This paper reports on the design, development and evaluation of a buffer algorithm named RESBAL, which exploits parallelism in order to provide high query execution performance in relational database systems. The algorithm aims to provide both predictive and efficient data buffering by exploiting the use of advance knowledge of query reference behaviour. Designed to offer a high level of flexibility, RESBAL employs a multiple buffering strategy both on page fetch level and page replacement level in order to improve buffer performance. The evaluation of RESBAL has been carried out in a parallel database system environment based on a transputer architecture. The results of this performance assessment allow comparison to be made between different buffer algorithms, and demonstrate the feasibility and effectiveness of the RESBAL algorithm. © 1998 John Wiley & Sons, Ltd.

Abstract There is a perceived need within the database community to extend the traditional relational database systems so as to accommodate applications which are deductive in nature. One major problem involved in such an extension is the efficient processing of recursive queries. To this end, parallel processing is expected to play an important role. While substantial work has been done in devising strategies for processing recursive queries in parallel, it is perhaps surprising that little has been reported on the implementation and the run‐time performance of these strategies. In the paper we report our experience of implementing a pipelined evaluation strategy on transputers. A wide range of queries, database structures and architectural configurations are considered as benchmarks in this study. The performance is studied in terms of both speed‐up factors and communication costs. The experimental results show the potential of processing recursive queries in parallel, and provide insight into the usefulness of using transputers for such applications.

This paper introduces the concept of a family relationship and classifies the different requirements and design specification methods into families. «Pure methods» and the methods based on them are identified separately and then correlated in terms of the historical family relationships between merged methods and the core methods on which they are based

This paper presents the Millar Polyhedron, a cubic spiral, by mathematical definition. The defined ordering is given by look-up tables and it is shown how these have a simple implementation on a computer system. A link between this ordering and an octree data structure is then established and it is demonstrated how the cubic spiral can be used to climb over voxel-based input data in the construction of an octree—directly yielding the octree nodes due to its particular ordering. The paper concludes with the suggested transputer implementation in occam 2 with some practical results.

This paper examines and compares four methods for real-time system development. The recently proposed MOON method, HOOD and the established methods of JSD and MASCOT are compared using criteria important for real-time system development and a simple real-time example application. The implications of using the methods for larger scale projects are also considered.

One approach to deductive database system implementation which has received much recent attention is the integration of a relational database management system and a logical inference unit. This makes the deductive manipulation of a large amount of data computationally possible. While several proposals for such systems have been made, differing terminologies and implementations make them difficult to compare. This paper presents a systematic study on the integrated approach to deductive database system implementation. In addition to serving as a foundation for the implementation of new systems, this study clarifies and emphasises the necessary features of integrated deductive database systems.

In his paper ‘Communicating sequential processes', C.A.R. Hoare introduced a concept for the design of concurrent systems. His proposal was intended as a notation and little consideration was given by Hoare to subsequent implementation. Much discussion has taken place concerning associated problems, and recommendations for enhancement have been put forward. This paper surveys the languages which have resulted from his proposal and discusses three of these languages.

This paper applies the use of parallelism in program design to the subject of data processing problems. It describes how parallelism is used as a tool in program design, showing the techniques involved and proceeding step by step through various stages from the initial design to a final implementation. This is illustrated by considering a particular data processing application.

Abstract It has been our experience that, when writing software for operating systems, the synchronization techniques available in Communicating Sequential Processes are inconveniently primitive. In this paper we investigate how different types of queue can be represented in C.S.P., and we show how this approach can be developed into a general queuing mechanism.

This paper demonstrates how the notation of Communicating Sequential Processes may be used in the design of an operating system.It goes further to show how such an approach assists in the design and development of a system distributed over a network of computers.The technique uses a welldefined design methodology.