Thanks skillz, I'm using a Sony sdx420c drive. Pretty damn slick little drives.
This is just an update and maybe a help out to those of you that might someday need this. Backups to tape are incredibly easy under linux. Using tar and mt, you can do pretty much anything you need to.
Just thought I'd pass that along.
edit: The only thing I haven't been able to figure out is how to turn on and off the hardware compression. I've got a drive here that should do 2.6:1 compression ( well, sorta ), but I have no idea how to turn that on.
too be honest I havent even looked at mine for over a year... It just runs ( the way backups should be)... If I remember correctly I setup my drive using amanda... Would have to double check though..