Buzzwords as a service

In his joint session (with Jeff Barr) on cloud computing at FOWA last week, Tony Lucas from xCalibre introduced three acronyms:

• SaaS - Software as a Service
• PaaS - Platform as a Service
• IaaS - Infrastructure as a Service

From top to bottom they are (approximately)... applications hosted in the cloud (e.g. Google Apps), cloud-based platforms on which you can build your own stuff, and cloud-based low-level (typically virtualised) compute infrastructure (e.g. Amazon EC2).

I appreciate that these aren't particularly new terms or anything... but I confess that two of the three were new to me (and on that basis may be new to others). 

Sitting under(?) these three I guess you have managed hosting (the phrase Hardware as a Service (HaaS) has been superceeded by IaaS, at least according to Wikipedia).  And then there's Data as a Service (DaaS), where data is hosted as a service provided to customers across the Internet.

All of which leads to Everything as a Service (EaaS, XaaS or aaS), the concept of being able to call up re-usable, fine-grained software components across a network.

I have to confess that I find the distinctions between these terms somewhat blurry... but that is pretty inevitable I guess.  Picking on something at random, the Talis Platform for example... I have no real sense for whether it is best described as SaaS, DaaS, PaaS or IaaS?  Perhaps it doesn't matter.

I particularly like the fact that the Wikipedia entry for PaaS currently says, "This article or section appears to contain a large number of buzzwords".  Quite!

Comments

[Andy Powell]

Definition by @dfflanders on Twitter:

DaaS = OS+WS+DB / PaaS = OS+WS+DB+SW / SaaS = OS+WS+DB+SW+Tel

http://twitter.com/dfflanders/statuses/962331490

[mr webservice]

There's a bunch of discussion and analysis, disgrams etc. over at my blog on this subject.

Frankly the preponderance of competing acronyms is just mightily confusing - especially when there are people keen to pudh their own agenda on what the acronyms even *stand for*! DaaS is one example of the war of the acronyms. More info here: http://thewebserviceblog.co.uk/2008/10/16/soa-definitions-and-terms/

I'm trying to build up more of a comprehensive guide to this mish-mash of terms so any contributions would be greatfully accepted!