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1500 questions
17
votes
2 answers
How does the Kickstart ROM load and start workbench?
As I understand, on the Commodore Amigas, the kickstart copies itself into a region of memory which is later made read-only. Does kickstart also copy workbench into this region?
How does kickstart find workbench? It might be on a floppy; so is it…
Omar and Lorraine
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17
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6 answers
Why didn't PC games eschew MS-DOS and deal with BIOS directly?
Given the memory referencing limits of MS-DOS for compatibility purposes, why didn't games produced for the 286+ processors eschew MS-DOS and talk directly with the BIOS or IO hardware, instead of all the optimisations necessary to maximise the…
Chorlton2080
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17
votes
2 answers
Was bootloading from punch cards possible on System/370 machines?
I have been idly looking into how System 370 works, though mostly at software and VM/370 OS. As a part of the system generation process, one needs to use DMKDDR utility and others. So I was curious how these work and get loaded.
The tape image I've…
Saphire
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17
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7 answers
Why did Linux standardise on RTS/CTS flow control for serial ports
I've recently been working out how best to wire up a serial cable for a vintage plotter, and it's thrown me down the rabbit hole of RS-232.
As far as I can tell, many RS-232 devices which act as DTEs (e.g. my plotter, DEC terminals) seem to prefer…
Peter Russell
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17
votes
3 answers
Does this 1978 code for a 6800 really clear ALL of memory?
On page 43 of the October 1978 Dr. Dobb's Journal (reprinted in Volume 3 Page 425 Issue 10 Number 29) is a letter to the editor giving three 6800 routines to clear ALL of memory, stating...
Routine 1 (8 bytes): fill memory with NOPs.…
Les
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17
votes
4 answers
Best way to locate data on ROM? (6502 Processor)
Lately I've been interested in how old machines work, in particular an NES. While there are quite a few resources on the basic operations and even some games that have been totally broken down byte by byte, there isn't much information on how this…
Aquova
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17
votes
5 answers
Programming languages that used degrees in trig functions?
Most programming languages that feature mathematical functions expect the arguments to be in radians. For example, sin(1) would typically return 0.841471, equivalent to sin 57.295°. But a couple of older languages didn't follow this…
scruss
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17
votes
8 answers
Why did they create PC games relying on a fixed CPU frequency instead of a clock function?
I know there have been computer games which rely on a fixed CPU frequency. Instead of a clock function they rely on the fact that the CPU needs some time to execute the code.
But why did they do it? Aren't there drawbacks only?
For example if the…
javanerd
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17
votes
4 answers
Document format for a DOS word processor where control commands begin with a dot
I successfully achieved the reading of several 5.25″ old floppies. They contain old documents from a retired lawyer.
For the memories, we want to read them correctly, nevertheless, I don't find which software was used neither he remember which…
David Sosa
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17
votes
3 answers
When was network byte order decided?
TCP/IP has some binary header fields which are affected by byte order, so defines 'network byte order' to settle the issue, specifically defines it as big-endian.
When was this decided? The earliest reference I've found so far is RFC 1700, but that…
rwallace
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17
votes
3 answers
When did the 386 overtake the 286?
The Intel 80386 was released in 1985, but was initially expensive, and took a long time to fully displace the earlier 80286 from the market; subjectively, I remember significant numbers of 286 machines around into the early nineties. Of course, the…
rwallace
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17
votes
2 answers
When did type punning through violating the strict aliasing rule become disallowed?
Looking at the C code from the Fast Inverse Square Root, the casting of a float to a long is done via pointer arithmetic:
i = * ( long * ) &y; // evil floating point bit level hacking
The hacking in question isn't of immediate interest to me. The…
Adam Hyland
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17
votes
2 answers
How did the Trap65 work?
The Wikipedia page on the MOS 6502 mentions a hardware device called the Trap65 which apparently sat between the 6502 and its socket to trap any undocumented opcodes. The wiki page has the usual citation needed so I suppose it could be a…
Omar and Lorraine
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17
votes
4 answers
Was the ZX Spectrum used for serious number crunching?
From Eurogamer’s obituary of Sir Clive Sinclair:
Sinclair never intended for his computers to be games machines, but
that was what the market decided they were. Within the space of a few
years, the idea of having a computer in the home had gone…
user1095108
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17
votes
8 answers
Why was the DOS kernel discarded?
I've read that the last DOS kernel based Windows was ME. Later versions use the NT kernel.
Why did Microsoft rewrite the whole kernel? Why was the DOS kernel discarded?
zomega
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