Cloud computing. It seems that whenever I hear talk about a new technology, the word Cloud is never that far from the description. From the humble, yet devastatingly handy Dropbox to the mysterious iCloud.
The question that I keep asking is, what is the Cloud? It seems to be a question that no two people can offer the same answer to.
Some seem to think that if they offer an online service, be it storage or an online word processor, that they are offering a Cloud based solution. To many it is just a new word to describe the Internet. Massive and a little fluffy round the edges. To an extent they are correct. The term cloud stems from the cloud like symbol used to represent the internet in simple network diagrams.
The thing is, it doesn’t mean everything online is a Cloud something, surely? Is my website a cloud based application because it is on the Internet?
It is this need for distinction that has produced the three most accepted categories of Cloud computing.
Software as a Service (SaaS)
Platform as a Service (PaaS)
Infrastructure as a Service (IaaS)
In brief, SaaS describes applications that you can use direct from your browser. So Google Docs would be a great example.
PaaS is a step away from SaaS. Rather than being a fully fledged service, it is a platform which allows you to create a service. So a web server, development environment or operating system that is hosted by a Cloud hosting provider. The Google App Engine is a prime example.
IaaS is a little different but would appear to be very similar to PaaS. Here you have the foundation for everything else. It is the servers, the storage, the administration and everything in between that is needed to run your applications. However in the case of IaaS it is all outsourced. Often this will be run in a Cloud system such as Amazons EC2. Here the client is charged flexibly dependant on the usage.
The thing these all share in common and which best describes the cloud for me is extensibility. They can all be switched on and off as needed. They can expand and contract as needed. In many cases you only pay for what you are using, not a fixes price for a fixed amount of anything.
This is in no way meant to be a definition to take to an interview. This is more me putting into words what floats in my head when I hear people talk about the Cloud (the clean version anyway).
I would just love it if people stopped using it to describe anything that is on the Internet or is new. It’s lime putting i in front of a word to make it more saleable. Or using the word doodle in an iPhone game. It doesn’t mean it is better!