tape problems

I'm having a tough time appending data onto my tape drive.
I have a Colorado 14Gb IDE drive. If I put in a new tape,
and do a:
cd /
tar -cvf /dev/ht0 .

everything works fine. After that, tar -rvf ........... does not work.
I read the man page for 'mt', but am not quite sure what I got out of it.

Anyone want to give a quick lesson?

Mike
mgcon@getnet.com
http://www.getnet.com/~mgcon
Phoenix, AZ
USA