high capacity backup tape for RS/6000

[jxt at ornl.gov]

I am seeking recommendations for a low-price, high-capacity tape backup system
for RS/6000's. I have seen advertised 4mm DAT drives (1.4GB) for PC's and
Macintoshes at around $1800. 8mm systems (2.2GB) for, say $2300. Alas, to get a
DAT drive and driver for AIX, the price seems to be about $4000-5000 (!). What
gives? Being new to unix, I don't understand the driver issue. Would some
generic unix tape driver work or does it need to be AIX and DAT (or 8mm)
specific? Any lines on a decent price for a DAT for RS/6000?

Thanks,
Johnny Tolliver (jxt at ornl.gov)