Bernard,

    The experimentation I've been doing has suggested a potentially
correct Zip geometry to use, however, there doesn't seem to be a way of
forcing NetBSD to use the geometry I want it to use.  NetBSD always
persists in using the fictitious geometry.

    I've been testing out various geometries by creating a disktab entry
and using disklabel and newfs to create a filesystem on the Zip drive. 
My disktab entry looks like

    zip100|Iomega Zip 100:\
        :ty=winchester:dt=SCSI:ns#40:nt#2:nc#2406:\
        :se#512:rm#3600:\
        :pc#192480:oa#0:ba#8192:fa#1024:

These are values that I gleened off of the Sun Zip disk setup info,
deduced by using a calculator, and derived by using diskpart(8).  I then
newfs using 6 cyl/group.  I think this might actually work; however,
since NetBSD refuses to use anything except the fictitious geometry
corresponding to

    fictitious:\
        :dt=SCSI:ns#32:nt#64:nc#96:\
        :se#512:rm#3600:\
        :pc#19668:oa#0:ba#512:fa#512:

I can't check if I'm right.  Does anyone else have suggestions or
experiences to share?

    -- Johnny C. Lam
       Carnegie Mellon University
       jlbg@andrew.cmu.edu
       http://www.contrib.andrew.cmu.edu/~jlbg