Questions tagged [hardware]

Retro hardware generally: boards, extension cards, power supplies, peripherals. Use more specific tags as appropriate; use [case] instead for enclosures.

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11
votes
5answers
2k views

6502 reset pin: always needed on power on?

The 6502 pinout has a reset pin, which presumably would be used if a reset button is pressed on the machine containing the CPU. But the 6507 contains the same pin. The 6507 was designed at the ...
12
votes
1answer
598 views

Did the Samsung SPC-650 have any hardware or firmware differences to the genuine Sinclair Spectrum+?

There was a clone of the Sinclair Spectrum+ in South Korea called the Samsung SPC-650 that looks identical to original British version with just an extra model number/logo. It even retains the ...
7
votes
1answer
400 views

Did the original Japanese Tamagotchi device really die *completely* (forever) if the digital pet died? [closed]

Ever since 1997, I've had this "factoid" in my head that the original release of Tamagotchi in Japan had no "reset" feature, and you could not remove the batteries to reset it ...
10
votes
1answer
575 views

How Amiga A590 autoboot ROM and bootable floppy disk works?

Commodore A590 was a peripheral hard drive and memory expansion unit for Amiga 500/500+ computers. It provides SCSI and XT-harddrive controller and 2MB Fast Ram. Here is the Big Book of Amiga Hardware ...
10
votes
2answers
321 views

How do I terminate an ISA bus correctly?

I am stuck by designing a 8 Slot 16 Bit ISA Backplane Do I have to terminate an ISA bus? My search results are: No termination at all Some homebrew projects use active termination for all signals ...
9
votes
1answer
552 views

Where are the Colossus schematics?

The Colossus series of electronic computers, considered by some to be the first fully electronic (as opposed to electromechanical) computer in the world, was originally a British state secret. This ...
1
vote
2answers
156 views

How many kinds of mass-producible ROM is avaliable before 1970? [duplicate]

Back in the days before mask ROM (when invented?) we got core rope memories, or Little Old Ladies memories, which required lots of human labor to build. Were there any kinds of ROMs which were ...
11
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4answers
2k views

Smallest/Simplest, modern pure relay computer with at least 4-bits data words

There are a lot of designs out there of modern home made relay computers (not just ALUs but real computers -let's call them Turing complete, although Turing complete is not enough for having an ...
5
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1answer
309 views

Were Harvard Mark I and Mark II using diodes?

My understanding is that diodes (and other electronic components like vacuum tubes) started to be used in this line of Harvard machines, only with the Mark III computer. Does anyone have some ...
4
votes
1answer
292 views

IBM 650 - how many logic gates?

How many logic gates did the IBM 650 have? I'm used to measuring the complexity of a CPU by transistor count, but the 650 was a vacuum tube machine; the number of tubes would also be an interesting ...
3
votes
2answers
242 views

How many 6SN7 tubes did it take to store a bit?

One of the most important components of a computer is a circuit called a flip-flop, which has two stable states (that it can flip-flop between, hence the name); it is used for temporary storage of a ...
5
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2answers
946 views

Were any vacuum tube computers built with wire wrap?

I'm trying to gain some understanding of how early computers were built; as discussed in What accounted for the cost of ENIAC? the cost of first-generation computers was not necessarily mostly about ...
15
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4answers
3k views

Is it possible to expand Amiga 500 rev 8 to 1.5 MB with a 1MB trapdoor expansion?

Is it possible to expand an Amiga 500 rev 8 (not an Amiga 500 plus) to 1.5 MB of Chip RAM using an A501+ expansion? It is plug and play or are modifications required? This is the board: Source: ...
97
votes
17answers
23k views

How was early randomness generated?

Many programs make use of randomness, from BASIC guess-the-number games to encryption key generators. This randomness could have been generated in many, many different ways: hardware, software, ...
13
votes
1answer
391 views

Why did the Rumble Pak for the Nintendo 64 require batteries when it actually apparently doesn't?

After watching this video tutorial: https://www.youtube.com/watch?v=AyJsOoQKRjQ I'm wondering what the whole deal was with the batteries. Apparently, you can resolder the circuit board inside the ...
32
votes
6answers
6k views

Why did Commodore sell CPUs to its competitors?

Many of the most popular personal computers and video game consoles of the 1970s and 1980s, including those made by Commodore, Apple, and Atari, used the 6502 CPU (or some close relative, such as the ...
4
votes
3answers
432 views

Were there low-end eighties computers that used dual-ported video RAM?

Going through schematics of several home or small office computers of the era, I was wondering why almost none of them (1) used dual-ported video RAM. I understand that those chips were initaly ...
10
votes
9answers
4k views

Were any external disk drives stacked vertically?

There was a time when floppy disk drives were big, expensive devices that in many cases, instead of being components of a computer, would be separate machines connected by a cable, in some cases with ...
0
votes
2answers
167 views

Z80 - “LD (nn), dd” command cycle [closed]

For a university assignment, I have to describe and draw the command cycle of the LD (nn), dd command. To be exact, I was given this command: LD (0x1000), BC which I interpret as putting the low ...
10
votes
2answers
2k views

Did the PDP-8 designers consider a stack?

The PDP-8 was a remarkable exercise in minimalist computer design; some of the aspects of its design are discussed in detail at PDP-8 transistor count One feature it did not have was a stack. Instead, ...
21
votes
3answers
7k views

What was the rationale behind 32-bit computer architectures?

Though today various power-of-2 word sizes seems to be the norm, back in the 50-60s multiple-of-6 word sizes was more popular and was required by Department of Defense(DOD) in particular. 36-bit ...
5
votes
2answers
368 views

How can I tell if my old PC supports > 137 GB hard drives?

I have an old PC from 1999 that has an ASUS P5A motherboard. When I power it on, it says ASUS P5A ACPI BIOS Revision 1011 Beta 005 and 05/02/2002-ALADDIN5-<<P5A>>: I recently read that up ...
27
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2answers
6k views

How did the “Programmer's Switch” work on early Macintosh Computers?

The early Apple Macintosh computers (original Mac, Mac 512K, Mac Plus) all came with a "Programmer's Switch" installed on the side. I believe this persisted for a long time, with the switch ...
22
votes
4answers
4k views

What accounted for the cost of ENIAC?

I'm used to the fact that first-generation computers were very expensive, which I had always assumed was because they contained large numbers of vacuum tubes, each of which is a rather complex, high ...
1
vote
1answer
244 views

8088 CPU A16-A19 address lines go crazy with nop test after 0FFFF address

I'm building a minimal, minimum mode 8088 computer. I started with an 80C88-2 (CMOS, static variant) CPU. My configuration is really simple. One CPU, one 74HCT245 (DTR->DT/R) for the data lines, ...
3
votes
2answers
162 views

Could early computers use existing punch card machines?

In the early decades of the industry, computers used punch cards for data storage and transmission, partly because they were already widely used for pre-computer data processing; indeed, a major ...
10
votes
1answer
1k views

Testing/using a joystick in AppleSoft?

How does one use joysticks in a program on the Apple //? I have three different joysticks here and I would like to visualize their state (pot and button values), maybe similar to the SDL joystick ...
-4
votes
4answers
582 views

Operating systems which have non-x86 instruction set architecture [closed]

What are the most famous operating systems for non-x86 computers? I mean, most famous OS which have different instruction set architecture. Background (to better understand my task): I ask this ...
8
votes
1answer
845 views

How many transistors in the CDC 1604?

The CDC 1604, released in 1960, was Seymour Cray's first supercomputer, and also one of the first computers made of transistors. (The IBM 7090 was released only the previous year.) How many ...
5
votes
0answers
223 views

Were vertical monitor arcade games programmed differently from those with horizontal monitors?

Many classic arcade games like Pac Man (Namco 1980), Assault (Namco 1988), Mercs (Capcom 1990), etc, use a monitor oriented vertically. I assume that they used the same physical hardware, with the ...
11
votes
10answers
3k views

Hardware assisted Graphical User Interface?

I have read a fiction novel in which a manufacturer in the 80s provided GUI by adding a dedicated drawing hardware besides videocard or by extending videocard. Fictional as it is, is this possible or ...
17
votes
4answers
2k views

Mind-Controller User Input from the late 90s

In the late 1990's, I recall that there was a piece of hardware being demonstrated in Best Buy that supposedly allowed you to control your computer via signals sent from your brain. The way it worked ...
1
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2answers
390 views

What is the brand and model of this AT chassis case from the early 90s?

A friend is trying find the original brand and model of this old 1990’s generic case. An ad from computershopper would help.
2
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2answers
386 views

How were the popular CPUs of the eighties implemented? [closed]

With the ubiquity of FPGAs, I find it relatively easy to design an eighties-like CPU. But it's maybe too simple now, with so many ways to implement any given CPU unit. What were the hardware ...
19
votes
2answers
1k views

How did the Apple IIGS automatically slow 5.25 inch disk I/O code for backwards compatability?

Apple II software often used hard-coded timing for 5.25 inch floppy disk I/O, for example to control the duration of each track step or the rate at which bytes are written and read from the disk. ...
12
votes
2answers
2k views

How did the Altair ensure that the −5 V supply was the first connected and last disconnected?

The Wikipedia page for the Intel 8080 processor describes pin 11 as The −5 V power supply. This must be the first power source connected and the last disconnected, otherwise the processor will be ...
6
votes
1answer
195 views

What were the different RAM refresh techniques in the 80s

I've looked at some techniques that were used at the beginning of the eighties to refresh the RAM (CPU-based refresh for the Z80, or the use of the video circuit for computers that shared the bus ...
13
votes
4answers
3k views

CPU frequency / memory wait states at end of the 80s

According to the advertisements of the late eighties, you could find RAM having an access time ranging from 120 to 80 ns (150 to 210 cycle times). A 386SX-25 could execute a typical register to ...
-3
votes
3answers
472 views

Were there ever plans published, or kits, or a machine made, for a noughts-and-crosses computer game which did not use electronics? [closed]

Were there ever plans published, or kits, or a machine made, for a noughts-and-crosses computer game which did not use electronics – using only wire, an electricity source, and light bulbs ? . A ...
-4
votes
3answers
293 views

What was the last personal computer to have the chips neatly arranged in rows and columns?

Once upon a time, the chips on the circuit boards of personal computers1 were arranged in a tidy grid pattern. Observe the board of the Apple ][+: Or the Commodore 128: Sadly, the zen of neat rows ...
6
votes
1answer
1k views

What was the first computer board to be wave-soldered?

The Wikipedia article on wave soldering does not give any information on its history. What was the first computer circuit board to use this process? I am specifically looking for computers that were ...
13
votes
1answer
3k views

Connecting Panasonic “Penwriter” RK-P400C to modern PC using USB to serial cable

I have a Panasonic "Penwriter" model RK-P400C electronic typewriter/plotter from circa 1985 I'd like to be able to connect to a modern PC. And hopefully even use to draw graphics! Bought in almost new ...
1
vote
1answer
264 views

Which Mac models included a software visible DSP chip

Which Mac models included a DSP chip that could be accessed by regular application code? (e.g. not hidden inside the mouse, WiFi chip, disk read/write chip, GPU, etc.) Did they ship before or after ...
3
votes
1answer
140 views

How do I setup this Kickstart switcher?

I can not find any documentation for this Kickstart switcher. It's labeled LS A9211-3 © FH 1992. How must the jumpers J1 and J2 be set and where must the KB and RES lines be connected to? I want to ...
10
votes
3answers
448 views

When was the first tri-state IC produced?

This was prompted by a question on the electronics site (which was asking why only an open collector variant of a particularly old part existed and how it could be part of a data bus). This was a ...
0
votes
2answers
223 views

Vector-06C Soviet home PC schematics

Looking for Vector-06C schematics in any form.
14
votes
3answers
3k views

Replacing 80286 with 68000

Suppose you wanted to take a 286 PC and replace the CPU with a 68000, not at the initial design stage, but actually modifying the finished machine, on the theory that they both have 24 bits of address ...
5
votes
2answers
245 views

Config information on ancient 16-bit Multi I/O card

I need to build a retro machine so that I can access an HDD that required manual input of BIOS parameters. (Yes, I have that information.) The only ID I can find is ES1O/4A 280695 which yields nothing ...
11
votes
3answers
2k views

Swapping endian-ness on the 68000

In the 80s, the two great 16/32-bit desktop CPU architectures were the x86, used in the IBM PC and compatibles, and the 68000, used in the Amiga, Atari ST, Macintosh, early UNIX workstations and ...
13
votes
5answers
3k views

Mapping more than 64kb of address space

I'm planning out a 6502 homebrew build but seem to be stuck in the issue of buying parts. My plan is to extend the addressing capabilities of the 6502 by giving myself 64kb of RAM, and another 64kb of ...

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