Why does 4.1BSD think I only have one TU78?

[govern at houxf.UUCP]

I can't get BSD to recognize that I have 2 tape drives.  They both
work on USG UNIX, but under Berkeley, tape drive 1 gets ignored.
I borrowed my operating system from someone with one drive instead
of booting from tape, but I've remade it a few times, and it still
doesn't like drive 1.

Can anyone tell me what to look for?
			Thanks;
				Bill Stewart houxf!govern
				ucbvax!ihnp4!houxf!govern
				BTL HO x0705

Here is the relevant part of the config-file:

	cpu		"VAX780"
	controller	mba0	at nexus ?
	controller	mba1	at nexus ?
	controller	uba0	at nexus ?
	master		ht0	at mba1 drive ?
	tape		tu0	at ht0 slave 0
	tape		tu1	at ht0 slave 1
	master		mt0	at mba1 drive ?
	tape		mu0	at mt0 slave 0
	tape		mu1	at mt0 slave 1

Here are the /dev entries:
brw-rw-rw- 1 root      7,  0 Mar 16 20:37 /dev/mt0
brw-rw-rw- 1 root      7,  1 Mar 16 20:37 /dev/mt1
brw-rw-rw- 1 root      7, 12 Mar 16 20:37 /dev/mt12
brw-rw-rw- 1 root      7, 13 Mar 16 20:37 /dev/mt13
brw-rw-rw- 1 root      7,  4 Mar 16 20:37 /dev/mt4
brw-rw-rw- 1 root      7,  5 Mar 16 20:37 /dev/mt5
brw-rw-rw- 1 root      7,  8 Mar 16 20:37 /dev/mt8
brw-rw-rw- 1 root      7,  9 Mar 16 20:37 /dev/mt9
brw-rw-rw- 1 root      7,  4 Mar 16 20:37 /dev/nmt0
brw-rw-rw- 1 root      7,  5 Mar 16 20:37 /dev/nmt1
brw-rw-rw- 1 root      7, 12 Mar 16 20:37 /dev/nmt8
brw-rw-rw- 1 root      7, 13 Mar 16 20:37 /dev/nmt9
crw-rw-rw- 1 root     22,  4 Mar 16 20:37 /dev/nrmt0
crw-rw-rw- 1 root     22,  5 Mar 16 20:37 /dev/nrmt1
crw-rw-rw- 1 root     22, 12 Mar 16 20:37 /dev/nrmt8
crw-rw-rw- 1 root     22, 13 Mar 16 20:37 /dev/nrmt9
crw-rw-rw- 1 root     22,  0 Jul  1 10:51 /dev/rmt0
...............................................rmt*