Object-Based Computing and the Ada Programming Language
Buzzard, Mudge · Computer · 1985
ing have coalesced during the past several years into a systems design methodology known as object-based computing. The primary benefit of this methodology is that it raises the level of abstraction available in the de-sign process. Among the events that have encouraged the development of object-based computing are: (1) advances in programming lan-guage design, such as program decom-position criteria and abstraction mech-anisms; (2) advances in operating systems design, particularly those which ad-dress data integrity and program security; and (3) advances in computer architec-ture that allow direct hardware sup-port for many operating system and language concepts. Object-based computing is charac-terized by the extensive use of abstrac-tion. Resources such as data, logical or physical devices, and, in some systems, program segments, may be represen-ted by abstract types. Instances of abstract types form the objects in object-based computing. These ob-jects are manipulated exclusively by operations that are encapsulated in a protective environment commonly referred to as a type manager or pro-tection domain.