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1500 questions
21
votes
6 answers
How were sprites in DOS games programmed?
I would like to know how sprites in DOS games for vintage video cards like Hercules, CGA, EGA and VGA were programmed.
I mean how was the duration of each sprite timed and how they were blitted on screen. Is there any source code I can view to…
Nicolas
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21
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3 answers
Compatibility of printers with HP54645D oscilloscope?
I am not entirely sure if this is the right place to ask, but I figured if someone knows y'all here would.
I have an HP54645D oscilloscope, and it can print the screen on a printer that's connected via parallel port. With the scope I got a HP…
Vincent Guttmann
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21
votes
2 answers
Who invented small string optimization?
In the source code of the 1972 Pascal compiler (a very large OCR-ed PDF), there are declarations of variables and record fields of type ALFA, which are "packed arrays" of 10 characters.
Characters were 6 bit wide on the CDC 6600, and 10 of them…
Leo B.
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21
votes
4 answers
Why are the Nintendo 64 memory cards' batteries *soldered* on?
After recently learning that it has a battery inside of it, I unscrewed my Controller Pak (N64 memory card) to put in a new battery. The old one says "98" on it, referring to 1998. So it's likely running out of power.
The battery is soldered on.
Why…
user23842
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21
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2 answers
What is this game featured in the film ‘The Year of the Jellyfish’?
In the 1984 movie The Year of the Jellyfish, featuring Valerie Kaprisky, at 00:13:42 we see her play a video game on a console like an old Atari, Philips, etc)
Does someone know which console or which video game is this? Can you suggest some words…
elbarna
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21
votes
5 answers
Was 10BASE5 a mistake?
https://en.wikipedia.org/wiki/10BASE5 gives a succint but vivid description of the physical layer of the first version of Ethernet and its subsequent replacement:
10BASE5 (also known as thick Ethernet or thicknet) was the first commercially…
rwallace
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21
votes
3 answers
What windowing system had the first size-proportional scroll bar?
I came across a link to a site that shows the history of the scroll bar. While the content of the site is pretty thin and devoid of explanation, it does show Xerox Star, Lisa, Mac, Amiga, Windows, NeXT over a few years.
I've never used a Xerox…
bjb
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21
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3 answers
Why doesn’t my VGA-to-HDMI converter work with my 286 PC?
I have a Commodore PC 30-III with a Cirrus ISA VGA card in it.
I wanted to connect to an HDMI display by using a mini VGA-to-HDMI converter
The converter doesn't generate any output. The machine works when directly connecting to a VGA monitor. The…
Peter Szanto
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21
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2 answers
How can a protected-mode Watcom C program access memory that a real-mode interrupt service returned in a segment:offset register pair?
I'm using Open Watcom 1.9 to write some 286 real mode, and 386 protected mode software for DOS in C.
In real mode, I can retrieve a pointer to the system ROM character bitmaps in real mode using int 10h where AX = 1130h:
const uint8_t far…
knol
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21
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3 answers
Is there a list of space-saving techniques for representing constants?
Since numbers in ZX BASIC are always floating point and take up 5 bytes, it's often possible to save space when representing integers by using several tokens, which take up 1 byte each.
I know of COS PI for -1, NOT PI for 0, SGN PI for 1, INT EXP…
forest
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21
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3 answers
What was the rationale behind 32-bit computer architectures?
Though today various power-of-2 word sizes seems to be the norm, back in the 50-60s multiple-of-6 word sizes was more popular and was required by Department of Defense(DOD) in particular.
36-bit UNISYS ClearPath IX series survive even today.
With…
Schezuk
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21
votes
3 answers
Z80 to x86 asm translator?
8086 is source code compatible with 8080. Zilog Z80 extended Intel 8080 with:
An enhanced instruction set including bit manipulation, block move, block I/O, and byte search instructions
New IX and IY index registers with instructions for direct…
Schezuk
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21
votes
1 answer
Where are the sources of the original curses library?
The curses library is a terminal control library for Unix-like systems used in text based user interface applications. It has been used in many games in the past. It was developed by Ken Arnold and originally released with BSD Unix.
Where can I find…
NoDataDumpNoContribution
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21
votes
17 answers
Were any IBM mainframes ever run multiuser?
Now of course there is a sense in which they were – some mainframe installations supported thousands of users! But there is a distinction.
Consider the familiar fixture in so many 80s computer science labs: a VAX running UNIX or VMS, with an account…
rwallace
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21
votes
1 answer
Why did the 6502 handle BCD with a special mode?
The 6502 had special support for BCD arithmetic, because it was widely used in those days; this much, it had in common with other CPUs.
But the 8080 and 6800 implemented this in the form of a 'decimal adjust after addition' instruction, the idea…
rwallace
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