Abstract
Differential and Integral equations can he solved by the use of Analog and general purpose digital computers. Solution methods, accuracy and solution times for each type of computer are described, followed by the introduction of the Digital Differential Analyser (DDA) as a special purpose computer for dealing with these equations. The principal unit of a DDA is the digital integrator and one example of achieving digital integration is explained. A full description is then given of the application of DDAs to equation solving together with the use of many integrators and the methods of data transfer between them. Programming and scaling are mentioned and interconnection methods introduced. Various integrating structures are described and the two main methods of organizing groups of integrators to form a DDA. Reasons for the choice of the Y/R integrator, its operating algorithm and the type of data transfer are discussed and this leads to a feasibility study which covers all the system design aspects of the two types of constructed machine. The logic, engineering design and hardware implementation of "Uniwic" and "Padawic" then follows and the resulting tests on these machines shows that their practical performance is superior to that predicted in the feasibility study. Explanations are given for the operational failures which occur at very high clockrates. A survey of interconnection methods is followed by a discussion giving the advantages of an electronic, programmable interconnection system for use with the existing integrators. One particular system is chosen and its logic and engineering design are described. The practical performance of the constructed units is noted and the combined behaviour of integrator/interconnect unit is discussed. Some suggestions for obtaining higher speeds and smaller, economical integrators are made in conclusion.