From: u894776@bruny.cc.utas.edu.au (James McCoull)
Subject: Re: NEW AMIGAS!
Organization: University of Tasmania, Australia.
Date: Thu, 3 Sep 1992 22:39:51 GMT

cadwallader@forty2.enet.dec.com () writes:

[Your arguments are futile.  I own both an archimedes and an amiga, and am
 a hardware level coder.]

>	He didn't mention that the "wonderful" OS can ONLY multitask from
>the desktop - which is a "slap on the top" affair, window, icons and such 
>aren't an integral part of the whole lot. Start something from the CLI -
>don't expect it to run WIMP & multitasking! Also, features such as
>multitasking filing/formatting have only be availabel in the latest OS -
>we've come to grow up with a FULLY multitasking OS!

BOLLOCKS.  A little truth but mainly bollocks.  Yes RiscOs is similar to
MacOs, in the way that it is a cludge.  But strangely enough I am sick of
people telling me how good AmigaOS is.  I dunno what they teach other people
in software engineering these days, but AmigaDOS and graphics.library
are not my ideas of well designed components.  Frankly its not the OS
that counts but what you can do with it - both programmers and users.

>	Nor did he mention that the 256 graphics are not true colour, they are
>a kind of EHB mode with limited palette selection - to claim else is complete
>crap! I don't think he would have liked to have mentioned how much CPU time
>running 8-bit sound channels and hi-res graphics takes up. I have seen many
>Arcs (friend's) and have not been impressed as I was expecting to...

Running sound and graphics takes *zero* cpu time.  Of course they do take
memory bandwidth.  Its fairly simple to calculate - take your bus speed,
the width in bits - work out the effective rate.  My machine has a 32megabyte
per second bus system, thus 1280x256x256 leaves me with about 1/2 the bandwidth,
on my amiga 640x256x16 leaves me with under 1/2 chipram bandwidth - and an
interrupt latency of about 200+ memory cycles.  Yeah fastram helps... but
the interrupt latency is still there.  Sound only takes as much memory
cycles as is required to fetch the data.  Yes there is only *one* dma
channel, but 8 sound channels.  You tell me if the new amigas have better
sound than this.  Interleaving 8 sound channels on a vblank/double buffered
basis is trivial, and takes few cycles.

>	I remember a funny occasion: 2 other Amigans & I were watching an
>Arc demo and a small yellow ball rolled around a scrolling screen then fell 
>into a box of about 7 others that bounced around. The owner looked at us and
>said "You couldn't get that many things moving at once on an Amiga!". We
>took him and showed him Shadow of the Beast and Red Sector MegaDemo!!! :-)

	The quality of demos, depends mainly on the size of the demo scene.
Look at a good atari demo - its almost as good as an amiga demo.  You are
refering to one of the earliest demos on the archimedes - the early amiga
demos were *no* better.  As a coder on both the amiga and the archimedes, I
can safely say yes the amiga hardware is *beautiful*, but unless *all* of
it gets upgraded, and a few modifications are made [blitter reversals,
blitter coprocessor, proper polygon fills] - then it will continue to fall
behind.

>	In all cases I have not been impressed by the Arc, Arc owners HAVE
>been impressed by Amiga.

	Yes, and no.  Yes the amiga 1000, is the best machine I have ever
seen for its time.  But it is *seven*+ years old.  I expect a new machine
with between 4x and 8x faster chipmemory system.  No one would dispute that
vector graphics *crawl* on the amiga - even brain dead 386sx with cheapest
video cards can do faster vector graphics - and the archimedes can do
much much much much faster vector graphics than the amiga.

>                         Falcons, Arcs, whatever still rely on the CPU for
>things that the Amiga can ask the best bit of kit ever to do - the Copper.
>Scrolling and raster interrupts are a pig on the Arc. Just ask the Copper
>to do something at a point on the screen and it does it!

	Scrolling a pig on the arc?  I think NOT.  I have full directional
1-pixel hardware scrolling going - I admit not many people have worked out
how to do this.  Of course the arc has no dual playfield or anything cool
like that - but with even a 4mips arm2 cpu, I can *render* dual playfields
with plenty time to spare in one frame.
	Raster interrupts, are not a pig on the Arc.  Seeing as the arm2
has a significantly less costly interrupt handling than the amiga or the atari
raster interrupts are fairly cheap.  Of course if the raster interrupts are
just used to change colours - then the amiga almost wins, because it can
just use the copper - if the amiga really needs interrupts then it loses by
a huge margin.

	Yeah the copper was great.  How many scan lines do you think it will
take "yesterdays" copper to change 256 palette registers?

>	Amiga has the ONLY truly multitasking OS! (from day 1), it has 
>superb custom chips that are about to be superceded.
>	To do copper effects,
		Yeah just checkout the new copper its changed.  NOT!
>	concurrent sound DMA,
		Yeah yeah... but surely a faster cpu, and then vertical blank
		buffering is the more intelligent design decision?
		How much do you think the new sound has improved?
>	scrolling,
		Yep, got this on the arc.
>	sprites,
		Ok... only *one* sprite on the archimedes, for the cursor.
		The new amigas sprites are nice - but sprites arent that
		great for most things. [Sprites would be cool for pop-up
		menus tho - so you don't have to lock layers].
>	BOBS,
		Ok more efficient using blitter than general purpose cpu
		but my arm cpu is fast enough to outblit a 280ns cycle, 16 bit
		wide blitter.  [Guess what the new blitter looks like?]

>	lines
		My line routine on the arc - costs me 6 cycles [@8MHz]
		per pixel - in 256 colour mode. - The amiga doesnt even
		come close.  Talk about texture mapping, or simple polygon
		fills... and the amigas hardware starts to quake.

> (and then something
>with the CPU :-) ) would be impossible on an Arc IMHO.

Not impossible at all.

I do agree that the amiga 1000 - was the most awesome machine for its time.
However when you design a machine, with high performance hardware engines -
you must make a commitment to keep the hardware moving.  Its more costly,
and from all accounts - some companies just don't have the bottle for it.

CBM management sucks - CBM employees are great.
Check out the new AA amigas.
Newsgroups: comp.sys.amiga.advocacy