Thanks to all who replied with the correct answer, to add definitions for the
drive
to the /kernel/drv/st.conf file.  Special thanks to Noli Aurea
<noli@nanospace.com> for including the lines defining the drive (and saving me
some surf time!)  Here are the entries to add:
"HP      C1537A",       "HP DDS-3 4mm DAT ", 
"HP      C1557A",       "HP DDS-3 4mm DAT loader",      "HP_DAT",
HP_DAT  =    1,0x34,0,0x9639,4,0x00,0x8c,0x8c,0x8c,1;
Mark W. Lundy
Sprint LDD/ATD
7101 College, Suite 1400
Mailstop: KSOPAC1401
Overland Park, KS  66210  USA
mlundy@sprintcorp.com
913.534.6525
913.534.6522 - FAX