Earlier Wednesday, I wrote about the consensus on the need for a cloud taxonomy that was reached by the participants of the Cloud Interoperability meeting prior to Cloud Connect last week. But a couple of cloud ontologies have come to light that provide a great starting point for taxonomy discussions.
They are very similar, yet they differ in some noticeable ways. Nevertheless, both serve their purpose admirably and are required reading for those considering common understanding in the language of the cloud.
The first was brought to my attention by John Willis via Reuven Cohen. It comes to us from Lamia Youseff of the University of California at Santa Barbara, and Maria Butrico and Dilma Da Silva of the IBM T.J. Watson Research Center. They bring us a relatively simple five-layer grouping:
This ontology starts with firmware and hardware as its foundation, eventually delivering us to "cloud applications." Along the way, the requisite terms for software as a service (SaaS), platform as a service (PaaS), and information as a service (IaaS) are categorized, as well as the more rarely used data storage as a service (DaaS) and communications as a service (CaaS), representing storage and networking respectively.
As Reuven notes, it was driven by a need to define a common cloud classification model to allow academic research to advance.
The second ontology is the work of my good friend Chris Hoff on his Rational Survivability blog:
The powerful thing about Chris' ontology--a work in progress--is the completeness of the stack, from facilities to hardware to software infrastructure to applications and services. He then maps it to several example concepts in what amounts to a very early taxonomy that meets this ontology.
Yes, it is much more complicated than the UCSB-IBM contribution, but it lays out classifications that many of us find somewhat intuitive and certainly very close to complete.
That being said, note the overlap between the two. SaaS, PaaS, and IaaS form the core basis of the cloud-centric classifications. In fact, the most striking difference in that regard is that Youseff's team classifies DaaS and CaaS as separate from IaaS, while Chris defines IaaS as containing all three (compute, storage, and network). I would tend to side with Chris on that point.
Both projects would accept feedback, I'm sure. Chris Hoff is looking for commentary on his post. (I have some minor adjustments to suggest myself.) I am betting that Youseff's team will be reading the commentary to Reuven and John's posts. And I would love to get your comments here on the relative merits of the two approaches.
2008 will be remembered as the coming-out year for cloud-computing services. I'm beginning to think that 2009 will be best remembered for cloud-computing understanding. I encourage you to get involved.