We had a(n LTO-1) drive do this periodically (in a non-SSO environment).
Sunday the drive became non functional and the vendor replaced it (good 
riddance!).  ;-)    
cheers, wayne

navadeepan sithambaram wrote, in part:

> I am facing a problem in my site. We have NB4.5
>Master on Solaris 7 with 3 Solaris 6 media server & a
>NT media server on a SSO environment with L180 Tape
>Library.
>All was working fine, all of a sudden the drive status
>is going down on veritas and the tape is not getting
>unloaded after the backup is over. this cause the
>drive as busy and other backups fails.
>  
>