Graceful Termination -- Graceful Resetting

Correct — let alone graceful — termination of parallel systems is sometimes thought to be a difficult problem. This is particularly imagined to be so under the pure message-passing MIMD discipline of occam and transputer networks, where global operations (like setting a shared flag or abortions) are not allowed and where time-outs cannot be set for every communication. This paper describes some common, but erroneous, occam approaches to this problem and contrasts them with what can be done in Ada [0, 1, 2]. These methods are all rejected on the grounds of insecurity and performance overheads. A simple, legal, secure and efficient occam method is then presented. This method also solves a much more important problem — the general (or partial) resetting of a parallel system (or sub-system). The resetting mechanism is quite independent of the parallel application algorithm, which can therefore be developed without worrying about such matters. This separation of concerns is good software engineering and is fully supported by the occam philosophy. Finally, an application of this resetting mechanism is described that permits the dynamic reconstruction of occam network topologies

Life of occam-Pi

This paper considers some questions prompted by a brief review of the history of computing. Why is programming so hard? Why is concurrency considered an “advanced” subject? What’s the matter with Objects? Where did all the Maths go? In searching for answers, the paper looks at some concerns over fundamental ideas within object orientation (as represented by modern programming languages), before focussing on the concurrency model of communicating processes and its particular expression in the occam family of languages. In that focus, it looks at the history of occam, its underlying philosophy (Ockham’s Razor), its semantic foundation on Hoare’s CSP, its principles of process oriented design and its development over almost three decades into occam-? (which blends in the concurrency dynamics of Milner’s ?-calculus). Also presented will be an urgent need for rationalisation – occam-? is an experiment that has demonstrated significant results, but now needs time to be spent on careful review and implementing the conclusions of that review. Finally, the future is considered. In particular, is there a future

Emulating Digital Logic using Transputer Networks (Very High Parallelism = Simplicity = Performance)

Modern VLSI technology has changed the economic rules by which the balance between processing power, memory and communications is decided in computing systems. This will have a profound impact on the design rules for the controlling software. In particular, the criteria for judging efficiency of the algorithms will be somewhat different. This paper explores some of these implications through the development of highly parallel and highly distributable algorithms based on occam and transputer networks. The major results reported are a new simplicity for software designs, a corresponding ability to reason (formally and informally) about their properties, the reusability of their components and some real performance figures which demonstrate their practicality. Some guidelines to assist in these designs are also given. As a vehicle for discussion, an interactive simulator is developed for checking the functional and timing characteristics of digital logic circuits of arbitrary complexity

Recognising the challenge: how to realise the potential benefits of ICT use in SME’s

There is evidence to suggest that small businesses often start with innovative business ideas but fail within the first 3 years because the proprietors lack the expertise to make them thrive. In this context, it has been suggested that SMEs would benefit from support to select suitable ICTs that can help them to make the most of their business potential. Such suggestions tend to overlook a need to design a system for use of these ICTs within the context of a particular business. Technology alone solves no problems. Managers need to develop relevant expertise to exploit all the assembled resources available to them, and design of an Information System that will be experienced as useful is a prerequisite for successful development of business opportunities. While the technical aspects of e.g. data processing and storage can be consigned to a contractor, responsibility for a customer’s experience in interacting with the business cannot. It is necessary to design business processes and technologies in synergy, paying as much attention to design of effective use of ICTs as to the technologies themselves. The authors believe it is vital for the proprietors of small to medium-sized enterprises to consider what may be the unintended consequences of investment in ICTs and to devote due time and effort to development of effective systems for use

Professional desire, competence and engagement in IS context

This paper attempts to address the failings of a predominant paradigm in IS research and practice that emphasises technological determinism. This paradigm makes use of a false belief in the power of rationality in organizational decision-making, and a mythology in which organizational actors can be viewed as passive ‘users’ of technology. We wish to create a discussion of the nature and role of professionalism as an expression of more than technical competence. Both system analysts and organizational stakeholders (e.g. ‘users’) are to be viewed as professionals. We discuss desire, exercise of will and their role in professional judgment in relation to transcendent values espoused within communities of practice. We go on to relate this to the environments of Information Systems research and practice. It is pointed out that many researchers, over a number of years, have dealt with these issues in relation to effective management of technological development and organizational change. The paper attempts to encourage renewed attention to interpretivist perspectives on IS development and organizational change, including recognition of the importance of contextual dependencies

Crisis! what crisis?

Abstract There is a crisis discussed in the discipline of Information Systems. Those who perceive such a crisis to exist are by no means agreed, as to its nature and origins. Our inquiry shows that there are a three distinct “crises” being debated. The first of these relates to the Substance and boundaries of the discipline itself and if it is even a discipline at all. Another “crisis” relates to higher education and a fall in demand for IS courses from new students. Commentators perceive this to threaten the existence of IS departments in Universities, and to have potentially serious consequences for both research strategies and career paths of academics. Thirdly, there is perception of a crisis in the wider world, characterised by fewer vacancies in IS-relevant occupations whilst, at the same time, employers complain of a shortage of suitably skilled applicants for the vacancies available. This paper examines evidence for the three “crises,” real or imagined, suggested above, in the Information Systems field

Sustainability in IS: the case for an open systems approach

Common sense tells us that cost cutting leads to saving, and spending should therefore be minimized. However, a little reflection tells us that this sometimes leads to false economies. In an organizational context, these can lead on to a downward spiral of organizational ‘suicide’. Examples of false economies may include: saving on maintenance; saving on research and development expenditure; saving on margins (waste or just-in-time management); and saving on ‘how’ we do things, as opposed to ‘what’ we do. Common sense cost cutting makes ‘how’ invisible, and only recognizes ‘what’. It is vital that we also remember to consider ‘why’ activities are undertaken. Professional competence implies not only skill/knowledge in a particular field, but also desire to apply that knowledge in accordance with certain values, and engagement with the context of application so that learning through reflection may take place. Professional work therefore includes scope for extra-role behaviour, such as suggesting innovative methods or identifying and developing new opportunities (Bednar and Welch, 2010). We suggest that a naïve pursuit of ‘efficiency’ is likely to constrict and curtail possibilities for extra-role behaviour, with disastrous consequences for the development and growth of the business. Creation of systems experienced as sustainable therefore requires us to focus attention on perceived usefulness, rather than efficiency

Evaluation of thermal sprayed metallic coatings for use on the structures at Launch Complex 39

The current status of the evaluation program is presented. The objective was to evaluate the applicability of Thermal Sprayed Coatings (TSC) to protect the structures in the high temperature acid environment produced by exhaust of the Solid Rocket Boosters during the launches of the Shuttle Transportation System. Only the relatively low cost aluminum TSC which provides some cathodic protection for steel appears to be a practical candidate for further investigation