VOGONS

Common searches


First post, by Cyberdyne

User metadata
Rank Oldbie
Rank
Oldbie

It just really bothers me, I understand old EGA cards, and the first VGA card for 8086 IBM PS/2. But the later clone market made some advanced EGA and even VGA cards but left them with only 8BIT ISA. Why cripple a fast thing. In VGA clone times, nobody was using a XT to VGA you know. Never found a definitive answer for that.

I am aroused about any X86 motherboard that has full functional ISA slot. I think i have problem. Not really into that original (Turbo) XT,286,386 and CGA/EGA stuff. So just a DOS nut.

Reply 1 of 26, by pan069

User metadata
Rank Oldbie
Rank
Oldbie

Not sure if there is a definitive answer. My guess would be costs? Why would you buy a 386SX and not a 386DX? I'm sure there must have been a market for 8 bit VGAs, probably people upgrading their XTs.

These are the only ones I can find (in one place). Doesn't seem to be that many:
http://www.vgamuseum.info/index.php/com ... &f[g][text]=

Edit: Nice. that link doesn't work, whats the point of sticking that stuff on the url... anyhow, just search for 8bit ISA and output 15 pin Dsub.

Reply 2 of 26, by Cyberdyne

User metadata
Rank Oldbie
Rank
Oldbie

Wow. this got to be a typo, a 8bit SVGA. Well only 256kb so it is only 800x600x16 SVGA maybe.

http://www.vgamuseum.info/index.php/component … si-logic-evc416

I am aroused about any X86 motherboard that has full functional ISA slot. I think i have problem. Not really into that original (Turbo) XT,286,386 and CGA/EGA stuff. So just a DOS nut.

Reply 4 of 26, by Caluser2000

User metadata
Rank l33t
Rank
l33t
maxtherabbit wrote on 2021-07-30, 13:08:
Cyberdyne wrote on 2021-07-30, 06:11:

In VGA clone times, nobody was using a XT to VGA you know.

I'm gonna call BS on this

I concur with your BS call...😉

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 5 of 26, by Zup

User metadata
Rank Oldbie
Rank
Oldbie

Not everybody uses a PC for gaming, nor can buy a new one.

I guess there were a market for:
- People with older PCs that wanted to upgrade to color graphics, but had not the budget to change to a new PC.
- Business that found "high resolution" (for that time) and color desirable, but didn't need fast video output.

BTW, there were XTs that were VGA equipped at launch. Amstrad PC 2086, 3086 and 5086, and Olivetti PCS86 came to mind.

I have traveled across the universe and through the years to find Her.
Sometimes going all the way is just a start...

I'm selling some stuff!

Reply 6 of 26, by BitWrangler

User metadata
Rank l33t++
Rank
l33t++

XT clones had a long life, still had a lot of mainstream use through the early 90s for DOS wordprocessing etc. Wasn't until Windows 3.1 came out that a lot of people began to see it as actually useful, and care about running it.

Lots of this going round lately, I expect to be told in a few years time that everybody instantly got given an Intel Core i9 in 2017 because that's when they came out, and it was impossible therefore that I was still using an I5 (and core 2s even) in 2021.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 7 of 26, by rmay635703

User metadata
Rank Oldbie
Rank
Oldbie

DCS Industries sold a 1mb SVGA upgrade for
Tandy 1000 series computers

Go figure?

My problem was that I could never find 8 bit VGA and had to test a stack of 16 bit units to find one that could do 8 bit.

As to why a company might make an 8 bit ISA is that in some cases the chip was only interfaced to 8 bit anyway and an 8 bit card was more universal
AKA it would work in anyone’s Pc old or new

Last edited by rmay635703 on 2021-07-30, 20:03. Edited 1 time in total.

Reply 8 of 26, by Jo22

User metadata
Rank l33t++
Rank
l33t++

Later 8086 machines from IBM had MCGA/VGA on-board.
Like that Model 25 from PS/2 series. Sure, it's no XT, but still.. 😀

I'm sorry. Since I started with a 286 PC first, I can't give a definite answer, as far as XTs are considered.
Many, many AT compatibles that were made later on either had Hercules or VGA on-board, though.

Hercules, because of its high-resolution monochrome graphics and because TTL monitors were much cheaper than anything else.
That was a perfect combination for cashier PCs, terminals and point of sale systems.

Alternatively, these systems had VGA. Or more precisely, SVGA. Almost all VGA compatibles had some extra modes.
Even the early models from 1987/1988 either supported 800x600 pels in 16c (original SVGA resolution) and/or did 640x400 pels in 256c.
Both was possible with 256KB of RAM.

My two cents:

EGA, as cool as it was, had a short lifetime, I think. The original IBM EGA was expensive, had a lousy 64-128KB of RAM and was a lame duck.
Super EGA cards were a thing until VGA showed up. Maybe for 2-3 years, dunno.
After that, Super EGA chips quickly evolved into VGA chips.
Late Super EGA clones even did mimicry and simulated VGA mode 12h (640x480 16c).
That way, ordinary VGA application software could run.

VGA also supported almost all EGA modes, so applications could continue using EGA as a video mode.
Minus the correct timing, of course. EGA in 640x350 was 60Hz, VGA in 640x400 70Hz.

From my experience (mid 90s), as far as DOS applications were considered (not GUIs),
VGA was widely adopted among all PC generations and CGA and Hercules were a curiosity.
EGA, if supported at all still, was more like a hidden feature.
DOS programs either required a special command line argument to use EGA
or relied on an auto-detection routine to use EGA as a fallback.
Like the Skyroads game did. Exceptions like Jill of Jungle and Commander Keen also existed, of course.

So long story short: VGA was a huge success from the very start.
Everyone seemingly wanted it, DOS programmers of the 90s even expected it to be available.
So I believe it didn't matter so much if performance was good or not.
An XT user , I think, that wanted to keep using current DOS software simply had to get a VGA-compatible card.
Otherwise "No EGA/VGA hardware detected" was all this user got. 😉

As usual, exceptions are th rule, of course. Hercules cards were still supported by professional software.
Since their resolution was higher than EGA even, they could still be useful.

By comparison, CGA in 640x200 was a imposition.The height was too low for applications to fit.
So unless recoding was done, QB45, Turbo Pascal, Turbo C programs didn't run properly.

I think we all know that problem from running Windows 3.x with the CGA driver.
Half the application is cut away, because the programmer expected a 640x480 screen (0r 640x350, at least).

One good thing of CGA, though: It used TV compatible timings.
So maybe some users kept using it in order to connect a PC to a TV or a VCR.
Some SVGA cards got CVBS and S-Video output capabilities in the later 90s.

Edit: I reformatted the text a bit, since I'm now at home on a real PC.

Edit: I did forget some important bit! Very important, maybe.
Generic CGA cards sometimes had a switch to select CGA/HGC, since both standards use the same Motorola chip.
So XT users could "upgrade" to Hercules if needed.
That way, professional software could be used.

Last edited by Jo22 on 2021-07-30, 18:22. Edited 3 times in total.

"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 9 of 26, by digger

User metadata
Rank Oldbie
Rank
Oldbie

Have any of you heard of the Little Game Engine for VGA and 8088/8086/286 on GitHub?

It's meant for developing DOS games that work well even in 8088 systems. It supports VGA only, the argument in the README being that VGA actually performs faster than EGA or even CGA, even on 8088 systems, as long as software is properly optimized for it, taking proper advantage of VGA hardware features, etc. Not just obvious stuff such as smooth scrolling, but also things like sprites and memory-to-memory copies, etc.

So if this is true, then 8-bit VGA cards actually do make sense. Except that many games (especially in the 16-color and early 256-color era) never tapped into this true potential that VGA offered.

This makes me wonder if perhaps an alternative Sierra SCI driver could be written that would take better advantage of VGA's hardware features, resulting in faster performance, even on older systems. I mean, it wouldn't make the 16-color games suddenly have 256 colors (although FreeSCI and by extension ScummVM do have a cool routine that converts dithered colors to solid colors, but I digress). As a nice bonus, such a VGA-optimized SCI driver for 16-color SCI games could also be made to offer a better-tweaked color palette, for instance the same palette as used in the Atari ST and Amiga ports of those same games. Also, the scrolling screen transitions (supported in the EGA driver) could be made a lot smoother in such a VGA-optimized driver.

(and yes, I know that 16-color SCI games shipped with a VGA/MCGA driver, but that driver had to cater to the lowest common denominator, which was MCGA, and MCGA lacked many of VGA's hardware acceleration features. That's why some VGA games don't work on MCGA. I'm really talking about a theoretical driver that would use VGA to its fullest advantage in 16-bit Sierra SCI adventures.)

But yeah, perhaps a topic worthy of further exploration in its own dedicated thread. 😉

Reply 10 of 26, by digger

User metadata
Rank Oldbie
Rank
Oldbie

Also, I wouldn't be surprised if VGA monitors very quickly become cheaper to produce than EGA monitors, perhaps even from the start. The fact that they no longer required TTL logic for converting the digital color signals may very well have outweighed the increased costs of having to support higher refresh rates at higher resolutions. That, plus analog signalling was more future proof. With that one change, we went from 64 colors to an infinite number of colors.

Reply 11 of 26, by mr.cat

User metadata
Rank Member
Rank
Member
digger wrote on 2021-07-30, 16:46:

But yeah, perhaps a topic worthy of further exploration in its own dedicated thread. 😉

Like this one?
FastDoom. A new Doom port for DOS, optimized to be as fast as possible for 386/486 personal computers!

OK that's not XT level but there's a suitable fps obsession going on in that thread, with benchmarks to back it up 😁
Digger that VRAM trick was a very interesting find, thank you!

EDIT: On second thought it doesn't seem like FastDOOM can benefit that much from this. Maybe FastDOOM's various tricks can be used for XT stuff though.

Last edited by mr.cat on 2021-07-30, 19:02. Edited 1 time in total.

Reply 12 of 26, by Caluser2000

User metadata
Rank l33t
Rank
l33t
BitWrangler wrote on 2021-07-30, 15:04:

XT clones had a long life, still had a lot of mainstream use through the early 90s for DOS wordprocessing etc. Wasn't until Windows 3.1 came out that a lot of people began to see it as actually useful, and care about running it.

Lots of this going round lately, I expect to be told in a few years time that everybody instantly got given an Intel Core i9 in 2017 because that's when they came out, and it was impossible therefore that I was still using an I5 (and core 2s even) in 2021.

I remember new XT systems being sold with VGA in 199o down our way.

There is a lot of what I call "revised IT history" going on these days. A quick look at wikipedia would show that what is being spouted is totally inaccurate. Unsure why? Laziness, can't be bothered to research the topic, never heard of wikipedia or an internet search engine. And it isn't just young'ns just getting in to the hobby either.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 13 of 26, by Caluser2000

User metadata
Rank l33t
Rank
l33t

Super EGA is a new one on me..?

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 14 of 26, by Jo22

User metadata
Rank l33t++
Rank
l33t++
digger wrote on 2021-07-30, 17:03:

Also, I wouldn't be surprised if VGA monitors very quickly become cheaper to produce than EGA monitors, perhaps even from the start. The fact that they no longer required TTL logic for converting the digital color signals may very well have outweighed the increased costs of having to support higher refresh rates at higher resolutions. That, plus analog signalling was more future proof. With that one change, we went from 64 colors to an infinite number of colors.

There also was the PGC, Professional Graphics Controller - expensive and certainly not a child's play. 😀
It had an 8088 graphics processor and could do 640x480 pels and display 256 colours. Just like VGA later could (but VGA could not in combination).
Also, it used the same analogue signals that VGA would later use.

So maybe IBM had that idea of going analogue much earlier than we assume? 😀
PGC is from 1984, just like EGA is.

The PGC monitor (model 5175) matches the original IBM PC just perfectly.
IBM 5175 PGA to VGA Conversion

https://en.wikipedia.org/wiki/Professional_Gr … hics_Controller

Attachments

  • vpzgpg7jd2531.jpg
    Filename
    vpzgpg7jd2531.jpg
    File size
    41.82 KiB
    Views
    1223 views
    File comment
    Source: https://www.reddit.com/r/retrobattlestations/comments/c1z1ra/and_they_said_it_couldnt_be_done_triple_monitor_xt/
    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//

Reply 15 of 26, by wiretap

User metadata
Rank Oldbie
Rank
Oldbie

I have an XT at work that came with a VGA card -- it was supposedly purchased in 1988 or 1989. The proprietary NUMAC software requires VGA. Came with an ATI VGA Wonder.

My Github
Circuit Board Repair Manuals

Reply 16 of 26, by the3dfxdude

User metadata
Rank Member
Rank
Member
digger wrote on 2021-07-30, 16:46:

Have any of you heard of the Little Game Engine for VGA and 8088/8086/286 on GitHub?

It's meant for developing DOS games that work well even in 8088 systems. It supports VGA only, the argument in the README being that VGA actually performs faster than EGA or even CGA, even on 8088 systems, as long as software is properly optimized for it, taking proper advantage of VGA hardware features, etc. Not just obvious stuff such as smooth scrolling, but also things like sprites and memory-to-memory copies, etc.

So if this is true, then 8-bit VGA cards actually do make sense. Except that many games (especially in the 16-color and early 256-color era) never tapped into this true potential that VGA offered.

I suppose that since we've now seen pushing best quality CGA FMV video across an 8-bit ISA bus as one example, having more off-screen video memory for EGA/VGA could take the pressure off the rest of the system in a game engine, and allow for a more demanding game on slower hardware. By the time people were thinking about optimizing for the video hardware available to push the limits (when PC gaming really was taking off), much faster systems already existed, and the 8-bit ISA slot was obsolete. So maybe a slightly interesting challenge, to produce a high quality graphical game with the best available graphics card, with the minimum CPU possible.

MDA/HGC/CGA generally did not have much in the way of video memory like EGA/VGA. Going outside of the IBM MDA/CGA design, although variants exist that had more, those were not as standard as EGA/VGA, making the latter a better all-round standard, even for 8-bit graphics, given a optimized enough code can be written. And if you really think about it, today VGA is easier to obtain for these old systems, we just need some more games that work on the slowest systems to support VGA and that can take advantage of the card better 😀

Reply 17 of 26, by kdr

User metadata
Rank Member
Rank
Member

EGA as an 8-bit ISA device makes perfect sense; although it was introduced at roughly the same time as the 5170 AT, there was a huge installed base of PC and XT machines that IBM had in mind. (That's probably why EGA has full support for both CGA and MDA monitors: it was the universal PC/XT display adapter that IBM should have been selling from the very beginning!)

But why was IBM's VGA designed as an 8-bit device? It was meant for the higher end PS/2 systems (and possibly also as an upgrade for the AT machines) so it would've been most natural for it to be a 16-bit device from the start.

Of course the lines between the EGA clones and VGA clones are quite blurred because -- once you've cloned the EGA -- it's almost trivial to just graft on a RAMDAC, change out the oscillator frequencies, and shift the CRTC registers around a little to turn it into a VGA.

Reply 18 of 26, by jakethompson1

User metadata
Rank Oldbie
Rank
Oldbie

Code would have to make 16-bit accesses to video RAM to actually take advantage of a 16-bit video card, right? Is it possible this was rare in the early days of VGA? Maybe something to do with planar memory?

Reply 19 of 26, by Jo22

User metadata
Rank l33t++
Rank
l33t++
jakethompson1 wrote on 2021-07-31, 01:21:

Code would have to make 16-bit accesses to video RAM to actually take advantage of a 16-bit video card, right? Is it possible this was rare in the early days of VGA? Maybe something to do with planar memory?

Maybe. The original IBM "VGA card" (the IBM PS/2 Display Adapter) was apparently 8-Bit, too.

Attachments

  • Filename
    IBM Announcement Letter 187-054.txt
    File size
    21.72 KiB
    Downloads
    43 downloads
    File license
    Fair use/fair dealing exception
  • IBM PS2 Display Adapter.jpg
    Filename
    IBM PS2 Display Adapter.jpg
    File size
    162.7 KiB
    Views
    1077 views
    File comment
    Source: http://minuszerodegrees.net/5162/cards/5162_cards.htm
    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//