I am trying to mount the TiVo drive on my PC with no success

My freshly prepared (from OZ image) 80 GB TiVo disk is on the primary
master and I boot with the OZ CD on the primary slave.
I am trying to mount the TiVo disk by typing

mount /dev/hda /mnt/tivo

But I get the "filesystem must be specified" error.
When I try the following command which I saw in one of the mailing
list threads

mount /dev/hda4 /mnt/tivo

I get one good line:
/dev/hda4 Sucesss
But then the second line is the same error message as before.

I do not understand what these numbers after the hdx are. Something
to do with the partition probably.
During the startup, I do get a message that no partition table is found
for the hard disk.

I tried swapping the master and secondary (so that the CD will be
hda and the tivo hdc - I understood from one of the postings that this
may affect byte swapping??), but same results.

I had no trouble mounting a dos floppy disk.

Ideas?

Thanks,

Gideon.