Partition ?'s

[Kevin McMahon]

One ? I am running out of space on the partition that I have ydl 4.0 on 
and this is the output for the command 'df'.

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/hda10             4820112   4344384    230876  95% /
/dev/hda13               99150     16088     77942  18% /boot
none                    386144         0    386144   0% /dev/shm

Is the /dev/shm available to me to add some space to the partition  that 
I have ydl on ? And if not what is /dev/shm