Explaining the Differences

What’s the difference between cloud computing and Software-as-a-Service?

Check out the answer given by Jimmy Pike from Dell: (Complete article here.)

Most discussion these days involves grid, utility, and cloud computing to which we will add software as a service (SaaS).

  • Grid computing is a fairly all encompassing concept and as you probably know, can be generally defined as: “a system that uses open, general purpose protocols to federate distributed resources and to deliver nontrivial qualities of service.” Or in other words, it uses standard “stuff” to make many distinct systems work together in a way that makes them useful.
  • Utility computing or on-demand computing is the idea of taking a set of resources (that may be in a grid) and providing them in a way in which they can be metered. This idea is much the same as we buy electricity or a common utility today. It usually involves a computing or storage virtualization strategy.
  • Cloud computing is a subset of grid computing (can include utility computing) and as I mentioned in my opening post, is the idea that computing (or storage) is done elsewhere or in the clouds. In this model many machines (Grid) are orchestrated to work together on a common problem. Resources are applied and managed by the cloud as needed. (In fact this is a key characteristic of cloud computing. If manual intervention is required for management or operations, then it probably doesn’t qualify as a cloud.) Cloud computing provides access to applications written using Web Services and run on these Cloud Services.

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