JavaScript OS

Suppose you have all the security crap sorted out.
What would be an obstacle to creating a JavaScript OS?

>>1
FrozenVoid aside, a guy from Google Japan (used to work for Nintendo, was in the deal that developed the Gamecube OS) is actually working on a Javascript OS, actually. He gave a lecture at my college about it last year or so.

And yeah, he's called Shiki. I wonder if he ever played Tsukihime.

http://code.google.com/p/es-operating-system/

>>98
PROTIP: Shiki is a fucking common name in Japan.