The history of KARL and ABL

This paper is not a tutorial. Because of limited space available here this paper gives only a limited survey on the evolution of the hardware description language KARL and its derivatives. We intend to stress such features, which are different from most other hardware languages. Before a comparison of KARL to other languages it is useful, to introduce a classification scheme for computer hardware description languages (CHDLs). These are graphic and textual languages. The number of abstraction levels covered differs between languages. That's why we start with a look at the language classification scheme. We may distinguish at least four different kinds of descriptions, procedural descriptions, structural descriptions, functional descriptions and topological descriptions. This is a modified version of the Gajski-Kuhn diagram, which does not distinguish functional and procedural descriptions as subclasses of behavioral descriptions. Another difference to Gajski-Kuhn is it, to distinguish pseudo-structural elements (to express partitioning without a physical meaning) from really structural descriptive elements (with a physical meaning). A third difference stems from the fact, that CHDLs do not deal with geometry. But there are only two CHDLs which are capable to express topology (which is close to geometry): #mu#FP (by Mary Sheran) and KARL. (orig.)Available from TIB Hannover: RN 7281(232) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman