Deadline handling in real-time distributed objects: issues and basic approaches

Deadline handling is a fundamental part of rear-time computing but has been practiced in ad hoc forms for decades. A general framework for systematic deadline handling in real-time distributed computer systems is proposed in this paper. The notions of hard deadlines and hard-real-time program components are discussed alongwith the advantages of a hard-real-time component based construction approach. To present approaches for implementation of systematic deadline handling in concrete forms, we use the time-triggered message triggered object (TMO) network structuring as the basic design framework in which deadline handling approaches are incorporated. The TMO structuring scheme is a general-style component structuring scheme and supports design of all types of components including hard-real-time objects and non-real-time objects within one general structure. An augmentation of the TMO structure with statistical performance indicators is also proposed.