All disks except for scratch ones (disk2,3,4) are weekly backuped (tared) on 2 tapes. If you accidentally remove some important file it can be restored from the tape in this way:
/disk1:tar tvf /dev/rmt/c201d5cnhp/disc archivetar tvf /dev/rmt/c201d5cn > filename_of_the_listhp/disk1/users/user_name/.../filename_of_xxx/disk1.
cd /net
tar xvf /dev/rmt/c201d5cn > hp/disk1/users/user_name/.../filename_of_xxx