Disk quotas have been enabled in /home.  This is a
mechanism where the system enforces disk space limits.

What happens when you exceed your limit?  You get "no
space on device" error messages.  There is a "soft limit"
and a "hard limit" (the "soft limit" is what you've paid
for, the "hard limit" includes the grace).  You can exceed
the soft limit for up to 7 days, at which point it becomes
a hard limit.  Once you've removed files such that you're
below the soft limit, it becomes a truly soft limit again.

Use the command "quota -v" to find out what your limits
are, and how much you're currently using ("wish" users
can get this information from the Stats option in the
Account Administration menu).  It doesn't seem to update
in real time, however (i.e. if you run quota, then create
or remove a file, the usage value doesn't change if you
run quota again).

If you absolutely need some extra space for a temp file,
use /tmp, however you must remove the file within 1 day,
preferably before you logout.