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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13
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7answers
2k views

What happened to exposed address pins/address bus?

This could be a question for the Electronics StackExchange, but I figured that if I couldn't find any info about it it might be more of a Retrocomputing thing. I've been poking around on Google and ...
4
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3answers
385 views

Does the Sega Megadrive 2 have built-in protection against reverse polarity

I have a spare universal power supply with regulated voltage up to 12 volts, max 1500mA. It has replaceable tips, where you can reverse polarity. As I understand the MegaDrive 2 (European / Australian ...
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0answers
131 views

Help debugging a circuit/code for Z80 and TMS9918ANL

I am working on designing a Z80 computer that utilized the TMS9918ANL for graphics. I am currently just trying to make sure the TMS9918ANL is working, so I hooked up the control pins the bus (...
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6answers
1k views

What are the advantages/disadvantages of using retro hardware vs. FPGA emulation vs. software emulation? [closed]

As someone who recently become interested in retro home computers of 80's and early 90's I'm wandering what are the differences between using a real hardware, FPGA based hardware emulators like MiSTer ...
20
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8answers
5k views

Which CPUs, if any, had an 8-bit address space?

Even the Intel 4004, which had a 4-bit word size, had a 12-bit address space. I'm wondering if any commercial CPUs had an 8-bit or similar address-space for programs, data, or both. I'm particularly ...
17
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7answers
8k views

Did any computer use a 7-bit byte?

In an answer to Why did IBM System 360 have byte addressable RAM I wrote regarding the choice of byte size: 7 bits would be a perfect match for ASCII, but engineers would instinctively recoil from ...
11
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2answers
643 views

Performance of the Rekursiv

I happened to find out about the Rekursiv today. Rekursiv is a processor that attempted to implement OOP concepts directly at the hardware level. Since it never got fully developed, I wonder what ...
3
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1answer
343 views

Atari ST series - bombs on boot

I have a faulty Atari 520STFM additional 4MB ram installed. It shows bombs on boot. I understand bombs are sort of code indicator of what is malfunctioning in the system, similar to what Guru ...
2
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2answers
155 views

Can I rewire a compact Macintosh SE or other compact Mac to play RCA Video?

I would like to take a compact Mac such like Macintosh SE, completely neglect the computing part of it, but be able to feed the CRT tube with an external video feed through Analog RCA cables. (Yellow ...
1
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0answers
106 views

Frozen horizontal width coil in old CRT monitor

I have an old Apple IIe CRT monitor which could use a small horizontal width adjustment. Unfortunately, as I try to rotate the hex key in the coil with a CRT adjustment tool, it doesn't want to move. ...
11
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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 ...
6
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1answer
251 views

Which x87 first acquired the ability to flush denormal to zero?

On modern Intel FPUs, you can set a flag to cause all denormals to be automatically flushed to zero. On some workloads, this improves performance. I cannot find any mention of that flag in the data ...
20
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2answers
3k views

Did playing sounds on the PC speaker keep the CPU busy?

The IBM PC and early successors came with an internal speaker that could play simple sounds. According to https://en.wikipedia.org/wiki/PC_speaker However, because the method used to reproduce PCM ...
20
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3answers
2k views

How was the 80186 incompatible with the IBM PC?

According to https://en.wikipedia.org/wiki/Intel_80186 The 80186 would have been a natural successor to the 8086 in personal computers. However, because its integrated hardware was incompatible with ...
8
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1answer
449 views

Was sector size under software control on the original IBM PC floppy drive controller?

The original IBM PC used a 5.25" floppy disk format of two sides, 40 tracks, 9 sectors per track, 512 bytes per sector, for 360K per disk. As I understand it, a significant amount of disk space ...
12
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3answers
2k views

What was the second most common incompatibility in MS-DOS machines? [closed]

When the IBM PC was released, it did not take long for people to figure out that there would be a big market for compatible machines. The first wave relied on MS-DOS as the compatibility layer. The ...
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5answers
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Pulling my hair out over a 4-bit architecture, there ought to be some law here somewhere, is there? [closed]

I am trying to build the most simple CPU possible. And doing it on bread boards. There is a popular movement, one of the biggest protagonists of that being a certain Ben Eater, who is a good teacher, ...
3
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3answers
173 views

'What' used spare memory on the TMS9918?

'What' used spare memory on the TMS9918 Video Display Controller? By 'what', was it Something pre-installed on the computer like Bios or Basic or something, I assume the main cpu s themselves were ...
5
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2answers
206 views

Why does the Galaksija's latch include some kind of address remapping?

The Galaksija has a 6 bit latch used for various bits and bobs, notably the part of the scanline counter which contributes to character generation, but also, it has a bit for clamping A7 high, and ...
1
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0answers
229 views

Is the thirty something year old RJ45 jack as small as it will ever get? [closed]

Why are micro-ethernet adapters not a thing? A physical adapter that takes our thirty year old standard sized RJ45 jack on one side and and plugs into a TabletPC on the other. Every other form of ...
4
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2answers
432 views

Aside from legacy systems, are there any contemporary uses for magnetic core memory?

Core has some interesting properties (nonvolatility, high reliability, resilient to radiation) that might make it useful in some situations. I know early versions of the computers on the Space ...
7
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0answers
138 views

Need help checking an ADC0808 / ADC0809 chip in a arcade shooting game

Main Question: How can I check a ADC0808 chip to determine if it needs to be replaced or if my issue is something else? Any advice you can offer is SO appreciated! ADDITIONAL INFO When the arcade is ...
1
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4answers
504 views

Is this a computer screen in 1956, and if so, what is it displaying?

The photo below shows what may be a CRT for the TX-0 (transistorized experimental computer) in 1956, referring to what may be a CRT on the left side, not to the CRT on the right side . If that is a ...
45
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2answers
10k views

Why does the 80486 take longer to execute simple instructions than complex ones?

The 80486 processor can execute many instructions in a single cycle, such as a register-to-register add instruction (ADD EAX, EBX, for example), which one would generally assume is fairly complex, ...
0
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2answers
252 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.
11
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8answers
6k views

Why were optical drives not used as secondary storage instead of magnetic drives?

What prevented optical drives from being used as the dominant secondary storage like the magnetic disk drives, in PCs? Was it entirely technical limitation or other issues like late development and ...
2
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1answer
204 views

Who built the first electric/electronic adder?

The first electricity-based adder presumably used relays. (The electromechanical relay was invented for the electrochemical telegraph for repeaters in 1831 by Joseph Henry (1797-1878). I can't figure ...
23
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7answers
4k views

Was it possible programmatically to manipulate the volume as well as the pitch on computers with no sound chip?

On early versions of many 8-bit computers like the Apple II, Spectrum, and even the IBM PC, there was no sound hardware other than the simple "beeper". Programmers made sound by hitting a hardware ...
-2
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2answers
206 views

Why did computers settle for instructions with multiple machine cycles instead of investing into larger ring counters? [closed]

On the 8080 and 8085 microprocessors, a LDA instruction took 13 timing(or T) states to execute. This could be solved by using a ring counter that could generate said 13 T states,as well as having ...
10
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1answer
418 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 ...
6
votes
1answer
301 views

Did the Timex Sinclair 2068 and the Sinclair ZX Interface 2 use totally different hardware and software techniques?

Sinclair released an add-on for the Spectrum called the ZX Interface 2 that provided joystick ports and a cartridge slot. It wasn't successful and only a few cartridges were ever produced. In the US, ...
1
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2answers
218 views

Reusing original Palm memory cards

I have a number of non-functional older PalmOS devices (of the 68000 processor variety, not the later ARM processor models). I'd like to be able to reuse the memory cards from these in new ...
7
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2answers
510 views

How do you use the INHIBIT pin on the Apple II bus?

Pin 32 of the Apple II bus is a signal called /INH (short for "INHIBIT"). Some of what I found online about using this pin for an Apple II expansion card suggests it was inconsistently implemented ...
9
votes
1answer
426 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 ...
8
votes
1answer
403 views

Which computers used the Intel 82786 graphics chips, and what sort of commercial success did that chip attain?

In the late 1980's, Intel offered the 82768 graphics chip, with specific support for windowed environments. I remember it being covered in Byte magazine, but don't remember seeing any applications of ...
12
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0answers
379 views

Why would installing Windows 9x on a Sager NP8200 or Wedge 466/DX2 laptop brick the system?

In the setup.txt file on the Windows 95 and 98 CDs (located in the \WIN95 [Windows 95] / \win98 [Windows 98] folder), which contains important information on setting up Windows and solving or working ...
1
vote
1answer
143 views

How can I fix this clacking sound made by the Game Boy speaker?

I have a Game Boy, and whenever it tries to play sound, the sound is very quiet but there's a loud clacking sound. Here is a sample. In this case, it is Tetris Attack playing: https://soundcloud.com/...
4
votes
1answer
283 views

Hardware implementation of the isometric tile engine. Is it possible, did it exist?

We are talking about a hardware (and not software over hardware, as for example in some games on the SNES console) tile engine with multi-overlapping rectangular (rather than square, when the image ...
25
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7answers
7k views

Purpose of turbo switch on systems unable to slow to 4.77 MHz?

I have a PC with an Intel P133 (133 MHz). The motherboard (PcPartner MB520NH) only allows for it to be slowed down to 75 MHz at the least via jumper settings, but no lower. Yet the PC's case has ...
13
votes
2answers
3k views

How did I fry my SID chip?

I recently got a SID chip (8580r5) for $35 and got it playing music. I was really happy about it. I hooked up a small amp chip to the 9V supply momentarily (it didn't work, I was building that part of ...
6
votes
8answers
315 views

What 8-bit microcomputer systems multiplexed multiple physical ports on a single controller?

The NEC PC-8201 had three serial interface ports on the back, "RS-232," "SIO1" and "SIO2." These were all driven by a single IM6402 USART, switched between each physical port via bits 7 and 6 of IO ...
1
vote
2answers
302 views

Performing 16-bit port I/O on the RTC

Why can’t the RTC (0x70, 0x71) read and write 16 bits at a time? For example: mov ax, 0xa8f out 0x70, ax I have found in a 286 BIOS that did this (BIOS ID string: S286-6181-...
6
votes
2answers
372 views

Why did the CDC 6600 expand the word size to 60 bits?

According to http://www.quadibloc.com/comp/cp0201.htm The CDC 1604 used 48-bit floating point with 11 bits exponent and 36 bits mantissa. There was also a double precision format (which I believe was ...
5
votes
1answer
388 views

How many hours of labor did it take to assemble a minicomputer?

A minicomputer like the PDP-8 contained several thousand discrete transistors and other components, all of which had to be soldered by hand, and that was among the simplest computers on the market; ...
14
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2answers
1k views

DEC Alpha: why no 8/16-bit load/stores?

The first version of the DEC Alpha had no load/store instructions for 8 or 16-bit values; if you wanted to deal with data of such sizes, you had to do it by shifting and masking values in registers as ...
2
votes
1answer
292 views

When first CMOS versions of Z80 became available and were they ever used in (non-portable) home computers?

When Z80 first became available on the market in 1976 it was made using NMOS technology. It is the version that is likely to be most familiar to people interested in retro-computers. For example, to ...
3
votes
2answers
285 views

What's the Motorola microprocessor with two sets of registers to avoid costly context switch?

I remember reading somewhere (maybe on Hacker News or Lobsters) that Motorola made a microprocessor some decades ago with two sets of registers. This means when handling an interrupt, it does not need ...
4
votes
2answers
601 views

Why did extracodes fall out of favour?

Once you have an operating system that provides services callable from programs, you need to provide a way for programs to request those services. These days the general approach only requires a ...
3
votes
1answer
251 views

How to set up a payphone phone network central office

I would like to setup a network of payphones inside my college as part of a retro phone systems / artistic interactive exhibit. I would like to be able to use the payphones to make calls inside the ...
2
votes
0answers
264 views

What was the cost of the PS2 chip in the last PS3 to have it?

The PlayStation 2 provided backward compatibility with the PS1 by essentially incorporating an entire PS1 on a separate chip. It kept this arrangement permanently. The PS3 started off providing ...

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