Making Sense of Cloud Computing

The terms virtualization, utility computing and Cloud computing are often used interchangeably which can be very confusing. A new report I have just authored aims to provide clarification - to identify the similarities and differences in those characteristics, and provide a framework in which organizations can decide which capabilities they require in specific situations – as it is unlikely that one model alone will suit all their requirements.
A visitor from outer space would be forgiven for thinking that virtualization, utility computing and Cloud computing are different capabilities. But most of us understand that many product and service offerings use the terms rather casually and the trend is to assume they are all describing the same thing, where virtualization is synonymous with utility computing which is synonymous with Cloud. Some might say these are just steps in the evolutionary process – where utility has simply evolved into Cloud.
So, are they the same or different? Can the terms be used interchangeably, or are there clear distinctions between them?

The answer is not straightforward. There are clearly some common, overlapping characteristics that allow the terms to be used interchangeably. But at the same time there are other characteristics that enable them to be distinguished from each other.

The report aims to provide clarification. To identify the similarities and differences in those characteristics, and provide a framework in which organizations can decide which capabilities they require in specific situations – as it is unlikely that one model alone will suit all their requirements.

ESB - Everyone's Silver Bullet?

Given its prominence in any discussions around SOA for several years, you might think that by now everyone has acquired an Enterprise Service Bus (ESB).  However, it is clear that there is still ongoing discussion about the need for an ESB, and questions still remain as to what exactly an ESB is.  Cloud computing seems to have renewed interest in the topic. In the same way that people asked "do I need an ESB to do SOA?", we now have "do I need an ESB to do Cloud Computing?" (at least amongst those who recognize that Cloud Computing is largely service-based).

I sometimes think a better expansion of the abbreviation might be “Everyone’s Silver Bullet”, such is the perception that all you need to buy is an ESB and all your problems are solved.

SOA in Context

SOA does not exist in isolation. Whilst it may be the centre of the universe for SOA aficionados, SOA is just part of a "bigger picture". That isn't to say that SOA can be marginalized. Far from it, as SOA is an important part of, and enabler of that bigger picture as the image below illustrates.