Building on compute and storage virtualization, and leveraging the modern Web, Cloud Computing provides scalable, network-centric, abstracted IT infrastructure, platforms, and applications as on-demand services that are billed by consumption. When a Cloud service is made available in a pay-as-you-go manner to the general public, it is called a Public Cloud; the term Private Cloud refers to internal datacenters of a business or organization. Three aspects are new in Cloud Computing as compared to classical computation:
1. The illusion of infinite computing resources available on demand, thereby eliminating the need for Cloud Computing users to plan far ahead for provisioning;
2. The elimination of an up-front commitment by Cloud users, thereby allowing to start small and increase resources when there is an increase in their needs;
3. The ability to pay for use of computing resources on a short-term basis as needed (e.g., processors by the hour and storage by the day) and release them as needed, thereby rewarding conservation by reverting resources to the pool once their use is no longer useful.
Cloud Computing services are organized in a layered architecture:
- Infrastructure as a Service (IaaS) implements an abstract view towards the hardware and allows to run virtual instances of mini data centers.
- Platform as a Service (PaaS) combines infrastructure, operating systems and application software and offers it as a utility.
- Software as a Service (SaaS) provides software products and service value nets to be consumed as a utility.
The partners of the focus COMMputation perform Cloud system research and development in all layers, ranging from infrastructure related topics to the investigation of service value nets.