Re: HD floppy on a IIgs?

["Bill Garber" <willy46pa@garberstreet.com>]

"David Empson" <dempson@actrix.gen.nz> wrote in message 
1jjgq8y.97z2a21kjfoqaN%dempson@actrix.gen.nz">news:1jjgq8y.97z2a21kjfoqaN%dempson@actrix.gen.nz... 
> mojoehand <mojoehand@gmail.com> wrote: 
>
> > On Jun 1, 10:53 am, Warren Ernst <wer...@gmail.com> wrote: 
> > > On May 31, 11:20 pm, mojoehand <mojoeh...@gmail.com> wrote: 
> > >
> > > > I know that you need a special interface card to support a 1.44 MB
> > > > floppy drive on a IIe. Assuming I had a compatible drive, does the
> > > > IIgs Smartport support HD drives?
> > >
> > > > In other words, can I take a HD drive from a vintage Mac and use it on
> > > > the IIgs? Can I format, read and write HD floppys with it? If so, is
> > > > it possible to read/write MSDOS disks?
> > >
> > > Just to be thorough, if you take a 1.44MB High Density 3.5" floppy
> > > drive from a suitably old Macintosh and plug it into the GS SmartPort,
> > > the drive will act like a normal 800KB floppy drive. It's the magic of
> > > the "SuperDrive Controller Card" that makes it read and write 1.44MB
> > > floppies.
> > >
> > > You should also note that Apple used two different types of HD floppy
> > > drives on old Macs, and it is the older ones that are shared with the
> > > Apple II. Basically, if the drive came from a 68K Mac, it should be
> > > good to use. If it came from a PowerPC-era Mac, then it is not only
> > > less likely to work properly with ProDOS disks, but you can't just
> > > pull the mechanism and expect it to work with an Apple II.
> >
> > Thanks to all for the input. I suspected that it wouldn't get me
> > anywhere, but I wanted to make sure.
> >
> > Pie in the sky question - Is it possible to write a IIgs driver that
> > would make the Smartport work with the 1.44 MB drive?
>
> No. The IWM controller chip can't transfer data fast enough (nor can it
> handle MFM-encoded data). In addition, a 1 MHz 6502 or 65C02 isn't fast
> enough to keep up with the data stream.
>
> The SuperDrive controller achieves the feat by using a SWIM chip instead
> of an IWM, and has its own CPU (a 2 MHz 65C02) and RAM for buffering.

However, a combination of external hardware, and a software driver could. 
I am not capable, yet, of creating such a system, but, it has crossed my 
mind many times, and I am working towards being able to do so. Of course, 
now that I have mentioned it in a public forum, someone else may get on 
it and create one before I can do it. That's just how it goes.   8^) 

Bill