However, I am using pre-used cartridges that have various media drivers on them. The low level format is essential to remove any evidence of that driver. Otherwise we end up with the well reported problem with Pluses being unable to use or format cartridges that have been "updated" with a later media driver.

Click to expand...

Yes I was using recent PC formatted cartridges, so they were not recognized by the Mac without the Iomega Init in the System folder, but were easily re-formatted with Iomega's 4.2 Zip Tools under System 6.

As for the updated driver problem, I thought the main issue was having to reformat the disk with the 4.2 driver Tools, meaning back it up and re-initialize, a real pain either way. All of my old Zip disks were updated to newer drivers at some point back in the day before I knew about this problem. However, I have since successfully restored all of them to bootable 4.2 drivers using the 4.2 Zip Tools alone (under OS 8.6 no less).

Also, I presume you formatted the Zip 250 disk with a third party utility and not the Zip tools which would require System 7 and likely not be recognized by the Plus?

This may be of some help with third party formatters from Michael Peters's defunct website:

This app uses the SIOUX console library

Choose 'Quit' from the file menu to quit.

 

Use fake disk names (/dev/scsi.; i.e. /dev/scsi0.1, /dev/scsi1.3, etc.).

 

Top level command (? for help): l /dev/scsi0.5

finding devices .......

 

Partition map (with 512 byte blocks) on '/dev/scsi0.5' (/dev/sdb)

#: type name length base ( size )

1: Apple_partition_map 80 @ 1

2: Iomega_DiskInfo 10 @ 81

3: Apple_Driver* 400 @ 91

4: Apple_HFS 196106 @ 491 ( 95.8M)

5: Iomega_backup 1 @ 196597

6: Iomega_DiskInfo 10 @ 196598

 

Device block size=512, Number of Blocks=196608 (96.0M)

DeviceType=0x0, DeviceId=0x0

Drivers-

1: @ 91 for 4, type=0x1

 

Top level command (? for help):