PhD Thesis - staffweb - University of Greenwich

PhD Thesis by John Ewer.from those which are tolerated in a pure research code. The previously enumerated points aboutdata passing mechanisms and procedural structure have much greater importance when thesystem is to be used for continued research by a multitude of researchers or when access to datais required by other modules and possibly even other co-operative processes.3.2.4 Archaic implementation languageThe traditional language choice that is most commonly used to implement numerical systems ingeneral, and CFD systems in particular, is FORTRAN-77. Whilst FORTRAN is indeed fast andportable it does suffer from being very restrictive particularly as far as data structures areconcerned. Furthermore the only conceptual mode of development that is generally supportedis for procedural implementations. Attempts at Object Oriented design and implementation usingFORTRAN have proved to be possible but these have had very limited acceptance and are oftenquite unwieldy. Studies [PARSONS94] have shown that ease of maintenance, code clarity andease of modular implementation and maintenance can be significantly enhanced by the use ofObject Oriented development techniques.3.2.5 Lack of any existing User InterfaceMost existing software systems that were developed as research tools are not generallysupported by any form of integrated user interface. Partly this is due to the priorities of theresearchers which tend to favour algorithm robustness, solution correctness, executionperformance and fast implementation rather than any form of interaction techniques. Also manyCFD codes started their development at a time when graphical interactive computer terminalswere unavailable and hence the CFD software could only be run as black box processes on preconfiguredsimulations.3.2.6 Few, if any, library toolsResearch development of software tends to design from the top down and does not oftenconcentrate on the generation of library software routines and modules that can be used in any3-33