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What is cloud computing?
After watching this, I realized that not many people really know what cloud computing actually is (including me), and many people have different ideas.
http://www.youtube.com/watch?v=6PNuQHUiV3Q
I thought I understood cloud computing as applications like online google "apps" (gmail, google docs, etc). Where you can use any computer, in any location to access your documents and emails. But, it has to be more than that... I can set up a web server at my house, with a web server running with a web based email and a ssh server running, and essentially you still get the "access your docs from anywhere" idea. Then I started thinking about the "cloud" term - it is more of where the data is stored - multiple servers. But, look at high availability web servers and their architecture - is that considered a cloud?
Then I started thinking about "cloud computing as a service" - Google, Amazon, and others are starting to offer idea/term as a service. What does that actually mean? Lets say I have an service that I would like to be in the cloud - do I have to re-architect to have it communicate with all nodes? What about race conditions? What about backend storage? Does the "cloud" only store the data part of the application? It doesnt make much sense to be able to take some arbitrary server, have some set of nodes it runs on, and it will just work.
Essentially I am trying to answer the following questions:
What is the cloud computing concept? How does it differ from high availably architecture? How does cloud computing as a service work?
If anyone has answers, or resources, would be very helpful. Thanks.