> 2.6.5

Thank you for this necessary context.

> Host scsi1 Channel: 00 Id:00 Lun:00
> Vendor: IOMEGA Model: ZIP 100 Rev: 0.3H
> Type: Direct-Access ANSI SCSI revision: ffffffff

Very good sign. That says your host can read enough bytes from the Zip drive to see that the name of its firmware is "IOMEGA" "ZIP 100" "0.3H" .

The game now is discovering what name your host gave to the device, and then trying to read bytes from an inserted Zip disk.

Myself, I'd next proceed to try to use my own:

http://members.aol.com/plscsi/linux/

I'd ask what is the result of: sudo plscsi -w

Also what is the result of: sudo plscsi /dev/sd[abcd]

However, I am already aware of the proper caution, I quote:

----- http://members.aol.com/plscsi/
...
Learning to use a tool like PLScsi will probably remind you of the need to backup often. If you won't enjoy that lesson, then please don't pick up the tool. Potential side effects include kernel panics, destroyed discs, destroyed devices, and even imperceptibly subtle forms of data corruption. Storage devices differ from modems first by being designed to record your mistakes permanently, and second by defining some commands or sequences of commands to mean self-destruct.

We have not yet heard of anyone hurt by trying `plscsi -w`, which lists all devices to which your O.S. has given one of the well-known SCSI device names. We do recommend first trying `plscsi -w` only while no drives are sleeping, spinning up, or spinning down.
...
-----