Run the "quota -v" UNIX command under 
gougnaud/arc2/ARC:
Filesystem usage quota limit timeleft files quota limit timeleft
/u/home 119308 512000 512000 924 -1 -1
Do it several times, sometimes the answer is crazy! In the above example you
have about 400Mo free, a scan file of scanners #1 to #4 (energy measurement)
occupies about 1Mo when unzipped and 300Ko when zipped, so you have room for
400 unzipped files or 1200 zipped files.