Leaning up 'obese' computer systems
Researchers at the University of Leicester, UK, are tackling the problem of software evolution and degradation in the framework of the EU-funded project Leg2Net (From Legacy Systems to Services in the Net). The project, funded under the EU's Sixth Framework Programme (FP6), focuses on the methodologies and technologies addressing the challenges that companies and organisations are facing for evolving their systems to operate and compete in the e-economy. 'To many people, software is something that allows us to use a computer to perform certain activities (like writing a piece of text),' says Professor José Luiz Fiadeiro of the University of Leicester, the coordinator of Leg2Net. 'However, software doesn't just sit inside the computer. It has a life of its own and evolves over time.' This means that - in order for the system to deliver the same level of satisfaction or even increase it - the system requires constant adaptation and maintenance. Software evolution has also been identified by Professor Meir Lehman and colleagues of the University of London, who have compiled them in a set of behaviours known as Lehman's Laws: - continuing change; - increasing complexity; - large programme evolution; - invariant work-rate; - conservation of familiarity; - continuing growth; - declining quality; - feedback system. The more complex the system, the more complicated the problem. 'Large organisations such as banks use very complex software applications and evolving them is a highly challenging task,' Professor Fiadeiro explains. 'For a start, there is not only one user to be kept satisfied. If one is not careful, complexity increases as software is evolved.' Frequently software updates, for instance, just add layer upon layer to the existing system without taking the overall structure into consideration. 'In modern terms, we could say that software becomes 'obese' as it lets 'fat' accumulate, for instance, old code that is no longer necessary,' Luis Andrade, CEO of ATX Software, says. 'As a result, applications become less and less efficient, more and more difficult to change. And, when this happens, systems begin to lack the agility, flexibility, and responsiveness that companies require to address the fierce competition and market volatility that characterises business today.' One way to make a system more flexible and 'keep it fit and agile' is the adoption of a service-oriented architecture, which does not rely on monolithic systems made up of statically linked components, but a dynamic structure. However, the software has to be carefully analysed first to 'understand what is 'fat' and what is 'muscle',' states Professor Reiko Heckel of the University of Leicester. 'We are doing research aimed precisely at re-engineering 'obese' (also known as 'legacy') software into such service-oriented architectures, and on ways of supporting evolution within those architectures.'
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Portugal, United Kingdom