TABLE OF CONTENTS In this book, there are four main themes: distributed environments, middleware and applications, middleware deployment and future trends. We begin by setting the scene and introducing three diverse, yet somewhat complimentary technologies, that have evolved over the past several years. These are peer to peer, Web services and Grid computing. Each of these technological areas addresses specific issues within the distributed system spectrum and, as we look ahead, it is highly likely that each will play an important role in contributing to our future distributed-systems infrastructure.
At the time of writing, there are one and a half billion devices worldwide (e.g., PCs, phone, PDAs, etc.), a figure which is rising rapidly. Surveys have stated that Internet users surpassed 530 million in 2001 and predictions indicate that this will double to 1.12 billion by year-end 2005 [175].
The computer hardware industry has also been characterised by exponential production volumes. Gordon Moore, the co-founder of Intel, in his famous observation in 1965 [140] (made just four years after the first planar integrated circuit was discovered), predicted that the number of transistors on integrated circuits would double every few years. Indeed this prediction, thereafter called Moore's law, remains true up until today and Intel predicts that this will remain true at least until the end of this decade [141].
Such acceleration in development has been made possible by the massive investment by companies who deal...
