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16-bit ISA EGA card?

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Reply 20 of 43, by Jo22

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Cool, I didn't know that! 😎

64 colours would have been cool to work with back in the 80s.
Heck, even 32 colours would have been neat! 😃That's what our BTX online services had used, I think. It was a CEPT based, like Ceefax/Videotex on TV.

That's one of those moments in which EGA was a bit ahead of Standard VGA, maybe.
Another one was "EGA Dual-Page Mode", as used by Commander Keen series (double buffering using two video pages, essentially).

Edit: What I mean is the ability to have more than 16c in high-resolution modes. 640x350 pels and up.
Two main modes of VGA are 320x200 @256c and 640x480 @16c.
640x480 @64c would have been nice to have back then.

Because, in the mid 80s, the rare IBM PGC did offer 640x480 @256c already. W/ VGA timings and similarly specs (31,5 KHz + 60Hz, but combined HC Sync).

If VGA had been made more like EGA, 64c would haven been possible as a regular video mode.
That would have been nice for both business and entertainment.

It would also have had affected MS Windows and GEM, maybe. The standard icons would have had been in 32c or 64c, maybe.
That way, fine pixel-art and pretty gradients would have been possible. A sweet spot, so to say.

But even 32c would have been somewhat satisfying already, I think. 🤗
It would have allowed for four different reds, greens, blues (16c palette had two of each of the important colours I believe).

Four intensities, so to say. That would have been a real gift, already, considering that "four" is a magic number in display tech.
CGA had 4 colours, Gameboy had 4 shades of pea-green, Nokia Communicator 9000 had 4 shades of monochrome etc.

That being said, VGA can emulate EGA. Old ISA VGAs have a dedicated emulation mode, even.
But the timing is ofc, sadly. EGA is all 60 Hz, while VGA does 70 Hz.
Not sure how compatible this is with the finicky timing of palette changing. 🤷‍♂️

Last edited by Jo22 on 2024-01-14, 14:48. Edited 1 time in total.

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In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 21 of 43, by dr.zeissler

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The biggest wow! effect to me was not 256colors but 16colors in VGA with a custom palette.
Some BitmapBrothers Titles like gods use that, looks fantastic and is FAST! on 286/8 !!

Retro-Gamer 😀 ...on different machines

Reply 22 of 43, by Jo22

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Yay! EGA also helped with porting games from Japan!
I'm not just talking about Cobra Mission: Panic in Cobra City (a PC-98 port), but game classics like Zeliard and Thexder.

The originals ran on an PC-88 which offered 640x200 resolution, which EGA has as well!
That's why some people find it better looking than with the MCGA/VGA driver.
So EGA was an aid at porting games, too.

Death Knights of Krynn is pretty, too! 😄
Re: MCGA Games (PC/DOS) - LCD vs CRT

Edit: Or how about La Aventura Espacial ? 😉
Re: MCGA Games (PC/DOS) - LCD vs CRT

PS: I forgot to mention, SOMI 2 had an 640x200 16c mode that worked with CGA monitors (=15 KHz SCART TVs).

The game was still using 320x200 pels source material, but used this EGA mode's wider resolution to insert dithering patterns (coloured dots).

That way, it could approximate the 256c MCGA graphics of mode 13h.
On a 15 KHz monitor, without resorting to normal interlacing.

I've taken some pictures. Sorry for the bad image quality, though.
The monitor I've used was intentionally blurry/grainy, for a good colour blending effect (good for 320x200 256c).

So there are no visible scan lines, as with a CGA/EGA TTL monitor.

Re: MCGA Games (PC/DOS) - LCD vs CRT

"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 23 of 43, by mkarcher

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Jo22 wrote on 2024-01-14, 10:38:

There also was an analogue 9-pin connector on early VGA cards, I vaguely remember.

There is analog video on 9-pin connectors. Different pinouts were used, but one of them turned into a de-factor standard. It's the one used by the IBM PGA ("professional graphics adapter", an early "high definition" video card for use in the original IBM PC and XT. It provided 640x480 at 256 simultaneous colors at 60 Hz, with video timings similar (but not identifcal to) the later IBM VGA. As there is no consumer affordable IBM video card that uses this pinout, competitors to those cards also do not use that pinout. On the other hand, this pinout is commonly used on monitors that are switchable between analog and digital input, like the NEC MultiSync II.

Jo22 wrote on 2024-01-14, 10:38:

It contained merely the very basis VGA signals, such as R, G, B, H Sync, V Sync, GND (3 x?), mono monitor detection pin
But I can't find an actual pinout diagram, sadly.

There were cheap monochrome monitors that were used as CGA displays. But those monitors were not MDA monitors. MDA used a fixed […]
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Pin 1: R
Pin 6: R Ground
Pin 2: G
Pin 7: G Ground
Pin 3: B
Pin 8: B Ground
Pin 4: CSync / HSync
Pin 9: Sync Ground
Pin 5: Mode Select / VSync
Jo22 wrote on 2024-01-14, 10:38:

Closest I can think of are MDA monitors that were being used as cheap CGA displays.
Some CGA/EGA clone cards had the ability to simulate the colours as shades of grey on an MDA monitor (Hercules monitor).

There were cheap monochrome monitors that were used as CGA displays. But those monitors were not MDA monitors. MDA used a fixed frequency of 18.4kHz, whereas CGA uses 15.6kHz. The IBM 5151 monochrome monitor is notorious for not tolerating lines that take too long, and might break if it is connected to a CGA card. These monitors were usually connected to the CGA card using the composite output.

On the other hand, there in fact were more advanced graphics cards like the "ATI Graphics Solution Rev. 3" that was indeed able to generate an MDA-like signal for CGA modes, but in that case, the graphics card had to do some magic, it's not plain "MDA monitor displays monochrome CGA image".

Reply 24 of 43, by mkarcher

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Grzyb wrote on 2024-01-14, 13:08:

Come to think of it, maybe there was a Super EGA card with 64 simultaneous colors?
I'm not aware of one, but we all know that absence of evidence is not evidence of absence.
There would be one big problem with such a card, though: difficult to convince software vendors to support such an oddball.

As all common Super EGA cards were built by running standard EGA chipsets at higher frequencies, the "4 bit per pixel" architecture was not extended by those cards.

Reply 25 of 43, by mkarcher

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Jo22 wrote on 2024-01-14, 14:33:

Because, in the mid 80s, the rare IBM PGC did offer 640x480 @256c already. W/ VGA timings and similarly specs (31,5 KHz + 60Hz, but combined HC Sync).

Nitpick: It's 30.5kHz on the PGA, not 31.5kHz like on VGA. The PGA monitor needs some trimming before it synchronizes the VGA scan rate, even if you generate a proper CSync signal.

Jo22 wrote on 2024-01-14, 14:33:

If VGA had been made more like EGA, 64c would haven been possible as a regular video mode.
That would have been nice for both business and entertainment.

This statement makes no sense. VGA is just "EGA on steroids", you can't make it even more "like EGA" than it already is. It's still the same 4bpp video core used on EGA, but the VGA card learned a new trick in the pixel output processing (the "attribute controller", which is what maps the 16 colors to 64 colors on the EGA card): It can combine two 4-bit values into one 8-bit value. This enables the 256 color video mode. Except for enabling this "4-bit to 8-bit conversion", the 320x200 256-color mode is implemented very similar to the 640x200 16-color mode. The enhanced attribute controller on the VGA outputs 8-bit values instead of 6 bits, and is connected to the only entirely new component on the VGA card: The RAMDAC that generates the analog signal.

Jo22 wrote on 2024-01-14, 14:33:

That being said, VGA can emulate EGA. Old ISA VGAs have a dedicated emulation mode, even.
But the timing is ofc, sadly. EGA is all 60 Hz, while VGA does 70 Hz.
Not sure how compatible this is with the finicky timing of palette changing. 🤷‍♂️

Most VGA monitors can sync everything between 60Hz and 70Hz. Increasing the vertical blanking in EGA modes to get down to 60Hz works on those monitors. There is another difference that is not that easy to overcome: VGA monitors require 31500 scanlines per second, whereas EGA monitors (in 350 line mode) only require 21600 scanlines per second. A program that wants to pull off the palette change trick on VGA cards must run fast enough to cope with the higher line rate. As most of these programs actively synchronize to the "horizontal sync" flag on the card, they will usually work on VGA cards as well, especially as VGA cards are usually combined with faster processors than EGA cards were.

Reply 26 of 43, by Jo22

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I've meant to say that if history was different, and if what had finally become "VGA", had rather been ended up more like an evolved form of EGA..

Some sort of Super EGA, so to say: No analogue output, but full 64 colour ouput for an EGA/TTL monitor.
With a dedicated 64 colour "on screen" video mode of 640x350 or 640x480 resolution.

The other thing was about the situation that EGA modes (say 640x350 16c, mode 10h) run at 60 Hz on an EGA card.
But on a VGA card, mode 10h will have 70 Hz instead (by default).

And I had worried that their dedicated "EGA emulation mode" via mode utility (vgamode, tvm89 etc) won't change much of it.

Some VGA cards may simply use a software solution to disable VGA compatibility.

Instead of having some EGA-specific circuitry in silicon, they rather hide VGA support in VGA BIOS to make the VGA card look like a plain EGA card with EGA BIOS.

Edit: I'm sorry about my English. My wording isn't exactly the yellow from the egg, I'm afraid. Need more practice. 😓

"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 27 of 43, by mkarcher

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Jo22 wrote on 2024-01-14, 20:08:

I've meant to say that if history was different, and if what had finally become "VGA", had rather been ended up more like an evolved form of EGA..

Some sort of Super EGA, so to say: No analogue output, but full 64 colour ouput for an EGA/TTL monitor.
With a dedicated 64 colour "on screen" video mode of 640x350 or 640x480 resolution.

What I meant to say: VGA is an evolved form of EGA, but even less evolved than you would have liked. EGA only processes four bits per internal clock, so you are limited to 16 colors. VGA did not change that at all!. The core video logic fetches 32 bits of video RAM contents every "character clock" and makes 8 pixels of 4 bits each from those 32 bits. On VGA, it's just post-processing that can convert 8 pixels of four bits to 4 pixels of 8 bits.

Jo22 wrote on 2024-01-14, 20:08:

The other thing was about the situation that EGA modes (say 640x350 16c, mode 10h) run at 60 Hz on an EGA card.
But on a VGA card, mode 10h will have 70 Hz instead (by default).

Which is actually a good thing in my oppion, because it reduces flicker. I really disliked the 480 line VGA mode because it ran at just 60 Hz, and at least the VGA monitors I experienced had a sufficiently short persistence that 60Hz video was annoying. Being able to configure 640x480 at 72Hz on the SVGA system I had later was a big relief regarding this pain point.

Jo22 wrote on 2024-01-14, 20:08:

And I had worried that their dedicated "EGA emulation mode" via mode utility (vgamode, tvm89 etc) won't change much of it.

This is indeed the case. For running applications like Word (in WYSIWYG mode), looking at graphs in Excel or running Windows, it makes no sense to not use the 70 Hz capability of the VGA monitor. Actually, running at 70Hz instead of 60Hz makes it an even better EGA card in this regard. You start getting issues with the higher refresh rate only if you look at animations, which mostly means games. Games were not a major selling point for IBM compatible systems at that time - an Amiga performed considerably better as gaming computer than an AT did.

And even if you increase the black time between frames to get down to 60 Hz in EGA modes, you can not display "true EGA timings" on a VGA monitor. The only line frequency a VGA monitor supports is 31.5kHz, which is way higher than the 21.6kHz used on EGA monitors. Sending 350 lines to an EGA monitor takes 16.2 milliseconds. Software that closely interacts with EGA timings might count on this time. Sending 350 lines to a VGA monitor only takes 11.1 milliseconds. There is nothing a VGA card can change about it. The only thing that can be changed is the time of the black period between two frames. The EGA card uses around 0.4 milliseconds, whereas the VGA card uses 3.1 milliseconds (to get down to 70 Hz, it could do EGA at an even higher refresh rate - in fact the VGA card uses the same frame time for the 350 line mode and the 400 line mode).

Jo22 wrote on 2024-01-14, 20:08:

Instead of having some EGA-specific circuitry in silicon, they rather hide VGA support in VGA BIOS to make the VGA card look like a plain EGA card with EGA BIOS.

As long as you don't ask a VGA BIOS whether it supports VGA stuff, it behaves sufficiently like an EGA BIOS that EGA software wouldn't even notice you have a VGA card installed. You only need to enable the EGA emulation mode if you either want to prevent some software with VGA support to make use of the extended VGA features, or if you have software that bypasses the video BIOS and accesses the silicon directly. The deviations in silicon between EGA and VGA is quite minor (given a suitable RAMDAC setup, which happens to be the default RAMDAC setup in all 16-color modes anyway), so switching the silicon to "EGA mode" mostly means deactivating some bits that were reserved on EGA but enable extra features on VGA.

Emulating CGA is a completely different piece of cake, though: Software that directly reprograms the CGA CRTC (to manually switch to graphics mode, to use the 160x100 16-color pseudo-graphics mode, to shake the screen, to enable the unofficial red/cyan/white palette) will not work on either EGA or VGA cards unless there is specific silicon support to emulate CGA behaviour. And, as expected, even with CGA emulation mode enabled, most VGA cards will still produce a 70Hz image instead of a 60Hz image - yet the virtual horizontal scan rate might be very close to what CGA actually expects. As VGA monitors require CGA modes to be double-scanned, you get an effective horizontal scan rate of 31.5kHz/2 = 15.75kHz, which is quite close to the actual CGA scan rate. As long as the hardware only reports every second horizontal blanking interval in the status register, CGA software might actually work quite well, even if it does scanline-level magic.

Reply 28 of 43, by rkurbatov

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That's interesting. It seems like EGA lived not a long life and never got its full potential.

I'm trying to make my new build like it's 1990 and want to have powerful 286. 12MHz is enough though there were even 16-20MHz options. And watching plenty of ads of year 1990 I see there were even XT I could buy at that time just like very expensive 486s with EISA bus (I have two cards with EISA of year 1990).

But as for display they proposed either Monochrome VGA or color VGA. So my Genoa SuperEGA card of year 1989 is somewhat out of time.

It seems like lots of apps and especially games were made with CGA in mind, even using its 160x100 16 color mode or Composite output. So even early EGA had to work in that compatibility mode. And then they switched to VGA when early SVGA appeared. Then VGA was used for games till year 1995-1996, for quite long time, exploiting Mode X and other pretty possibilities of VGA adapter.

So it seems like EGA was ugly duckling of early PC era.

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Reply 29 of 43, by the3dfxdude

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I would say that EGA had a long life. The problem was when it was king as a standard, it was expensive, and could only get around some color limitations on a CGA TTL monitor, unless you wanted to buy a more expensive EGA TTL monitor (and RAM expansion, which is even more money). EGA got more use when it was extended upon, and that was during the VGA era as EGA/VGA on a VGA card and screen. The VGA clone makers eventually made the market collapse to where it was cheap to have the capability of the VGA cards. It was then EGA modes were popularized enough to get its widespread use. Even if it was kind of not 100% EGA.

I would say CGA was the ugly duckling of the early PC era. While many games also used CGA up until around 1990 because of the market, most targeted the typical use case of 320x200 4 color, which was not pretty.

Reply 31 of 43, by rmay635703

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dr.zeissler wrote on 2024-01-14, 14:08:

There was a demo-program that shows all 64colors at once in hires. I ran it on my Schneider EGA machine.

One of the old dos EGA graphics drawing programs bragged about 4096 colors on the box (the number you get if you dither 64 colors)

Reply 32 of 43, by rkurbatov

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Btw, what is it?

s-l1600.jpg

https://www.ebay.com/itm/276284606622

Very strange Everex 680 card. Cannot be found by FCC ID. 16 bit, has 2 9 pin ports. Dual port EGA? Strange attachment card.

16 ZIP memory ICs of 12 (24) pins each. Looks like 1M of video memory - way too much for EGA. That's probably SVGA with 9 pin VGA cable (I've seen such converters).

Upd. As it's not EGA card, I'll probably open a new topic.

Last edited by rkurbatov on 2024-02-15, 14:38. Edited 1 time in total.

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Reply 33 of 43, by Grzyb

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"Also in 1987, Truevision, the pioneer of the desktop digital video editing industry, introduced the Targa Board for IBM PC compatible computers. The Targa Board provided video capture in 512 x 480 TGA truecolor file format and could display over 32,000 colors anywhere on the screen. A lower cost video capture board for the PC, the Everex ev680, with the same capabilities as the Targa Board soon followed."

http://www.appleoldies.ca/a2b/SHRConversionUs … WithA2B2016.htm

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 34 of 43, by rmay635703

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Grzyb wrote on 2024-02-15, 01:52:

"Also in 1987, Truevision, the pioneer of the desktop digital video editing industry, introduced the Targa Board for IBM PC compatible computers. The Targa Board provided video capture in 512 x 480 TGA truecolor file format and could display over 32,000 colors anywhere on the screen. A lower cost video capture board for the PC, the Everex ev680, with the same capabilities as the Targa Board soon followed."

http://www.appleoldies.ca/a2b/SHRConversionUs … WithA2B2016.htm

Yep RGB Analog, the 15khz version of PGA video pinout used on Amiga.

Targa style video capture cards were used on the CASI Colortron 3400 computer portrait systems.

There were also Sony targa video flatbed scanners and the Kodak ccd4000 flashsync cameras that all used this format

Reply 35 of 43, by rkurbatov

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Oops, sorry, missed your responses 🙁 Maybe you can provide a little bit more details in a special theme I created?

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Reply 36 of 43, by Jo22

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mkarcher wrote on 2024-01-14, 19:07:
Grzyb wrote on 2024-01-14, 13:08:

Come to think of it, maybe there was a Super EGA card with 64 simultaneous colors?
I'm not aware of one, but we all know that absence of evidence is not evidence of absence.
There would be one big problem with such a card, though: difficult to convince software vendors to support such an oddball.

As all common Super EGA cards were built by running standard EGA chipsets at higher frequencies, the "4 bit per pixel" architecture was not extended by those cards.

Hi again. There's something I've just discovered by coincidence.
At least one game made by Taito (Rambo III) has additional support for "EGA Enhanced" (Boca, Paradise).
The special support seems to be related to the colours/palette.

https://www.mobygames.com/game/5023/rambo-iii/screenshots/

So a bit of deviation was apparently possible, provided that someone was willing to leave IBM territory.

Anyway, just wanted to let you know.

"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 37 of 43, by Grzyb

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That doesn't look like more than 16 simultaneous colors...
more like 16 colors picked out of palette of 64...
but EGA monitors don't allow for that in the 200-line mode...

Perhaps those Boca and Paradise cards allow to almost-double-scan 200-line modes into 350 lines?

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 38 of 43, by Jo22

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Grzyb wrote on 2024-04-27, 12:35:
That doesn't look like more than 16 simultaneous colors... more like 16 colors picked out of palette of 64... but EGA monitors d […]
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That doesn't look like more than 16 simultaneous colors...
more like 16 colors picked out of palette of 64...
but EGA monitors don't allow for that in the 200-line mode...

Perhaps those Boca and Paradise cards allow to almost-double-scan 200-line modes into 350 lines?

I was looking for a Boca/Paradise manual in order to get more information.
The closest I got so far was this, however:

Doing that stuff in low-res required both an "extended" EGA clone and a multisync or analog monitor (some of those later cards actually had vga connectors). Rambo III did something like that too.

Re: Why did DOS games never use anything but the default EGA palette?

So it's old news, already. To my defense, I've missed that thread back then.

It's just kind of satisfying that an 5153 or 1084 monitor isn't the solution for everything. A bit of diversity is cool. :D

"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 39 of 43, by Grzyb

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Doing that stuff in low-res required both an "extended" EGA clone and a multisync or analog monitor (some of those later cards actually had vga connectors). Rambo III did something like that too.

OK, multisync monitors had switches like 3/8/16/64 colors:

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Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.