get a trident card?
those were really compatible with DOS games, not like ATI

I have a trident card but the image-quality is REALLY bad. fuzzeling lines on spaces with the same color on tft..bah!
et4000 from diamond (SpeedstarVGA) is superbe against that trident-card. In another thread I found a patch. I'll check this.

Old ATI should also be fine, but ATI-Wonder does not work with A2286 and I don't own an ATI Mach32/1MB.
The ATI's have excellent image-quality and they are 100% centred on tft. On et4000 when textmode 80x25
and ega-lowres 320x200 are 100% centered, the lowres VGA 256colors is 0,5cm off right. there is no way of fixing that.

dr.zeissler wrote on 2020-06-02, 06:46:

on my setup keen seems to be OK but crystalcaves&dangerous dave have issues with ET4000/1MB.

I doubt that anybody would be able to help you if you don't tell us what those "issues" are.

Try to be as precise as you can be. Don't leave out any information. Tell us which entry/entries of the Dangerous Dave series and which episode(s) of Crystal Caves you're talking about. Screenshots and/or videos showing off these issues might also be of great help.

dr.zeissler wrote on 2020-06-02, 14:06:

A2286

If you're trying to get this combo of games and video card to work on a system that might not even be 100% IBM PC compatible to begin with, I would suggest eliminating that factor first. And by that I mean you should put that ET4000 into a "real" 286 PC and see if the behavior changes at all when trying to run the same copy of these games.

I thought I did tell you exactly what the issues are, but it's gone...so I'll do it again.
The A2286 is a REAL 286/8Mhz and afaik it behaves like a real machine.

The "patcher" requires Win9x so it refused to work on the A2286 Dos5 and also on my main PC 486/DX2/66 Win95a,
so I need to setup a Win98se Machine on the following weekend to try to run the patch on ccaves and try it on my A2286.

In crystal-caves1-3 on my A2286 I get either a flickering screen while mooving or a flickering HUD (setting "alternative mode" on/off in the game).
Beside that I noticed a smooth scroller downwards on the intro-screen and upwards it's obvious not that smooth. (has some hick-ups)

On dangerous-dave hunted-mansion the screen get's either a shadow on 1/3 from above that stays until I press quit,
or I get strange flickeriing text-characters in different colors that also stay until I press quit/or go back to the menu.
All I need to do is one "jump" in the game and after that I get those erros described above.

If you like I make a video of that this weekend.

Greetings
Doc

I have never seen or used an A2286, but based on what I've heard, it's a 286 add-on for an Amiga 2000 (or an Amiga 2000 with a 286 card in it). But having the same processor as the IBM PC doesn't necessarily mean that the entire system is fully compatible with the IBM PC. That's why I suggested that you take the graphics card out of that system and test it in another system with the same games, preferrably booting both systems with the same boot disk and running the games from the same floppies on both the A2286 and the other system, so that we can be absolutely sure that the graphics card is the problem, not the A2286 itself or other programs running in the background. The 486 PC you mentioned should be able to use the ET4000 graphics card, which I would assume is an ISA card.

If the patch you're referring to is this one, then it won't help you fix the issues you're experiencing in Crystal Caves. That patch just prevents the game from stretching the first row of pixels from the top of the screen all the way down to the bottom of the screen. The patch doesn't do anything else.

By the way, if you're having trouble using my patching utility on Windows 95, then Windows 98 is probably not going to work either. The patcher works fine on Windows XP (32 bit) and Windows 10 (64 bit) and might also work on Linux via Wine (I haven't tested in on Linux).

As for the issues you are experiencing in Crystal Caves, there is probably no definitive solution that will work on all systems. It may be possible to modify the code and fix these issues for your particular system, but such a fix may cause problems on other systems. EGA compatibility was a problem even before the days of VGA and SVGA:

In truth, the EGA standard is less standard than, say, the PC standard, because the PC is built out of off-the-shelf hardware, not custom VLSI chips, and because the EGA video BIOS is twice as large as the entire PC BIOS. There's no solution to this, but broad testing is a reasonable substitute.

-- "Inside the EGA" by Michael Abrash, Programmer's Journal, January/February 1987

Your description of the errors in Dangerous Dave In The Haunted Mansion is not as precise as I had hoped. Which parts of the screen get corrupted, the top or the bottom? A picture or a video would have been more helpful. If the bottom part of the screen gets corrupted and the corruption flickers, then I would say that this sounds like an SVGA compatibility issue to me. Do you get similar issues in Commander Keen 4-6 or BioMenace with SVGA compatibility mode turned off? If so, you should try starting Dave 2 with the parameter "/COMP" to enable SVGA compatibility. Version 1.12 of Dave 2 should have that option. Use the "/VER" parameter to check which version of the game you have. If the "/VER" parameter doesn't show you a version number, then you have an earlier version of the game that probably won't recognize the "/COMP" parameter.

Thx for these informations. I'll make additional tests and perhaps a video next weekend.
As you said, the CrystalCaves-patch linked above does not fix anything for me, but the patcher runs fine with win98se.
BioMenace is not usable on that A2286, because it requires "stacks=9,256" in the config.sys and with stacks other like 0,0 I do not get the amiga-mouse working.
Keen1/2 seem to be fine, but I don't know what version I am using and what switches are active. Perhaps a video of that machine would be helpfull. (I also have keen 4-6)
DangerousDave Hunted-Mansion the upper part (1/3) is OK after a jump, the other part (2/3) is flickering or has wiered characters that also flicker.

Interestingly sometimes everything is OK, but that is only 1/20 times. It seems that this has to do with games I started before that change something.
I do experiment with vmode that comes with the diamond speedstartVGA. Vmode EGA sets the card in "ega-mode" but this is slower, the picture is smaller
but it does not help by the issues described above.

There are only 1or2 games that require setting to ega-mode, otherwise they don't start...but I can't remember what games that are...

Keen 1-3 use a different approach to the scrolling and therefore don't have SVGA compatibility problems at all. Keen 4-6 (and also Keen Dreams) use a method similar to what was used in Dave 2 and therefore should exhibit the same graphical glitches without the SVGA compatibility option.

The way to test if your system needs SVGA compatibility mode is to turn SVGA compatibility mode off, start a new game and then make the screen scroll up and/or to the left. If the bottom of the screen starts flickering and showing either black pixels or random garbage, then your system needs the SVGA compatibility option. If you don't get to see any issues like that, you can leave SVGA compatibility turned off, since having it turned on would just waste CPU cycles.

I am currently checking for another vga.-card in that A2286 solution to get the machine as good as compatible for old cga/ega/vga games and other software. Which ISA gfx-cards (chips) would you recommend me to test ?