'Division of Chemical Information and Computer Sciences'
Abstract
Dataflow has historically been motivated either by parallelism or programmability or some combination of the two. This work, rather than being directed primarily at parallelism or programmability, is instead aimed at maximising the overall utility to the programmer of the system at large. This means that it aims to result in a system in which it is easy to create well-constructed, flexible programs that comply with the principles of software engineering and architecture, but also that the proposed system should be capable at performing practical real-life tasks and should be as widely applicable as can be achieved. With those aims in mind, this project has four goals: * to argue for a unified global dataflow coordination system, extensible to be able to accommodate components of any form that may exist now or in the future; * to establish a link between the design of such a system and the principles of software engineering and architecture; * to design a dataflow coordination system based on those principles, aiming where possible to embed them in the design so that they become easy or unthinking for programmers to apply; and * to implement and test components of the proposed system, using it to build a set of three sample algorithms. Taking the best ideas that have been proposed in dataflow programming in the past --- those that most effectively embed the principles of software engineering --- and extending them with new proposals where necessary, a collection of interactions and functionalities is proposed, including a novel way of using partial evaluation of functions and data dimensionality to represent iteration in an acyclic graph. The proposed design was implemented as far as necessary to construct three test algorithms: calculating a factorial, generating terms of the Fibonacci sequence and performing a merge-sort. The implementation was successful in representing iteration in acyclic dataflow, and the test algorithms generated correct results, limited only by the numerical representation capabilities of the underlying language. Testing and working with the implemented system revealed the importance to usability of the system being visual, interactive and, in a distributed environment, always-available. Proposed further work falls into three categories: writing a full specification (in particular, defining the interfaces by which components will interact); developing new features to extend the functionality; and further developing the test implementation. The conclusion summarises the vision of a unified global dataflow coordination system and makes an appeal for cooperation on its development as an open, non-profit dataflow system run for the good of its community, rather than allowing a proliferation of competing systems run for commercial gain
