation behaviours is given, together with a sketch of an approach to the transformation between such a specification and an implementation in Ada. The model of implementation is that each specification is regarded as defining a mechanism, the ´object manager´, which controls the occurrence of events in the system. Each object manager is implemented as an Ada package that provides a collection of procedures to a collection of tasks. Hidden inside the package are ´shared´ data structures and a synchronisation task which schedules the start of execution of each procedure call.