I can't directly speak for the time, but today, almost all DAT/DDS and LTO mechanisms are the same two mechanisms produced in the same place, with different brand labels applied.
Have you tried doing things like putting the tape drive at the far end of the SCSI chain, or making it the first item, and ensuring that you don't have any termination before the end of the chain?
Additionally, it is best if you access the tape using the same software that originally created it (in many cases, right down to the point version). (I'm not sure about UNIX where 'tar' was fairly standard, but the impression I get is that until LTFS came along super duper recently (like, 2010) no two Windows/Mac apps had the same tape formats.)
Have you tried doing things like putting the tape drive at the far end of the SCSI chain, or making it the first item, and ensuring that you don't have any termination before the end of the chain?
Additionally, it is best if you access the tape using the same software that originally created it (in many cases, right down to the point version). (I'm not sure about UNIX where 'tar' was fairly standard, but the impression I get is that until LTFS came along super duper recently (like, 2010) no two Windows/Mac apps had the same tape formats.)