VOGONS


First post, by Joeb

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Hey everyone,
Not too long ago I acquired an IBM 5170 with a 5153 monitor.
My goal is to play the old sierra games in CGA mode, which is how I experienced them as a kid.

When I launch Space Quest this is what I get:

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If it hit CTRL R I get it in color:

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This is definitely not how I remember CGA looking as a kid. I played this game a lot. The was limited colors but never the busy horizontal lines, Roger Wilco was very clear on the screen.

My big questions are: Why is it defaulting to Monochrome every time I run it? And why does the color image look so bad?
The system came with an STB Systems Graphix Plug II video card.

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I found the manual and the switch settings are set to 'color only'.

I also replaced the bios with an AMI to get support for a 3.5 floppy.
https://www.minuszerodegrees.net/bios/bios.htm#5170
Here's the video settings in the CMOS setup.

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I'm aware of the 5170 having a switch on the motherboard for color of monochrome, I have it switched to color.

The only other potential issue I can think of is the memory expansion card, I can't find any documentation on this card but it appears to have a built in parallel port and Video.
It's an Emulex Persyst card. I can post an image if anyone thinks it could be the cause.

If anyone could help I'd really appreciate it, I don't have a ton of experience with these early systems and it's been fun hobby trying to get this thing working. At this point I feel like I'm out of options.
Thanks for any help, it's much appreciated!

-Joe

Reply 1 of 11, by Jo22

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CGA can indeed be that ugly. It's "CGA RGB" graphics.

https://www.mobygames.com/game/114/space-ques … hots/dos/21864/

The monochrome thing is strange, though. Maybe a software issue.

I'm using Quadtel BIOS in emulation, btw. 😀

Edit: Now that I think of it.. Maybe Space Quest is using NTSC "artifact colors", which usually consists of a monochrome signal and special stripe patterns.
Just attach an NTSC TV via Cinch, err, RCA..

"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//

Reply 2 of 11, by Great Hierophant

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There is nothing wrong with your game, your graphics card or your computer, it is your monitor that is lacking the proper functionality in this instance. You need a composite color monitor or TV, then run the game as plugged into the RCA jack on that video card and you will see color. Do not use Ctrl + R. Whether the color is correct or can be made correct may depend on that TV's tint control.

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog

Reply 3 of 11, by Joeb

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This is interesting, unfortunately I don't have a CRT that takes composite. If I want to view this on my monitor properly, do I need a different CGA card?
My memory of how this should look it similar to what we're seeing, but without all the dithering of pixels.

Reply 4 of 11, by Great Hierophant

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You need an EGA card for an IBM 5153, then you can see the game in all its 16-color glory.

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog

Reply 5 of 11, by mkarcher

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Joeb wrote on 2023-02-28, 17:32:

This is interesting, unfortunately I don't have a CRT that takes composite. If I want to view this on my monitor properly, do I need a different CGA card?

I am not aware of any CGA card doing composite artifact color emulation on the RGB output. I'm also not aware of any EGA or VGA card doing it. There are NTSC-to-VGA and NTSC-to-HDMI converters with minimal latency, like the RetroTINK that you could use to display the composite picture from your CGA card on a modern monitor. It seems those converters are currently not available due to the chip shortage, though.

Reply 6 of 11, by Joeb

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Maybe my expectations are wrong. When I was a kid I swear I played Space Quest with 4 color CGA graphics, but the colors were solid. There was no dithering effect, as least not like we see in the above screen shots.
Our family had an IBM clone with a CGA monitor (or so I was told) It wasn't a composite TV, it took the 9 pin monitor cable.
I've seen screen shots of other game in CGA and they look accurate to what I remember, but the Sierra games look pretty bad.
Is there a better version of CGA out there or is my memory failing me?

Also I didn't realize the IBM 5153 would work on an EGA card. I thought it was meant for CGA only.
That's something I might want to try.

Reply 7 of 11, by Jo22

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Joeb wrote on 2023-03-01, 00:59:

Maybe my expectations are wrong. When I was a kid I swear I played Space Quest with 4 color CGA graphics, but the colors were solid. There was no dithering effect, as least not like we see in the above screen shots.

Not necessarily. It depended on the setup back then.
Red/cyan/white/black 4-colour CGA was very common on PCs not fully CGA compatible.

Or maybe, you had a different version of the game - Sierra games had a lot of different interpreter versions over the years.
The re-release versions use much newer versions, for example.

Early AGI Sierra games will try to autodetect your setup, but you can use override switches.
Like using SIERRA -T to force Tandy 3-Voice sound on systems without Tandy 1000 graphics.

Edit: I've attached pictures with the SIERRA -C override switch (DOSBox, S3 SVGA).
Maybe that's what you remembered back then.

Edit: The -C switch may also work the same with an EGA card.

Joeb wrote on 2023-03-01, 00:59:

Our family had an IBM clone with a CGA monitor (or so I was told) It wasn't a composite TV, it took the 9 pin monitor cable.
I've seen screen shots of other game in CGA and they look accurate to what I remember, but the Sierra games look pretty bad.
Is there a better version of CGA out there or is my memory failing me?

Joeb wrote on 2023-03-01, 00:59:

Also I didn't realize the IBM 5153 would work on an EGA card. I thought it was meant for CGA only.
That's something I might want to try.

It's other way round, maybe, actually. The IBM EGA board could do CGA timings for video resolutions below of EGA (640x350 16c).

The CGA card can do 16c on that monitor, but only in text-mode.
The EGA board just makes full use of RGBI (i=intensity) on same monitor.

Some IBM EGA boards, however, merely had 64 of 256 KB installed and couldn't do all resolution/colour combinations.
VGA cards, however, started with 256KB.

If your main goal is getting that monitor of your childhood to work,
you can look for old ISA VGA cards with a second 9-pin port.
They usually can be hardwired to CGA, EGA or Hercules modes/monitors.
That way, you can get out of the most of your monitor.

Also interesting are the ATI Small Wonder and EGA Wonder series.
They're not VGA cards, yet, but can emulate different video modes on the "wrong" monitors.

PS: The CGA card is nice, per se. With a Commodore 1701/1702 or similar video monitor (American NTSC models),
you can have a nice Composite CGA experience.
So please don't sort it out, if you decide to use that monitor with a different card. 🙂

That being said, The Geat Hierophant knows much more about the matter, even runs a fascinating blog, afaik. 👍

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"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//

Reply 8 of 11, by Joeb

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Or maybe, you had a different version of the game - Sierra games had a lot of different interpreter versions over the years.
The re-release versions use much newer versions, for example.

I have a feeling I played the early version of SQ1.
https://tcrf.net/Space_Quest:_Chapter_I ... roids_R_Us
The difference between versions seems subtle, but I'm pretty sure I saw a "Droids R Us".
I also remember getting stuck for a long time because I didn't know the box I needed to push was called a "trunk".

Edit: I've attached pictures with the SIERRA -C override switch (DOSBox, S3 SVGA).
Maybe that's what you remembered back then.

The first image is the closest to what I remember, though I think the 4 colors used were different.

Edit: The -C switch may also work the same with an EGA card.

It's other way round, maybe, actually. The IBM EGA board could do CGA timings for video resolutions below of EGA (640x350 16c).

I want to get a hold of an EGA card and try this out. That may be my next step.

Some IBM EGA boards, however, merely had 64 of 256 KB installed and couldn't do all resolution/colour combinations.
VGA cards, however, started with 256KB.

This is good to know!

If your main goal is getting that monitor of your childhood to work, you can look for old ISA VGA cards with a second 9-pin por […]
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If your main goal is getting that monitor of your childhood to work,
you can look for old ISA VGA cards with a second 9-pin port.
They usually can be hardwired to CGA, EGA or Hercules modes/monitors.
That way, you can get out of the most of your monitor.

Also interesting are the ATI Small Wonder and EGA Wonder series.
They're not VGA cards, yet, but can emulate different video modes on the "wrong" monitors.

Thanks for all your help! I'm going to try different video cards and see if I find what I'm searching for. If I do I'll post my findings here!

Reply 9 of 11, by Great Hierophant

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Space Quest I and every other AGI game shows only two types of graphics with a real CGA card and an IBM 5153 :

This is the default presentation if you run the executable with no switches :

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These graphics are only intended for composite color monitors and TVs, are wrong for a 5153 and on composite color displays they show colors like this :

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This is the alternate CGA graphics display, which you can see if you run the executable with the -r command line option or hit Ctrl + R in game :

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These graphics are intended for RGBI displays like the 5153 and the best a CGA card can do with an RGBI monitor.

Anything Jo22 showed using a light cyan/light magenta/white palette is EGA trying, and failing, to simulate CGA using the high-resolution composite color graphics mode.

These are the only graphics an EGA, Tandy, MCGA or VGA should show :

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And finally, if you had a Hercules Graphics Card and an IBM 5151 display, you would see this :

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Any other kind of graphics are wrong or not contemporaneous with the games. (Text fonts may vary depending on the system).

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog

Reply 10 of 11, by Jo22

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.. I can think of a few other possibilities.
a) Joeb's version of back then was, err, "patched" or incomplete (not that uncommon back then).
b) The CGA board from back then was an unusual clone or enhanced version (Plantronics or similar).
c) The board in the old PC was EGA, but lacking video RAM.
Because of this, the IBM EGA tried as best as it could to display EGA.
Maybe that's why it showing unusual colours or lack of colours.
(The game graphics are low-res, but the AGI interpreter likely tries
to use an higher resolution mode to draw text in fine quality) .
Early EGA software used merely 8 colours, maybe because of this ? 🤷‍♂️

"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//

Reply 11 of 11, by Great Hierophant

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Sierra's AGI engine games use a 320x200 resolution with 16 colors on EGA, PCjr. or Tandy. This mode requires 32KiB of RAM to hold a page of graphics data, with each pixel taking half a byte to represent (320 x 200 x .5 = 32,000 bytes). Even an unexpanded IBM EGA card with 64KiB can display these games correctly and do so. A Tandy 1000 or PCjr. require 256KiB of conventional memory to run AGI DOS games because they use a portion of conventional memory for their video memory.

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog