Back for a shorter article this time. It's just an idea that I wanted to throw away here. Maybe start a discussion too.
The more I learn about the cloud topic, the more I think at the IBM Parallel Sysplex. The cloud have to be a redundant system that is administrated with low costs and and high automation level. A cloud has to be transparent so that it can be administrated as a single system would-another Sysplex property.
The mainframe has the software stack for running Web software and Web Services. CICS and IMS support Web Services, but it's not the only possibility you have. Websphere Application Server runs on System z, and even PHP has an interpreter for z/OS. I admit, z is probably not adapted to every use case, but it fits pretty good some of them.
So well, sure it still miss some software for easying the administration, life-cycle management, etc. But in the infrastructure, the Sysplex is what lots of cloud infrastructure products try to be. Because IBM have developed the mainframe for years with the same ground ideas that are now making the cloud-and this because mainframe customers have had very complex environments for a long time, this is an old mainframe requirement to be handy at virtualisation, automation, availability, backup,...
I'm aware this post can sound a little kind of a sales pitch, but really it's more from a need to present that idea, that what the IT world is thinking of with "cloud", is the direction the mainframe has always be developed in. But, as far as the mainframe is, it's probably still not free of improvements. So come in & comment!