What is cloud computing?

There is so much chatter about cloud computing these days that it is really hard to get people to agree on a common definition not only for cloud computing but also for SaaS and other acronyms. Fnally, I found a presentation from the NIST that is probably the best overview of cloud computing , its economics, standards and case studies. I can't recommend these slides enough to anyone involved with cloud computing.

A quick summary of this great material:

"Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction."

This cloud model promotes availability and is composed of

Five essential characteristics:

1. On-demand self-service
2. Broad network access
3. Resource pooling and Location independence
4. Rapid elasticity
5. Measured service

Three service models:

1. Cloud Software as a Service (SaaS): Use provider’s applications over a network
2. Cloud Platform as a Service (PaaS): Deploy customer-created applications to a cloud
3. Cloud Infrastructure as a Service (IaaS): Rent processing, storage, network capacity, and other fundamental computing resources

Four deployment models:

1. Private cloud: enterprise owned or leased
2. Community cloud: shared infrastructure for specific community
3. Public cloud: Sold to the public, mega-scale infrastructure
4. Hybrid cloud: composition of two or more clouds

Cloud computing often leverages:

• Massive scale
• Homogeneity
• Virtualization
• Resilient computing
• Low cost software
• Geographic distribution
• Service orientation
• Advanced security technologies

It looks like we have now a common ground to discuss cloud computing!