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1500 questions
46
votes
2 answers
Locked-up DOS computer beeped on keypress. What mechanism caused that?
Long time ago I had an old IBM PS/2 that I had fished out of a dumpster. It ran IBM DOS 5.0 and was a solid little machine. Occasionally I would encounter the following scenario, and I recently started wondering what was going on…
smitelli
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45
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3 answers
Why are the symbols on the number keys of PC & Mac keyboards different to ASCII keyboards?
On a US-layout PC keyboard, the symbols above the number keys are as follows:
Whereas the keyboard on an Apple II is different:
Note, for example, the '(' and ')' symbols are now above 8 and 9, and '&' is above 6 instead of 7.
The order of the…
Kaz
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45
votes
2 answers
Did IBM encourage Bill Gates to retain the rights over PC-DOS?
As is well-known, Microsoft's negotiations with IBM to deliver PC-DOS 1.0 with the original IBM PC resulted in:
IBM licensing the OS from Microsoft, as opposed to purchasing it outright.
Microsoft retaining the rights to license PC-DOS to…
Brian H
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45
votes
3 answers
Why does nobody attempt to build Charles Babbage's Analytical Engine?
The Difference Engine was built in the 90s.
Why has nobody succeeded in building the Analytical Engine?
Charles Babbage designed the Analytical Engine as a general-purpose computer to succeed his more limited difference engines. The Analytical…
Peter Parker
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45
votes
10 answers
Fastest non-emulated CP/M Z80-based computer ever built?
What were the fastest CP/M computers ever built?
I'll restrict this to the Z80 variant of CP/M, no CP/M-86, CP/M-68k etc.
Z80 compatibles with higher clock frequencies or more instructions/clock or other modifications count, as long as it ran CP/M…
dirkt
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45
votes
8 answers
Executable ASCII files before x86?
I've known about a technique allowing to bootstrap arbitrary 16-bit x86 code from a subset of instructions representable as printable ASCII bytes since the early 1990s.
The first example of an ASCII executable I saw was a short text that could be…
Leo B.
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45
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3 answers
How was a demo mode implemented in arcade machines
On many arcade machines when running in attract mode, they often show a demo gameplay. I wondered how they did this?I guess those are not pre-recorded movies, so I think that they probably ran the game engine with some pre-defined input. On some…
Devolus
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45
votes
4 answers
How did Woz write the Apple 1 BASIC before building the computer?
According to his 1984 interview with Byte magazine, Steve Wozniak created the BASIC for the Apple 1 computer before he actually built the computer:
I sat down and wrote the BASIC first, and that took a lot
more time than the computer design. Once…
DrSheldon
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45
votes
1 answer
What warning was given on attempting to post to USENET, circa 1990?
I recall a confirmation/warning message that read something like
"this will post to thousands of sites... are you sure?"
What was a typical such message in the days of pay-per-minute dialup access?
Whit3rd
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45
votes
9 answers
What was the point of separating stdout and stderr?
I occasionally need to work with console commands and 100% of the time I want to redirect my output to a file I fail to redirect stderr as well as stdout the first time. I can't think of a single reason one would want the output and the error to got…
Sidney
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44
votes
2 answers
Why does the original Donkey Kong update the screen in a curtain closing pattern?
For those of you who don't know, Billy Mitchell, the former Donkey Kong world record champion was caught cheating due to differences between the original Donkey Kong format, and MAME. In other words, he had been using an emulator to fabricate his…
Badasahog
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44
votes
26 answers
How were files transferred between different systems in the late 1980s?
Today there are adapters available allowing you to connect historic floppy drives to a modern PC. This allows you to copy data from historic floppy disks to the PC.
In the late 1980s and the early 1990s many users switched from an 8-bit system to a…
Martin Rosenau
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44
votes
7 answers
The history of the NULL pointer
As we know, in C to dereference a null pointer is undefined behaviour. From what I understand, the PDP-7 and the PDP-11 both have ordinary memory that can be written to and read from at address 0.
On the PDP-11, that address is part of a memory…
Omar and Lorraine
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44
votes
9 answers
Is DOS being shipped with or as an installed OS?
Given the very small size of DOS, it would seem it might still be ideal for some applications such as handheld games. Is any system manufacturer still shipping DOS with their machine?
If no one is shipping DOS, when was the last shipment?
Barnstormer
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44
votes
4 answers
Why did 80x25 become the text monitor standard?
Prior to the 1981 release of the IBM PC, the VT05 (72x20 1970), VT50 (80x12 1974), VT52 (80x24 1975), and VT100 (80x24 1978) text terminals were used on many Unix machines and the PDP-11 (probably the most widely used computer at the time). However,…
Barnstormer
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