Re: More GS printer information

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

A2MG <a2mg@aol.comNomail> wrote:

> > You just need a CDA that provides the 56k port speed option.
> 
> Most AppleWorks 5 and all AppleWorks 4  users use a patch to turn off GS desk
> accessories as it launches - or they avoid them altogether. This is because
> they interfere with UltraMacros.

I think you have that backwards.  UltraMacros interferes with many
useful features of the IIgs (notably AppleTalk and anything else using
time-critical interrupts), so I never used it.

I don't understand why UltraMacros could not be modified to remain
compatible with these features of the IIgs.  If it was only a speed
issue, then an accelerator should solve it.

There is no excuse for a normal application program having to take over
an entire low-level interrupt for its own purpose, especially when the
interrupt in question already supports calling application functions.

(Sorry for the mini rant - this is my major peeve with AppleWorks 4/5.)

> This DA turn-off is an option in AppleWorks 5 and is the default in
> AppleWorks 4. It is a ClrHeartBeat.  I don't know if that particular tool
> call - which is part of the AppleWorks 4 and 5 startup process - would
> negate the 56K CDA or not.

It shouldn't.  ClrHeartBeat removes all heartbeat tasks, which run every
vertical retrace (50 or 60 times a second).  (It also loses track of
them permanently.  I hope UltraMacros does some tricks to save the
original value, so the tasks can be reinstated when AppleWorks quits.)

This interrupt is the one that UltraMacros needs to either steal or
disable for timing reasons.  I don't know whether it also has a problem
with the "quarter second" interrupt, which is used by AppleTalk.

The desk accessory menu doesn't interact directly with the heartbeat
task queue (the Ctrl-Apple-Escape sequence has its own special
interrupt), but some CDAs might need it.  A 57k6 speed select CDA only
needs to poke some values into serial port hardware registers (and
possibly hook into the serial firmware to ensure the setting sticks).

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