Cloud computing shifts the emphasis from locally managed
server-client installations and information technology related services to
externally located web-accessible computing centers consisting of thousands of
servers. However, unlike the internal standards and protocols serving as the
foundation of proprietary system software there is no single uniform precise
definition of the cloud computing. There are different types of clouds.
The hardware and all layers of the software - web browser,
suite of applications, operating systems, web servers, system software, and
scalable database - are subject to the competitive forces of proprietary software
providers, open source software alternatives, infrastructure specific to
organizational enterprise, and intellectual property in a global economy. Cloud
computing is evolving from concept to a practical working implementation.