IPS - a Forth-like Language for Space: HIGH LEVEL PROGRAMMING OF SMALL SYSTEMS IN SPACE

The IPS System - 1 General design considerations - IPS was primarily designed to allow the speedy writing of programs intended for the control of satellites, scientific data collection and other engineering applications. There are many programming languages claiming to be suitable for these applications. But on closer inspection most of these require either rather large systems and thus are not very practical for microcomputers or they have serious limitations, like insufficient speed or no multiprogramming. Most control oriented languages are derived from languages created for mathematical or commercial data processing. Generally, this means that the real-time part needs to be handled by the operating system, and the power of this combination is highly dependent on the capabilities of the operating system.With IPS a different approach was possible, since there is no real need to maintain compatibility with other languages and an entirely different approach could be taken. Every programming language represents an interface between machine and men. Thus, it must comply with two requirements: 1. The language should allow the translation of programs making efficient use of the underlying processor, both from a speed and memory economy point of view. This is essentially an engineering problem. 2. The language should allow the expression of problems in a way matching the human understanding and decomposition of problems; the system is to be "user-friendly". Achieving this is not an engineering problem, but a problem of psychology and aesthetics - a form of art. Let us look at the second point first. In order to be able to put the problem into perspective it would be necessary to define the "human way of understanding"; obviously an impossible task because it would have to take into account the different backgrounds of all the people intending to use the system.The second best approach would be to isolate certain general aspects of a problem area and make sure that these are matched by the language.