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Questions tagged [hardware]

For questions about the components of retro devices (computers, etc.)

12
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1answer
778 views

Why does the C64 have the following palette?

The Commodore 64 has the following fixed palette of 16 colours: (Your palette may vary due to tuning of screen, etc.) What was the reason for this selection of colours? Are these colours ...
25
votes
4answers
2k views

Which ports are which on this Soviet ZX Spectrum clone?

Today I got my (first) Soviet ZX Spectrum clone. The person who sold it to me had inherited it and had no idea how it worked. It seems to be a home-made clone, rather than a factory-built one. See ...
11
votes
6answers
1k views

Why did tactile-feedback keyboards lose popularity?

IBM spoiled me for hardware quality. I've gone through many computers, including a TRS-80, Heathkit H-89, Commodore Vic-20 and C-64, and countless PC's but my first original IBM PC will always be my ...
4
votes
1answer
187 views

Is there a way to get code off an old Sharp Wizard?

I have one of these lying around somewhere... There was a really cool game on it called Dungeon which I'd love to get the code for. Is that possible? What would be the steps to try? I do have the ...
6
votes
3answers
591 views

How do you find information about your hard drive in MS-DOS?

Context: I'm running an original MS-DOS. I suspect the hard disk is failing, but don't want to shut it off for fear of not being able to get it started again if I can't swap the hard drive into ...
58
votes
5answers
13k views

Is it safe to turn on a 40-year old TRS-80?

My father is a retired programmer. When I was in high school in the late 1970s, he purchased a TRS-80 model 1 (on which I learned to program in BASIC). At some point in the early 1980s it, together ...
7
votes
1answer
201 views

In what ways is DRAM likely to fail?

A ZX Spectrum is likely to lose the same bit of every memory address if a single DRAM chip fails completely. However, if a DRAM chip partially fails, this could cause... interesting issues, ...
9
votes
1answer
273 views

When did Great Valley Products, stop producing hardware?

I had a GVP 68040 card in my old Amiga 2000 (ah those were the days). 25Mhz 68040, 16MB of RAM, SCSI controller to my 750 MB SCSI drive (if that was even 3200rpm I was probably lucky) and it was SO ...
4
votes
2answers
195 views

With better character handling capability, why didn't PC-98 system succeed in rest of East Asia?

From my understanding, an important advantage PC-98 have over IBM compatible PC was that it is better at handling ideograph based characters which are common in East Asian countries. Why didn't other ...
5
votes
1answer
388 views

How does the SAM Coupé refresh its RAM?

The SAM Coupé was a ZX Spectrum compatible computer with a 6MHz Z80, 256K RAM minimum, enhanced graphics and sound and an improved BASIC amongst other features. My question is about its memory. The ...
13
votes
3answers
2k 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 ...
4
votes
2answers
405 views

Manufacturing cost breakdown for a 16-bit computer

The dynamics of the market, of what platforms end up being used at what times in what contexts, depend not only on what is technically possible, but even more on what can be done for what price, so ...
19
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5answers
2k views

Were there any LSI-11 like home computers outside of Russia?

In my childhood I had one of these: https://en.wikipedia.org/wiki/Electronika_BK Note, that the CPU of this is based on LSI-11. This is rather surprising because PDP-11 took a room (I was lucky ...
11
votes
3answers
618 views

z80 crashes after executing some instructions

I'm building my own Z80 computer but I'm having a very strange problem. Consider this code: ld a,0xaa out (00),a jp a That works as expected, outputting 0xaa on port 0x00. Now consider this code: ...
4
votes
3answers
344 views

Retrieving text documents from a 2.0Mb/2.0 HD floppy disk?

I'm attempting to retrieve text documents from a floppy disk that is a 2.0Mb/2.0 Mo DS HD floppy similar to: The only thing he knows is that the documents were created on a mc around 1996. What are ...
30
votes
8answers
8k views

Why do articles use the term “UART” instead of “serial port”?

I am learning about old computers, and I have found the following image from this article: They use the terms "UART" instead of "serial port" and "UART driver" instead of "serial port driver", I have ...
12
votes
4answers
591 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. How it worked is ...
23
votes
5answers
4k 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 ...
3
votes
3answers
204 views

The baud rate of which serial card does the “stty” command returns in UNIX V7?

I am using a PDP-11 emulator with UNIX V7 installed on it. The stty command returns the baud rate: To which serial card does this returned baud rate belongs to, is it the terminal serial card, or ...
5
votes
2answers
245 views

Could we change the baud rate for the two serial ports on a terminal and on a computer?

Say we have a terminal (for example: VT100) that is connected to a computer (for example: PDP-11), and UNIX V7 is installed on the computer. The terminal will have a serial port that is connected ...
0
votes
1answer
192 views

Is this a UART chip? [closed]

Based on my understanding, a UART chip is a chip that exists on a serial card, and it is responsible for the actual sending and receiving of data over the serial port. I want to see what a UART chip ...
21
votes
3answers
3k views

Does an ISA card have a fixed memory address?

A PCI card does not have a fixed memory address, the PCI card specifies how much memory it wants, and the OS will assign whatever address it wants for this memory, and will set this address in the PCI ...
10
votes
5answers
2k 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 ...
22
votes
2answers
1k views

Why does waggling the joystick of a C64 cause errors loading from tape?

When loading a game from the tape drive on a C64, if you wiggle the joystick around too much the program will not load correctly. Is there an explanation for this? EDIT: Perhaps someone can try to ...
4
votes
1answer
267 views

How were the electronics in the Elektronika IM (Электроника ИМ) designed?

Elektronika in the Soviet Union created a series of handheld games in the 80s (Электроника ИМ) similar to the Nintendo's Game & Watch. How were the electronics in these games designed, especially ...
5
votes
1answer
199 views

Collection of older EPROM IC's

I acquired a collection of older EPROM IC's and am wondering what the rarity of them are or if they are rather common. Do people collect these items? 89142 NM27C512Q ~~ B9212 NM27C512Q ~~ B9312 ...
7
votes
1answer
350 views

Is it possible to chain TMS9918 chips to get better graphics?

I'm considering creating a retro system but without requiring the sacrifice of any retro machine in order to get parts. The TMS9918 chip seems the only "generic" retro graphic chip, all other chips ...
5
votes
1answer
223 views

Primary manufacturers of picture tubes for early monitors

Which companies were the most important manufacturers of picture tubes for monitors (both monochrome and color) in the seventies and eighties? That is, it's easy enough to find lists of monitors by ...
9
votes
3answers
1k views

Game cartridges on the S-100 bus?

Many Z80 computers in the seventies and early eighties used the S-100 bus, into which you could plug many kinds of expansion cards. Would it have been possible to plug suitably designed game ...
8
votes
2answers
671 views

Can the ADB keyboard and mouse be converted to the 128K Macintosh?

As you probably know, the original Macintosh 128K, 512K (Fat Mac) and the Macintosh Plus (IIRC) have a different keyboard and mouse connection than the later ADB versions such as the Macintosh SE ...
4
votes
1answer
218 views

What are the major differences between the ColecoVision and the SG-1000?

According to Wikipedia, the ColecoVision and the Sega SG-1000 were almost identical. I'm curious about that "almost" part. For example, they both used the same video generator (TMS9918/28). They ...
10
votes
6answers
2k views

Were there any “off the shelf” graphics chips that supported 2D sprites in the 70's and 80's?

I'm looking for "off the shelf" graphic IC's that supported hardware sprites. By "off the shelf" I mean chips that were designed to be used in various machines and not designed specifically for one ...
7
votes
4answers
538 views

When did the tower form factor appear and when did it become popular?

Essentially, my question is there in the title. Tower cases are commonplace these days, and probably are the "default" form factor for personal computers (or at least were, before they were surpassed ...
23
votes
9answers
5k views

Graphics chips in 1980

Suppose you were trying to build a computer with a color graphics display in 1980, you have limited engineering resources and time to market is critical, so you want to get as many of the parts off ...
10
votes
3answers
961 views

Why should 2 CPUs ever share the same bus?

The complexity of the Sega Saturn's technically impressive hardware played a large factor in its downfall. It seems to me that one of the largest things that was difficult to work with was that the 2 ...
3
votes
2answers
373 views

What chemicals or materials were used to create the logic for logic gates?

Back in school I took a couple electrical engineering classes and we did a lot of Boolean math using logic gates (AND, OR, XOR, NAND, etc), but never talked about how exactly the logic in a single ...
1
vote
1answer
99 views

PCB Black Spot: Leakage?

Photo album, sorry for the hassle Quick question: Ceramic disk capacitor has leaked? Or a dodgy soldering technique? This is a quite old calculator, it's an arbitrary model nowhere to be found. Any ...
26
votes
9answers
8k views

Should 486s have a heatsink?

I'm building a 486 computer. I plan on using a 100 MHz 486-DX4 that I have which I believe is about as fast as 486's went. The motherboard I will use (Socket 3) appears to support putting a heatsink ...
10
votes
2answers
1k views

How powerful was Knuth’s computer?

The Art of Computer Programming, volumes 1–3, was written in the late 1960s, with vol 3 finalized in Sept 1972 after a delay of “almost 3 years” because of rapid development of the subject matter. I ...
5
votes
2answers
137 views

Recover files from Dell PP04L Hard Drive

I have my mom's old Dell Inspiron 2650 model PP04L. She is passed away now but I'd like to salvage some of the old pictures and things she had on there. Is there a way to buy an enclosure and mount ...
8
votes
1answer
293 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 ...
17
votes
3answers
2k views

DIY Project using 1970s 8-bit CPU, is it possible?

I've recently really wanted to try and design a computer system around a retro 8-bit CPU such as the Zilog Z80 or the Intel 8080, and I would appreciate some sanity checks! I was inspired by Ben Eater'...
16
votes
6answers
840 views

Separate code and data address spaces on the Z80

Reading through the Z80 datasheet, I noticed something interesting. The Z80 separates its instruction execution into separate phases (which are called "machine cycles" in the official literature, but ...
14
votes
4answers
646 views

Original Mac capacitor inspection

Which capacitors should be inspected and, if necessary, replaced before attempting to power up an original Mac (purchased January 1984, but "upgraded" to a 512Ke) that has been sitting unused for a ...
-7
votes
1answer
566 views

How many old computing methods are still with us today? [closed]

Reading some of the questions here got me to thinking... how many of the old methods, software or hardware, are still with us today? My two examples: HTML. It's line oriented, for crying out loud. ...
15
votes
1answer
2k views

Is it possible to adapt a standard PC floppy drive to work in an IBM PS/2?

I have three different IBM PS/2 machines and all of them are in perfect working order—except for the floppy drives. None of the floppy drives will read disks, which means all I can do is key in BASIC ...
16
votes
10answers
5k views

640x480 color display in 1980

I'm working on an alternate history story in which the protagonists, Silicon Valley computer entrepreneurs, are trying to release a graphical workstation in 1980, with the capability of displaying ...
10
votes
3answers
310 views

What kinds of expansion ROMs and cartridges are available for the BBC Micro?

The BBC Master 128 has 3 empty expansion ROM sockets and 2 cartridge slots, which seems like a lot of potential. I have already discovered that it is common to add an expansion ROM to support a filing ...
5
votes
2answers
228 views

What was the first system to use flash or beep codes as a diagnostic?

It has long been the case that computer systems can signal serious faults using a series of beeps or flashes, where such faults occur too early in the boot process for them to be communicated in more ...
6
votes
1answer
473 views

I have installed MS-DOS 6.22 on Virtual Box, do I have an ISA bus or a PCI bus?

I have installed MS-DOS 6.22 (released in 1994) on Virtual Box, and I want to know if Virtual Box is emulating an ISA bus or a PCI bus. The settings for my virtual machine don't show any information ...