Hi, I think some ATI Wonder cards had auto-sensing for monitor..
The rest needs the correct DIP switch setting for the monitor, I think.

For genuine IBM EGA and faithful clones:
- set the DIP-switches for the MDA monitor
- keep in mind that only modes 7 and F are supposed to work

Some later EGA clones may be configured in software instead of DIP-switches, and may support more modes on the MDA monitor.

Unfortunately, games rarely use these modes. Windows 2 and paint programs, might, however.

Mode 7 is Hercules Monochrome and Mode F is the exotic "640×350 pixels in monochrome" mode.
In essence, both modes are mono with 350 lines.

An ATI Small Wonder might be better for gaming on an MDA monitor, but it can't do EGA.
So an ATI EGA Wonder 800 makes more sense, maybe. Not sure if it can do 640x350 16c EGA on an MDA monitor, though.

An original IBM EGA is nothing for the faint-hearted, I think.
It usually doesn’t have the full 256 KB of video memory by default, for example.
And the special memory upgrade board is very costle. 🙁

I figured it out. What I don't understand is why the output is so ugly? Like every second line is missing. See attachment. One image is normal Hercules while the other is EGA pretending to be Hercules.

Half-Saint wrote on 2024-11-14, 10:05:

What I don't understand is why the output is so ugly? Like every second line is missing. See attachment.

Characters are 8 scanlines high = 200 scanlines total.
Looks like your EGA card is configured for CGA monitor.

Grzyb wrote on 2024-11-14, 11:45:

Characters are 8 scanlines high = 200 scanlines total.
Looks like your EGA card is configured for CGA monitor.

Exactly, and that monitor obviously is capable of syncing at 15.6kHz, which is not true of every MDA-type monitor. There were some dual-mode monitors that could sync to CGA frequencies for CGA graphics and MDA frequencies for better text mode. Compaq for example had a graphics card that would run text modes at 350 lines and CGA graphics at 200 lines.

mkarcher wrote on 2024-11-14, 17:39:

Grzyb wrote on 2024-11-14, 11:45:

Characters are 8 scanlines high = 200 scanlines total.
Looks like your EGA card is configured for CGA monitor.

Exactly, and that monitor obviously is capable of syncing at 15.6kHz, which is not true of every MDA-type monitor. There were some dual-mode monitors that could sync to CGA frequencies for CGA graphics and MDA frequencies for better text mode. Compaq for example had a graphics card that would run text modes at 350 lines and CGA graphics at 200 lines.

Ooh, that's interesting as a topic! That reminds me of the EGA Wonder which had the ability to output CGA/EGA via Composite in monochrome.
But there was a catch! The EGA 640x350 mode was not supported as 15 KHz interlacing video, but as a custom video signal.
That's because the output was meant for use with the internal monitor of a portable computer (Compaq?) which was dual frequency.
That in turn meant that users of a conventional video monitor couldn’t enjoy EGA in 640x350, but all other standard resolutions seemed to work. Except VGA modes 11 and 12, of course.
The manual of the card has further information on this, I think.