Once swapped the system disc of a netware server live. Can't remember why exactly, I think it stared to count bad sectors as we watched and we needed to keep it alive copying the data to the new, to-be system disk. Then we made sure, nobody was logged in, it was about midnight, hit Alt-LeftShift-RightShift-Esc and while Netware paused in the kernel debugger, swapped the disks. Continued the debugger and - it worked :)