Well, it looks like we finally figured out what was wrong with those
pre-formatted Iomega cardridges. I added section 4.12 - written by Mike
Sienicki - about them to the FAQ (http://www.netbsd.org/Ports/atari/faq.html).

Just to be complete, the FAQ text is added below.

Leo.

--------- snip ---------
4.12 Using (Iomega and MS-DOS formatted) Zip disks

Iomega 100MB Zip disks designated as PC100 (_as_is_ right out of the box)
can be mounted as follows: 

     # sleep 100</dev/rsd*c &
     # mbrlabel sd*
     # mount -t msdos -o rw,-l /dev/sd*a /mnt

Note that the file structure of the disk will not be modified by these
steps.  Replace the '*' by the number your Zip-driver got during the device
probing. Study the output of 'dmesg' for the occurence of 'ZIP' to
determine this. Include the '-l' option to maintain Windows95 operating
system's long filename support. Performing a 'disklabel' on the disk should
give you the following partition info:

     # disklabel sd*
           ...
     3 partitions:
     #        size   offset     fstype   [fsize bsize   cpg]
       a:   196576       32      MSDOS                        # (Cyl. 0*- 95)
       c:   196608        0     unused        0     0         # (Cyl. 0 - 95)

After mounting, 'df' should yield the following (if you 'rm' the demo
program from the disk first):

     # df
     Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
     /dev/sd*a       98078        0    98078     0%    /mnt

If a Zip disk is formatted under Windows95 _without_ Iomega Zip Tools
installed then only the following command is required to mount it:

     # mount -t msdos -o rw,-l /dev/sd*c /mnt

After mounting, 'df' (with no files or directories) should yield:

     # df
     Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
     /dev/sd*c       96050        0    96050     0%    /mnt

If you 'mbrlabel' a zip disk with this latter format then you will get the
following:

     # mbrlabel sd*
     Warning: NetBSD partition 'a' includes AHDI bad sector list

At this point you will need to start over (using eject sd* is an easy way
to do this).