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1500 questions
20
votes
6 answers
C64 BASIC: How to suppress the '?' sign when using the INPUT command?
When you are getting INPUT in Commodore BASIC it always adds a question mark at the end of the string you want to show.
Is there a way to suppress the question mark when using the INPUT command?
user6734
20
votes
5 answers
Why does the Z80 have a half-carry bit?
The Z80 apparently had a 4-bit ALU, and computes 8-bit values in two stages.
The half-carry bit preserves the carry from bits 3 to 4.
Why did the designers of this chip choose to preserve that value in the flags register? Presumably, that…
Omar and Lorraine
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20
votes
1 answer
How does the 4MB mod for 8-bit Atari work?
On the local auction portal I have spotted ads for some "supercharged" 8-bit Ataris (800XL, 65XE etc) - modified to support 4 megabytes of RAM.
The auctions were scarce in details, more concentrating on praising the product than providing any actual…
SF.
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20
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1 answer
Why BGR color order
Blue Green Red (BGR) byte ordering exists in a few image processing libraries "for historical reasons", mostly because it seems to have been a Microsoft standard.
Does anyone know the historical reason?
Color spectrum is almost always read as "Red…
Martin Beckett
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20
votes
2 answers
Why did nobody ever succeed in "clean room" cloning the Apple Macintosh?
As is well recorded, in the PC/MS-DOS world, Compaq and Phoenix (among others) successfully "clean-room" implemented their own versions of the IBM BIOS, thus opening the door to the PC clone market.
The section about unlicenced Macintosh clones at…
dgnuff
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20
votes
2 answers
Did 486 SMP systems provide Total Store Ordering?
Cache-coherent SMP (symmetric, or shared-memory, multi processing) systems can provide various grades of memory ordering guarantees, the stronger ones being more expensive but making it easier to write correct code:…
rwallace
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20
votes
10 answers
When did computer manuals and books start using monospace fonts for code, and why?
At least through the early 1980s, the source code in non typewritten computer manuals and books was usually typeset using proportional fonts, sometimes with syntax highlighting such as keywords in bold. When did these works start switching to…
Paolo Amoroso
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20
votes
1 answer
What is the arcade game played in the "The Boys Next Door" movie?
This is from the movie The Boys Next Door (1985). The character is playing an arcade game.
There is the name, but is impossible to read. I read "mrrruders" but searching on the net nothing came out. It is not properly a video game, but an…
elbarna
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20
votes
3 answers
How much did the 6502 and Z80 cost?
It is said that the 6502 was cheaper than the Z80.
As of 1978, what were the actual prices of the two chips, in wholesale quantity?
rwallace
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20
votes
2 answers
Did the IBM ServiceFree really reach 80 MIPS in 1975?
According to Computer Wars by Charles H Ferguson and Charles R Morris, page 40-41, an IBM researcher named Cocke in the early 70s built a RISC minicomputer called the ServiceFree (because it was meant to be simple enough to require little…
rwallace
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20
votes
3 answers
What are these keys on the БК-0010-series keyboards, and what do they do?
(Picture taken from Wkipedia)
The БК-0011M keyboard has these keys across the top row:
ПОВТ (perhaps short for Повтор, which means Repetition; perhaps used for key repeat)
КТ
Three arrows which look like they could be for cursor movement
Possibly…
Omar and Lorraine
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20
votes
4 answers
What is the serial protocol commonly used over RS-232 (among other links) and where did it come from?
The RS-232 standard (and ITU V.24 and V.28, which as I understand it are basically the same thing) specifies connectors (DB-25), electrical characteristics (-15 to -5/-3 V for "mark," +3/+5 to +15 V for "space"), signal wires (ground, TX, RX, etc.)…
cjs
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20
votes
5 answers
The Cray 1 used 115 kW of power. How was that much grid power physically delivered to the unit?
We are talking power plant levels of current to power the the thing. Did it just have 2 inch lugs?
R Gi
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20
votes
3 answers
Was QotD (and RFCs 862-867) actually insecure?
I am fascinated by these 6 obsolete internet protocols, all written up as seperate RFCs by Jon Postel in May 1983. They are hilariously simple. (Which I mean as a compliment; their simplicity inspires me.) Several of the RFCs are less than one page…
John Skiles Skinner
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20
votes
3 answers
when did command line applications start using "-h" as a "standard" way to print "help"?
I am interested to hear about the history because I have a prominent command line product that has decided to use -h for something that does not print a help message.
when did command line applications start using "-h" as a "standard" way to print…
Trevor Boyd Smith
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