What is Virtualization?

What are the challenges faced by IT Managers today?
Leading business challenges confronting CIOs and IT managers today are:
1) cost-effective utilization of IT infrastructure
2) responsiveness in supporting new business initiatives
3) flexibility in adapting to organizational changes
How are these challenges addressed?
Virtualization is the technological innovation to address these challenges.
What is Virtualization?
Virtualization is the separation of a resource or request for a service from the underlying physical delivery of that service.
What is the use of Virtualization?

Virtualization provides optimal resource utilization.Resources include Server,storage,network,CPU.