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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Why does the Vic-20 have two VIA chips?
The Vic-20 uses the 6522 VIA for peripheral I/O. However, it has two of them. I find this surprising, particularly considering minimizing cost was an important design goal. Is there a reason why it ...
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What is the difference between the 6522 VIA and a UART?
The 6522 VIA is an I/O chip used in the Vic-20. I was under the impression that UART (Universal Asynchronous Receiver/Transmitter) is the general term for such chips, so was surprised to see this: ...
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Did any European computers use 10-line fonts?
Most 8-bit computers implemented hardware text mode, and most of those used 8x8 fonts. This was logical for American computers; the title safe area on NTSC is about 200 scan lines; font height 8 gets ...
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Could any computers use 16k or 64k RAM chips?
An interesting feature of the Apple II was that it had three rows of sockets for RAM chips, each of which could take either 4k or 16k chips. That meant the minimum configuration was 4K (cheap) but it ...
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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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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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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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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 ...
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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 ...
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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 ...
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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....
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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 ...
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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, ...
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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 ...
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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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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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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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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 ...
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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 '...
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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:...
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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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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 ...
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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 ...
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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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How does the Everdrive handle all the special chips and stuff that were put in cartridges?
An "Everdrive" is like a cartridge that looks just like a NES/SNES/N64/whatever cartridge, and is put into a real, original console. So you need the original hardware for it to work. And ...
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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 ...
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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 ...
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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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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'...
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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 ...
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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 ...
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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 ...
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What is the interface of the proprietary memory card connector in CDTV
Is this an IDE or something completely different. Could it be used to connect gotek?
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How can the number of cylinders be different from the number of tracks?
In the IBM PC 5150 documentation, it is stated that the floppy drive has 40 tracks, 8 sectors/track and 512 bytes/sectors, for a total of 163 840 bytes of data. It makes sense, 40×8×512 = 163 840 ...
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Could the STC Executel possibly have had any games available?
Could the STC Executel possibly have had any games available ?
It had a very small inbuilt CRT screen on the right side.
It looked somehow impressive with how it displayed things on the screen, a very ...
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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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Were any M68000 systems capable of generating a "spurious interrupt"?
When an interrupt occurs on a Motorola 68000-family processor, it enters an interrupt acknowledge state, which continues until one of three signals are asserted:
An external device places the ...
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Was the Ram Turbo the only 3rd party Interface 2 ROM cartridge interface for the ZX Spectrum or were there others?
One of the original Sinclair peripherals for the ZX Spectrum was the Interface 2 which provided joystick ports and also a slot for ROM cartridges:
The cartridges did not catch on though and only ...
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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 ...
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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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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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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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. ...
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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 ...
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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 ...
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