Microsoft Windows Azure and Amazon EC2 on Collision Course
Microsoft's Windows Azure and Amazon's Elastic Compute Cloud tackle two very different cloud computing technology problems today, but are destined to emulate each other over time. Whereas Windows Azure is a platform-as-a-service cloud, giving developers the tools they need to build and deploy Web applications, Amazon EC2 is primarily an infrastructure-as-a-service cloud, offering on-demand access to customizable virtual machine instances.
Azure simplifies the building of web applications in a way that Amazon does not, but Amazon's cloud-based virtual machines have the benefit of working with multiple programming models. O'Brien, senior director of Microsoft's Platform Strategy Group, predicted that over time Microsoft will move more into IaaS and Amazon will cross over into PaaS.
IaaS pro
The reason people like IaaS is because it's programming model agnostic. The bare metal VM doesn't care what language you wrote the application in, it doesn't matter what tools you use and what runtimes you've targeted. If it runs on Windows or Linux, give it a virtual machine and it will run just fine.
IaaS con
The problem is it's a lot of extra work. You're responsible for that virtual machine the same way you're responsible for a server sitting under your desk. You're responsible for turning it on. You're responsible for turning it off. You're responsible for applying a patch or an update. If Red Hat applies a Linux patch, and you have a Linux VM running on Amazon, you have to apply that patch yourself. They won't do that for you."
PaaS pro
All of that stuff is completely abstracted away, it's a friction-free development, you basically code up an application, you hit deploy and it'll go run on the platform that's supplied by those runtimes. So in our case its PHP, C Sharp, in the case of Google App Engine it's Python and Java. While building new applications is easy, and removes the need for owning internal hardware and software, other than a Web browser.
PaaS con
The biggest problem with PaaS may be difficulty migrating existing applications from the internal data center to the cloud.
Next Step - Microsoft
Microsoft has already announced that "at some point (in the next 12 months) we will be offering the ability to provision a bare-metal VM, and run your application on that.
Next Step - Amazon
While Amazon provides a variety of Windows and Linux virtual machine images through EC2, the company's Web Services business offers a variety of other tools that might be useful to developers, including databases, storage services and load balancing.
Conclusion
O'Brien predicts that just as Microsoft moves into IaaS, Amazon will build a PaaS offering that more closely resembles Azure than anything Amazon offers today. It's not a matter of one is better than the other; they accomplish different things. But what you'll see happen in the marketplace is a convergence of those two, where IaaS providers like Amazon will move up the stack toward Paas. You'll also see PaaS providers like Microsoft provide some of that infrastructure-like capability, just so we can handle those migration scenarios much easier, and the lines will get blurred.
Reference : By Jon Brodkin on Fri, June 25, 2010 @Network World Inc.