VOGONS


First post, by 0kool

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I'd like to play around with monochrome (green, orange, b&w etc) picture, but currently don't own an appropriate monitor. Does anyone know if there is a software solution for this? Not talking about just making DOS prompt green in nature, but a resident program that will process everything coming through graphics card (programs, games, Windows 3.1). Real hardware, no emulation.

Reply 1 of 3, by Jo22

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Hi, which graphics modes/systems do you think of ?
For VGA, there's the possibility to switch to monochrome mode (bw). However, it may only work for programs using BIOS routines.
If you'e looking for a hardware solution, too, it might be pissble to combine (resistors required)
the RGB signals from the VGA card to a single R/G/B line of your VGA monitor. Haven't tried this myself, yet, so be careful doing so.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 2 of 3, by 0kool

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Sorry for the delay, but the routine got the best of me.

Jo22 wrote:

Hi, which graphics modes/systems do you think of ?

Do you mean the machine I want to try this with (just an average P54 with S3 VGA card and CRT), or how I want it to behave (believe I already answered the question, I'll take what I can get)?

Jo22 wrote:

For VGA, there's the possibility to switch to monochrome mode (bw). However, it may only work for programs using BIOS routines.

How could this be achieved? Can you give me a few examples of what might work?

Jo22 wrote:

If you're looking for a hardware solution, too, it might be possible to combine (resistors required)
the RGB signals from the VGA card to a single R/G/B line of your VGA monitor. Haven't tried this myself, yet, so be careful doing so.

Sounds exciting, but I would expect that a lot of video data would be lost this way (due to complete loss of the 2 colors you'll have to ignore), don't you think?

So, I guess it's not as easy as I thought it might be after all. Makes sense. I expected there should have been a software utility for backwards testing for older systems. But it probably was too much for the hardware of the time and already irrelevant when P2-P3 came around.

Reply 3 of 3, by Jo22

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0kool wrote:

Sorry for the delay, but the routine got the best of me.

Jo22 wrote:

Hi, which graphics modes/systems do you think of ?

Do you mean the machine I want to try this with (just an average P54 with S3 VGA card and CRT), or how I want it to behave (believe I already answered the question, I'll take what I can get)?

Um, both, actually. The first one mainly, though. 😅

0kool wrote:
Jo22 wrote:

For VGA, there's the possibility to switch to monochrome mode (bw). However, it may only work for programs using BIOS routines.

How could this be achieved? Can you give me a few examples of what might work?

VGA has a convert to grayscale feature built-in. It was used when a monochrome VGA monitor was connected.
If a PC is switched on, the VGA BIOS willl check if such a monitor is connected (there's a mono pin on the VGA connector).
So if a monochrome monitor is connected, or no monitor at all, the VGA BIOS will switch to monochrome mode.
Normally, if you attach a monitor later on, the graphics output will still be monochrome.
Well-behaved programs like Norton Commander or the utilities that come with DOS 5/6 will still be monochrome.
Certain games, too. Abouth everything that uses calls to the BIOS or the VGA BIOS.
However, programs with their own drivers (Windows 3.1) will ignore that and appear in full colour.
It's possible to trigger that "convert to grayscale" feature of VGA cards/the VGA BIOS from DOS by using a little utility.
Not sure how such a program is named, though. There used to be lots of little utilities from shareware sources or BBSes.

Edit: Not quite what you're looking for, but might be useful - SETMONO and SETCGA.
These little utilities are comparable to MODE command in later DOSes (MODE mono and MODE co80).
- I found them on my fathers disks. Quick tests showed that they work on VGA cards, too.
When running SETMONO, Norton Commander looses all colour. SETCGA brings it back.
So I guess it should work okay with text mode games, too. Just keep in mind that it may be intended for
switching between MDA/Hercules and CGA cards, rather than changing only colour.
Anyway, it seems to work for our purpose on VGA systems.. 😀

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  • Filename
    setmono.zip
    File size
    230 Bytes
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    File comment
    Contains SETMONO and SETCGA.
    May work on any DOS version.
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//