Newbie question - cannot add new disk

[Oliver Iberien]

Hi,

I have been trying to add a second IDE hard drive. I can't seem to get it 
mounted, or to get what I put into sysinstall and what comes out when I use 
the command line to agree.

I can use sysinstall and then run newfs:
bsd# newfs /dev/ad1s1c
/dev/ad1s1c: 39205.5MB (80292804 sectors) block size 16384, fragment size 2048
        using 214 cylinder groups of 183.77MB, 11761 blks, 23552 inodes.
super-block backups (for fsck -b #) at:
 160, 376512, 752864, 1129216, 1505568, 1881920, 2258272, 2634624, 3010976,
[...]
 78281376, 78657728, 79034080, 79410432, 79786784, 80163136

So it looks as if there is a slice there using the whole 40G disk, called 
ad1s1c. But:

bsd# disklabel ad1
disklabel: /dev/ad1 read: Input/output error

And with the following line in /etc/fstab

/dev/ad1s1c             /disk2          ufs     rw              1       1

bsd# mount -u /dev/ad1s1c /disk2
mount: /dev/ad1s1c on /disk2: specified device does not match mounted device

Using the command line utilities:

bsd# disklabel -Brw ad1 auto
bsd# disklabel -e ad1s1
disklabel: /dev/ad1s1: No such file or directory
bsd# disklabel -e ad1c
disklabel: /dev/ad1c read: Input/output error
bsd# newfs /dev/ad1s1c
newfs: /dev/ad1s1c: could not find special device
bsd# fdisk -BI ad1
******* Working on device /dev/ad1 *******
fdisk: Geom not found

And so I go round and round, as at that point I have to use sysinstall again. 
I tried this with two disks, both of which were good under linux. The 180G 
Seagate spat out DMA errors at startup, and I got nowhere with it. This one 
is a 40G Maxtor.

I suppose I could change out the cable (I have none handy otherwise I would 
have) although I can't see why a cable that worked for linux would not work 
now. Master/slave are set correctly. I could not mount linux partitions, 
either, despite the recompile -- don't know if that's related. I'd be 
grateful for any ideas. 

Oliver