Re: //c wonky internal drive

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

Roger Johnstone <rojaws@mac.com> wrote:

> ----------
> In article <3a2bf09e.3264957@news.videotron.ca>, 
> mark.REMOVE.percival@videotron.ca (Mark Percival) wrote:
> 
> > On Sat, 02 Dec 2000, Eric Shepherd <sheppy@sheppyware.net> wrote:
> >
> >>in article is7i2t46o2lrca7gvmjgb2t48nsgqp961r@4ax.com, Spamshooting
> >>Paranewsgrouper at spamgun@[127.0.0.1] wrote on 12/2/00 7:53 PM:
> >>
> >>> So one question: I'm sure there is a way to trick the computer into
> >>> thinking the external drive (5.25) is the main drive. Anyone know how
> >>> to do it?
> >>
> >>As I recall, the external 5.25" drive on the IIc is slot 7, so PR#7 should
> >>boot it.
> >
> > I seem to recall the same but I think that this may have been true
> > only in the original IIc.  I think that starting with the Unidisk 3.5
> > enhanced motherboard is was moved back to slot 6, drive 2.
> 
> In the original IIc ROM version there were no ports mapped in to the slot 7
> space. The external drive was still accessed as slot 6 drive 2, but Apple
> put some code in the unused slot 7 space to allow booting from the external
> drive. It worked with ProDOS, but with DOS 3.3 disks it would start to boot
> from the external drive then after a second or two try to continue loading
> from the internal drive. Presumably DOS 3.3 was hard coded to boot from
> drive 1.
> 
> I can't remember if it was still there in the UniDisk 3.5 ROM revision

It wasn't.  This revision of the IIc firmware has the rudimentary
AppleTalk firmware in slot 7.  PR#7 just gives you an error message
about not being able to find the network.

(In case anyone here hasn't seen earlier discussion on this feature and
thinks that this somehow means the IIc can be connected to an AppleTalk
network: forget it.  This code was designed to work with an external
network adaptor box with its own CPU and memory.  Apple never released
this box, and removed the support for communication with it in the next
IIc firmware revision, which was the memory expansion IIc.)