Re: IIc hard drive hack?

[mairsil@my-dejanews.com]

In article <1dfha0t.hjo1c8li93pcN@dempson.actrix.gen.nz>,
  dempson@actrix.gen.nz (David Empson) wrote:
> TWS <adoyson@nccn.net> wrote:
>
> > The Apple IIe, IIc and IIc+ all use the same
> > technology, don't they?
> >
> > On the IIc and +, the motherboards are built
> > without slot connectors. Aren't the same
> > signals used on the IIc for 5.25 drive access,
> > serial access, etc?
>
> Some of the same signals are used, but several critical ones are
> missing.
>
> In particular, the IIc has no support for separately addressable
> firmware areas for each slot.  All "slot firmware" is part of the main
> motherboard ROM.
>
> In addition, the IIc doesn't support the 2K bankswitched area at
> $C800-$CFFF.  It is permanently used by the 80-column firmware.
>
> Trying to hack a card into a IIc would at the minimum require rerouting
> several address lines through address decoding circuitry to identify
> address ranges for the slots in question.
>
> The IIc also doesn't generate the DEVSEL signals (16 byte I/O window for
> each slot) in the same way.  The MMU and GLU chips generate specific
> select lines for each chip that requires addressing in these areas (the
> two 6551 ACIAs and the IWM).

In other words, you'd have to make the hard drive from scratch? :-/ Say,
didn't Tony Diaz try replacing a IIc floppy drive with a hard drive, once?

>
> --
> David Empson
> dempson@actrix.gen.nz
> Snail mail: P.O. Box 27-103, Wellington, New Zealand
>



Ralph Glatt

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