But they do still have a desktop, which is a bit of a head-scratcher. Why not go all-metro for WinRT? Will anyone write any non-metro Windows software for ARM, apart from Microsoft's own Office?

From what I remember of the demo, the desktop is for the Intel version only and the arm version is 100% metro. Just google'd this though and couldn't find anything confirming either way.

If this is confusing people on HN, think what it will be like for consumers since the two devices look very similar. Imagine trying to explain to someone that their laptop can't run software X that someone else's otherwise identical (or near enough) laptop can because "it has an ARM chip not an intel one".

Instead of saying " Supports Windows 8 " , non metro software will now have to say " Supports Windows8* "

I wonder how many developers will bother with metro since we already have a bewilderingly huge choices of platforms to support with our software, including "Just give up and do a web app".

Reminds me of when Microsoft's marketing-based product management crazily shoehorned the ".Net" moniker onto everything that the company sold whether it made sense or not. Now the actual .Net technology was pretty nice when everything settled down - but I don't understand now that Microsoft finally managed to make decent virtual machine technology foundation, why they're pushing forward with a path with Windows 8 (ARM) incompatible with Win 8 (x08) why not something a bit closer to run everywhere on a VM?

I'm assuming you can do that and MS will encourage people to write code for .Net rather than C++. You would probably need to add some thing for metro but I'm guessing MS will try and make it as painless as they can.

My guess is that they decided to ship an incomplete Windows RT rather than wait until they could do the obvious thing (provide a complete metro). It's a question of practicality winning over perfection. Think of this as MS Tablet 1.0. It's not perfect, but Windows 9 will be better, and so on.

Will anyone develop software? I'm sure they will for one definite reason - hope. Lots of folks in the ecosystem with skills in ms tool chain etc. who will prospectively develop stuff. But key developers will only ship stuff if the platform is successful.

Windows 8 is certainly a sign that MS is steering in the right direction. Its income base isn't disappearing immediately, so it may have the time to do its usual thing of getting it good enough in version 3. Windows 8 seems close enough that MS might even have it right by version 2.

Here is where I think Microsoft may have screwed the pooch:

* Orphaning WP7.

* Possibly orphaning/pissing off its third party partners. (When will they give up their abusive relationship?)