Guest editorial—special issue on cloud computing

Cloud Computing has been receiving a lot of attention from both the academic community and the computing industry. As recently as four years ago, it was easy to find people who perceived cloud computing as the “buzzword of the day”, the latest computing fad soon to be replaced by a new idea promising to revolutionize the information world. Nowadays one can still find a lot of excitement and some hype around the term, but the discourse has shifted. There is a general acknowledgement that this new model for delivery of computing services has already had lasting impact in our industry and that it will continue to influence how computing resources are accessed and managed, how datacenters are built, and how business and economic models for computing services evolve. Much of the basis for Cloud Computing comes from a collection of many old and few new concepts in several research fields like Service-Oriented Architectures (SOA), virtualization, and distributed and grid computing. Cloud Computing introduces challenges and new possibilities in many aspects of computing, including Internet architecture, protocols, services, and applications. The computing community is in the process of refining and reframing problems and ap-