Questions tagged [hardware]

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

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1answer
48 views

Macintosh IIci not booting

I have an old Macintosh IIci that worked until a few weeks ago but now doesn't turn on anymore. When I press the power button on the keyboard all the lights on the keyboard and the one on the main ...
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2answers
2k views

Why did the 8087 need a special socket?

The IBM PC included a coprocessor socket for the 8087 floating-point unit. Logical enough; some customers wanted to use the 8087 to make numeric calculations run faster. But why was the 8087 designed ...
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5answers
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Why did mainframes have big conspicuous power-off buttons?

Some fascinating stories in this discussion thread. It starts with discussion about computers overheating, but about halfway through the thread, it switches to discussion of mainframe installations in ...
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0answers
105 views

Why did Gran Trak 10 cost so much?

In 1974, Atari released a driving game called Gran Trak 10. The development prototypes had used real car steering wheels and pedals, but it was realized these were too expensive, so they were changed ...
18
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8answers
3k views

Why user-assembled kits?

Many early computers were sold as self-assembly kits (you get a box of parts and an instruction leaflet and have to solder them together yourself). For example, the Altair was priced at $439 kit, $621 ...
3
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2answers
372 views

How did wave soldering work? [closed]

While it is not used as much nowadays, wave soldering was a big advance in the productivity of manufacturing electronics, compared to soldering all the components by hand. It consists of placing all ...
9
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2answers
649 views

Did any 8-bit CPUs use dynamic memory for registers?

According to https://jamiestarling.com/project-8088-the-8088-cpu-pinout/ One thing to note – the 8088 registers are made from dynamic memory cells – they have to be refreshed. The minimum clock speed ...
12
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4answers
835 views

Did the Commodore datasette interface provide greater reliability?

Cassette, being cheaper than a floppy disk drive, was a popular storage medium in the 8-bit era. Some computers such as the Sinclair Spectrum, just provided a port to plug in an existing cassette deck....
13
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4answers
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How did 2-chip CPUs work?

The 1970s saw a big transition from CPUs built from thousands of discrete components, to CPUs implemented on a single chip, with the occasional use of bit-slice components along the way. There were, ...
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2answers
212 views

Could the 6502 have worked with an Altair-style front panel?

I have fond memories of programming the 6502, though I never did any hardware hacking with it. I notice that the Altair, with its iconic front panel, was based on the Intel 8080, and from then on, ...
18
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1answer
3k views

What is the function of this strange IBM apparatus?

Does anyone know what kind of device this is? I found it in my late dad's stuff, probably from the 1970s. It has no number, type, model, serial number or anything else on it that could be used for ...
12
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4answers
4k views

How can a ST-412 MFM hard drive be integrated with a modern PC?

I have a Seagate ST-225 20MB hard drive. It used a ST-412 MFM (Modified Frequency Modulation) controller which unfortunately went to the great bit bucket some time ago. Is it possible to get this ...
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2answers
472 views

S-100 bus and device drivers

It is said that the S-100 bus provided a standard hardware format for expansion cards across many models of computers, including ones using different system software and even different CPUs. Having ...
2
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1answer
103 views

Intel vs Motorola device communication protocols

On this page about "An S-100 68000 CPU Board" it is said: From a hardware perspective there are some very significant differences how Intel and Motorola CPU's talk to the world. Somewhat ...
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7answers
4k views

Why not constant linear velocity floppies?

The outer tracks of a disk are longer than the inner tracks, and could therefore potentially hold more data. Constant angular velocity puts the same number of bits on every track, which wastes much of ...
36
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2answers
3k views

Was AGP only ever used for graphics cards?

Reading on the AGP spec, the little bits I've found on sites like https://old.pinouts.ru/Slots/agp_pinout.shtml, say: The Accelerated Graphics Port (also called Advanced Graphics Port) is a high-...
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1answer
103 views

Why was the SWTPC 6800 Computer System cheaper than the Altair?

In 1974, Intel released the 8080, which basically was the first microprocessor good enough to build a serious computer around. That led to the Altair 8800 the following year, which was the beginning ...
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2answers
1k views

Was natural convection ever a consideration in orienting expansion cards?

Many computers have followed the design pattern of a backplane with expansion cards, including arguably the three most influential microcomputers ever built: the Altair 8800, the Apple II and the IBM ...
10
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3answers
574 views

What is the model of the cash registers used in Walmart in the mid to late 90's and very early 2000's?

What is the type or model of cash registers used in Walmart in the mid to late 90's and early 2000's? See this video. Note the strange sounds that Ann says is when the cash register is printing. Also ...
6
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2answers
330 views

VAX 11/780 16MB memory board - what was the physical size?

I'm trying to get a feel for what it looked like when you designed a computer to have a lot of memory chips stuffed into it. To that end, I found this: https://commons.wikimedia.org/wiki/File:...
5
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1answer
320 views

How much did the RM 380Z weigh?

The Research Machines 380Z was an early British microcomputer, released in 1977. Unlike many other early microcomputers, the design was industrial style, a hefty metal box, sometimes described as '...
13
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5answers
382 views

Preventing socketed chip corrosion?

I spent a couple hours repairing an Amiga A3000 that wouldn't boot yesterday. The fix was to remove Kickstart ROMs, clean the DIP leads and sockets with contact cleaner, and re-insert. Apparently a ...
18
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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 ...
2
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2answers
132 views

How to limit RAM available to Workbench

Is there a way to limit Fast RAM used by Amiga OS 3.1, i.e. if A500 with 030 MMU detects full 64MB in address ranges 0x40000000 to 0x44000000. Instead, can I choose to map only 8MB in lower ranges at ...
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2answers
759 views

Bakelite as data storage

Was bakelite used for computer data storage like it was used for grammophone records? My brother says he remembers this but I cannot find it on Google.
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2answers
336 views

Vintage computer composite graphics

I am working on designing a vintage computer and I have been using the TMS9918ANL. After working with it for a month or two and not making much progress, I really want to switch to another chip. I am ...
24
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3answers
5k views

Why does DOS ask for the current date and time upon booting?

In most versions of DOS, when they are started from a medium that lacks an AUTOEXEC.BAT file, the very first thing COMMAND.COM does is ask the user to confirm the current date and time: Starting PC ...
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2answers
288 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-...
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10answers
3k views

Why did CP/M and MS-DOS use the BIOS instead of their own drivers to access hardware?

Modern versions of Windows (and other modern operating systems I suppose) have their own drivers to access hardware. But as I have read, in the old days, if CP/M or MS-DOS wanted to access hardware, ...
11
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1answer
774 views

How did the Zip Chip and RocketChip accelerators work for the Apple II?

Though there is already a similar question on the site, this one is more specific to these chips and their technical implementation. There were two accelerators for the Apple II series that were drop-...
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4answers
221 views

Does anyone remember analog computers in the early 70s? [closed]

In 1972, when I was 16, I was sent on a one-week computing course at the local technical college in Worcester (UK). I was one of a group of girls who were intending to take Maths A-level the following ...
9
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2answers
323 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 ...
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4answers
2k views

Parallel to serial conversion

Two very common connectors used in the eighties were the Centronics parallel port (particularly used for printers) and the RS-232 serial port (particularly used for mice and modems). Suppose you have ...
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17answers
2k views

Was there a retro computer susceptible of being damaged only by issuing instructions at it?

The question 'Can a USR command damage a ZX Spectrum?' has led me to wonder if there was once a microcomputer that could actually be damaged by software. More specifically: Is there a case that a ...
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2answers
2k views

How does the Everdrive handle all the special chips and stuff that were put in cartridges?

The "Everdrive" is very intriguing to me. Having been continuously disappointed -- not to say appalled -- by every single emulator I have ever tried, for every single console, I've given up ...
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2answers
804 views

How can I connect this 3-pin Slot 1 CPU fan to my system that uses a 2-pin connector?

I'm trying to put a new CPU cooler in my 1999 IBM Aptiva 2163-580 (which has an Intel 440BX chipset, in case that's relevant). The system uses a Slot 1 CPU. The old cooler had a 2-pin connector, which ...
2
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1answer
140 views

Peripherals needed to run Tiny BASIC interactively on an Intel 8080

I have an Intel 8080 core and would like to build the minimal computer system around it to run Tiny BASIC interactively. I am building this computer on an FPGA, so I am not asking about actual ...
17
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2answers
2k views

Did the 68000 separate A/D registers save circuitry?

The Motorola 68000 has sixteen integer registers, which was considered a very generous complement at the time it was introduced. They are divided into address and data registers, eight each. Many ...
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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 ...
14
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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. How it worked is ...
11
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2answers
705 views

Why was SLI for gaming introduced and supported in the first place?

(I'm not sure if this is the correct place to ask this, please let me know if should post this somewhere else) For a long time, using SLI for gaming has been dying out and for good reason. From what I'...
11
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2answers
631 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 ...
126
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4answers
34k views

It's now safe to turn off your computer

One thing I remember very well from my childhood is the screen you got at the end of a shutdown process on old computers: I don't know if this was a Windows 95/98/2000/ME only thing but I wonder why ...
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2answers
214 views

What does “cycle-accurate emulation” mean? [duplicate]

Note: I've attempted to ask this question several times in the "Arqade" category. Just like with the "History" category, anything I ask there is deleted by their broken bots soon ...
11
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3answers
2k views

Small RAM 4 KB on the early Apple II?

Most of the reference material for the Apple II that I have seen refers to the 4116 RAM chip which held 16x1 kbit. This provided 16, 32 or 48 KB in banks of 8 chips. The Apple II motherboard layout ...
5
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1answer
411 views

On Amiga, what happens when I write to $DFC5A0 by mistake?

I'm fixing a game (TV Sports Basketball) that tries to write in audio data (using the range $DFF0A0 to $DFF0D0) but for some reason (bad programming), the index is sometimes (not always) bogus MOVEA.L ...
7
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1answer
616 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). ...
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4answers
1k views

Why is the ColecoVision AC adapter so big?

Why is it ColecoVision AC adapter so big? I never had seen someting like this in any console of the era or even after it. What are the design choices made by the designers? Was it to turn the project ...
3
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1answer
257 views

When did the faster versions of the NMOS 6502 become commercially available?

The 6502 was released in 1975 with an advertised speed of about 1mhz but I can't find reliable information on what year faster versions became available (was 2mhz possible at launch?) or what the true ...
5
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1answer
233 views

How does DMACON/R registers on Commodore Amiga platform work?

I have a specific question about the DMACON/R registers found in Commodore Amiga range of computers. As you may know they are the DMA control registers that controls all the DMA channels used by the ...

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