Who provides what in the cloud

Sun Microsystems: An on-demand grid, and perhaps more

With its "the network is the computer" mantra, Sun provided much of the inspiration for the cloud computing movement. And its Sun Grid Engine was one of the first on-demand cloud offerings, providing access to compute and storage resources optimized for parallel-processing applications.

The company also has a research venture dubbed "Project Caroline" meant to provide a configurable pool of virtualized compute, storage, and networking resources to small and medium-size SaaS providers, so they don't need to develop their own infrastructure. There have been recent reports that Sun is planning to turn Project Caroline into a full-blown business, but there's been no official word from they company yet.

TerremarkWorldwide: Resource pool for on-demand servers

The Terremark Enterprise Cloud is designed to give datacenters an Internet-optimized computing infrastructure. Enterprise Cloud clients buy a dedicated resource pool of processing, memory, storage, and networking, from which they can deploy servers on demand. A Web portal allows server to be dynamically provisioned from a pre-allocated pool of dedicated computer resources. Terremark promises that its cloud servers behave exactly like their physical counterparts, allowing applications to be run without modification.

XCalibreCommunications: Self-provisioned virtual servers

Described by some observers as Europe's answer to Amazon's EC2, Scotland-based XCalibre's FlexiScale provides self-provisioning of virtual dedicated servers via a control panel or API. Persistent storage is based on a fully virtualized high-end SAN/NAS back end.