This document is not listed on the IBM web site so i have attached it here (hope the mods will let it stay)
It details the LTO drive status codes and there true meaning. We all have seen the Media errors from Netbackup, backupexec, and so forth. This document details what you see from the web gui of a 3500 series tape library or maybe you have another gui accessing this information. Either way i hope you get some good use out of it. I know i have.