All Questions

18
votes
1answer
998 views

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

The objective of Dig Dug is to eliminate underground monsters by inflating them until they pop, or by squashing them with large rocks. Once all of the monsters have escaped or been defeated, the level ...
91
votes
5answers
19k views

How can tilting a N64 cartridge cause such subtle glitches?

When the N64 cartridge is tilted in Super Mario 64, it reliably produces glitches such as this. Mario's limbs disappear, he rotates 90° and sinks into the floor, and the music gets messed up (usually ...
16
votes
9answers
4k views

Did early assembly games use hardcoded memory locations?

In the era of C64, Apple][ GS, and SNES, did the games use hardcoded memory locations, or did they let the assembler help them (like modern assemblers)? If yes, how did they manage the memory?
12
votes
1answer
214 views

Can Extra Joystick Ports be Added to the Atari XL/XE Series of Computers?

The original Atari 400 and Atari 800 machines each had four joystick ports, which was frankly ahead of their time and made for some amazing experiences. M.U.L.E. with four players was an absolute ...
34
votes
1answer
6k views

Why does the kill-screen glitch occur in Pac-man?

Pac-man is a game where you navigate a small yellow circle around a maze, collecting dots and fruit whilst avoiding brightly-coloured monsters, or ghosts. As long as there was at least one 'man left, ...
26
votes
3answers
3k views

What was the first operating system to feature a separate kernel?

Kernels are programs that abstract the hardware of a computer to some extent, allowing other programs to use standardised system calls (e.g. malloc) to perform hardware tasks (e.g. writing to memory, ...
25
votes
4answers
7k views

Can I image Amiga Floppy Disks on a Modern computer?

Is there any way of reading Amiga floppy disks to PC hard-drive? Can I use a standard Floppy drive with a firmware program that will translate it? Do I need an external drive or a working Amiga ...
10
votes
2answers
1k views

What is the instruction set of the PDP-7?

The PDP-7 was a bookshelf-sized "minicomputer", with keyboard, magnetic and paper tape and printer I/O. According to Wikipedia, the first version of UNIX (then named Unics) was programmed in assembly ...
21
votes
4answers
3k views

Why did Pokémon Red have so many overflow bugs?

(This question also applies to other Game Boy games, but Pokémon seems to be one of the best-documented.) Pokémon Red & Blue (Red & Green in Japan) is a pair of Game Boy games about capturing ...
14
votes
3answers
493 views

Did any computers use automatically-operated mechanical storage as electronically-read-addressable memory

From what I understand of ENIAC, it had a very large number of manually-operated rotary switches which behaved as ROM. While programming ENIAC in the early days required a plugboard, the machine was ...
22
votes
4answers
3k views

What register size did early computers use?

Prompted by this question querying the prevalence of byte-addressable memory on machines with 32 bit registers: Why is every address in a micro-controller only 8 bits in size? I'm familiar with the ...
20
votes
3answers
2k views

How did Elite (BBC Micro) compress resources?

Elite, an Acornsoft game for the BBC Micro, is a game in space. Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is.     -- Douglas Adams ...
12
votes
1answer
238 views

Will the Atari 800 work without any expansion cards installed?

The Atari 800 had 4 user accessible slots for adding RAM and a ROM card. Normally, your machine came with at least two cards from what I understand. The question is, if I removed all the cards from ...
22
votes
3answers
2k views

Main board of the original Game & Watch (Ball)

The Game and Watch was a series of single-title games consoles created by Nintendo from 1980 until 1991. Each machine contained a custom LCD screen (containing images related to the software), some ...
38
votes
2answers
7k views

How did the Z80 instruction set differ from the 8080?

The Zilog Z80 microprocessor, known for its use in the ZX Spectrum, was designed to be a backwards-compatible extension to the Intel 8080 processor. It introduced several new instructions to the 8080'...
8
votes
1answer
1k views

Can I use a UK power adapter in NTSC NES

I have an old US (NTSC) NES system which we found in the garage. Sadly the power supply is missing. As I now live in the UK, I was wondering if it is possible to use a UK NES power supply with it. ...
10
votes
4answers
434 views

At what address do Apple II Applesoft programs get stored?

Online references disagree on whether Applesoft programs were stored at 0x801 (2049) or 0x3001 (12289). A quick test on my OpenEmulator install with an Apple II Plus definitely puts it at 0x801. ...
7
votes
3answers
475 views

Arithmetic operations on multiple words on the PDP-8

For the PDP-8 with its strange ISA, I've always wondered what the "standard" (i.e. fastest) way to do arithmetic operations (add, subtract, maybe multiply) on integers consisting of multiple words was....
14
votes
3answers
633 views

Conditional skip instructions of the PDP-8

I am interested in the SKIP instructions on the PDP-8. These test the accumulator and Link bit, and they skip the next instruction if the condition holds. The instructions are: OR GROUP SMA - Skip ...
23
votes
4answers
2k views

Use of undocumented opcodes

I figure this is fitting for Retrocomputing.SE because CPUs like the 6502 and Z80 and the PDP-8, and probably others, have undocumented instructions and will happily execute them, in contrast with ...
7
votes
1answer
360 views

P′′ Language Interpreter/Compiler Resources

According to Wikipedia, P′′ is a "primitive computer programming language created by Corrado Böhm in 1964 to describe a family of Turing machines." P′′ contains only four instructions has influenced ...
16
votes
4answers
581 views

A good method for formatting a modern device in HFS (Not HFS+)

I started this project ages ago and it's just been sitting on my bench for ever. I have this old MacIIci and I put a LAN card in it, maxed out the memory, has the turbo proc in it. The next step I ...
11
votes
2answers
412 views

How to connect an Apple IIe to an external Sider hard disk drive

I am a sucker for 8 bit junk components, and recently picked up a Sider hard disk for my Apple //e. I was able to talk myself into the purchase by fondly remembering how I lusted after this piece of ...
16
votes
1answer
528 views

Was the Atari 400/800 internal speaker of any use besides key click?

Sounds from the Atari 8-bit computer line came through the RF video cable into your television much like video game systems from the time. The original Atari 400/800 also had a built in speaker, ...
18
votes
4answers
3k views

Quick way to tell how much RAM an Apple IIe has

What is a simple way to tell how much RAM an Apple IIe has? The main RAM is fixed, but Aux RAM can vary. I'd like a solution that can be typed quickly from the keyboard: the context is that I'm ...
5
votes
1answer
247 views

Checking if RAM is functional

I'm trying to revive an old travelMate 518tx and I'm currently in the process of searching for bottlenecks. I want to check if the RAM sticks are still functional or not, but they're both very old, ...
12
votes
6answers
2k views

Converting SCART to VGA/Jack

I have a few home-microcomputers that use SCART to output both audio & video to TV screens such as the Atari STE 1040 and the Sony MSX Hitbit 501. I don't have room to store old cathode-ray ...
11
votes
4answers
644 views

Troubleshooting and reparing an Atari 800XL with a single key not working

I recently purchased an old Atari 800XL off eBay. The machine was untested/as-is and not guaranteed to work, but it was cosmetically in mint condition with original box, manuals, and even the ...
12
votes
1answer
1k views

Can polarity inversion damage a ZX Spectrum?

I have a ZX Spectrum+ and it didn't came with it original power supply. I bought a 9 Volts and 2.25 Amps power supply with switchable connectors. There was a mistake and the polarity was inverted, ...
5
votes
1answer
154 views

ZX Spectrum+ with SCART Interface doesn't display anything

I have an ZX Spectrum+ that came with a SCART interface (unknown brand, all I know is that it's french and that the blue logo seems to spell "IS"). It didn't came with its original power supply so I ...
32
votes
4answers
5k views

Are old versions of Windows at risk of modern malware attacks?

On my answer to a previous question (Can I run Windows 98 and games from the same era on an AMD Duron CPU?) I finished with a warning about using Windows 98 on the Internet, which received the ...
10
votes
2answers
539 views

Why does my Acorn RiscPC display the POST boot error?

After removing the Intel DX 486 card from my RiscPC (running RiscOS 3.6), the computer doesn't start up properly. Instead, it displays the text POST in red. What does this error message mean?
10
votes
1answer
316 views

Was Apple's automatic disk ejection mechanism patented?

I always though it was an awesome idea, but no one ever copied it. Even if more complicated than a standard eject mechanism, I guess it should not have been so outrageously expensive not to be ...
13
votes
1answer
641 views

What is the Kelly chip?

The Amiga 3000+ DevCon 1991 notes says: On the A3000+, these resources include the Amiga "Pandora" chip set (Alice, Lisa, Kelly, and Paula), However, a Kelly chip is not part of the official ...
10
votes
2answers
729 views

What was the A1200 Flash ROM support meant for?

Question inspired by this answer's last paragraph: https://retrocomputing.stackexchange.com/a/1307/2155 The Revision 1 A1200 schematics show that the system originally had support for a two internal ...
12
votes
2answers
479 views

What was the end of line convention for text files on the 8-bit Commodores

A two part question: Did an agreed upon convention for end of line (EOL) within text files exist on the 8-bit Commodores? If there was a convention, what was it?
10
votes
2answers
867 views

Atari Centipede Video and the GBS-8200 didn't seem to work - looking for ideas

So I ordered the GBS-8200 (It's a v4.0) and tried to use it to convert the 15KHz RGBHV monitor output to VGA. I did a direct connect to P11 with Red, Green, Blue and Hsync and Vsync and Video return ...
10
votes
1answer
252 views

What does the H protection bit mean under classic AmigaOS?

The AmigaOS file protection bits allows for Read, Write, eXecute, Delete permissions on files, similarly to Unix (save for the Delete permission). Additional bits are Archive (reset when a file is ...
3
votes
2answers
258 views

External power supply for 16.5V portable computer (Zenith SupersPort 286e)

I have acquired a Zenith SupersPort 286e portable computer without its battery and the external power supply unit seems dead (corrosion and/or leaking capacitors). The problem is that the power suppy ...
47
votes
1answer
20k views

How exactly does Sonic & Knuckles' 'Lock-On Technology' work?

The cartridge of Sonic & Knuckles is a little special: It flips open to allow you to connect another Sega Mega Drive (Genesis in US) cartridge to the top of it like so: I know why the Sega ...
3
votes
1answer
135 views

Zenith SupersPort 286e doesn't boot at all

I have acquired a Zenith SupersPort 286e without its battery but with its (seemingly working) power supply. Sadly, the computer doesn't boot at all, nothing happens when I flick the On/Off switch. ...
6
votes
3answers
1k views

Converting from 15Khz RGB to VGA for an 80's Atari Centipede arcade machine?

I have been hunting around to find a replacement flat panel monitor to replace the honking CRT in a 1980's Atari centipede machine. The existing monitor supports 15Khz RGB which is not really ...
6
votes
1answer
605 views

Where can I find windows 10 driver for old Syquest Drives?

SyQuest made portable hard drive diskettes. I believe they have been out of business going on a couple of decades. At any rate I have some disks and the hardware, but I am unable to find drivers. I ...
9
votes
1answer
279 views

Methodology for imaging Atari disks

I have a pretty decent collection of retro computers, but I have always been a Commodore and Apple guy. I recently picked up an Atari 800XL and a 1050 disk drive, so I am investigating the ...
7
votes
1answer
286 views

ROM programs on the Sony MSX HitBit HB-501

I have acquired a Sony MSX HB-501 F (F stands for France, it only defines the keyboard's layout). It is fully functionnal, I can play games from cartridges on it and it displays MSX-BASIC if no ...
12
votes
5answers
2k views

Can I run Windows 98 and games from the same era on an AMD Duron CPU?

I have acquired an old motherboard with a socket 462 and a AMD Duron (I think its a "Spitfire" model 3). The copyright on the CPU is from 1999 and it apparently doesn't require a dedicated CPU fan as ...
21
votes
2answers
1k views

Was the MC680x0's TAS instruction forbidden on Amiga systems only when operating in CHIP memory?

(Note: a previous version of this question asked about the CAS instruction, that was added by Motorola from the MC68020; the original one is the TAS instruction). TAS is the acronym for Test And Set, ...
12
votes
1answer
865 views

Upgrades for the TRS-80 Model 100 portable

The TRS-80 Model 100 portable officially allowed for RAM expansion to 32k and an external acoustic coupler for the model. What other upgrades and peripherals exist for the Model 100? I had one of ...
12
votes
2answers
3k views

Computer graphics before the modern GPU [closed]

Modern computers use a graphics processing unit in order to provide hardware-accelerated graphical operations. Conceptually, I am used to thinking about graphics as a bidimensional array of ...
7
votes
2answers
2k views

Repairing/Lubing/Fixing Amiga 500 floppy drive

I have acquired an Amiga 500 that seems fully functional, but the floppy disk drive seems to have mechanical issues. I could get it to read a few floppy disks until the last one wouldn't pop out when ...

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