Hibernation?

I'm sure if someone has thought of doing this before, but I haven't found mention of it anywhere.

Has any work been done toward the goal of "Hibernation"?  I'm writing of the type that would use a separate partition equal to ram + swap space to store the current memory state.  If no one has done any work to this effect, how difficult would it be?  I may be willing to help the effort.  I've never programmed for a BIOS, but I've done mmap() stuff before.

--Kevin