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66 votes

Could Pac-Man be replicated perfectly on the ZX Spectrum?

Both the Sinclair ZX Spectrum and the Pac-Man arcade machine used the Zilog Z 80 CPU. Pac-Man's display was slightly larger and vertical at 224×288 while the Speccy's was horizontal at 256×192. The ...
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62 votes
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What was Pong called in Britain?

Pong. I've lived in the UK for many years and never heard it called Ping! That is news to me. Now, when talking about the video game called Pong, we call it Pong.
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  • 34.8k
60 votes

Why did early arcade games use vertical displays?

Having the display vertical reduces the width of the cabinet. This means that a game machine can be fitted into a smaller space in a pub/bar, or in an amusement arcade where machines are in rows you ...
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  • 649
57 votes
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Why does the kill-screen glitch occur in Pac-man?

There are only seven fruit in Pac-man. The way the game calculates the number of fruit to draw is as follows: LD A,(#4E13): Load the level number (at memory address 0x4E13) into A. INC A: Increment A....
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  • 17.5k
40 votes

Why does the original Donkey Kong update the screen in a curtain closing pattern?

This isn't a deliberate animation, it's an accident of the way the screen is being photographed, combined with the fact that a Donkey Kong arcade machine uses a CRT turned on its side. A typical CRT ...
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  • 11.3k
39 votes

How do arcade ROMs work

The way I understand it, ROMs are like virtual games, Not really. ROMs are a piece of hardware storing a bit image. Like a disk, a tape or a punch card. It holds an image of the game's software. ...
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  • 173k
37 votes

Why does Ms. Pac-man turn upside down?

The reason for this glitch is rather obscure; it's not surprising that the developers didn't catch it. It all starts with the tunnels on the sides of the screen. These tunnels allow Ms. Pac-man and ...
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  • 17.5k
37 votes
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Why does the original Donkey Kong update the screen in a curtain closing pattern?

Ken's answer is close but not quite right. On the real arcade hardware the signal sent to the CRT monitor is read directly from RAM as the electron beam scans over the screen. That means that ...
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  • 14k
36 votes
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How was a demo mode implemented in arcade machines

Most of the time, game coders are not going to program an A.I. just to show the demo so the moves are pre-recorded, and generally the demo ends quickly with the main character dying/exploding (maybe ...
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35 votes
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Did arcade monitors have same pixel aspect ratio as TV sets?

CRTs don't have pixels, they don't work that way. Also, arcade monitors expose all the picture controls at the back so it is possible to adjust them quite extensively. Operators would have made sure ...
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  • 14k
33 votes
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Unlicensed home computer ports of arcade games

To understand what was going on with licensed and unlicensed ports of popular arcade games in the 1980s, you have to understand two critical factors. The video gaming culture of the time, and the ...
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  • 57.3k
32 votes
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Arcade game: pseudo-3D flying down a Death-Star-like trench

Yeah, I remember this arcade game, too. My brother was quite good at it, so I saw it a lot. Could it be Space Encounters? It was a full-sized arcade cabinet with an aircraft-yoke type controller ...
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  • 14.2k
29 votes

Why can you not move on the last level on Dig Dug?

Dig Dug stores the positions of objects in tables in memory. There are two tables for this: an enemy table containing the positions of up to four Pookas and four Fygars, and a rock table containing ...
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  • 17.5k
27 votes

Was it actually possible to do the cartoon "coin on a string trick" for old arcade and slot machines?

I actually did this with pinball machines in 1980-ish. Getting 3-5 games before the coin was lost wasn't impossible, and some of my friends did better than that.
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  • 371
27 votes

What was Pong called in Britain?

According to Atari co-founder Nolan Bushnell, Pong was marketed as "Ping" in the UK. He said so in this 1982 BBC interview ("because evidently Pong is not a good word in England"), ...
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  • 7,854
22 votes

What API did the "math box" provide?

The 6502 accesses the Atari Math Box, via a pre-defined memory map and address decoder,[1§I] as a memory-mapped I/O device.[1§IV] The top four bits of the External Address Bus are sent to the address ...
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  • 17.5k
22 votes
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Details of video memory access arbitration in Space Invaders

Space Invaders uses a simple display format where bytes are read from memory in order via an address counter, and shifted out via a shift register. Timing is controlled by discrete hardware. The ...
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  • 14k
21 votes
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How do arcade ROMs work

The other answers already covered a lot, but there is something else that is important but which hasn't already been addressed in detail: Despite appearances to the contrary, arcade machines are ...
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  • 12.4k
21 votes

Was it actually possible to do the cartoon "coin on a string trick" for old arcade and slot machines?

It's difficult to be sure that there was never a system in use that was vulnerable to this trick, but certainly there were systems available from a very early stage that weren't. This coin acceptor is ...
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  • 2,072
20 votes

Why did early arcade games use vertical displays?

(From the perspective of the electronics, that means the displays were drawn sideways.) Not necessary. There is no inherent reason for drawing sideways. A video circuit can easy be made for either, ...
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  • 173k
17 votes
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What API did the "math box" provide?

Here are my findings: Disclaimers: This answer is entirely based on mame's mathbox.cpp source and assumes it is correct. This answer focuses on succinct high-level description, even at the cost of ...
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17 votes

Was it actually possible to do the cartoon "coin on a string trick" for old arcade and slot machines?

You could fool purely mechanical devices with mechanical tricks. One trick I have used when a kid, was with bottle caps. We wore them out underneath our shoes, until they were the size of a coin, fit ...
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  • 418
17 votes

How was a demo mode implemented in arcade machines

For space invaders what happens is the game has short list of movements (11 in ROM but only 10 are used) left and right or stay still. If there is no bullet in flight the player fires, each time the ...
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  • 5,155
16 votes

Was it actually possible to do the cartoon "coin on a string trick" for old arcade and slot machines?

I can personally confirm this worked on at least some video arcade machines in the 80s, when I was young. I can vividly remember being at an arcade at one point, and losing a quarter in the machine. ...
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15 votes

How did Z80 multiprocessing work in the Namco Galaga hardware?

The three CPUs were designated as follows: CPU 1 - Main game logic and control of the other two CPU 2 - Graphics and enemy movement CPU 3 - Sound The three CPUs communicate via shared RAM. CPU 2 and ...
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  • 14k
15 votes
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How did Z80 multiprocessing work in the Namco Galaga hardware?

Galaga has specialized graphics hardware that draws 64 individual sprites, so to update a screen full of objects you only need to update 256 bytes at the most. The star field is generated completely ...
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14 votes

Did arcade monitors have same pixel aspect ratio as TV sets?

Did arcade monitors have same pixel aspect ratio as TV sets? Short answer: No, not necessarily. Long Answer: To start with, 'Title Safe Area' is an idea to define the parts of one transmission to ...
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  • 173k
14 votes

What is language use for level name in level 3 and 5 of Strider arcade game?

(Links are to the pertinent points in the video) 00:15 Казахскся. ССР. A.D.2048 "Kazakh SSR A.D.2048" (Russian script, Latin date) 02:49 Сиби́рь 1 "Siberia" (Russian script) 06:...
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  • 8,930
14 votes
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What's the point of the CPS-2 suicide battery?

This was an anti-piracy measure. If a "bootlegger" wanted to duplicate the board, they would only have access to encrypted ROMs, thus making it impossible to reproduce the arcade board with ...
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