By now you’re heard about Microsoft’s big splash into the tablet market with Surface. CEO Steve Ballmer showed off two versions: one with an x86 processor running Windows 8 and one with an ARM processor running Windows RT (the same OS ported to ARM).

The announcement did two things: it annoyed the heck out of Dell, HP, Lenovo and just about every other hardware vendor that was also planning to make tablets. And it confused potential customers, because Microsoft didn’t announce any prices, availability dates, retail channels, or applications for Surface. All we know is that Surface is coming, but not when, how, where, or for how much. (more on all this later, in a full article.)

We also got some insight into Windows RT: it’s a bad choice for tablets. Even through WinRT is “real Windows,” it won’t run Windows applications. The ARM processor is just the start of the problem; you could always recompile, after all. But WinRT also costs more than Win8, maybe as much as 3x more. There are reports of a $90 licensing fee for WinRT, which is a big chunk of change for a tablet and more than even Windows 7 costs.

Finally, it’s been rumored that WinRT devices aren’t allowed to run Windows apps, This has nothing to do with the technical challenges; the licensing terms reportedly prohibit recompiling old apps. You have to write new code using the new APIs and OS model. If true, this means programmers have to start all over, not just recompiling, but rewriting, their existing Windows apps. All for a tablet market that doesn’t yet exist.

Windows RT is a fantastic technical achievement, and probably a very good OS for embedded systems with ARM processors and a full-featured user interface. It’s just not looking like a good choice for tablets. That may have been Microsoft’s (and ARM’s) goal all along, but the Surface announcement suggests otherwise.