From: tsarna@endicor.com (Ty Sarna)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: OS/2 vs. AmigaOS (was Re: Amiga 4000/Atari Falcon)
Date: 29 Aug 92 00:32:12 GMT
Organization: Endicor Technologies, Inc., San Antonio, Texas

In article <1992Aug28.175748.42640@kuhub.cc.ukans.edu> thompson@kuhub.cc.ukans.edu writes:
> OS/2's Multimedia extensions probably qualify it as a real time
> system.

Well, I don't know what these extensions are, so I can't comment. I've
never seen the "multimedia extensions" for a number of OSes really well
described, and it seems to be somewhat of a blanket term. Then again,
multimedia seems to be somewhat of a blanket term.

> I don't think IBM sat down at the table one day and said, "Let's not
> make OS/2 a realtime os."  Having VM does not mean you can't have

No, I don't immagine many companies do.  They decide "these are the
features we want", and those features which aren't on the list or which
conflict, at least enought to make implementation difficult or too time
consuming, don't make it in. 

> a realtime os.  VM can be turned off.  You can lock an application
> in memory.  Etc...

Which is exactly what I said. Some operating systems even let VM and
realtime exist for the same task, though I'm not sure quite how.

> Well, you just turn off background execution in OS/2, and then the
> task doesn't run "at least once in a while."  There is no tradeoff.

Yes, there is a tradeoff.  If you always did or didn't want background
execution then the ability to choose wouldn't have been put in as a
feature, would it? :-) Obviously, there's a tradeoff there; sometimes
you want it, and sometimes you don't.

> VMS uses virtual memory.  You said it was realtime.  It is a pretty
> run of the mill os.

Yup, and it's an example of the realtime/VM systems. As I said, they do
exist.

> What can be guaranteed in a multitasking system?  Even with no VM,
> task A can be done in by task B, unless task be is suspended.

Not true. If that were the case, there would be no such thing as
realtime. If you want to make that claim, it's your job to prove it. I'm
sure you'll get plenty of disagreement from all the realtime programmers
out there.

> As said earlier, realive to what?  

Relative to more featureful OSes with VM, MP, etc. Again, it's a
tradeoff. OS/2 provides tons of functionality with a commensurate
overhead incurred. Writing 80x86 assembly that goes to the hardware for
everything gives you no overhead and no functionality to build on.
Sometimes you want that. Sometimes you want the features. You pick the
system that best suits your need and you use it. No one system is
perfect for every application, or even most applications.

> I think we all can agree on what real time is.  The question before us
> is why you think AmigaOS is real time and OS/2 is not.  I don't agree.
> I would invite civilized debate on the subject.

I didn't say that OS/2 isn't. I said that OS/2 with VM certainly isn't,
and that I believed that it wasn't under other circumstances either, but
apparently that's wrong (though anyone has yet to prove it. personally,
I'm willing to take you're word for it, though you won't extend the same
curteousy to me)

> > you attack me for that. Do you know which system I use and/or prefer?
> 
> What difference does that make?  You could prefer an Osbourne computer,
> but that doesn't change the central question.

I was trying to point out that I'm not the enemy. I agree that OS/2 2.0
is a reasonable OS with more built-functionality than AmigaOS and that
it is a valid choice for users. If I were given the choice between DOS,
Windows, and OS/2 2.0 I would certainly choose OS/2. Others might have
different needs. A secretary who only types letters into WordPerfect
should probably choose DOS. The Amiga too is a valid choice, as is Unix,
the Macintosh, and many other systems. I merely wanted to discuss
tradeoffs, not start a religeon battle.

---
Example tradeoff and difference in philosophy between the two systems,
and the kind of discussion I'd like to see:

OS/2 provides all sorts of different IPC mechanisms.  The Amiga OS
provides one.  OS/2 gives the programmer the choice of the best
mechanism for his needs, while the Amiga programmer has to roll his own
if he wants something different.  The Amiga only has one base system on
which others can be built and is thuss lean and mean, while OS/2 is
bloated a little by throwing in everything.  OS/2 only has one
implementation of a specific form of IPC, while everytime the Amiga
programmer wants an implementation there's yet another one written.  The
Amiga programmer isn't bewildered by all the choices everytime he
reaches for the OS manual, while the OS/2 novice might well be.  And so
forth...  Every coin has (at least) two sides.  Sometimes OS designers
choose to merge two different paradigms.  For example, mmap() under some
versions of unix merges some shared memory and some VM features and
blurrs the lines a bit.  That has yet another interesting set of upsides
and downsides. Devices-as-files is another example of somthing that was
once radical but now doesn't get a second thought.

--
Ty Sarna				           tsarna@endicor.com

	"Staring faces, set in celluloid,
		Welcome to the late show, starring null and void"
Xref: sparky comp.sys.amiga.advocacy:23090 comp.sys.amiga.misc:13434