Raven. A homemade Atari-like computer

[agranlund]

At 256 colors there are a lot of artifacts:

Hmmn, that looks like it could be something caused by the bank-switch code not working as intended.
I tested that stuff on my GD5426 and perhaps there are differences between the models that I did not know about and take into account.

[Oldskool]

Keep in mind that blitter and other hardware 2D acceleration features didn't appear until GD5426.
But the older GD542x cards were still good MS-DOS performers so in the context of Atari they're probably as good a pick.

Did some benchmarks on my dx2. The Isa cards perform similar although the et4000 cards seem to have 1 or 2 fps more in Doom (Max screen) VS the gd542x cards or mach.
Performance seems to max out in the range of 16-18 fps. On a vlb gd542x I almost reach the max of the game at about 30fps. Some benchmarks show a 2x.

I can imagine for pure dos that et4000 is king on the isa bus although the isa bus is severly bottlenecking performance on the dx2. (And Raven)

[agranlund]

Did some benchmarks on my dx2. The Isa cards perform similar although the et4000 cards seem to have 1 or 2 fps more in Doom (Max screen) VS the gd542x cards or mach.
Performance seems to max out in the range of 16-18 fps. On a vlb gd542x I almost reach the max of the game at about 30fps. Some benchmarks show a 2x.
I can imagine for pure dos that et4000 is king on the isa bus although the isa bus is severly bottlenecking performance on the dx2. (And Raven)

Yeah absolutely! VLB was a huge upgrade for MS-DOS gaming.
Some games hurted more than others by the ISA bus and I think Doom was especially so on machines with fast cpus.
They used planar mode-y which probably made sense back then, trading an increased bus cost in favor of lowering cpu cost (and double buffering on the card etc)

For the Raven port you'll reach much higher fps even on ISA as it only ever writes to the card and in chunky mode so no slow I/O port access is needed either. Eg, the port has the luxury of knowing that it can prioritize minimal bus penalty since it knows everything else in the system is faster.
So game renders to fastram and pushes the 64Kb to the gfxcard after each game-frame.
(The same with Tyrian which also maintains 30fps easily that way even over ISA)
I would guess a PC port doing the same would probably benefit equally?

Edit: apparently there is such a port already. Doing the same thing, which is the only thing that makes sense when the bus is the bottleneck

In FastDoom, Mode 13h uses a single framebuffer in RAM, which is copied to VRAM after the entire scene is rendered.

I believe ID went away from the planar stuff by the time of Quake, or maybe even Hereic, where it no longer made sense to trade higher bus cost for lower cpu or ram cost.

But for sure, for most PC 486 games you wanted fast everything. Not just raw mem-write speeds but also read, as well as I/O port speed especially if doing planar Mode-X or the like where you needed to do a bunch of IO access too.
On Raven, or a fast 486 for that matter if the game only cares about that as a target, only the cards ability to do fast zero-waitstate mem-writes really matter (for 320x200 games)


Also.. your talks of dx2 really makes me want to build one
For some MS-DOS and Windows 3.1 fun!

[Cyprian]

Backporting is probably not advisable since it relies on running the x86 vgabios and that's a bit of a dealbreaker on a stock 68000.

I use ET4000 (Nova interface and Idek's drivers) in my Mega STE and booting time is acceptable.
And it would be a nice to have a new accelerated video cart for it.

[Mikerochip]

Also.. your talks of dx2 really makes me want to build one
For some MS-DOS and Windows 3.1 fun!

Blasphemy!!

I guess, coming to PCs late. (I got a samsung laptop in 1996, and built a P200MMX in 1998, with Voodoo II eventually!)
I never really got nostalgic for early (non-3D) PC gaming the way other people do.
Anything before vga and soundblaster just ran better elsewhere. (eg Amiga )
And, EGA stuff ... looked worse than the ST

It's big, bulky, slow and ... ???

I was quite interested in the tiny Llama project for a bit, but, even then, it's just a single board computer, on a breakout box.
Little different to a raspberry pi and dosbox ... (Well. No, not true. It's a lot different, but, still just ... a crappy DOS PC )

I'm sure people will lynch me for such an opinion

Coming from the ST, and seeing the Amiga, then Super Nintendo...
We got Sonic and Super mario world in 1991? '92? 8 channel stereo sound with 256 colour graphics for $300.
PCs seemed very clunky at the time.
And nowhere near the Amiga, especially in terms of sound and graphics.
But, well, Soundblaster, and eventually 3DFX changed all that, didn't they...

How about, one of those ISA cards with a 486 on it??
Integrate it into the Raven...

Something like the Bridgeboards, on the Amiga...

Now, *there* is some fun

[agranlund]

@Mikerochip you're probably right about all the things you said but nostalgia is strong
(why else would we still be playing with Atari when the equivalent Amiga was objectively better at.. everything? )
But yep, consoles were way ahead on all fronts but it's funny I never saw it that way back then. I was only interested in computers.

I went from stock Atari ST to 386SX, then 486DX2, and after that it's hard to keep track because technology started moving so quickly and it was easy to upgrade the machine piece by piece between needing a new motherboard. It feels like we stuck around the ~50-100mhz mark for quite a while and then it somehow exploded and we jumped several hundred Mhz per new generation..

Windows 3.1 nostalgia is for me quite big
But even more so MS-DOS and the 386/486 era of MS-DOS games.

But fair to say the time when I had the Voodoo3 is really strong in memory too.
I suppose many people today share the same feelings as those 3dfx cards are not cheap today.

Raven is basically that for me.. Atari, but influenced by the 386/486 times with interesting expansion cards that slowly by steadily competed with finding new ways of overcoming old limitations and crappy bus speed by improving the hardware.
And the almost zero common standards for all but the lowest common denominator stuff, nor unified driver stuff (until Windows saved the day)
So.. shit for the user and maybe even worse for developers, but it's so much part of the charm from that time

[PhilC]

We need an Amiga emulator

[agranlund]

We need an Amiga emulator

I hear Aros is open source, cross platform, and builds for 68k Amiga.. hint hint
I’m not strong enough to tackle such a beast but wouldn’t it be pretty cool to ”steal” their OS. They have EmuTOS on the Amiga after all.

[PhilC]

We need an Amiga emulator

I hear Aros is open source, cross platform, and builds for 68k Amiga.. hint hint
I’m not strong enough to tackle such a beast but wouldn’t it be pretty cool to ”steal” their OS. They have EmuTOS on the Amiga after all.

Oh if only I had that sort of programming skills.

[Mikerochip]

@agranlund Weellll, funny you say Voodoo ...

I went Atari XEGS, ST, SNES, 166MMX, 200MMX, K6-300, K6II-500.
CL-GD5424 (I think!), ATi Mach 32 (hated it!!), Matrox Mystique 220, then back to the Millennium but, added 1x Voodoo II and eventually, Voodoo 3 3500.
Same with sound.
A shuttle Hot... something. OPL3 ISA card, then Ensoniq PCI, Soundblaster Live! With 5.1 speakers, etc etc etc.

Exactly as you say, it was much easier to upgrade a component, one at a time.
Despite my whole tirade...

I still have both my Voodoo II cards here
And, a PCI Matrox Millennium II (2mb I think?)
Just itching to go back into a machine.

And, an Ensoniq PCI card, along with a Soundblaster Live! and X-Fi

While browsing ISA video cards... (And ignoring the fact I still have no ram or processor... *shh*)
I've been looking at Socket 7 and Super Socket 7 motherboards too.

So. Some slight hypocrisy there, on my part

I did, though, switch over to 2D consoles when I, strangely, got my first one...
A Gameboy. Original, 1989 model, with horrible headphones and Tetris.
I was hooked!

But, gaming changed forever, when Street Fighter II was released.
I'd never seen anything like it.
Despite the fact that the ST port was ... not exactly playable, I had to own it!
And I played it a bunch, until I could afford a Super Nintendo

But, yeah. Nostalgia is a strong pull.
That's why I *still* play the Atari ST version of Prince of Persia.
You're right... the Amiga version is probably better. But, I'll never know

@PhilC ... the Amiga users got an Atari ST Emulator! It's only fair we get one back