Dinosaurs?
Mr Bjoernsvik, I think you had better reread current publications. The idea of the mainframe being a dinosaur is at best a cheap shot or maybe be a better word is "Changing with the times". If you are saying that IBM mainframes can't run MS's flavor of the day OS then that is indeed the case. But it can run LINUX and UNIX and at least 3 flavors of IBM's OS's, which btw has been around a lot longer that LINUX and any of MS offerings and possibly UNIX (but it may be arguable which flavor of UNIX you are talking about). Does age mean "bad?" if so I think you might have a lot of AARP (Association of Retired People) to come to blows with over than comment. The age of the typical US citizen is going up and IIRC in a few years going to out rank the number of people under 60. Old age (OK I am 60) is not a bad thing nor does it mean unable to do the job, nor does it mean someone (younger) can do the job better (or cheaper).
Most IBM operating systems can (and do) out perform any and all current OS's (UNIX,LINUX,MS flavor de'jour). There have been conflicting opinions on which is the cheapest. That is somewhat up for debate, for every one you can come up with I can come up with a different opinion) There are many many items that come into TCO. It is a complex subject that really needs almost a few chapters to argue one way or the other.
Yes IBM is monopolistic when it comes to their hardware. But it is similar to Macintosh's in a way. When you buy the hardware and use IBM's OS it runs PERIOD. The same can't be said with MS's OS. And to a lesser extent UNIX and LINUX are dependent on the CPU being run on and then it gets a little sticky because as we just witnessed MS Vista was tied to INTEL CPU. AMD should not be called Plug Compatible because of that (but I am digressing). If UNIX (or any other OS for that matter) uses a(n) "special" instruction(s) that works differently on the cpu it is running on chances are it will not run correctly. The idea here the OS is designed to run the best in the manufactures CPU. IBM's OS(s) runs best on IBM MF's. PSI probably reversed engineered a lot of their code to emulate IBM instructions. That may or may not have been legal and I will defer to the legal experts on that issue. PSI was a definite competition to IBM in the extremely small world of maybe a one or two person shop. IBM IMO does not offer a small developer like system currently, they did but I believe it was discontinued a year or two ago. IBM may have pulled the plug as a step in the PSI lawsuit, I don't know and I suspect IBM won't tell either, but there was some (I think legal?) reason why they discontinued it. Possibly IBM will offer it again once this whole PSI issue is forgotten. IBM did not put forward its finest foot in this PSI fiasco. This is the new IBM and it isn't like the old IBM at all. IBM may be changing to shake off its old image but it will be a few years to come up with its new image (maybe its like a lobster that discards its old shell before growing a new one). IBM is changing and its not for the better, unfortunately.