67 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 ...
hippietrail's user avatar
  • 6,666
63 votes
Accepted

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.
Omar and Lorraine's user avatar
62 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 ...
Owain's user avatar
  • 679
58 votes
Accepted

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....
wizzwizz4's user avatar
  • 18.6k
41 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 ...
Ken Gober's user avatar
  • 11.4k
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. ...
Raffzahn's user avatar
  • 223k
39 votes
Accepted

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 ...
user's user avatar
  • 15.2k
39 votes
Accepted

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 ...
Jean-François Fabre's user avatar
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 ...
wizzwizz4's user avatar
  • 18.6k
37 votes
Accepted

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 ...
user's user avatar
  • 15.2k
32 votes
Accepted

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 ...
Brian H's user avatar
  • 60.8k
32 votes
Accepted

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 ...
DrSheldon's user avatar
  • 16k
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 ...
wizzwizz4's user avatar
  • 18.6k
29 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.
markai's user avatar
  • 399
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"), ...
Michael Graf's user avatar
  • 10.1k
23 votes
Accepted

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 ...
user's user avatar
  • 15.2k
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 ...
wizzwizz4's user avatar
  • 18.6k
22 votes

Do people fix software bugs in old arcade games?

Yes they do, for example see this list which mentions Defender bugfixes for example. Don Hodges has done quite a few.
Alan B's user avatar
  • 4,535
21 votes
Accepted

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 ...
Jules's user avatar
  • 12.9k
21 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, ...
Raffzahn's user avatar
  • 223k
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 ...
occipita's user avatar
  • 2,357
20 votes

Identify a vertical arcade shooter from the very early 1980s

found it :)) it was Astro Fighter
Torsten's user avatar
  • 429
19 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 ...
PeterI's user avatar
  • 5,307
18 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. ...
Chris Sunami's user avatar
18 votes
Accepted

Drawing Asteroids DVG vector objects

The weird results come from interpreting the vectors as absolute coordinates instead of relative coordinates. Let me demonstrate. Here are the coordinates that you show in your example code. Plotting ...
2012rcampion's user avatar
17 votes
Accepted

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 ...
secondperson's user avatar
17 votes
Accepted

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 ...
8bitworkshop's user avatar
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 ...
chthon's user avatar
  • 700
17 votes
Accepted

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 ...
Brian H's user avatar
  • 60.8k

Only top scored, non community-wiki answers of a minimum length are eligible