ILIAD is a high-evel language for programming real-time applications which involve concurrent processing. It was designed to help scientists and engineers write reliable programs that can be read and maintained. An ILIAD program consists of a group of concurrent tasks. The tasks are autonomous and must cooperate in using the shared memory and devices in the execution environment. The language has facilities for providing secure access to these resources and for creating and synchronizing parallel instruction streams. In providing an overview of the language, the factors motivating the major design choices are discussed. A programming example illustrates how ILIAD might be applied. An assessment of the language includes a discussion of potential problem areas, both technical and nontechnical.

Abstract This paper reports on the design and development of a high level language, Malus, for use in implementing a time‐sharing system. Emphasized are the ways that the language and its compiler accommodate the specialized requirements of systems programming and programmers. Among these are the need to generate highly efficient object code, to allow inter‐programmer communication by program self‐documentation, and to define and organize system tables and data. In addition, the Malus compiler is highly modular; thus the language may be modified or augmented in response to user needs unforeseen during langauge design. Systems programs cannot be machine independent and Malus allows explicit control of emitted code when an application requires particular efficiency or use of privileged instructions. There is also a facility allowing nested redefinition of identifiers. Efficient storage management and data access is effected by the availability of based structures, a register storage class and built‐in functions to facilitate their use. Malus is evaluated both in terms of some general criteria for systems implementation languages and by an appraisal of user reactions. While this assessment shows a few areas where the language might be improved, it is felt that Malus is a valuable and effective tool for systems implementation.