I am backing up a RedHat Linux-based server to a Hewlett Packard DLT 40e SCSI-based drive. I have been just using the tar cvf /dev/st0 / command to initiate a backup and tar xvf....... to restore from it. For two months this has been working fine. All of a sudden I am getting a 'device or resource is busy' error after I type in the tar cvf....command. I am new to Unix and Linux and am not that familiar with kernel and device manipulation/problem solving. Would anyone know why this would happen all of a sudden?