Iterative multi-level modelling. A methodology for computer system design

The paper presents a method of modelling a computer system design as it evolves, so that evaluation can be made an integral part of the design process. The paper introduces the concept of concurrent existence, within a single model, of several representations of the system being modelled, at differing levels of abstraction. Thus important design decisions are expressed directly in terms of appropriately abstract quantities, facilitating understanding, validation, and modification of the system design. The paper includes brief details of an experimental implementation of the modelling technique and of the use of the technique to model both hardware and software components of a multi-processing system.