A comparison of the asynchronous transfer of control features in Ada and the real-time specification for Java']Java™

Asynchronous Transfer of Control ("ATC") is a transfer of control within a thread,(1) triggered not by the thread itself but rather from some external source such as another thread or an interrupt handler. ATC is useful for several purposes; e.g. expressing common idioms such as timeouts and thread termination, and-reducing the latency for responses to events. However, ATC presents significant issues semantically, methodologically, and implementationally. This paper describes the approaches to ATC taken by Ada [2] and the Real-Time Specification for Java [3,4], and compares them with respect to safety, programming style / expressive power, and implementability / latency / efficiency.