Questions tagged [hardware]

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

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45
votes
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
votes
2answers
202 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
4k 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
votes
1answer
185 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 ...
22
votes
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
181 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 ...
6
votes
1answer
186 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, ...
0
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2answers
185 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
votes
2answers
458 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 ...
8
votes
1answer
174 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
302 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 ...
10
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0answers
257 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
115 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
241 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
votes
7answers
6k 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 ...
5
votes
8answers
292 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 ...
4
votes
1answer
172 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
330 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
votes
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
203 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
254 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 ...
3
votes
2answers
374 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
219 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
212 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 ...
7
votes
1answer
318 views

In the 1970s, had there been a way that a home computer using a TV as monitor could get FCC approval for Apple II style slots without cheating?

I’m reading the book “Atari Inc.: Business is Fun” by Curt Vendel and Marty Goldberg. (By the way, it’s a fun read, highly recommended.) It states that when the Atari engineers had been developing the ...
11
votes
2answers
2k views

How did most fifth-generation consoles avoid wobbly graphics?

According to Why do 3D models on the PlayStation 1 “wobble” so much? the PlayStation had a problem with wobbly graphics because Filling a triangle involves visiting every pixel within it and ...
5
votes
1answer
406 views

How much memory did the PlayStation development kit have?

The PlayStation 1 had two megabytes of main memory, one megabyte of video memory and half a megabyte of audio memory. Squeezing everything to fit into these limits was one of the big challenges of ...
11
votes
3answers
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 ...
11
votes
6answers
4k views

Did any RISC CPU ever take more than one clock cycle per instruction?

Classic RISC CPUs like ARM and MIPS basically offer the trade-off: simple instruction set, but instructions execute in one cycle for good overall performance. (It gets more complicated in later times, ...
38
votes
6answers
9k views

Why did early arcade games use vertical displays?

Surprisingly many early arcade games, such as Pac-Man, Galaxian and Galaga, mounted their displays vertically, in portrait rather than landscape orientation. (From the perspective of the electronics, ...
7
votes
1answer
515 views

How did the Donkey Kong arcade hardware provide 128 sprites?

According to https://en.wikipedia.org/wiki/Donkey_Kong_(video_game) The Donkey Kong hardware has the memory capacity for displaying 128 foreground sprites at 16x16 pixels each and 256 background ...
3
votes
1answer
146 views

ABEL HDL: What was the purpose of the 'flag' keyword?

Some context first: ABEL (Advanced Boolean Equation Language) is an old hardware description language which has been mainly used in the 80/90s to program CPLDs. Unfortunately I have not found any ...
21
votes
3answers
2k views

Why was it not possible to cost-reduce the Amiga 500?

According to 'Commodore: The Final Years' (whole trilogy highly recommended, BTW), page 129, 'Jeff Porter realized it would not be possible to significantly cost reduce the Amiga 500 to get it into ...
18
votes
7answers
3k views

Cost of unrestricted sprites

All the game consoles of the second through fourth generations, and several early home computers, had sprites, which were valuable though costly, e.g. the VIC-II spent 2/3 to 3/4 of its area on ...
9
votes
2answers
308 views

Were expansion slots fundamentally incompatible with FCC regulations?

The Apple II provided the ability to connect to your TV (as opposed to purchasing a dedicated monitor). However, at that time, the FCC criterion for applying stringent RF emission limits was 'device ...
-1
votes
1answer
116 views

Fan for old socket A Athlon cooler [closed]

I put together a retro gaming setup with a 2000ish spec (can post specs if required) and it's come together pretty nicely except the CPU fan is insanely shrill (it's a Coolermaster something). If I ...
2
votes
1answer
125 views

Vic-20 tape I/O dependence on CPU speed?

As I understand it, the Vic-20 reads and writes the cassette deck by the low-tech expedient of just using the CPU to bit-bang a one-bit serial line. This presumably means that for a given code ...
8
votes
3answers
2k views

Did multiplexed address/data lines make memory access slower?

Looking at the pinout of e.g. the 8088, it multiplexes the data lines onto eight of the address lines; presumably the designers judged that being able to squeeze the chip into a 40-pin package, would ...
5
votes
2answers
243 views

Could monochrome systems produce better output for monitors than TV sets?

Many classic computers could optionally use a TV set as the display. At least in the early (pre-SCART) days, the TV would typically only have RF input, but if you were using a monitor, you could get a ...
6
votes
2answers
573 views

What was the title safe area on PAL TV sets?

Computers that used TV sets for display, needed to worry about the title safe area. By consensus, on NTSC sets, it was 200 scan lines, or 192 if you wanted to play it really safe. What was the ...
2
votes
1answer
439 views

How much did it cost to develop the Z80 CPU?

How much did it cost, in dollars at the time, to develop the Zilog Z80 CPU? According to Wikipedia, The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. ...
1
vote
1answer
87 views

How does the ZX81 ULA generate a full ROM read address?

On the ZX81, when the ULA that functions as the video chip is generating display output, it takes the character cell byte (that the CPU was tricked into fetching as an opcode) and combines it with an ...
3
votes
2answers
238 views

What does the ZX81 ULA use A14 and A15 for?

As I understand it, the ZX81 video system, which resides in the ULA like all the rest of the machine-specific logic, works by using the CPU as an address generator: during active scan line, it lets ...
2
votes
4answers
986 views

What is the analog component of sound output in an early home computer? [closed]

For a concrete example, take the Vic-20. It is well documented that the 6560/6561 Video Interface Chip was also responsible for sound generation, having three voices and one noise generator. The ...
2
votes
1answer
135 views

Did the ZX80 RAM pack pass the expansion bus through?

The ZX80 only came with 1K of RAM, which had to be shared between program and screen memory, so many customers bought the Sinclair 16K RAM pack, which plugged into the expansion bus (the edge ...
29
votes
3answers
5k views

Why did the ZX80 CPU run at only 3.25 MHz?

The Sinclair ZX80 used a Z80A running at 3.25 MHz. But this chip was rated for 4 MHz. Why was it run below rated speed? Apparently the master clock in the machine ran at 6.5 MHz, so the CPU clock ran ...
6
votes
1answer
552 views

How did the ZX80 RAM pack use DRAM?

The Sinclair ZX80 was the most popular personal computer in Britain at the beginning of the 1980s, due to its low price which was enabled by extreme minimalism; it consisted of not much more than a ...
2
votes
1answer
114 views

How long would a 41256 take to do 4 accesses in fast page mode?

I have been surprised at how little use eighties computers made of fast page mode access to RAM. (A notable exception being the Sinclair Spectrum, which used it to get the necessary bandwidth to video ...
9
votes
1answer
1k views

Were single-sided floppy drives really more tolerant of rough handling?

The Osborne 1 was a luggable computer that contained a pair of 5.25-inch floppy drives. According to https://en.wikipedia.org/wiki/Osborne_1 Adam Osborne decided to use single-sided disk drives out ...

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