Questions tagged [video]

For questions regarding hardware and drivers used for video output.

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9
votes
1answer
224 views

What was the purpose of the Apple /// interlace mode?

I know that a video interlace mode was available on the Apple /// prototype and eventually on the Apple ///+, but I haven't seen anything that says what it was for. Did it provide a higher resolution ...
4
votes
3answers
185 views

Are there standard DIN pinouts for cassette and video ports on early Japanese 8-bit computers?

I have several different Japanese 8-bit computers, and they use similar DIN connectors for video and cassette I/O: Composite video: 180° 5-pin DIN: Fujitsu FM-7, NEC PC-8001mkII Color TTL (digital) ...
5
votes
2answers
755 views

GPU chip implementation on CPU - will it be faster? [closed]

So, modern video cards include two devices - a video signal generator and a graphic accelerator. The first of them converts data from video memory into MDA / CGA / VGA / RCA / DVI / HDMI / etc format....
9
votes
3answers
413 views

What are the Ultra-Highres registers in ECS and AGA for?

The Amiga custom chip set, in its ECS and AGA versions, seems to contain some registers for what is called an "Ultra-HighRes/DUAL" mode: DFF078 SPRHDAT W Ext. logic UHRES sprite pointer and ...
13
votes
2answers
574 views

Atari ST DRAM timing puzzle

From the Atari SM124 Monochrome Monitor Service Manual, I get that the video signal timing for one line is 20µs. With the horizontal resolution of 640 pixels, this gives a 31.25ns pixel clock. Using ...
35
votes
7answers
12k views

Why did computer video outputs go from digital to analog, then back to digital?

While early microcomputers used analog video outputs (often to use a television as a display), higher end machines such as the BBC Micro or Commodore 128 supported a digital RGB (or RGBI) video output....
6
votes
4answers
1k views

High-end PC graphics circa 1990?

I remember CAD being a major driver for PCs with high-end graphics cards; specifically AutoCAD was rising quickly in popularity around 1990 as PCs were able to compete with very costly CAD ...
51
votes
6answers
11k views

How did old MS-DOS games utilize various graphic cards?

Nowadays each graphic card has some driver in operating system that translates some (typically) standard API such as OpenGL, so that programmers use some standardized API code to tell graphics cards ...
3
votes
1answer
194 views

Apple I and II video output to a contemporary TV set?

Is it possible to connect the unmodified video output from an Apple 1 and Apple II (with their non-standard/our-of-spec NTSC sync pulse levels and/or timings) to a (currently in-production and ...
9
votes
3answers
1k views

What is the best option to connect old computer to modern TV

I was exploring different options of connecting both my Atari ST and C64 to a modern TV. I opted for a composite signal passed through a cheap AV to VGA converter, and although the display works, ...
4
votes
1answer
179 views

Atari 1040ST AV video output - blurred and jagged vertical edges

I have an AV cable that connects Atari 1040STE with a AV to VGA converter. For some reason the vertical edges are not sharp, rather jagged or pixelated. I red that old atari would have an issue with ...
6
votes
1answer
348 views

When did MS Windows get Dual Monitor support?

I remember one of the features I admired on the Macintosh in the late 80s was support for multiple displays. First time I saw this was on an SE/30, using the internal display along with a big external ...
1
vote
0answers
92 views

Cannot get K prompt on Timex 1500 [closed]

I started tinkering with a Timex Sinclair 1500 I was given awhile ago. When I first tried starting it, I got a K prompt in the lower left of the screen. I turned it off and did not return to it for a ...
11
votes
1answer
222 views

Could suitably-written Apple-I software force bytes into the display shift register, and do modern recreations emulate that?

The original Apple I didn't use RAM to hold the contents of the display, but instead used a group of six 1024-bit shift registers to hold the display contents and a seventh 1024-bit shift register to ...
4
votes
2answers
339 views

When were sprites first displayed in the border area?

I assume one of the first undocumented effects on the VIC-II was the ability to display sprites in the (upper and lower) border area. I wonder how and when this was first discovered and used? Was it ...
10
votes
4answers
1k views

Did any machines alternate between two video memory banks?

If a home computer or console has two banks of memory, A and B, then the following design is possible: The video chip only connects to bank A. The CPU connects to both. During active scan line, CPU ...
6
votes
3answers
874 views

Commodore 64 with red and white RCA cable

After discovering my old Commodore 64 in the garage, I wanted to test if it still works. The power light comes on but the video connection to a modern TV is obviously an issue, as mentioned here. Well ...
6
votes
1answer
313 views

Is there a comparative analysis of the evolution paths of chips inheriting from TMS9918?

This is primarily about VDP from the Sega Master System game console and video chip from the MSX 2 series computers. Specifically about Yamaha YM2602 (aka Sega 315‑5124) and Yamaha V9938 respectively. ...
6
votes
1answer
338 views

How did the original TRS-80 generate video?

I'm curious how the original (Model 1) TRS-80 generated video. I understand that an RF modulator was used but what kind of circuitry did it use to feed the RF modulator? The TRS-80 Color Computer ...
8
votes
1answer
323 views

Possible cause for C128 A/V output containing faintly coloured columns and failing shortly after?

I recently acquired a Commodore 128. It worked fine for about an hour, in both C64 and C128 mode, at the exception of some coloured bars, before displaying garbage and not booting anymore into any ...
8
votes
1answer
536 views

On the bbc-micro, a half-size mode 1 screen mode with 16 colours instead of 4 can fit in memory but can the video chip be programmed for it?

Screen Mode 2 on the BBC micro is 160 x 256 with "16"* colours. This uses up 20Kb of memory. Horizontal-rectangular pixels ( 2 x squares each). 4 bits per pixel (0-15 values for 16 colours) Screen ...
8
votes
2answers
780 views

Why did certain color combinations look terrible on the Commodore 64?

As I recall, on the Commodore 64's text mode, if you chose certain colour combinations, the letters would be badly obscured by some kind of interference which seemed to affect each character cell ...
5
votes
5answers
3k views

Is my understanding right about the actual differences between 240p and 480i?

After reading around on the web, including the authoritative site Scanlines Demystified I still am having trouble understanding the difference in signal between 240p and 480i. After reading the wiki ...
79
votes
9answers
13k views

Why were CLIs typically light text on dark background, whereas GUIs typically use(d) dark text on light background?

My experience is that CLIs were typically shown with light text on a darker background. For example, the IBM PC would use white/light gray (depending on your point of view), amber or green (the latter ...
4
votes
2answers
332 views

How does the PMD 85 display colour or greyscales?

I stumbled across this computer in an article on hackaday, Home computers behind the Iron Curtain and since it has this bizarre resolution, I looked closer into it. Some claims from Wikipedia: ...
11
votes
3answers
3k views

Visible resolution of C64 video output, including borders

The VIC-II in the C64 outputs 320x200 pixels inside the borders. What is the full visible resolution including the borders? To clarify, I am interested in the full screen size in units of normal ...
7
votes
6answers
2k views

What Video Chips/Video generation techniques are usable for the Z80?

I'm building a Z80 home computer and I need color graphics for it similar to other home computers such as the C64. I thought that, like Motorola or MOS, Zilog would have a peripheral chip dedicated ...
1
vote
1answer
246 views

Spying on old computer monitor RF signals [closed]

In the mid 80's, several national news outlets showed people able to reproduce a computers monitors screen at least 100ft away. How were early computers compromised like this?
9
votes
4answers
649 views

Columns of text in early microcomputers

As discussed in some previous questions here, 80-column text was established by IBM as the standard for business computing as early as the sixties, but monitors capable of displaying that resolution ...
10
votes
1answer
396 views

VIC-II transistor count

I'm curious about the transistor count of the VIC-II, the video chip in the Commodore 64. According to http://visual6502.org/wiki/index.php?title=Chips_in_our_collection the Atari 2600 TIA chip has ...
7
votes
2answers
1k views

How to connect a Tandy Color Computer to a Composite Monitor?

Ok, I'll admit I'm out of my element on this one. I'm an Atari/Commodore/Apple guy, but I have this Tandy color computer kicking around and a spare Amdek Composite monitor and I thought they would ...
13
votes
5answers
2k views

Can the wrong sync frequency really destroy a CRT monitor?

I've read in various places that an incorrect signal of the wrong refresh rate can cause physical damage to a CRT monitor, but I've never found an adequate explanation of why this is so. Is this true? ...
11
votes
3answers
1k views

What specific technical advance(s) allowed PCs to play “Full-screen full-motion” video?

In the early 1990s, the new buzzword for PCs was "Multimedia", and the gold standard for multimedia performance usually talked about was "full-screen full-motion" video playback. Many will remember ...
11
votes
3answers
2k views

Were video chips specific to the CPU?

Modern graphics cards are essentially miniature supercomputers in their own right, with their own memory and instruction sets, but in the eighties and late seventies, a very common kind of personal ...
13
votes
1answer
489 views

How do Amiga “Monitor” drivers work?

A "Monitor" driver for an Amiga is a file which, when placed in DEVS:Monitors, enables additional screenmodes. The standard PAL or NTSC driver, which provides screenmodes compatible with consumer TV ...
6
votes
1answer
328 views

Timex Sinclair 1500 and screen “jail bars”

I have tried to eliminate "jail bars" on the screen after UHF mod to video out (based on that: http://zx81stuff.org.uk/zx81/ts1500_video.html) by adding 460uf 16V capacitor between +5V and GND but it ...
34
votes
4answers
7k views

What determines the color of every 8th pixel on the Apple II?

On the Apple II there's an interesting way to add a little color to the bitmap, since the high bit select the palette used for the three-and-a-half pixels represented by the byte. Like this: 0: Black,...
6
votes
3answers
972 views

A different kind of sprite system

Early consoles and home computers that were optimized for games, often provided sprites. From the viewpoint of a game developer, these were good to have, though one always wanted bigger sprites, to ...
19
votes
7answers
4k views

What video connections were common in Europe?

What video connections were common on European TVs and monitors during the "retro" era? In the USA, first there were none on TVs (RF screw terminals only) and monitors had composite (yellow RCA, CVBS)...
9
votes
5answers
2k views

How can I adapt a digital CGA/C128 signal (RGBI DE-9) to a modern monitor?

IBM's CGA and the Commodore 128's RGB video output both use a DE-9 connector. How do I adapt the CGA video output from an IBM XT 5160 or Commodore 128 to a modern monitor?
5
votes
2answers
399 views

Timex 2048 RAM contention ULA/video output

I used to own a Timex TC-2048 ZX Spectrum 48K compatible clone. I programmed it in assembly extensively, both for fun and when learning, and also when testing things for writing my own ZX Spectrum ...
13
votes
3answers
1k views

What is going on in the overscan area of Sega Genesis games?

What is going on in the overscan area of Sega Genesis games? I noticed that different games display different things in the overscan area. I understand this was never intended to be seen. However,...
18
votes
6answers
1k views

Limiting factor on sprite sizes

Early consoles and home computers that were optimized for games, tended to provide sprites. From a game programmer's viewpoint, these were good to have. Of course, one always wanted more and larger ...
11
votes
6answers
2k views

Z80 and video chip contending for random access

Back in the 8-bit days, I used 6502 computers, where the story about memory access was easy to understand. RAM chips of the late seventies and early eighties could do 2 MHz (or a bit more e.g. 2.6 in ...
9
votes
4answers
759 views

Video chip for hypothetical 1988 arcade game

I have a project where I aim to create a retro arcade game cabinet, the technology would be ~1988. For now I am planning to only simulate the system on my PC in order to develop the game. The ...
7
votes
1answer
397 views

Is it possible to chain TMS9918 chips to get better graphics?

I'm considering creating a retro system but without requiring the sacrifice of any retro machine in order to get parts. The TMS9918 chip seems the only "generic" retro graphic chip, all other chips ...
24
votes
9answers
5k views

Graphics chips in 1980

Suppose you were trying to build a computer with a color graphics display in 1980, you have limited engineering resources and time to market is critical, so you want to get as many of the parts off ...
8
votes
1answer
370 views

What was the difference between the original Video Toaster and the 4000 version?

There were two versions of the Video Toaster hardware: an original one designed for the A2000 and a later one designed for the A4000 which was suitably called the Video Toaster 4000. While I can ...
6
votes
1answer
481 views

Transistor count of early video chips

There are a number of sources that give transistor counts for different CPUs over the decades. I'm looking for transistor counts for early video chips. in particular, I'd be interested in transistor ...
2
votes
1answer
280 views

Using a NeoMagic 256XL with Windows 98SE

I have a Sony Vaio PCG-F560 notebook and I have installed Windows 98SE on it. The only issue is that the display works only in 16 colors mode with 640x480 resolution. I think the problem is that ...