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5 answers
What were wait-states, and why was it only an issue for PCs?
PC compatibles in the 1980s were often advertised as having zero, one, two, or sometimes more "wait states". Zero wait states was the best.
Basically, the wait-states I am asking about are due to the main system DRAM being too slow for the CPU, so…
Brian H
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3 answers
Did MS-DOS itself ever use blinking text?
I know that it was possible to create blinking text, but did the operating system itself (I mean, in output from functions of COMMAND.COM and similar executables) ever make use of blink formatting?
You'd think it would be useful for confirmations of…
KlaymenDK
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5 answers
How do you open an SE/30? (a.k.a. what is a "pull-apart tool"?)
I have been trying to work out how to open a Mac SE/30, in order to have a better look at its internal condition. I have the repair manual, and in the "Take Apart" section it references a "pull-apart tool". However, I cannot find any mention of this…
felixphew
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How did the ZX80 store both a useful program and screen memory?
I have a vague recollection from my earliest days that the ZX80 only shipped with 1K of RAM.
If this RAM was used to store both the program and the contents of the 32x24 screen, wouldn't that mean only about 256 bytes were available for…
user6464
25
votes
2 answers
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.youtube.com/watch?v=A3Po8zneaLE
Why are they doing…
Andreas Hartmann
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9 answers
What were the early PC applications requiring a hard disk?
I had to wait about 5 years before hard drives (HDs) became affordable enough to begin moving off of floppies. During this time, I remember my desire for an HD being based on convenience. All the software I used was designed to run fine from…
Brian H
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25
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8 answers
How did debugging software run without memory protection?
Debuggers are carefully written programs that peek and poke other programs while they run. In retrocomputers, programs could use any part of the memory they could access.
So how did debuggers insert themselves into memory so they could be executed,…
wizzwizz4
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25
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3 answers
How did programs on coding forms get run?
At some point in the past, around the 1970's or so, programmers wrote their code on paper. Considering the fact that modern computers have replaced paper in so many ways, the whole idea seems a little backwards.
I have no first hand experience with…
Laurel
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Why do all the Speech Synthesizers have that same Voice?
The first time I ever played with software speech synthesis on a microcomputer (not hardware synthesis, like in TI's Speak & Spell) was around 1983, using S.A.M for the Commodore 64.
A year later, I remember hearing the speech synthesis from the…
Brian H
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2 answers
Why does waggling the joystick of a C64 cause errors loading from tape?
When loading a game from the tape drive on a C64, if you wiggle the joystick around too much the program will not load correctly. Is there an explanation for this?
EDIT: Perhaps someone can try to reproduce this on their C64 and see if it's just…
WW.
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25
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4 answers
Z8410 DMA chip as GPU?
There are basically two ways to design a 2D graphics system:
Provide lots of hardware support in the form of tiles, hardware scrolling and sprites, to put together each frame on the fly from a small quantity of data, so you can have lots happening…
rwallace
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25
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8 answers
Separate code and data address spaces on the Z80
Reading through the Z80 datasheet, I noticed something interesting. The Z80 separates its instruction execution into separate phases (which are called "machine cycles" in the official literature, but I don't like that terminology because it is too…
Jules
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25
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3 answers
Adapting a "modern" keyboard to a ZX Spectrum
Is there a way, such a specific interface adapter, which would allow me to connect a PS/2 keyboard to an original ZX Spectrum?
I expect the keyboard to work similarly to the ZX Spectrum itself -- in other words, pressing P would trigger send the…
Sklivvz
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Why are there two, different, Kickstart 1.3 ROMs with the same 34.5 version number?
The Kickstart 1.3 ROM file that is supplied with Cloanto's Amiga Forever (amiga-os-130.rom) is very slightly different to that which you'd get by dumping a real 1.3 ROM from an Amiga 500.
Specifically:
Byte at 0x0019d changes from 0x08 to 0x20…
Richard Downer
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25
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2 answers
Why are the | and ¦ keys labelled the wrong way around?
Note to close-voters: There is a meta question concerning the on-topicness of this question. Please provide an answer or comment. A comment from downvoters wouldn't hurt either.
The UK QWERTY keyboard layout has the button labelled with a split…
wizzwizz4
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