smartctl

yesterday, unfortunately my computer crashed due to a raid failure (http://www.datarecovery.org/raid-failure.html) i still do not know why.. we assumed that one of the hard disks is problematic and took it off .
in order to figure out if there is a problem on hard disks, we have to test bothof them, before installing open suse on the machine again.. we used smartctl to do that.
an article on smart : http://www.linuxjournal.com/article/6983
some commands:

smartctl -t long /dev/sda : starts long test on specified disk
smartctl -t short /dev/sda : starts short test on specified disk
smartctl -l selftest /dev/sda : reports about all tests carried out on specified disk

btw, in my computer, starting a new test caused the previously started test on the same disk to abort..