Mike McCarty wrote: > I have a dual-boot WinXP/FC2 machine, and took a look > at my setup today. I don't recall seeing the /def/shm > output from df before, and wonder what it might be. > > Can anyone shed some light? > # df > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/hda5 7633264 6928080 317436 96% / > /dev/hda3 99075 24602 69358 27% /boot > none 124044 0 124044 0% /dev/shm $ mount | grep shm /dev/shm on /dev/shm type tmpfs (rw) Firstly, tmpfs is the latest idea in RAM disks. It stores data in Linux's virtual memory. This means that when you have plenty of otherwise unused memory, files in a tmpfs filesystem will physically be stored in memory. When you need to use that memory for other things, they'll be written into swap. This has two major benefits: * tmpfs normally has very fast accesses (no disk accesses a lot of the time) but doesn't permanently eat memory. * stuff in tmpfs will be lost on system reboots (often a good thing)... /dev/shm is, apparently, needed for POSIX shared memory. And it's supposed to be wiped over a reboot. Hope this helps, James. -- E-mail address: james | It is a mistake to allow any mechanical object to @westexe.demon.co.uk | realise that you are in a hurry.
