🚀 go-pugleaf

In article <3845@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>... When you can run a compile concurrently with Photon
>Paint then you can make the claim that the Mac supports background processing.

I think the Mac's almost there (is "almost" good enough? :-)) Certainly
I can run Kermit transfers behind the scenes. I'm typing this in from a
Mac running NCSA Telnet, which can happily scroll windows in the background.
We can also do background backups from Mac to Sun invisibly (apart from
activity on the Mac's hard disk).
   One of the problems is that the Mac world in inhabited by programs which
think that it's quite alright to throw up a modal dialogue and then go away
and think. Lightspeed C does this, although it could conceivably allow itself
to be backgrounded, giving the behaviour you want.
   Note my words: "allow itself". You're right: there's a burden on the
programmer with GetNextEvent() and all that stuff. This is sad. I think the
reason that the Mac doesn't timeslice is that it has to define exactly
when objects in memory might move around under the application. So: it only
happens at event-time. How does the Amiga handle this? Or doesn't it have
the same kind of heap management?

>Because on the Amiga, as on UNIX, the operating system handles time-slicing.
>Your program can completely ignore the user interface, sit on the CPU as long
>as it wants, and the system will happily chug along.

That isn't always what you want... If the application is "chugging along",
then it can't respond to asynchronous events generated by the user
interface, such as window-uncovering or highlighting - or should the
system do this, by hanging onto bitmap images? UNIX does it by virtue
of having another layer: my compilation runs fine in an X-window, because
there's another process emulating the terminal and responding to user
events. I don't think this is feasible for the hardware we're talking about.

>If you guys had written a decent conventional O/S for the Mac and stuck the
>user interface on top of it I'd be using it now instead.

There are benefits to the fact that the Mac's insides are tied together
in the way that they are: the event and dialog managers present a very
well crafted interface to the user (dialogs and menus come up before
refresh events take place, dialogs can be dismissed before they're fully
drawn, etc.). As a "power user", I really appreciate this attention to
detail. I don't know if a "conventional OS" can ever do this. X, SunTools
and the like don't. Of course, the downside is all the things you've
mentioned...

I'm sure we've had this conversation before... :-) I love my Mac. You love
your Amiga. But I'm all for healthy discussion of these kinds of issues...

>Peter da Silva

		Nick.
--
Nick Rothwell,	Laboratory for Foundations of Computer Science, Edinburgh.
		nick@lfcs.ed.ac.uk    <Atlantic Ocean>!mcvax!ukc!lfcs!nick
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...while the builders of the cages sleep with bullets, bars and stone,
they do not see your road to freedom that you build with flesh and bone.