© Roland N Ibbett & Nigel P Topham 1996

Computer architecture has been defined in a number of ways by different authors. Amdahl, Blaauw and Brooks [1], for example, the designers of the IBM/360 architecture, used the term to "describe the attributes of a system as seen by the programmer, i.e. the conceptual structure and functional behaviour, as distinct from the organisation of the data flow and controls, the logical design and the physical implementation." Stone [2], on the other hand, states that "the study of computer architecture is the study of the organisation and interconnection of components of computer systems." The material presented here is better described by this wider definition, but is particularly concerned with ways in which the hardware of a computer can be organised so as to maximise performance, as measured by, for example, average instruction execution time. Thus the architects of high performance systems seek techniques whereby judicious use of increased cost and complexity in the hardware will give a significant increase in overall system performance. The material is presented from a historical perspective, i.e. most of the examples describe relevant parts of the computer in which the mechanism was first introduced. Manifestations of most of these techniques can be found in modern processors and computer systems.

  1. G.M. Amdahl et al., "Architecture of the IBM System/360" IBM Journal of R & D, Vol 8, pp 87-101, 1964
  2. H.S. Stone, "Introduction to Computer Architecture", Science Research Associates, Chicago, 1975

About this website

The text in this Computer Architecture website is based largely on the textbook "Architecture of High Performance Computers" by Roland N. Ibbett and Nigel P. Topham, originally published in two volumes by Macmillan Educational Ltd. The website is structured similarly to the book, with each section roughly corresponding to a chapter in the printed books. Many of the descriptions of specific hardware systems are written in the present tense, even though the systems themselves no longer exist.

A number of HASE simulation models relevant to the text can be found at Computer Architecture Simulation Models. Links to specific models are included in the text.