HyperSpace instant-on OS pops up while Windows boots
 

"We've all been there: we power up our laptops and then find something else to do for several minutes or more while our computers boot up." Phoenix's pitch for HyperSpace may be just slightly hyperbolic, but the idea behind the new instant-on operating system is cool nonetheless. In short, HyperSpace Hybrid pops up while Windows is booting, and you can toggle back and forth between the two OSes by hitting F4 on your laptop keyboard.

http://techreport.com/discussions.x/16208

Windows 7 will kill off all these instant-ON solutions, MAC users already know the joy of instant-on with Mac OS X, put the OS in sleep, battery is drained at very very low rate, memory is kept powered on; if you want to boot up, you're back in action in less than 5 seconds.

Windows Vista sleep was already quite quick, but not as quick as Mac OS X, Windows 7 recovers from sleep in less than 3 seconds, extremely fast.

these instant-on OS's were fine if we all stick with Windows 2000/XP for the next 20 years... but I don't see that happening... you? :)

Same for linux, 3-4 seconds to recover from standby :) .
Booting takes a lot longer, but I can't imagine that it would take long enough for anyone to do something usefull in "hyperspace".