General CHILL is a strongly typed@ block structured language designed primarily for the implementation of large and complex embedded systems. CHILL was designed to: ? enhance reliability and run time efficiency by means of extensive compile-time checking; ? be sufficiently flexible and powerful to encompass the required range of applications and to exploit a variety of hardware; ? provide facilities that encourage piecewise and modular development of large systems; ? cater for real-time applications by providing built-in concurrency and time supervision primitives; ? permit the generation of highly efficient object code; ? be easy to learn and use. The expressive power inherent in the language design allows engineers to select the appropriate constructs from a rich set of facilities such that the resulting implementation can match the original specification more precisely. Because CHILL is careful to distinguish between static and dynamic objects@ nearly all the semantic checking can be achieved at compile time. This has obvious run time benefits. Violation of CHILL dynamic rules results in run-time exceptions which can be intercepted by an appropriate exception handler (however@ generation of such implicit checks is optional@ unless a user defined handler is explicitly specified). CHILL permits programs to be written in a machine independent manner. The language itself is machine independent; however@ particular compilation systems may require the provision of specific implementation defined objects. It should be noted that programs containing such objects will not@ in general@ be portable.