Let me step back. At the most basic level, any operating system has two �jobs�: it needs to manage the underlying hardware, and it needs to provide a platform for applications. The fundamental role of an operating system has not changed, but the scale at which servers are deployed and the type of applications now available or in development are changing massively. On the hardware front, the �unit� of hardware abstraction that a server OS manages has now reached the �datacenter� level. And by that I mean a datacenter ranging from the smallest cluster of a few servers to the very massive footprint of one of Microsoft�s global installations with thousands of servers across multiple geographically distributed datacenters. In response to the needs of large-scale service providers pushing the limits of technology every day, networking, storage and compute vendors have responded by delivering significant innovations to help increase scale, performance and to help remove bottlenecks. These industries have all driven this transformation in parallel. Now, we must think beyond a server at a time and instead look at the OS as the driver of the datacenter. Today�s datacenter is a scalable, intelligent, automated environment spanning all of the shared resources, and it is the magic of software that brings this all together to orchestrate the three resources of the datacenter: network, storage and compute. In other words, a cloud OS.