tofro
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How long can a HD floppy disk hold 2.88MB before erasing itself?
Accepted answer
8 votes

Experimentally verified data retention duration: 0 seconds. Because you asked and I was curious too, I have just cut an ED notch in one of my old HD disks (to trick the drive into thinking it were an ...

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How much faster is the Z80H?
Accepted answer
8 votes

The Z80H is, to my knowledge, an exact drop-in replacement for the original Z80, just with a higher clock frequency. The instruction set and the pin-out (if purchased in the same package) are 100% ...

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Are there any articles elucidating the history of the POPCOUNT instruction?
8 votes

I would guess the answer is very simple and obvious: CPU makers don't just implement what they want, what "looks nice in a spec" or "what's easily done". They are driven by the market and implement ...

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How did the "rub joystick port to continue" in the Creatures 2 infinite lives cheat work?
8 votes

Assuming it really does work and we are not hunting an urban legend: Every game needs some sort of cheat mode during development and testing in order to be able to test and verify later levels of the ...

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Largest ratio between base and maximum RAM
8 votes

The Sinclair ZX-81 came with a single K of memory and could be expanded to 64kBytes (using third-party memory expansions, Memotech, for example). I think none of the later (home) computers ever ...

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Dealing with old laptop batteries?
8 votes

Ni-Cd cells like the ones used in the last century have one strong advantage over the Li-based battery cells we use today: They simply die silently. As long as they are not leaking and contaminate ...

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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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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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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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Why are older Shift keys shaped the way they are?
7 votes

Simple answer: When there is a definite place where the key has to be pressed, there is much less probability that the key is pressed off-center and binds, thus you could possibly do without the wire ...

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Which microcomputer manufacturers developed their own Local Area Network systems?
7 votes

Sinclair's ZX network was implemented in both the ZX Spectrum (with Interface 1) and the Sinclair QL - Some QL compatibles that came later implemented it as well. It was a serial multidrop network ...

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Parallel to serial conversion
7 votes

Yes, there were such gadgets that converted serial to parallel. The attached picture shows a Miracle Serial to parallel converter for the Sinclair QL, courtesy of 1984. The QL had no ex-factory ...

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Was 1991's Hellcats the first instance of incremental screen updates?
7 votes

Basically all graphical user environments (MS Windows [1985], X11 [1984], Atari GEM [1984] send a running application a list of screen regions that need to be re-drawn when one of this application's ...

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CP/M without floppy drive
7 votes

There were quite some diskless computers that could run CP/M from ROM (notable examples the Epson PX-8 and similar), but those computers booted CP/M from ROM instead of tape (even if the PX-8 had a ...

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Why did C have the return type before functions?
7 votes

Note C has much fewer places where a function definition can appear than languages like Pascal. Pascal supports nested functions, so a function definition can appear within any function, so basically ...

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What is the title of this Macintosh programming book?
Accepted answer
7 votes

Could it be this one? Byte's Mac Programmer's Cookbook Paperback – May 1994 by Rob Terrell (Author) I once had (and enjoyed) it when I still had a Macintosh. Just like the Mac, my issue has ...

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What was the first piece of software to be called an engine?
7 votes

The first Game Engine that literally used the term Engine was, to my knowledge, the Doom Engine by id Software in 1993. Database Engines, however, used this term much earlier. dBase and, especially ...

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How was parity used with modems?
7 votes

Parity is a "one-bit checksum over a single character". It can be used to detect single-bit errors in a serial asynchronous link (As the checksum is only one bit, two or more bits/char failed ...

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What libraries do I need in order to compile for Windows 98?
7 votes

You are probably not linking to the winsock library. Depending on the winsock version you are targetting, you should use either ws2_32.lib for Winsock 2 (which you seem to be using), or wsock32....

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How and why did the ZX Spectrum use so many voltages?
7 votes

This is the boring (or, rather, the trivial) part of the answers - How the +5V voltage is being generated in a ZX Spectrum: The ZX Spectrum uses (like basically any other home computer of the time) ...

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Appropriate battery replacement for my A3000
7 votes

On all my retro computers, I tend to replace the on-board batteries with cables and a double AA battery holder like this that I can store off-PCB (typically, I fix it somewhere within the computer ...

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Bit one of the Intel 8080's Flags register
6 votes

According to the manual, the only thing that is explicitly set after RESET in the 8080 is the program counter. Everything else is indeterminate: Note, however,that the RESET has no effect on status ...

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Was the ancestor of SCSI, the SASI protocol, nothing more than a draft?
6 votes

The point is: When SASI was en vogue (and that was only a very short timeframe, because technology was soon superseded with SCSI and the simpler ST506 and later ATA standards), hard disks weren't very ...

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Is there a program I can run on the C64 to speed up booting of a game?
6 votes

There were quite a number of software-only fast loaders for the C-64+1541: Hypra Load Speed Load ...and many others (a quite comprehensive list can be found in the C64-Wiki) Fast loaders are (...

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How do you open an Amiga A590 Power supply?
Accepted answer
6 votes

The last (and only) Amiga 590 PSU I have ever seen actually had four screws, all hidden under plastic cones that need to be removed first. (All four holes visible in the picture hold a screw). EDIT ...

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Did people back then build powerful computers out of multiple smaller machines?
6 votes

The average (and even far-above-average) computer user was actually pretty lucky having one single computer at his disposal back in the days. So it was pretty unlikely they could connect more than one ...

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Intel 8080 and Altair 8800. 256 I/0 ports, but only 7 free RST (interrupt subroutine) - how it works?
6 votes

1 I/O port <> 1 hardware device 1 RST vector <> 1 interrupt from one device You have read the datasheet under false assumptions. There is no such thing as a 1:1 correlation between these ...

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How did software engineers test their code in 19xx?
6 votes

Admittedly, your question is way too broad - Even today, that question cannot be answered for the bandwidth of what commonly qualifies as "software". Embedded Software requires (and required) an ...

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How did DoubleDOS work?
6 votes

Multitasking is absolutely not depending on modern CPUs like the 386 or anything - Those CPUs go one step beyond and protect multiple tasks from each other, while earlier MT OSs had to rely on ...

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Transferring files between Commodore PET and IBM PC
6 votes

CBM disks used GCR drives, something beyond the capability of any PC disk drive that I would know of - They use MFM. Direct disk-to-disk transfer seems to be out of the question other than on a 1571 ...

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