Markus Klems' Blog

In an attempt to better understand the nature of cloud computing I tried to draw a classification of some companies and applications that spawn in the cloud.

Three different cloud computing levels

Infrastructure

The heart of the cloud is what some people call Infrastructure as a Service (IaaS). This is as near to bare metal as we can get: pure storage and compute capacity. With virtualization techniques it is packaged into small units that are delivered like water or electricity (notion of utility computing).

Infrastructure as a Service

Platforms

The next layer is Platform as a Service (PaaS). Here we find more complex platforms, such as Google App Engine or Salesforce.com AppExchange. Marc Andreessen, who coined the phrase “Web as Platform”, once wrote: “[a] platform is a system that can be programmed and therefore customized by outside developers — users — and in that way, adapted to countless needs and niches that the platform’s original developers could not have possibly contemplated, much less had time to accommodate. [...] If you can program it, then it’s a platform. If you can’t, then it’s not.” (Source)

Although I would not consider Amazon EC2 or S3 to be a platform but rather IaaS, the elastic infrastructure provided by Amazon has enabled third-party developers to build platforms on top of it. I asked myself where in my diagram to put the other Amazon Web services (FPS, DevPay, etc.) but haven’t come up with a plausible place, yet. It should probably be somewhere between IaaS and PaaS.

Apps & Services

The outer layer of my onion is formed by all the applications and services that are built on top of either IaaS or PaaS. I am not satisfied with the outer layer. I feel that it needs further categorization, such as grouping by types of applications, e.g. Social Network Apps, Backup Services, and so on.

API

Each layer has a different set of APIs. Near to the core, developers have standard Web technologies and protocols to access and use the cloud. Further away from the core, levels of abstraction are added, making APIs more vendor-specific. On the application & service layer, we find a mix of standardized and less standardized APIs.

Cloud APIs

Suggestions?

I want to improve and extend my diagrams and find a more proper categorization of cloud vendors and services that sit on top of the cloud. What are your ideas and comments on this one? And another thing is: Would you consider firms that use IaaS, like Mosso and cohesiveFT, as PaaS vendors? How are they different from, say Joyent or FlexiScale?


[This analysis appeared originally here and is republished in full by the kind permission of the author.]