Re: Single sided drives and Mirage mice...

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

In article <4leb3k$btj@nyx10.cs.du.edu>,
Will Baguhn <wbaguhn@nyx10.cs.du.edu> wrote:
> In article <4l7r19$bjo@atlantis.atlantis.actrix.gen.nz>,
> David Empson <dempson@atlantis.actrix.gen.nz> wrote:
> >
> >The only way you can connect a Mac 400K drive to an Apple II is to use
> >the "Universal Disk Controller" card that was sold by Central Point
> >Software some time ago, but is not available any more.
> 
> <sigh> OK, i messed up.  you can't use a real APPLE card, you have to
> use the fancy one that i managed to kill (got it second hand).
> 
> curiosity... will the gs smart port run one?

No.

> for some reason, i can't figure out why just "any" 3.5" disk
> controller won't run it... (oh yes.. firmware.).

Not just firmware.  The main reason it won't work is that the original
Mac 400K drive requires a timing signal from the computer which
controls the disk rotation speed (this uses the same wire as the write
protect input from a 5.25" drive).  The original Mac generated this
using the square-wave output of one of the VIA ports, and varied the
frequency according to the track band that was being accessed.

This is done automatically by the Apple 3.5 Drive (as used on the
IIgs, Mac SE and later, and usable with the Mac Plus) and UniDisk 3.5.

The Universal Disk Controller is the only Apple II 3.5" disk controller
which can provide this timing signal.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand