Re: M0131 drive on a //gs?

[dempson@actrix.gen.nz (David Empson)]

BLuRry <brendan.robert@gmail.com> wrote:

> Is the older mac-style 3.5 drive (sans eject button) compatible with
> the //gs at all?

Not with the built-in disk controller. It might work on some versions of
the Universal Disk Controller, but I have no experience with trying it.

The Mac 400K and 800K drives require a timing signal from the computer
to control the rotation speed (which varies based on the zone of tracks
being accessed).  The IIgs disk controller doesn't generate this signal
(and if I remember right it conflicts with a different signal which is
specific to the Apple II).

The variable speed mechanism was built into the Apple 3.5 Drive.

You may be able to extract the mechanism and put it into an Apple 3.5
Drive case. I haven't investigated that.

I don't know offhand if that model number is the 400K or 800K drive. A
400K mechanism (single sided) would be of limited use on a IIgs, since
it wouldn't be able to read any 800K disks.

> I ask because I found one sitting on a shelf at a local goodwill for $5,
> and I figured that would be really convenient if that just worked.  It was
> sitting on a //e that had a 3.5 controller card in it (it probably came
> along with that at some point, but was marked for sale separately)

Apple made two 3.5" controller cards that would work in the IIe.

The older "Apple 3.5 Floppy Disk Drive Interface Card" (which says
"Liron" on the back and was made around 1985) only supports the UniDisk
3.5 (and other intelligent SmartPort drives).

The "Apple II 3.5 Disk Controller Card" (a.k.a. SuperDrive card) was
made around 1992 and supports the Apple 3.5 Drive, SuperDrive and
UniDisk 3.5. It has rather more cicuitry than the older card, and has
its own 65C02.

There was also at least one third party card, the Universal Disk
Controller. It supports the Apple 3.5 Drive and 5.25" drives. Early
models support the UniDisk 3.5, but I'm not sure about support for
Macintosh drives.

-- 
David Empson
dempson@actrix.gen.nz