Robert F. Pointon

Parallel and Distributed Haskells

Parallel and distributed languages specify computations on multiple processors and have a computation language to describe the algorithm, i.e. what to compute, and a coordination language to describe how to organise the computations across the processors. Haskell has been used as the computation language for a wide variety of parallel and distributed languages, and this paper is a comprehensive survey of implemented languages. We outline parallel and distributed language concepts and classify Haskell extensions using them. Similar example programs are used to illustrate and contrast the coordination languages, and the comparison is facilitated by the common computation language. A lazy language is not an obvious choice for parallel or distributed computation, and we address the question of why Haskell is a common functional computation language.

Preserving coordination properties when transforming concurrent system components

Complexity in concurrent or distributed systems can be managed by dividing component into smaller components. However, such transformations change the coordination behaviour between components, which may change the behaviour of a whole system. We explore this problem through the Hume programming language and explore the Hierarchical Hume extension which enables the localisation of component transformation.

Functional Vs Object-Oriented Distributed Languages

Conventional distributed programming languages require the programmer to explicitly specify many aspects of distributed coordination, including resource location, task placement, communication and synchronisation. Functional languages aim to provide higher-level abstraction, and this paper investigates the effectiveness of this for distributed co-ordination. The investigation contrasts and compares contrasts Java and two Haskell-based distributed functional languages, Eden and GdH. Three distributed programs are used as case studies, and the performance and programming effort are reported.