System is hard-disk install from Knoppix-3.4

I have a 100Mb ZIP disk-drive in the computer. Is there a way to mount
and use it?

Since lilo.conf line contains hdd=scsi, I thought that

# mount /dev/sda4 /mnt/test

will work but it says
mount: /dev/sda4 is not a valid block device
(I get similar message when trying to mount /dev/hdd4..)

Any ideas?
-ishwar