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71 votes
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How do DOS games like DOOM benefit from a PCI graphics card?

DOOM itself doesn’t do anything special to benefit from PCI graphics cards. It runs faster with PCI graphics cards (and VLB, AGP, and PCI Express cards) than with ISA graphics cards because the ...
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48 votes

Why doesn’t my VGA-to-HDMI converter work with my 286 PC?

The manual says that the smallest resolution it can handle is 800x600. That is almost certainly the key. Original VGA supported 640x480 16-colors and 720x400 (essentially a small step up from the ...
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33 votes
Accepted

How did DOS games manage to have multiple background layers?

Seems like VGA only has one background layer, it appears to be a typical bitmap screen like most home computers of the 80s (Amstrad CPC, Commodore 64 etc.) where each pixel's color is stored in a ...
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30 votes

How do DOS games like DOOM benefit from a PCI graphics card?

(When selecting an answer, use Stephen's - I just put this here because it is too much text for a comment) Most Important: It's a Game of Raw Numbers. We can ignore more complicated stuff and simply ...
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  • 166k
29 votes

Why did Super-VGA offer the 5:4 1280×1024 resolution?

VGA's 640x480 mode was the first to offer square pixels and an exception among all VGA modes available (320x200, 640x200, 640x350 and 720x400 for Text). Square pixels weren't the standard back then. ...
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  • 166k
29 votes
Accepted

Why was NEC able to wrestle PC graphics standards away from IBM?

VGA was introduced in 1987 with IBM's PS/2 line. NEC and VESA developed SuperVGA in 1988, but at the time it used the old and slow 8/16-bit ISA bus. Improving video performance was a top priority ...
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23 votes

Why doesn’t my VGA-to-HDMI converter work with my 286 PC?

DOS is almost surely not outputting 800x600 or up, and is probably in the ballpark of 720x350 or thereabouts. Further, it's likely 70Hz, which this adapter may not like. I'd recommend you get a ...
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21 votes

What video connections were common in Europe?

In the UK in the 1980s and the early 1990s, no video input at all was common. Early video recorders and set top boxes (for the new digital channels) would use RF out. You would disconnect the aerial ...
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  • 1,812
21 votes

Is the s-video output on the Commodore 64 different from "normal" s-video?

The 64 has separate outputs on the video port for luma and chroma which you can adapt to an S-Video output. There are a few caveats, however. The chroma signal is a bit "hot" compared to the S-Video ...
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  • 4,032
20 votes

What video connections were common in Europe?

Up until ~1980 the only connectors TV sets had were Belling-Lee type antenna in. So most VCR and next to all home computers did use RF modulated output toward the TV set (*1). This included even cable ...
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  • 166k
20 votes
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Do all VGA cards implicitly support CGA and EGA?

All VGAs support the “official” CGA and EGA modes, so most CGA and EGA games work fine. However, compatibility can only be relied upon at the BIOS level; a VGA can be implemented without strict ...
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19 votes
Accepted

With a 15 kHz video signal (240p or 480i), does VGA have any real-world advantage over S-Video?

S-Video relies on colour transformation from RGB to YUV, and then takes the U and V and modulates them using a colour subcarrier. The TV has to undo all these steps in order to get the original RGB ...
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17 votes

Invert LCD screen in DOS 5.0

Some laptops have built-in support for inverting the screen in one form or another; Toshiba laptops for instance have a setup menu to configure gray-scale translation and inversion, as well as a pop-...
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16 votes
Accepted

What video connections were common in Europe?

Before SCART, European TVs often had not video input at all or S-Video on 6-pin or 8-pin DIN sockets (not Mini-DIN). Cinch composite was uncommon until VCRs came out. After that the old S-Video ...
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  • 2,048
16 votes

Why was NEC able to wrestle PC graphics standards away from IBM?

I think that this was part of the larger trend of IBM losing the leadership of the “PC”, especially after the PS/2 and the MCA debacle (although the PS/2 line did introduce many new features which ...
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15 votes
Accepted

For fast scrolling DOS games, when was Mode13h preferred over Mode X?

[I]s there ever a circumstance where Mode 13h is a better choice for fast scrolling DOS games over Mode X? Sure, to start with, any single pixel operation on in Mode X is slower than for Mode 13, as ...
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  • 166k
15 votes
Accepted

What DOS games used Mode X as described by Michael Abrash?

Many PC pinball games use Mode X, notably Pinball Fantasies, Pinball Illusions and Epic Pinball. Nerdly Pleasures also has a comprehensive post on games using “unofficial” resolutions, which includes ...
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15 votes

Physical resolution and control of old VGA (color) CRT monitors

What was the phosphor resolution? The usual specification quoted for CRT resolution is the 'dot pitch', or distance between groups of RGB phosphor dots. Here are some examples of IBM monitors ...
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  • 5,458
14 votes
Accepted

How can a Z80/8080/6502 use VGA?

Preface: The question sounds as if you're missing a basic understanding of interfacing and communication between different chips/systems. At the core it can't be answered without a whole course in ...
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  • 166k
14 votes
Accepted

How to use "AND," "OR," and "XOR" modes for VGA Drawing

Running your code as-is on a real 286/VGA (Cirrus Logic CL-GD5420) produces this image: Inserting one dummy read before the second fill cycle (just mov ax, es:[0]) gives the image you were expecting: ...
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  • 1,236
13 votes
Accepted

Game Boy DMG to VGA

A direct connection is not going to work - The Gameboy's pixel clock is much too low to drive a VGA screen: GameBoy VGA Pixel clock 4 MHz 25 MHz V-Sync ...
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  • 27.4k
13 votes

Why did Super-VGA offer the 5:4 1280×1024 resolution?

1280x1024@24-bit fits in 4 MiB. Why wouldn't you take extra screen space? Keep in mind that games didn't usually run in 1280x1024 at the time. Back before LCDs became the dominating screen technology,...
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  • 727
12 votes

Acorn Electron to VGA/HDMI?

It cost me something like $50 all up to connect my Electron to the TV using an RGB to SCART cable (this one from eBay) and an RGB to HDMI converter like the one pictured below: You can get this model ...
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11 votes

Acorn Electron to VGA/HDMI?

The Electron outputs an analogue interlaced 625-line image, with a line rate of 15.625Khz. HDMI is a digital input, so cannot comprehend the Electron's analogue output. VGA is analogue but many ...
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11 votes
Accepted

Why does the Amiga 500 have half the HSYNC pulses seperately compared to those in CSYNC?

In analog TV, there was such thing as interlace. Roughly speaking, it kind of increased vertical resolution by putting scanlines of one "halfframe" (the one that lasts 20ms or goes 50 times ...
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  • 9,071
10 votes

How did DOS games manage to have multiple background layers?

Is it on its own plane somehow? No, as you assumed, VGA has only one plane(*1). Is every letter a "mouse cursor?" Or, is the screen constantly being redrawn with the letters in their new ...
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  • 166k
10 votes

How to use "AND," "OR," and "XOR" modes for VGA Drawing

The 16-color modes on the VGA use a hardware design borrowed from the EGA. On the EGA (and VGA), the bitwise drawing modes don't act upon memory directly, but instead act upon values stored in four ...
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  • 26.3k
9 votes

Converting SCART to VGA/Jack

Black-and-white hi-res from the 1040 STE on a VGA monitor should work with a direct connection and no tricky electronics at all (just the adapter cable) Atari VGA GND ...
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  • 27.4k
9 votes

Do all VGA cards implicitly support CGA and EGA?

The other answers are good, but one specific area where VGA cards are generally incompatible with CGA is with respect to CGA's Composite mode. In the video "CGA Graphics - Not as bad as you thought!", ...
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9 votes

Why are my VGA vram to vram copies so slow?

Your problem is mostly going to be rep movsb changing that to use rep movsw should help. If the VGA card is on a 8MHz (or 6MHz) original AT bus then the timings work like this: 3 cycles to read or ...
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  • 5,135

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