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1500 questions
29
votes
2 answers
What exactly is/was threaded p-code?
Quickbasic 4.0 added threaded p-code which at the time I remember thinking was magical. But I have no idea what it means. What exactly is/was threaded p-code (and is the p actually the Greek letter rho)?
Simd
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29
votes
5 answers
When/why did computers come to have push-button main power switches where on and off is the same push action?
In the top answer to Why were animated screensavers used instead of a black screen on CRT monitors? the main reason was said to be that it avoids users accidentally turning off the machine, thinking it is turned off and trying to turn it on.
Well,…
leftaroundabout
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29
votes
2 answers
Correct pronunciation of `vi` (Unix editor)?
According to this video with Brian Kernighan, the correct pronunciation of the classical Unix editor ed is "Eee. Dee." — not "Edd".
So that made me wonder — what about the other classical editor, vi... should it be pronounced as "Vee. Aye." or as…
Baard Kopperud
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29
votes
3 answers
Why do Game Boy Colors not want nickel-cadmium batteries?
This is a page from the manual for the Game Boy Color:
There is no explanation as to why this is, or how this can be, but it claims that one must not use rechargeable nickel-cadmium batteries.
Why is this? I don't know if any other kind of…
Bacus
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29
votes
1 answer
How did anti-Y2K-bug boards work?
During the Y2K bug hype, I remember seeing a store announcing some kind of board that one would connect to the motherboard of a PC and the problem would be fixed. Were these devices legit and, if so, how did they work?
Guest
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29
votes
2 answers
Did INI files work in a different way on Windows 3.x than today?
I am dealing with an application that still uses INI files for configuration. I wanted to make a temporary change to an INI file, but the result was not what I expected.
Let's say the original INI file is
[mysection]
mykey=myvalue
and I wanted to…
Thomas Weller
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29
votes
1 answer
Did the original MS-DOS Quake not have a menu item for freelook, and if so, why?
I know that Quake (the 1996 MS-DOS game) is a "full" 3D engine, and always had some kind of mouse support.
However, even the original Wolfenstein 3D from 1992 also had mouse support from the get-go, only it was of course not "look up/down" mouse…
Faisal
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29
votes
5 answers
Why did old IBM-PC-compatible computers only have 16 colors available?
In the MS-DOS Editor, the only choices for colors were a collection of 16 colors:
That's 16 colors:
Black
Blue
Green
Cyan
Red
Magenta
Brown
White
Gray
Bright Blue
Bright Green
Bright Cyan
Bright Red
Pink
Yellow
Bright White
How were these colors…
no ai please
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29
votes
2 answers
Why was IBM's Scientific Subroutine Package superseded?
It is a familiar fact that scientific software tends to do a lot of vector arithmetic and similar, that one does not want to keep rewriting the low-level code for such, so the usual practice is to use an off-the-shelf arithmetic library such as…
rwallace
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29
votes
1 answer
Where is the ancient preprocessor?
I found the old C compiler from V6, and, though it seems to the modern eye a little different from good, idiomatic C, evidently it uses things like #include and #define, but I do not see how it implements these.
Was this an external program at that…
Omar and Lorraine
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29
votes
2 answers
Why did Sinclair choose the Z80 for its range of home computers?
The Sinclair computers are known for their low cost compared with other computers that were popular in the early 1980s. This is why they had membrane keyboards, or that rubber stuff in the case of the ZX Spectrum, and did not include a CRT as did…
Omar and Lorraine
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29
votes
3 answers
Why did many 9-pin printers use only 8 pins for graphics?
In the answer to another question about printers, the following claim is made about 9-pin printers:
The Epson MX-80, upon which many other printers were based, had nine round pins which were vertically spaced at 1/72" intervals… The MX-80 graphics…
Psychonaut
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29
votes
2 answers
Why does 6502 indexed LDA take an extra cycle at page boundaries?
On the 6502 CPU, this instruction:
LDA $0380,Y
takes either 4 or 5 cycles, depending on whether the indexing crosses a page boundary. But this instruction:
STA $0380,Y
takes 5 cycles regardless of page boundaries. Why is one fixed and the other…
fadden
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29
votes
3 answers
Why did the ZX80 CPU run at only 3.25 MHz?
The Sinclair ZX80 used a Z80A running at 3.25 MHz. But this chip was rated for 4 MHz. Why was it run below rated speed?
Apparently the master clock in the machine ran at 6.5 MHz, so the CPU clock ran at half that, but that just rephrases the…
rwallace
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29
votes
4 answers
Was there a clearly identifiable "first computer" to use or demonstrate the use of virtual memory?
The NPR.org news article and podcast How The World Has Changed! Science During The 40 Years Of 'Morning Edition' includes the photo below with the caption
Before the introduction of the personal computer, mainframe computers were the norm. The IBM…
uhoh
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