FLEX - TOWARDS FLEXIBLE REAL-TIME PROGRAMS

Programs for hard real-time systems have stringent timing requirements. To ensure that these deadlines will always be met, real-time programs are usually designed for the worst-case scenario. In addition to being inefficient in the normal case, such programs are susceptible to environmental variations. We describe a language called FLEX which makes it possible to program real-time systems which may respond to dynamic environments. In the worst-case when certain resources are not available, the program may produce approximate, imprecise results. This ability to write programs which are flexible in their execution time is provided by using constraints to express timing requirements, and sieves and imprecise values to obtain imprecise results.