Originally Posted by fhj52
The kernel needs a little swap space.
Try 100MB(it actually uses less but that is a good number). The only other time swap is used depends on how much you have running at once or if some errant program has a memory leak.
If, like me, you never wish to reboot, but prefer to suspend to disk before switching off and later resume, with all applications left running, you'll need a swap area to be used by the suspend system. The version I use is what used to be called SWSUSP2 (software-suspend2) now called 'tuxonice'. I simply install the kernel and kernel-devel packages prepared by Matthias Hensler, here for Fedora users.
If you are using Ubuntu you may be able to find another site. Try running synaptic and tell it to search for tuxonice.
It is probably a good idea, as a precaution, to have a swap area twice the size of your physical memory, if you have lots of spare disk space. (In the past that was often said to be an absolute requirement). If all your running processes are much smaller than the total amount of physical memory, then the need to swap stuff out in order to claim a large contiguous chunk of physical memory is unlikely to arise. Maybe modern memory-management designs make that unnecessary anyway.