Mary Jo Foley reported on the origins of Windows Phone 8 and Windows RT, revealing the surprising finding that the Windows NT kernel has better performance on the same hardware than Windows CE, which ultimately forced the move to ARM.
The team who first developed the technology demonstration, then called Experiment 19, wrote on Microsoft Research:
"We started from a Windows core (called MinWin) and a port of the Windows NT kernel to the ARM processor. Working closely with MinWin pioneersâ€”Adam Glass, Mark Russinovich, Richard Pletcher, Richard Neves and Bryce Cogswellâ€”and with partners at NVIDIA, we created the device drivers and firmware necessary to boot and run MinWin on our prototype phones. We created an ARM JIT (just-in-time) compiler for the CLR and ported the CLR runtime to ARM. To complete the system, we ported the phone implementation of Silverlight to run with our ARM implementation of the CLR."
The above video demonstrates the MinWin Windows NT kernel running faster on an ARM6 chipset as found in the original Tegra in2009 (think Zune HD and KIN) than the same chipset running Windows CE 6.
Of course the video also makes it somewhat of a nonsense that Windows Phone 7 handsets can not handle Windows Phone 8, but then there are other, security related, reasons why an upgrade could not come to current gen devices.
Read more at ZDNet here.