In my 20 years of working with computers, I've always assumed that the hardware reset button on a desktop machine was hard-wired to the motherboard, causing some kind of short-circuit which would reset the machine no matter what state it was in (except for power off of course).
I was completely surprised to learn that on my current Core i5-2500 machine, with an ASRock H67M-GE motherboard, this doesn't seem to be the case, at least not when running Ubuntu.
Instead of resetting immediately, the reset button now does nothing when pressed shortly. When pressing it for a few seconds, the machine shuts down instead, to a somewhat mysterious state (it's not the 'normal' shutdown state, I'll see if I can elaborate on that later).
When running Windows, the reset switch works as expected. Also, the reset switch works fine when I'm in the BIOS / EFI. As soon as any Ubuntu component has been loaded (it starts from the moment I see the startup menu from the Live CD), the reset button stops working normally.
Can anyone explain to me how such a thing is even possible? Has the reset button 'wiring' perhaps been changed since the introduction of EFI? And could this be described as a bug in Ubuntu?
I'm running Oneiric since earlier versions of Ubuntu wouldn't even start from the live CD. Not even MemTest (!!) would work properly. Again, Windows booted just fine, no matter the version. I must admit I didn't try installing from the Alternate CD, but IMHO that shouldn't be necessary on a 'normal' desktop PC. And it also shouldn't be related to the reset button problem :-)