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 Subject: RE: A New MIDI Atari?
Author: Johan Klockars (as28-3-8.va.g.bonet.se)
Date:   06-19-2003 02:57

> >> PC architecture is same old that in first 8086...
> > The programming model changed a _lot_ with the 386.
>
> OK...they change memory 64k-blocking to fake 32-bit thinks.

There's nothing fake about the 32 bit addressing on the 386 and up. You can set things up to behave exactly the same as on a 68k processor (but there's the additional option of using the segment/selector registers for memory protection purposes).

Anyway, the 32 bit addressing is only part of the difference between the 80386 and the 8086. The registers themselves have obviously been extended to 32 bits, there are less restrictions on which registers can be used for what, new instructions have been added, and even two new segment/selector registers (;-).

Incidentally, I've recently had the somewhat dubious pleasure of having to write various startup and initialization code for an embedded x86 Linux platform. I must say that getting from initial bootup to a 32 bit flat memory space in protected mode was easier and cleaner than I thought it would be (I had to get back into 16 bit real mode again too, but that wasn't much worse).

> >> there is no memorymapped-io,
> > Of course there is memory mapped I/O. That
> > not all hardware uses it is mostly a matter
> > of legacy support and convenience.
>
> Ok...but programs cannot use them Atari way.

Well, 'programs' can't really use either memory mapped or I/O mapped hardware under a real OS due to memory protection.

Memory mapped I/O is done in exactly the same way on an x86 as on a 68k.
On the PCI bus, for example, most things are usually handled with memory mapped I/O.

> OK. I have seen actually PC/Mac soundcard that have four DSP-chips, but and big but you cannot program them yourself.

Well, the supplied soundcard software usually does more than you could hope to implement yourself, and the main CPU is probably a lot faster in any case.

> >> no graphics in memory,
> >Thank God!
>
>If you see how Silicon Graphics do that, you wound say that way.

I know SGI used main RAM for graphics on at least some O2 models, and some x86 machine ( neither of my two (old) SGI machines do that, nor do any of their current models, AFAICS on their web site).
That was likely for price/performance reasons rather than actual performance, though, since you give up a significant amount of potential performance that way.

I found an old (well, August 2001) press release about an O2+ that claimed 2.1 Gbyte/s total for the unified memory system. That's not even one tenth of what you can get on a $400-$500 graphics card today (but the O2 could have more memory).

> And with Atari Falcon is very nice to make up and down scrolling with only set where videl reads graphics...of course double or trible buffering is nice too...

Neither of those have anything to do with the main RAM being used for graphics, and you can easily do both on even the old RageII used with the Eclipse.

> > (Some chipset built-in graphics hardware
> > does have that, though.)
>
> Problem is that PC cannot take real advantage of it.

What is the advantage you'd like to take?

There aren't a whole lot of graphics operations that aren't better handled by special hardware with its own memory, combined with fast block transfer from main RAM (via for example an AGP bus).

> >> no sprites...
> > Just about every graphics card has a sprite > for the mouse pointer.
>
> cool...at last...old cards don't

I don't know when they started adding mouse pointer sprites, but at least it's in the old RageII. It's a rather simple thing to do.

> > For more generic sprites you'll have to look
> > at some games consoles and their relatives.
>
> PS2 would nice architecture...

Does the PS2 really have sprites at all?
I would think that hardware like that would simply make use of its polygon drawing capabilities for that.
The data at http://www.consoleinfo.co.uk/ps2.html certainly seems to suggest that they are only talking about masked blitting.

> What would you classify as new and nice?
>
> how about PS2, Gamecube...SGi it's only nice, because architecture is actually old.

Neither the PS2 nor the Gamecube are anywhere near a modern PC when it comes to CPU performance. And the graphics hardware is a few generations behind as well.

What SGI are you talking about, by the way? They've been building computers for many years, so obviously some of their architectures might be considered old. They are still in business, however, and there's certainly no way anyone could consider the Altix 3000 (http://www.sgi.com/servers/altix/) old.

>> homecomputer at price 150euros/dollars like
>> I buy at 1985...
> useable PC's for $200 at various places in
> the US
>
> cool...(why they don't sell them in europe)...

Well, you should be able to put together something near that price yourself.

I just tried an online store in Sweden and was able to put together a pretty decent looking machine for about $300 (excluding VAT).

> > What do you want sprites for, anyway?
>
> It is nice if you can move thinks on the screen and you can draw under it without memory programming

Blitting things around on a graphics card is extremely quick. Even the old RageII used with the Eclipse does something like 50 Mpixels/s, IIRC.

Sure, sprites could sometimes enable you to move even more things around, but for what purpose?
IMO, sprites were useful for certain types of games in the day of non-accelerated graphics. Today, I can't really see a use.

> and it's save a lot memory bandwidth.

Not that memory bandwidth is likely to be a problem for 2D stuff on modern graphics hardware.

For that matter, I'm not so sure sprites would necessarily save you much, anyway, due to the effects handling them could have on the memory system (RAM page misses).
(Well, if you can keep a static background image in the sprite case, that would probably be a win. But even 1600x1200x32bit@85Hz is less than 1 Gbyte/s to move around, while current high end consumer cards have bandwidths in the 20-30 Gbyte/s range.)

 Topics Author  Date
  A New MIDI Atari? new GD 06-07-2003 19:59 
   RE: A New MIDI Atari? new mintboy 06-08-2003 03:09 
   any alternatives to x86? new replicant 06-08-2003 17:18 
    RE: any alternatives to x86? new Nate Downes 06-10-2003 04:00 
    RE: any alternatives to x86? new Alex 06-11-2003 16:44 
     RE: any alternatives to x86? new replicant 06-11-2003 17:56 
      reality and possibilities new Alex F. (not Alex) 06-11-2003 19:24 
       RE: reality and possibilities new replicant 06-11-2003 22:55 
        RE: reality and possibilities new Alex F. 06-11-2003 23:22 
         RE: reality and possibilities new replicant 06-12-2003 00:59 
    RE: any alternatives to x86? new Alex 06-11-2003 16:45 
     RE: any alternatives to x86? new Johan Klockars 06-11-2003 16:57 
     RE: any alternatives to x86? new Nate Downes 06-11-2003 17:20 
     don't get overheated; that's a x86 thing to do! new replicant 06-11-2003 18:09 
      RE: don't get overheated; that's a x86 thing to do new Ragstaff 06-12-2003 15:07 
    RE: any alternatives to x86? new replicant 06-11-2003 18:13 
    What about the PegasosII G4-1Ghz for 499,- EUR? new Henri 06-13-2003 17:56 
     RE: yummy new replicant 06-13-2003 18:43 
      RE: yummy new J.O. Aho 07-06-2003 18:15 
    RE: any alternatives to x86? new J.O. Aho 07-06-2003 18:02 
   RE: A New MIDI Atari? new Alex F. 06-09-2003 01:24 
    RE: A New MIDI Atari? new replicant 06-09-2003 02:39 
     RE: A New MIDI Atari? new Damion 06-09-2003 02:52 
      what type CPU? new replicant 06-09-2003 04:55 
       RE: what type CPU? new Damion 06-09-2003 23:16 
      RE: A New MIDI Atari? new tero 06-09-2003 18:31 
       RE: A New MIDI Atari? new Damion 06-09-2003 23:26 
        RE: A New MIDI Atari? new tero 06-10-2003 18:14 
         RE: A New MIDI Atari? new Damion 06-10-2003 22:45 
          RE: A New MIDI Atari? new tero 06-13-2003 14:55 
           I DO want to continue new replicant 06-13-2003 16:59 
            RE: I DO want to continue new Johan Klockars 06-14-2003 00:37 
             RE: I DO want to continue new replicant 06-14-2003 01:16 
            RE: I DO want to continue new Tero 06-17-2003 21:09 
           RE: A New MIDI Atari? new Johan Klockars 06-14-2003 00:07 
            RE: A New MIDI Atari? new Tero 06-17-2003 21:41 
             RE: A New MIDI Atari?  Johan Klockars 06-19-2003 02:57 
     RE: A New MIDI Atari? new Alex F. 06-09-2003 13:17 
      RE: A New MIDI Atari? new Damion 06-09-2003 23:31 
   RE: A New MIDI Atari? new GD 06-09-2003 10:06 
    RE: A New MIDI Atari? new Ragstaff 06-09-2003 13:47 
     RE: A New MIDI Atari? new velvetfr 06-09-2003 15:17 
      RE: A New MIDI Atari? new Alex F. 06-09-2003 16:12 
    RE: A New MIDI Atari? new tero 06-09-2003 18:50 

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