The revolution in web world led to increasing users needs, demands and expectations. By the time, those needs developed starting from ordinary static pages, moving on to fully dynamic ones and reaching the need for services and applications to be available on the web!.. Those demands changed the perspective of our web today to whats said to be a cloud of computing that aims mainly to provide applications as services for web user. As time goes by, applications were just not enough; users needed their applications and data available anytime, anywhere. For these reasons, traditional operating...