tofro
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How did old computers address far more than 64K of memory despite only having a 16 bit address bus?
15 votes

There are a number of approaches that can allow a CPU with a 16-bit address bus to address more than 64kBytes of memory: Bank Switching - explained in another answer,basicaly switching for example 8- ...

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Was there ever a microcomputer with a full-size keyboard and a hex numpad?
19 votes

Apparently you misunderstood the reasoning behind a hex keypad: It never was a means to ease input of hex characters, but rather the cheapest method to input anything at all. Early single board ...

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Does 10BASE-T need more sophisticated electronics than 10BASE5/10BASE2?
20 votes

Your question seems to ignore the topology of a network completely: If you want to connect, say 20 computers via Thickwire or BNC, you need: A length of the chosen cabling 20 MAUs if you want ...

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BYTE Magazine outside the U.S
8 votes

BYTE used to be available at well-sorted newsagents all over Europe (I can confirm UK, Germany, France, Italy and Spain at least) starting from the late 80s. I don't really remember a European or ...

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Cheapest way to store and load small dataset in the 80s?
5 votes

The cheapest ways for storage of data are the ones that are high-volume, off-the-shelf products that are not specifically produced for the computer market - and operate on high-volume consumer ...

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If a PS/2 device on a 32-bit x86 sends a byte to the IO port 0x60 and you read it, what happens next?
Accepted answer
19 votes

On standard PCs, the main CPU and PS/2 controller use a handshake mechanism in the status register at port 0x64: Main CPU wants to read (probably because it received a keyboard interrupt): Read port ...

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Was `wchar_t` ever widely adopted by the Unix culture in actual practice?
2 votes

I think your question must be put a bit differently for a first step towards an answer, like "was it common to use localized Unix applications from 70ies to nineties?" - In my opinion, the ...

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What's this computer in the 1988 movie "Vampire's Kiss"?
Accepted answer
79 votes

That's a Minolta PCW1 Word processor of Minolta Camera Co. Ltd The "computer part" is in fact a PC with 512kBytes memory and a 80186 CPU running DOS 2.11 and proprietary word processing (or, ...

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Why not constant linear velocity floppies?
3 votes

Early 8" floppy drives using mains-powered induction motors were speed-locked to the 50/60Hz mains frequency which determined (in most cases including a reduction gearing using a belt drive) the ...

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How did Apple IIc daughtercard expansions work?
3 votes

Z-RAM installs into the CPU and MMU sockets of the IIc (the chips have to be removed from the motherboard and placed on the Z-RAM). The memory expansion connector that later IIcs have is not used. ...

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Cleaning buckling spring keyboards
Accepted answer
12 votes

As always: depends. What do you want to clean? Cleaning the outside (keys, case,...) is done like with any other keyboard (soap foam, clean rags,...). Be aware the structured paint that IBM used for ...

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Unicomp's IBM model keyboards
Accepted answer
3 votes

IBM Model M and Model F keyboards (and their heritage manifested in Unicomp re-makes) are known and loved even today for a number of specifically unique features: Buckling spring key mechanisms. ...

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How do I clean/refurbish an Apple IIc Keyboard?
3 votes

The (non-Alps-keyswitch) keyboards for the Apple IIc were not particularily good even when new. Binding keys and uneven required force were somewhat normal. This has obviously not fixed itself during ...

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What's the origin of terminating strings by setting the high bit of the last character?
Accepted answer
19 votes

The method was pretty common for small systems that had to do case-insensitive comparisons to user input or, simply, storage, of a lot of short strings (a standard case in BASIC interpreters). ...

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Emulators running on 8-bit personal computers
3 votes

There's a number of (pure software) ZX Spectrum Emulators on the Sinclair QL if you count that as an 8-bit machine (quite obvious, as many QL owners were upgrading from a Spectrum), and there is a ...

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Protecting 6502 decimal mode code from interrupts
4 votes

There's absolutely no reason for an interrupt service routine to save and restore the decimal flag - On interrupt, the flag is being saved to the stack automatically, and restored on RTI, so any "...

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The Slowest Microprocessor
8 votes

Not the slowest in clock speeds (a whopping 1MHz), but probably the simplest and slowest in raw performance of its time may be the Motorola MC14500 CPU - It only has a 1-bit data bus and only 16 ...

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Is there a way to work around the maximum clock rate of Z80 PIO chips?
Accepted answer
10 votes

The Z80 PIO is much more of an I/O co-processor than a classic I/O peripheral chip. For this reason, it needs to be connected to the system clock of the Z80 main CPU. The PIO listens to various ...

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Why did BASIC programs tend to READ a redundant copy of DATA?
1 votes

The only alternative aproach to DATA is to assign initial values to initialized variables either directly (which doesn't save anything, the data is still present twice, both in the variables area and ...

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DOS serial printer formats
7 votes

Your problem is two-fold: You want to print in a retro-printer language "to a modern PC". That involves a bit of hardware (no modern PC can technically receive parallel or serial printer ...

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8 pin Mini-DIN to USB converter; where can I buy one?
2 votes

You could maybe solve the 2-step conversion in 2 separate steps: Belkin used to offer a Sun keyboard/mouse to PS/2 adapter as part of their KVM product line (these adapters seem to be available fairly ...

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How many kinds of mass-producible ROM is avaliable before 1970?
3 votes

IBM's TROS (Transformer Read-Only Storage) and CCROS (Capacity Coupled Read-Only Storage) both were ROM-alike, entirely free of semiconductor material, and basically one-time programmed like punch ...

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Which retro system controllers are compatible with Amiga out of the box
0 votes

This shop on Tindie sells modified Chinese NES64 controller rip-offs that connect directly to any 9-pin joystick connectors. The mod is available as a kit or fully assembled and ready to plug into ...

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Did any notable product use Intel's first RAM?
22 votes

The 3101 was not a product that came out of thin air. According to Intel's own sources, Honeywell Inc. had anounced they would buy 64-bit memory chips from any vendor that could supply them (so even ...

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CRT Mitsubishi Diamond Pro 1000 black screen: flashes BIOS logo during boot, but otherwise black
Accepted answer
8 votes

In the following I'm assuming you don't have the manual brightness control turned down to the minimum. That is the only trivial problem that might cause the issue. When the CRT isn't even able to ...

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Are there other examples of CPU architectures mostly compatible with Intel 8080 other than Z80?
7 votes

Obviously what's compatible (or an advancement) to the Z80 also has to be compatible to the 8080. That includes the Hitachi HD64180, the Zilog Z180 (which is essentially the same thing), the Toshiba ...

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Was there a specific benefit to inverted (XOR) mouse cursors other than aesthetics?
67 votes

XORing a cursor into a frame buffer (which is what you seem to be calling "inverted cursor") is actually simpler than ORing it in there: when the cursor has to be removed again (to move to ...

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Were there any filesystems support tag based key-value pairs before the 90s?
7 votes

The Sinclair QL's file system has a 64-byte "File header" providing metadata for the file. Among system-owned fields like modified/access dates, file length, type and name, it also holds 8 ...

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What was the last personal computer to have the chips neatly arranged in rows and columns?
1 votes

Apple Mac Mini M1 2021 - Not many chips on there, but the ones that are present are nicely arranged So, I guess your observation is wrong.

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How were UHF channels allocated to home computers?
2 votes

Europe: UHF Channel 36 was reserved for aerospace navigation until the 1980s (at least in Europe), thus was used for both VCRs and home computers. (The manufacturers could be sure their device wouldn'...

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