I got a Dos 3.3 patch that works with the Uni Disk 3.5. I looked for about 2 years and finally found one. The one I have allows you 2 400K volumes on a 3.5 disk. I stuck all my Dos 3.3 stuff on 3.5 disks, and haven't used them very much since. Lots of software wont work on it because Dos 3.3 software looks for the 140k disk...