Re: IIgs RAM drive question

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

Jeff Blakeney <CUTblakeney@home.com> wrote:

> On Sun, 19 Dec 1999 01:16:09 +1300, dempson@actrix.gen.nz (David
> Empson) wrote:
> 
> >I'm pretty sure you are right, and Adalbert is mistaken.
> 
> I'm leaning more toward Adalbert being right.  ProTERM can't do
> anything that the hardware and firmware of the IIgs won't allow and
> ProTERM isn't the only program that lets you set slot 2 to "Your Card"
> and still be able to use the modem port.

My point was that it is ProTerm (and other programs which have this
feature) which are doing something special here.  It is _not_ a built-in
feature of the IIgs.

There is no standard software (either system software or firmware) which
lets you use the serial hardware, except the built-in serial firmware,
and the firmware is only available if slot 2 is set to "Modem Port" (or
"Printer Port" on a ROM 3).

Any program which lets you use the modem port despite slot 2 being set
to "Your Card" must be implementing its own driver which bypasses the
firwmare.

As for "doing anything that the hardware and firmware won't allow": the
IIgs serial hardware is designed in such a way that it doesn't depend on
the slots, so a program which wants to bypass the firmware can do this
if necessary (as long as it doesn't interfere with something else using
the serial hardware, such as AppleTalk).

> It is the design of the IIgs hardware and firmware that allows direct
> access to the modem port while letting another card in slot 2 use the
> slot's address spaces.

It has nothing to do with the firmware, just the hardware.

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