Try Linux? This is a SCSI drive, right? I got Tandberg sL24 working on modern Debian. The HW is Core2Duo with PCI slots mobo so I could use AHA-2940UW that I rescued. I didn't even bother with any fancy tape programs at first, I just cat file.bz >/dev/tape and it worked, both ways. I did end up using something more tape-oriented in the end but I can't remember the package name now - command line stuff. Can also rewind, find files, erase, etc.
I had some issues with the drive throwing parity errors after a second or two during write, that went away when I set the Adaptec card to narrow 8-bit interface instead of 16-bit wide. Can't quite tell what is wrong, maybe the cable is somehow flaky.

AFAIK Windows software is not great, seems like you might need a specific program, or even a specific version of it to have support. That is, if there ever was Windows support in the first place.

I know windows server side of things backup software always recommended using their included drivers. In my case it was typically Arc Serve or Backup Exec.
HP/Compaq also had standalone drivers for their drives but are kind of hard to find these days, can image smaller company like Archive would be almost impossible!

More input please, what OS are you running, how is the drive connected?
The NT line of windows had integrated tape backup tools, but sometimes extra device drivers are needed.
Usually SCSI drives are pretty generic, but e.g. W2K needs extra drivers for using an LTO1 drive.
Sytos Plus or ARCSolo may be other options if you are staying DOS.

Hi guys, thank you very much for the replies and ideas!! Eisapc, yeah, that would have been a good idea to include in the original post - I am using a 386 running DOS 6.22 and Windows 3.11! I will try some of these ideas out and report back! Thanks again!

Whoops, and it is connected via SCSI, using an AHA-1540CF card.

Hi everyone, thanks again for the ideas! I ended up scrapping this particular project with this computer, as I think my main problem is all of my tape drives are just slightly too new for this to work. Ah well, I will try in a new machine later!