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1500 questions
23
votes
8 answers
Why not constant linear velocity floppies?
The outer tracks of a disk are longer than the inner tracks, and could therefore potentially hold more data. Constant angular velocity puts the same number of bits on every track, which wastes much of the potential capacity of the disk. A solution…
rwallace
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23
votes
11 answers
What was the equivalent of "America Online" (AOL) outside America?
The rise in popularity of home PCs with modems in the U.S. coincided with the rise of America Online. Of course, many of us in America were online for years before this - using Compuserve, GEnie, and BBS's mostly. But for mainstream America first…
Brian H
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23
votes
1 answer
When was QDOS changed to MS-DOS?
So a while back, I heard that MS-DOS was originally named QDOS (Quick and Dirty Operating System), and that it was later changed is MS-DOS (Microsoft Disk Operating System). This was probably a marketing strategy to fix a rather unappealing name. My…
Badasahog
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23
votes
7 answers
How can I connect a modern USB keyboard to a system requiring PS/2?
I have a DEC VT525 terminal base (recently repaired) that requires a PS/2 keyboard. The Digital OEM keyboard was a LK 411, with a PS/2 plug. There was also a PC-style keyboard available.
I could get lucky and find a good keyboard for $100 or so,…
Adam Eberbach
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23
votes
2 answers
What's a good way to implement this "splashing water" effect on the C64?
This pillow fighting game set in Venice
depicts the two opponents fighting on a wobbly gondola on a canal. It was apparently known as "Pillow Fight" in English and as "Kissenschlacht" in German, and was part of a bundle called Alternative World…
Omar and Lorraine
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23
votes
2 answers
What are these tiny TSRs doing?
I've been puzzled by this for a while now. The (very old) game Phantasie comes with three small TSRs that are run prior to running the main game executable. This is the content of the file PH.BAT, used to start the game:
@echo…
db2
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23
votes
2 answers
The origins of fork()
Is fork() older than C? What are its origins? I might think that fork() was created along with C (1970s) but I recently read a reference to a 1963 paper where fork() was mentioned.
Niklas Rosencrantz
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23
votes
4 answers
Why not one pixel per color clock?
Early home computers and game consoles output video to TV sets. The NTSC color clock frequency is 3.58 MHz. This informed the design of some video systems:
http://pineight.com/mw/index.php?title=Dot_clock_rates
In particular, the Atari 2600 and…
rwallace
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23
votes
6 answers
ZX Spectrum tokenisation
The BASIC used in the early ZX Spectrum (and also its ZX predecessors) had this weird thing where every single BASIC token was printed onto the keyboard, and for example PRINT or LOAD were entered by a single keypress. In particular the ZX Spectrum…
Omar and Lorraine
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23
votes
8 answers
Which BASIC interpreters support techniques for hybrid programming in Assembly?
It was common with Commodore BASIC (and others, I'm sure) to have machine language encoded in BASIC programs using POKEs or READ/DATA. This was needed for both performance and to access certain machine functions not accessible from BASIC syntax.
Of…
Brian H
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23
votes
4 answers
How can I access an old pre-IDE disk?
I have a wonderful Zenith SupersPORT 286 laptop (ZWE-0200-40) whose power circuitry seems faulty and it no longer powers up. I have useful material on the disk which I'd like to extract.
The disk (a Connor CP-343) interface is pre-IDE, and I can't…
Brian Tompsett - 汤莱恩
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23
votes
5 answers
Were there any LSI-11 like home computers outside of Russia?
In my childhood I had one of these:
https://en.wikipedia.org/wiki/Electronika_BK
Note, that the CPU of this is based on LSI-11. This is rather surprising because PDP-11 took a room (I was lucky enough to be able to tinker with it at parent's work)…
Andrew Savinykh
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23
votes
2 answers
How to convert Amiga DMS to ADF?
Our demoscene group managed to release only one demo before it fell apart, but these being the early days of the Internet in my country, and me getting lucky with obtaining access to it and creating our own webpage, I published the demo on the net…
SF.
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23
votes
4 answers
How was digital sound playback achieved on the Commodore 64?
The Commodore 64 did not have any hardware dedicated to digital audio playback, so how were some games and songs able to achieve this on an unmodified and unextended Commodore 64? Did these techniques require specific hardware revisions?
rcntxtlztn
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23
votes
3 answers
Did any x86 CPU optionally trap unaligned access?
x86 CPUs have always supported unaligned load/store.
Early RISC CPUs didn't. So imagine writing portable code on a 386. It seems to work fine, but how do you know you haven't accidentally misaligned some data, so that when a customer tries running…
rwallace
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