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Choosing the best video standard for your old PC (MDA/CGA/EGA/VGA)

Windows XP

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There are 4 different video standards that work on old PCs:
-MDA
-CGA
-EGA
-VGA

MDA
MDA only supports monochrome 80-column text. If you would like the least expensive video standard and don't care about no color, graphics, or 40-column modes, then this is for you.
CGA
CGA is the least expensive standard that supports 40-column text, as well as color and graphics modes. However, the graphics modes are limited to 320x200 with 4 colors and 640x200 in monochrome. CGA uses a 16-color palette.
EGA
If you'd like 16 colors and a higher graphics resolution, then EGA is for you. EGA supports up to 640x350 resolution, and all resolutions support 16 colors. EGA uses a 64-color palette.
VGA
VGA supports the highest possible resolution, 640x480. With 320x200 mode, you can even get 256 colors. VGA uses a 262,144-color palette.
Conclusion
If you don't know what to choose, choose EGA. It can display 16 out of 64 colors at once, and you get a resolution of 640x350.

If you need more information, please reply to this thread.
 

SpidersWeb

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It's only really IBM's MDA adapter that was limited to text-only
Hercules and the various clones (which most MDA systems will have) are capable of 720x350 graphics, the only real reason not to use it is because of the lack of colour. But many games such as SimCity, tend to be much more enjoyable on an MDA/MGA setup than CGA.

CGA is also capable of more than 4 colours at 320x200 if you use the composite output thanks to NTSC artifacting. Many 80's titles had a "Composite CGA" mode to make the most of it.
CGA also works fine in 80 column mode and most people will use it like this, the character's aren't quite as defined as MDA but easily legible on a TTL display.

Another nice thing with CGA and MDA is you can run both in the same system. So you could have an MDA display for text and high resolution graphics, and a composite monitor attached to a CGA card for color graphics.

Other standards I can quickly think of would include JR/TANDY, PGA, Plantronics etc.
 

nc_mike

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I use VGA on my modified 5160 since I can run everything from DOS through Windows 3.1. Even in DOS its nicer on a 20" flat panel. I use anauto-sensing ATi 38800-1 Graphics Ultra Mach8 SVGA adapter with 1.5MB of video memory driving a a 20" ViewSonic flat panel display at 1024x768x256 SVGA resolution in Windows - although most folks don't have such a need.

112023.e42ee4919f751df48a8c112ea676da33.a333e1ce8c346f5b5a4f859fccb7a17e.1600.jpg
112023.f25faec9736d74b739ec672d244d6387.1fbba5159b266110575f58dd5544fbf3.1600.jpg
112023.fd46c721084a72b9bfc5f946e3344b69.4569c911ef404ba9641fadd6fd160201.1600.jpg
112023.e6c14e4aaa87c33099ea6b6d684f7355.eaeae3b4f03dbff531b5e4d005476520.1600.jpg

Mike
 

pinkdonut666

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the HUGE problem with EGA is the rarity of the monitors... unless you plan on spending $$$ on a real EGA monitor, or a Converter box such as the MCE-VGA. then EGA really isn't the best option.

an ISA VGA card is more often then not the most convenient solution. (yes I know compatibility can be an issue with some old CGA and EGA software) Most VGA chipsets are "pretty good" backwards compatibility wise.

Personally for my "all IBM" builds like my 5150, 5160 & 5170 nothing but the period correct adapters and monitors will do.

but On clone machines, who cares? I have a generic Taiwanese 8mhz turbo XT clone that CAME WITH a VGA card FROM NEW. (very late budget PC from a local computer shop my guess around 1989) its a slow old OAK technology VGA card, but it allows me to use any common as dirt VGA display, CRT, LCD, whatever. It also is like 90% compatible with all the software and games I have tried. Even Windows 3.0 with the hacked VGA driver works.

Q3cOkyCl.jpg


So I would have to argue especially for those just getting started, a VGA card is much more useful and convenient unless you already have a CGA/EGA display.
 

VileR

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Depends on the use case, obviously. If your only requirement is just getting visual output in whatever form, then it's a matter of convenience and VGA obviously wins there, since it will work with still-common dirt-cheap LCDs.

I have a CGA in my 5160 because (1) part of my hobby involves producing code/graphics for it, (2) most 8088 software doesn't take advantage of VGA (or doesn't perform that well if it does), and (3) I prefer such software to retain its intended appearance when I run it, and VGA's backward compatibility is very partial which doesn't help on that front.

In terms of monitors, there's little value for me in using LCDs with anything 'vintage'. I'm a visually-oriented guy, and if I can only have badly-scaled output with aspect/gamma errors, I might as well use an emulator to get it. ;) But that's just me.
 

Stone

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the HUGE problem with EGA is the rarity of the monitors... unless you plan on spending $$$ on a real EGA monitor, or a Converter box such as the MCE-VGA. then EGA really isn't the best option.
Multisync monitors aren't that rare or expensive and do EGA as well as CGA and VGA. And their wide latitude makes them quite useful in other areas as well.
 

1ST1

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I think it should be possible to convert digital RGB Video (MDA, Hercules, CGA, EGA) to VGA signal just with a few components.

https://forum.classic-computing.de/...&postID=204969&highlight=intensity#post204969

Here is a circuit which works for monochrome signal (MDA, Hercules) with a good VGA multisync monitor by mixing the monochrome video with the intensity signal. Look at the posting 23. Dezember 2019 for update about the resistor values for mixing the signals. The same should also be possible for separated RGB signal (CGA, EGA) by enhancing this idea.
 

SpidersWeb

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I think it should be possible to convert digital RGB Video (MDA, Hercules, CGA, EGA) to VGA signal just with a few components.

https://forum.classic-computing.de/...&postID=204969&highlight=intensity#post204969

Here is a circuit which works for monochrome signal (MDA, Hercules) with a good VGA multisync monitor by mixing the monochrome video with the intensity signal. Look at the posting 23. Dezember 2019 for update about the resistor values for mixing the signals. The same should also be possible for separated RGB signal (CGA, EGA) by enhancing this idea.
Yes it has been done before. It does work, but with CGA you'll be missing yellow without extra circuitry, and you need a VGA display that'll sync down to 15Khz, most don't.

I used a CPLD to double the line frequency and do the "yellow fix", then output pulses to a resistor network. This worked fine as an experiment.
But then the C128 RGB thing came out (same idea), and then MCE2VGA.

My recommendation is to use MCE2VGA, which supports MDA/CGA/EGA input and outputs a correct VGA signal. These are open source and available prebuilt from multiple sellers also.
I had one attached to an LCD VGA monitor on my workbench, so I could connect almost anything up to it and have it display.
 

bladamson

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Hannnnnnnngon. VGA is backwards compatible with everything except Hercules/MDA and TGA, isn't it?

Hercules/MDA uses a different memory chunk than VGA/MCGA/EGA/CGA, so you can install them both in the same machine and switch with "MODE CONS". Clever software can even use both at the same time.

TGA is pretty much a "Tandy Thing".

So my opinion is, have a box with both VGA and Hercules (and a soundblaster), and then also keep a Tandy 1000 (with an ad-lib) around for the really old games for which TGA is the best graphics mode.

Edit: Part of the fun of old hardware, for me, is seeing how much I can stuff into it and how far I can push it. If that means using some period-incorrect expansion cards, I am ok with that, as long as it's not a permanent modification (cutting/throwing out RF shields doesn't count lol).
 
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Plasma

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Multisync monitors aren't that rare or expensive and do EGA as well as CGA and VGA. And their wide latitude makes them quite useful in other areas as well.

Compared to VGA monitors they are. Just about any monitor made in the past 3 decades can display VGA.
 

Eudimorphodon

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Kind of an aside:

A mildly annoying thing I've noticed recently in playing with setting up an old thin client to act as as a pure DOS box is that it seems like at least some VGA-equipped LCD monitors don't do the 400 line @ 70hz mode of VGA very well. This is the mode that's used for CGA/EGA emulation and 320x200 VGA 13h graphics. I've tried two different mid-late 2000's vintage LCD displays (including a very high-end at the time Dell 30") and both have issues with positioning and cropping modes using this timing set reliably. The scalers of these displays really want to whack off the overscan and just display the active area between the screen border, and they definitely have trouble actually deducing the proper bounds of the screen, often resulting in a little bit of the active area being cut off.

(Normally this mode is pretty much unused for anything other than the boot-time text display on any computer made since the 2000-aughts, so I don't suppose it's surprising they don't care much about making it work.)

Not a huge deal or anything, but mildly disappointing. I guess the takeaway is if you have a CRT monitor in good working order there are still a few little reasons to keep it around.
 

Stone

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I dunno... I sold around ten of them in the last several years. So they can't be that rare. And they weren't expensive either. Do you have firsthand information to refute that?
 

maxtherabbit

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Multisync meaning they will sync to SVGA+ and down to 15kHz?? Those are scarce as hens teeth around here
 

Plasma

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I dunno... I sold around ten of them in the last several years. So they can't be that rare. And they weren't expensive either. Do you have firsthand information to refute that?

Did you sell them for $0? People are literally giving away VGA monitors.
 

wmcbrine

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If you don't know what to choose, choose EGA. It can display 16 out of 64 colors at once, and you get a resolution of 640x350.

That's a weird conclusion, to me. I'd pick VGA, where possible -- it's easily available and works with modern displays. If going for period authenticity, probably CGA or MDA -- EGA had the shortest reign of any of them.

I'd mention that MDA resolution is 720x350 pixels, although of course it's only addressable as 80x25 text, unless you get the Hercules-compatible version. I remember the first time I ever saw an MDA screen -- coming from a world of CGA-like resolutions, it was stunning. (But then, VGA text mode is even a little better, at 720x400 pixels.)
 

Eudimorphodon

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That's a weird conclusion, to me. I'd pick VGA, where possible

I'd second that it's a pretty weird conclusion to come to. VGA is almost perfectly register-backwards-compatible with EGA so, to put a fine point on it, anything EGA can do VGA can do better. Because CGA is capable of some stupid pet tricks that aren't directly replicable on EGA or newer (composite color, the various "ASCII from Hell" pseudo-graphics mode, etc) there are legitimate reasons to still want an actual hardware CGA instead of relying on VGA emulation for running some software, but I just don't see it with EGA.

(I'm sure there must be *some* software out there that runs on EGA but not VGA, but I don't know that I've ever actually encountered any.)

The one place where an EGA card is kind of interesting is the edge case of using it to drive a CGA monitor (which are still rare now but at least more common than EGA monitors) in the 200 line 16 color modes. A 286 or early 386-class machine so configured is basically the generic alternative to a late-model Tandy 1000 in terms of graphical capabilities.

Some early VGA cards came with utilities that could switch them into register-compatible CGA and Hercules modes. (My first VGA card was an OAK unit that included this.) You still can't run composite color software but it would run some of those compatibility holdouts like Round42 with the help of that utility. Hercules software looked a little weird on that card because it displayed it in a "squished" aspect ratio using the 720x400 VGA mode but it likewise worked fine.
 
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