Re: Query re: disk free (df) output

[Felipe Sateler <fsateler@gmail.com>]

andy wrote:

> Hey all
> 
> Quick questions about the output of df -lh on a single-user Etch:
>  
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/hdb1              12G  3.7G  7.8G  32% /
> udev                   10M   96K   10M   1% /dev
> devshm                443M     0  443M   0% /dev/shm
> /dev/hdb3             169G  4.3G  156G   3% /home
> 
> What are "/dev" and why is "shm" a sub-folder of /dev mounted separately?

/dev is a tmpfs, that is, it is not stored on disk, but on RAM. This is due
to the small and volatile nature of the /dev tree when running under udev.
shm stands for SHared Memory, and I don't know specifically why it's there.
It seems like it is a way of passing data between applications via shm_*
glibc calls.


-- 

Felipe Sateler