SLA and Advance Reservation in Wide Area Distributed Systems

The terms Software on demand, Software as commodity or Software as a service (SaaS), represent the keywords of a new trend in the field of distributed computing where the main attention is directed towards the users and their needs, in order to compose a set of new market/research segments. Within this trend, two set of technologies have emerged: Grid and Cloud. Through them, web is becoming a marketplace where each user can find, use and compose services and applications offered, with different qualities, from different providers. From the users point of view, this scenario allows them to have what they want, when they need it, with a specific quality of service, without having to care for the management or ownership of hardware and software resources. From the service provider s point of view, instead, the ability to offer all these functionalities implies the adoption of an effective strategy for services and resources management: the providers have to cope with new and complex challenges in order to guarantee the satisfaction of the user s requests. The aims of this thesis are to investigates these challenges both in a wide area Grid based service marketplace and in a Cloud based multicore environments, proposing for each one an effective solution and discussing the obtained advantages.