Newsgroups: comp.sys.amiga.advocacy
From: dnavas@oracle.uucp (David Navas)
Subject: Re: Oh my God! Help my friend not buy an IBM!
Organization: Oracle Corporation, Redwood Shores CA
Date: Thu, 19 Nov 1992 17:10:07 GMT
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In article <1992Nov18.214850.16780@ncsu.edu> linville@garfield.catt.ncsu.edu (John W. Linville) writes:
>First, let me thank you for your well-reasoned, informed response...You moron!

Well, I know this isn't directed at me, but what you've posted isn't any
more informed.  Shame on you, speak to yourself in a mirror before you say
things like this....  [The Amiga guy was no better, but this is "his"
newsgroup, after all....]

>You're right that a ray-tracer (or any other CPU-bound process) will use as
>much CPU time that it can get until it is finished.  The point that I was
>making (and that you obviously missed) is that the OS should (and OS/2 does)
>keep the system responsive to user requests and should continue to give time
>to other running processes.  I know the AmigaDOS has this capability as well,
>but to maintain acceptable responsiveness, you usually have to manually lower
>the priority of the trace, and this often results in the trace taking FOREVER.

Let's take this example, shall we?
Ray Tracer in background, Editor in foreground:

Amiga:
    Ray Tracer and Editor get round-robin scheduled so Editor will get no more
    than 50% of the CPU.  If these are the only two tasks, it will also get
    no less than about 50% of the CPU....

    If you feel that 50% of a 25Mhz 040 doesn't flub your goose feathers in
    the right way, you've got a couple of options:
       Lower the priority of the Ray Tracer:
          Editor gets as much CPU as it needs.
          Ray Tracer gets the rest.
       Use JM and assign CPU percentages to your editor/ray tracer.
          Hopefully obvious (haven't used JM myself, dunno how well this works)

OS/2:
    Editor gets as much CPU as it needs.
    Ray Tracer gets the rest.  Exactly like Amiga case 2:

    If you feel that the trace is going too slowly, make the ray tracer a
    foreground process (is this possible?) and it will be round-robin
    scheduled -exactly-like-the-Amiga-

Would someone please tell me, besides the fact that OS/2 has a better -default-
option for handling bg/fg processes, what the devil the difference is here?

John, do you know what a "moron" you look like when you change the Amiga to
work -exactly- like OS/2 and then claim poor tracing speed as the problem?
Os/2 has this "problem" as the -default-.

Really, OS/2's advantages come when running many "background" processes, this
ray-trace example is hardly useful, as there is nothing that is significantly
different.

Again, I am assuming (stupid me) that OS/2 2.0's priority classing and
scheduling have remain unchanged from 1.3.  They may, indeed, have changed,
but I do not know exactly how.

If someone can give a technical discussion about how OS/2 2.0 does better
time slicing than AmigaOS, I'd be more than interested to read it.  Until
this happens, these purely subjective analysis posts are just grand-standing at
their worst.

>> I*M multitasks.  Amigas have been doing it for 7 years,
>> and they do it better!  Try to play a stereo mod file on IBM
>                 ^^^^^^
>That is a relative, and subjective, term.  My opinion is that since the Amiga
>doesn't protect running tasks from trashing each other, it does not multitask
>better than OS/2.

See, subjective.  Exactly the problem.  And you're right, the Amiga case, in
this discussion, is no "better" (#define better faster) than the OS/2 case
except if you want to take into account task switching times.  Which it is
my guess that Amiga's do faster than OS/2, but I do not have timings, anyone?

>Really?  So did you enjoy the Cray or the DEC Alpha more?

Trick question?  The Cray, of course, because it had that really spiffy
Silicon Gfx front-end "terminal" on it ;)
David C. Navas						dnavas@oracle.com
Working for, but not speaking on behalf of, Oracle Corp.