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5
votes
1answer
2k views

Atari 2600 has no sound, no video. Any advice?

I have 2 Atari 2600s. I got them both at a garage sale. I plugged them both in with a coaxial adapter. No sound, no video. I opened them up, didn't see any shorts, the boards looked good. There ...
14
votes
1answer
572 views

Did the Macintosh Classic series use DMA to display video?

I'm learning more and more on how the original Macintosh series worked. I can't, however, find information in my research on how the Mac's video generator accessed the video RAM. My assumption is ...
29
votes
2answers
4k views

Why did Sinclair choose the Z80 for its range of home computers?

The Sinclair computers are known for their low cost compared with other computers that were popular in the early 1980s. This is why they had membrane keyboards, or that rubber stuff in the case of the ...
3
votes
2answers
206 views

IBM PS/2 Model 53 Not Powering On

I bought a PS/2 with the intent of robbing it's case for a restomod project, but since that is on the backburner right now I decided to see if it would work. When I flip the power switch, the PSU ...
10
votes
1answer
980 views

How does the Mac SE/30 send video to the analog board?

I can't seem to find where the video signals leave the digital board of my Mac SE/30 and travel to the analog board that is connected to the monitor. I even searched for pinouts online but I guess my ...
14
votes
3answers
1k views

Why did the Sinclair ZX-Spectrum use a membrane keyboard?

As a kid, I always had problems with the keyboard. Membrane was hard to come by and expensive. I did not have Kempston/Protec. So I had to play on the keyboard. I was using QAOPMN combination, and ...
7
votes
4answers
1k views

Writting DSK images onto a 3'' floppy for Amstrad/Sinclair computers

For a project I'm working on, I need to write some disks to test on my Amstrad CPC 6128. I've got some 3'' inch blank disks, and all my Amstrad computers (CPC and PCW) have 3'' inch disks, as well as ...
9
votes
2answers
3k views

What did the Supercard “patch” program actually do to GBA and NDS ROMs to make them playable?

The Supercard is a flash cart for the Game Boy advance which can play ROMs and other files off of assorted flash memory. I recently found my Supercard SD and Superkey for NDS, which acts as a ...
6
votes
2answers
730 views

SheepShaver failing to install application; Not Enough Memory

I am trying to install "Kid Pix Deluxe 4" on Mac OS 9 using SheepShaver on Ubuntu 16.04. A problem I am having is that when I try to install it, I get an error saying that I don't have enough memory. ...
13
votes
5answers
601 views

What computer first facilitated multi-precision arithmetic

While early microcomputers were often 4- or 8-bit designs, with larger word sizes coming later, that pattern did not hold for their predecessors. None of the earliest computers used a word size that ...
5
votes
2answers
463 views

Compaq Contura Aero 4/33C - moving data to CF/IDE disk - No operating system detected

I've got a Compaq Contura aero 4/33 laptop with original DOS system installed. As the HDD is old and dying, I've decided to copy the drive to a CF card on a CF/IDE adapter. After connecting the drive,...
6
votes
0answers
190 views

What is the model of the Emachines Etower 366i2's Monitor?

I've an old 1999 Emachines Etower I want to restore. I have all the original parts except for the monitor. It just isn't a complete set without it. Does anybody know the specific model of that monitor....
22
votes
2answers
605 views

What API did the “math box” provide?

Some classic vector arcade games, such as Battlezone and Red Baron, were based on the 6502 CPU. The processor wasn't fast enough to do the 3D computations, so a co-processor commonly known as the "...
9
votes
2answers
939 views

Atari 2600 high voltage output

I've never worked on a Atari 2600 before. The first time I did, I wasn't getting anything on my old box TV. Not being able to do much at the time, I decided to check the voltage. The output voltage is ...
6
votes
1answer
242 views

How do I make a Unibus device?

The Unibus was an innovative I/O system used by DEC PDP-11 machines. A device would choose some memory addresses to respond to, register an interrupt vector, then communicate with software that was ...
19
votes
3answers
1k views

Why did the Atari 8-bit computers make beeping noises while accessing the disk and cassette drives?

If you've ever used an actual Atari 8-bit computer with either a cassette or disk drive, you would have noticed that it made a variety of "beeping" noises while accessing the devices. Specifically, ...
10
votes
2answers
742 views

How were Lisps usually implemented on architectures that has no stack or very small stacks?

I am thinking about architectures like the 6502 (the stack is limited to 256 bytes -- hardly enough to evaluate any reasonably sized Lisp expression) or the PDP-7 and PDP-8, which stored the return ...
10
votes
2answers
375 views

Creating an System Extension (INIT) for classic mac os

I have some old macs that I would like to remove their clock batteries so that I don't have to worry about them leaking and destroying logic boards. That being said I do want to operate them from time ...
71
votes
2answers
16k views

Why does the Minus World exist?

In Super Mario Bros. for the NES and Famicom there exists a secret world, accessible by clipping through a wall to the first warp zone and entering the left-most pipe. This pipe will take you to ...
14
votes
4answers
1k views

How can a computer use the drive's momentum for emergency power?

I remember reading an answer about a computer that, in the event of a power failure, would write the important parts of the memory to disk - using the momentum of the still-spinning drive to do so. ...
8
votes
3answers
817 views

To wash or not to wash a Mac SE/30

I have a Macintosh SE/30 that I'm trying to bring back to life. When I power it on, I get the dreaded horizontal stripes. Or, zebra stripes. Also called Simasimac. I have re-seated all of the ...
13
votes
1answer
2k views

Sega Genesis/Mega Drive ROM Disassembler

I am looking for a disassembler that supports Sega Genesis ROMs. Ideally, any 68000 disassembler should be able to do this (IDA Pro supposedly does an amazing job but their demo version does not ...
18
votes
1answer
2k views

Why does Ms. Pac-man turn upside down?

Ms. 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. This time, however, the yellow dot has an ...
17
votes
2answers
1k views

Power cycling old hardware

For those of us that use an old computer daily, is it safer for the hardware if the machines are turned off every night, or should they be left on? I assume that powering up is more stressful for the ...
18
votes
1answer
1k 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 ...
94
votes
5answers
20k 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 ...
17
votes
12answers
5k 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
218 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
8k 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 ...
22
votes
4answers
4k 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
499 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 ...
24
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
253 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
3k 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. ...
12
votes
4answers
529 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
488 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
649 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
373 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
589 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
447 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
562 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
250 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, ...

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