Cloud - Cloud computing

Cloud, Cloud computing the buzz words heard everywhere now a days. But what is it?   I started googling about it as we do for most of the things. The first opinion when most of them heard about the word "Cloud Computing" is working from the cloud (Be it while travelling through the clouds or working from the clouds.. :) Of course nothing is impossible for a man. He even can create a workstation in a cloud ;) ) . 

As per Wikipedia the Definition of cloud computing is : 

Cloud Computing is an internet-based computing, whereby shared resources, software, and information are provided to computers and other devices on demand, like the electricity grid.

Why Cloud Architectures?

1) It address key difficulties surrounding large-scale data processing. In traditional data processing it is difficult to get as many machines as an application needs.

2) It is difficult to get the machines when one needs them.

3) It is difficult to distribute and co-ordinate a large-scale job on different machines, to recover if one machine fails

4) it is difficult to auto-scale up and down based on dynamic workloads. 

5) It is difficult to get rid of all those machines when the job is done.

What are the Business benefits?

1) Almost zero upfront infrastructure investment

2) Just-in-time Infrastructure

3) More efficient resource utilization

4) Usage-based costing

5) Potential for shrinking the processing time

Cloud based services can be broadly divided into: 

•  Infrastructure as a service (IaaS) (Data as a Service (DaaS) is a subset of IaaS)
•  Platform as a Service (PaaS)
•  Software as a Service (SaaS)

IaaS is all about hardware, data storage, networking and bandwidth

 i.e. Server, Routers, Switches etc. Amazon and Rackspace are good examples.

PaaS is OS+Application Server stack like .Net framework, VS.Net, SQL Server etc. Best examples of PaaS are Microsoft's Azure & Google AppEngine.

SaaS is simply order an application & start consuming in minutes. Salesforce.com is the best example for this category.

Top 10 cloud Providers:

1. Amazon (Specialized in IaaS)
2. Google (Specialized in PaaS & SaaS. As SaaS it offers Google Apps a web based communication, collaboration & security apps which incudes Gmail, Google calender, Google talk, Google Docs, and Google Sites. As PaaS it offers Google App Engine a platform for developing and hosting web applications in Google-managed data centers. Currently the supported programming languages are Python and Java)  
3. VMware (Offers vCloud)
4. Rackspace (Offers Rackspave Cloud)
5. Salesforce.com (Leader in SaaS)
6. Microsoft (Specialized in PaaS.It offers Azure, a Windows-as-a-service platform consisting of the operating system and developer services that can be used to build and enhance Web-hosted application.)
7. Joyent (The only cloud provider company that delivers all the three layers of the Cloud stack.)
8. IBM 
9. NetSuite (Specialized in SaaS)
10. 3Tera (Offers CloudWare. Cloudware is a big step towards bridging the clouds, and creating standards which will lead to open environment for clouds. With this Consumers will be able to move around with their application and data that will span multiple clouds.)

The key concept is that serveral people, companies or organizations can use the same common services, software, hardware and other infrastructure components. By using common components, the costs are driven down, effieciencies go up and everyone is happy :)