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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9
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3answers
516 views

Origin of the NZVC condition codes scheme?

The NZVC condition codes scheme, and corresponding set of 14 conditions for branches, is almost the only one in current ISAs that utilizes condition codes at all. The first computer I know that used ...
11
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2answers
855 views

How does ‘Trent’s circuit board strategy’ work?

For those of you who are unaware, professional speedrunner Trent Hall discovered a now-banned speedrunning trick in GoldenEye 007 for the Nintendo 64. The trick (called ‘Trent's circuit board strategy’...
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3answers
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Does 10BASE-T need more sophisticated electronics than 10BASE5/10BASE2?

In a discussion on the history of Ethernet and 10BASE5, Stefan Skoglund commented Was 10BASE5 a mistake? One reason why 10BaseT became possible is Moores law (and the same for the other designs after ...
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0answers
390 views

How would toggling a bit in the POWCNT1 register cause hardware damage on the Nintendo DS?

From GBATEK, writes to a certain I/O port for power management may damage hardware: 4000304h - NDS9 - POWCNT1 - Graphics Power Control Register (R/W) 0 Enable Flag for both LCDs (0=Disable) (...
16
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2answers
843 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 ...
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5answers
6k views

Was 10BASE5 a mistake?

https://en.wikipedia.org/wiki/10BASE5 gives a succint but vivid description of the physical layer of the first version of Ethernet and its subsequent replacement: 10BASE5 (also known as thick ...
6
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4answers
1k views

What was the first Ethernet hub?

An Ethernet hub is – well, Wikipedia does an impeccable job of summarizing what it is: An Ethernet hub, active hub, network hub, repeater hub, multiport repeater, or simply hub is a network hardware ...
2
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2answers
454 views

What was the DRAM refresh interval on early microcomputers?

Dynamic RAM is denser than static RAM, but needs to be refreshed every few milliseconds to avoid losing data. How many milliseconds, exactly? If the answer has changed over time, then I'm interested ...
25
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3answers
4k views

When did 5.25″ floppies exceed the capacity of 8″?

When 5.25″ floppies were introduced, in the mid-to-late seventies, they would have had less capacity than the older 8″ because, well, less area on which to store data. On the other hand, being cheaper ...
22
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4answers
4k views

Why did the TRS-80 CPU have priority over the display?

The original TRS-80 had a separate bank of static RAM for video memory, so that there would be no interference between display and CPU when the CPU was just doing calculations in main memory. When it ...
16
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5answers
3k views

What was the first mass-market, 16-bit microcomputer system?

To qualify what I mean by "16-bit microcomputer system", I am talking about a system that has not only a 16-bit (or 32-bit) microprocessor CPU, but also a 16-bit wide external data bus connected to ...
10
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10answers
456 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 ...
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4answers
5k views

Why was manual branch suggestion abandoned?

Once pipelined CPUs became common, a common issue arrived as a result of taking the wrong branch of a conditional jump, and thus needing to flush the pipeline. As a result branch prediction mechanisms ...
12
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1answer
2k views

What is purpose of the “CH” button and “CH” switch position on this calculator?

What is purpose of the CH button and CH switch position on the Omron Elite 8002 Taschen-Rechner? (For those who don't know German, “Taschen-Rechner” just means “calculator”.) The switch has three ...
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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. The way it worked ...
11
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1answer
519 views

Why can't special controllers or accessories be used with Super FX games?

SNES games with the Super FX processor generally do not support special controllers or accessories such as the Multi Player 5 multitap, SNES Mouse, or Super Scope. Yoshi's Island, for example, ...
5
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1answer
515 views

What's wrong with SNES original controller's shoulder buttons?

This is probably a hardware-related question. I have recently bought a total of 7 (seven) different original SNES controllers from different sources, all of them being somewhat used but mostly ...
17
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4answers
4k views

Is it possible to expand Amiga 500 rev 8 to 1.5 MB with a 1MB trapdoor expansion?

Is it possible to expand an Amiga 500 rev 8 (not an Amiga 500 plus) to 1.5 MB of Chip RAM using an A501+ expansion? It is plug and play or are modifications required? This is the board: Source: ...
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4answers
4k views

Amiga 500 OCS/ECS vs Mega Drive VDP

Superficially the Amiga 500 and Mega Drive are similar. Both run a Motorola 68000 CPU at similar clocks and both have dedicated hardware for sprite and other graphics operations. Comparing the arcade ...
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6answers
1k views

Amiga floppy disks and GCR vs MFM

According to the Wikipedia article on GCR, the Commodore 1541 disk drive used a particularly efficient GCR encoding scheme to cram 170K onto the same 5.25" disks that in an Apple drive only ...
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4answers
8k views

What determines the color of every 8th pixel on the Apple II?

On the Apple II there's an interesting way to add a little color to the bitmap, since the high bit select the palette used for the three-and-a-half pixels represented by the byte. Like this: 0: Black,...
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3answers
3k views

Documentation for the ZX Spectrum ULA

I am writing a Spectrum emulator, however I am finding it difficult to find official or reliable information about the ULA, its functioning and its pins. Are there official sources documenting its ...
22
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8answers
4k 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 ...
23
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8answers
5k 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 ...
5
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1answer
197 views

What was the first control display unit with selector keys around the display?

If not the first, then the one that became popular first (in any application; this is not limited to aviation systems). A control display unit, CDU for short, is fairly common in aviation, perhaps ...
7
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2answers
202 views

How did Apple IIc daughtercard expansions work?

I've been doing a lot of reading about the ways Apple IIc owners expanded their machines in the absence of the IIe's slots, and it's very intriguing stuff. The ones that I'm most curious about are the ...
5
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1answer
284 views

What kind of graphics hardware did Nichibutsu's 1985 arcade game "MagMax" use?

The arcade game MagMax by Nichibutsu came out in 1985 and features for its time an impressive 3D scrolling effect which, in my observation, is not widely discussed yet, although it should be ...
6
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1answer
1k views

What was the price of a Winchester-Drive for the HP-85 desktop computer back in 1980?

I wrote my first computer programs in HP-Basic on a HP-85 desktop computer. The year was 1980 and we stored our programs on special "high-speed" cassette tapes. I remember proposing to buy a ...
15
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4answers
2k views

How was the real-time clock implemented in the original IBM PC and PC/XT?

I know that the IBM PC/AT added a battery backed real-time clock chip that independently maintained time whether the system was powered or not. I've also seen many of those big DS1287 clock chips on ...
16
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3answers
4k views

What happened to ZIP RAM?

I have several retro machines and add-on cards for the Amiga that use ZIP RAM. This vertically mounted chip design enjoyed a brief popularity in the early 1990s, in between the original DIP DRAM and ...
24
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2answers
3k views

Why do old computers perform a long memory test on every boot?

Basically any computers from the mid 90s and earlier perform a slow memory check on every single boot. The more memory there is present, the slower that process becomes, for example: https://www....
7
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2answers
330 views

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, 40x8x512 = 163 840 ...
5
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2answers
469 views

How can I tell if my old PC supports > 137 GB hard drives?

I have an old PC from 1999 that has an ASUS P5A motherboard. When I power it on, it says ASUS P5A ACPI BIOS Revision 1011 Beta 005 and 05/02/2002-ALADDIN5-<<P5A>>: I recently read that up ...
11
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1answer
1k views

How can I edit CMOS hard drive geometry settings on a 1991 PC?

First, I am NOT asking how to use the BIOS Setup utility. I'm asking how to OVERRIDE the built-in settings my BIOS Setup supports for the HD geometry. I have a 1991 NCR PC with a 386SX, on-board IDE, ...
26
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3answers
7k views

In what ways was the Soviet STRELA computer "designed to function during a nuclear winter"? Or at least parts of it?

From Strela computer: Strela computer (Russian: ЭВМ Стрела, arrow) was the first mainframe computer manufactured serially in the Soviet Union, beginning in 1953. This first-generation computer had ...
5
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2answers
543 views

Modern heat sinks for Commodore C64/C128

The VIC-II and SID chips in the C64/128 are prone to over-heating and are rather expensive to replace nowadays. Some other ICs in these machines may have the same issue. An unmodified machine includes ...
47
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2answers
11k 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, ...
14
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4answers
1k views

Did Apple bundle a specific monitor with the Apple II+ for schools?

Sometime in 1980 (or maybe 1981) my school district purchased its first batch of Apple II+ computers. I remember vividly they had absolutely no idea what to do with them, and so the machines were ...
48
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6answers
17k views

Why did CPU designers in the 70s prioritize reducing pin count?

A lot of 70s era microprocessors were packaged in DIP packages with 40 pins. This was a reasonably good fit for 8-bit processors: 16 address lines, 8 data lines, 2 power and clock are all absolutely ...
3
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2answers
3k views

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 ...
3
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3answers
624 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 ...
4
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1answer
122 views

Quadram odd IBM PC card bracket

I came across an early IBM PC ISA realtime clock/calendar card made by Quadram called the "Chronograph" (picture). It's basically the same clock feature they incorporated into their ...
11
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5answers
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 ...
13
votes
1answer
645 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 ...
7
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1answer
494 views

Did the original Japanese Tamagotchi device really die *completely* (forever) if the digital pet died? [closed]

Ever since 1997, I've had this "factoid" in my head that the original release of Tamagotchi in Japan had no "reset" feature, and you could not remove the batteries to reset it ...
10
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1answer
672 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 ...
10
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2answers
386 views

How do I terminate an ISA bus correctly?

I am stuck by designing a 8 Slot 16 Bit ISA Backplane Do I have to terminate an ISA bus? My search results are: No termination at all Some homebrew projects use active termination for all signals ...
9
votes
1answer
575 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 ...
1
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2answers
163 views

How many kinds of mass-producible ROM is avaliable before 1970? [duplicate]

Back in the days before mask ROM (when invented?) we got core rope memories, or Little Old Ladies memories, which required lots of human labor to build. Were there any kinds of ROMs which were ...
12
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4answers
2k views

Smallest/Simplest, modern pure relay computer with at least 4-bits data words

There are a lot of designs out there of modern home made relay computers (not just ALUs but real computers -let's call them Turing complete, although Turing complete is not enough for having an ...

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