Apple IIc and 800k 3.5" external floppy drive

[EvieSigma]

This is just something I'm curious about...is the external 800k 3.5" Apple Unidisk compatible with the Apple IIc, or just Macs (and probably the IIGS)? I hope it is, because the IIc Plus is pretty rare and I could theoretically write software for the IIc using a USB floppy and a box of 720k disks...

 

[NJRoadfan]

The Apple IIc will work with the Unidisk 3.5" (and the FloppyEmu in Smartport mode) as long as it has ROM 0 or newer installed. You can display the ROM version by typing PRINT PEEK(64447) from the BASIC prompt. If it prints anything other than 255, you are good to go.

 

[EvieSigma]

This one I was looking at is a ROM 3 unit so that's not an issue. Thanks though.

 

[Gorgonops]

Just to be sure you're clear on something: the Unidisk 3.5 is *not* the same as the normal IIgs or external Mac drive, and is in fact completely *incompatible* with Macs. Since the IIgs does work with both the Unidisk and the similarly styled A9M0106, which is totally incompatible with the IIc other than the IIc+, people sometimes mix them up. Here's a decent reference for keeping them straight in your head:

http://www.vintagemacworld.com/drives.html

 

[EvieSigma]

Yeah I think I got tripped up too...thanks for the guide. 

So the Unidisk 3.5 works but not the A9M0106, guess I have to hope that sellers know what they have so I don't end up with a paperweight.

 

[Scott Baret]

I recall there used to be something you could disconnect in a UniDisk 3.5" to make it work on a Mac, but I don't remember what it is. I know I did the modification once a long time ago on one of those drives!

The UniDisk 3.5" is specifically designed to work with two things: the IIc and the LIRON card for the Apple II series (the original 3.5" floppy controller). LIRON cards are pretty rare (and honestly, the UniDisk is too compared to the newer 3.5" drive).

EDIT: I think it works on the IIGS as well, but I remember there is some caveat with it and the 3.5" drive is preferred. 

 

[waynestewart]

Bypass the daisy-chain board and it'll work on a Mac.

The issue was that GSOS would keep polling the drive so the drive access light would keep flashing.

 

[Cory5412]

I don't believe you would be able to use a USB floppy diskette drive to write disks for the IIgs or IIc 800k diskette drives. You'll need to use a beige G3 or older.