Reading through the comments, I wonder why you are disqualifying PaaS vendors like LongJump and force.com as “true PaaS”? Could you elaborate on that? Based on your classification and explanations, these to me seem prime examples.

Thank!

However, one possible example, going back to my LAMP stacks again, would be some of our customers who rent IaaS (virtual machines etc) from us, install and manage the application infrastructure software themselves (Linux-Apache-MySQL-PHP/Python etc – “LAMP” stacks), and then provide managed Web hosting services to their customer who are less technical and just want a platform to run their e-commerce shop or whatever. Those Web hosting resellers, for want of a better name, are in effect providing PaaS, though usually not on the granular level we tend to think of with cloud.

The big issue I see with PaaS at the moment is that no one has worked out the right way to bill for it. Google App Engine’s new billing is more like IaaS (instances etc). I think charging per-user would be best for PaaS, but then you’re having to poke up into the software layer in most cases.

I hate to say it but the most interesting pure PaaS play at present looks to be Azure – provided that they can crack the gnarly problem of seamlessly scaling a relational database. Google App Engine (GAE) is a poor cousin by comparison with its huge restrictions on coding and its non-relational data store. Also, GAE have recently priced themselves out of the market.

Can I have your permission to reuse the “Service Layers Definition” picture in an offline article? I’ll make sure to mention the URL and you as the author.

Thakns in advance
Jan Martens

If it is possible, could you provide an example of and SaaS application, like box.net that was developed (and runs?) on a PaaS (like ??) and is hosted on a IaaS like Amazon. I am guessing the above scenario could be true but I can’t find an example of it.

thanks for any help

Bud