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1500 questions
15
votes
7 answers
Amiga floppy disks and GCR vs MFM
According to the Wikipedia article on GCR, the Commodore 1541 disk drive used a particularly efficient GCR encoding scheme to cram 170K onto the same 5.25" disks that in an Apple drive only stored 140K.
However, for the Amiga 3.5" disks, they…
rwallace
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15
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1 answer
Why does AT&T syntax use * and $?
In a comment to an answer about AT&T assembly syntax, another-dave asked the following:
DEC used #foo for an immediate operand in -11 assemblers; the Unix guys apparently preferred $foo, which to my eyes lacks any mnemonic significance. Similarly @…
ninjalj
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2 answers
Did the transmeta processor architecture work by binary translation?
Transmeta Corporation produced the Transmeta Crusoe Processor architecture. (Transmeta was also famous for having Linus Torvalds work there at the time.)
We can see from the wikipedia article that the Crusoe processor appears to implements Code…
hawkeye
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1 answer
What did Microsoft customize on Windows 95 installation floppy disks?
I have a Windows 95 Upgrade 3.5" DMF installation disk set where several disks were infected by the boot sector virus known as "Chance.A". I'm interested in restoring these to their original contents.
Before rewriting the disks using disk images…
rakslice
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15
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5 answers
May the PDP-11's stack grow in either direction?
According to this answer, the stack grows downward. It's in §4.4 of the cited document:
As another example, the DEC PDP11 range has a hardware
stack which grows with decreasing store addresses.
Now, but the way this works is by the…
Omar and Lorraine
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15
votes
2 answers
Weak bits on floppy for copy protection
How did the vendors using copy protection create weak bits on the floppies?
This always fascinated me as a kid. I ended up finding a weak bit emulator that would intercept the floppy disk interrupt and substitute different values and would be…
enorl76
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15
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2 answers
1980s game with a guy with an axe on a flying disc
I'm trying to identify a game I remember from the 1980s. The game was shown from a bird's-eye viewpoint (or maybe isometric?), on Apple IIe, IIRC.
You controlled a guy with an axe, who was constantly walking forward, but you could rotate him left…
Matija Nalis
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15
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3 answers
Role of the Z80 co-processor in GBA games
The Nintendo Game Boy Advance had a Z80-like processor which was typically used for backwards compatibility with GB and GBC games. According to its Wikipedia page, an uncited comment claims that this CPU was also used by GBA games to supplement…
forest
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15
votes
3 answers
Using a modern PC or other digital audio recording device as a cassette recorder replacement
I'm having a hell of a time getting this to work. I've got a Casio fx-720p + FA-3 cassette interface, a TRS-80 PC-3 with its cassette interface and printer dock, and a Tandy 102 with a cassette cable.
I've tried hooking all three of these to both a…
db2
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15
votes
4 answers
Where can I find an external 8-inch floppy disk drive?
Where can I find an external 8-inch floppy disk drive?
I have some data I would like to retrieve from a really old 8-inch (200 mm) floppy disk, but have no working computer than has a drive to read it.
Are external drives for that size still sold?…
Jeff
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15
votes
4 answers
What was computer "Fuzzy" logic?
In the mid 1980's computers began to be advertised as having or being capable of "Fuzzy" logic. How was "Fuzzy" logic added to a computer and what was it suppose to do better than a computer without it?
jwzumwalt
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15
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1 answer
"Your program is testing for optimal display performance" in older Windows games
I remember seeing the following a lot when I was younger, and recently saw it again in a DOSbox setting:
For those that haven't seen it, the squiggly red lines shift and undulate quite a bit, and it actually looks like it's doing something fairly…
LSM07
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8 answers
Why did common floppies never advance past 1.4 MB in size?
The chronology of some early floppy standards was: 80 kB, 160 kB, 360 kB, 720 kB, 1.2 MB, finally 1.44 MB. (There were less common sizes such as 250 kB, 800 kB, 1 MB) mentioned by comments: 120 kB, 2.88 MB :)
The last size (and still the most…
jwzumwalt
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15
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3 answers
Windows 95 installation floppy images are larger than 1440 KiB. How can I fit their contents on standard floppies?
I have an old laptop with only a floppy drive. It came with Windows 95 on it but suffered from some terrible BSoDs that I could not resolve. I figured I would just download some Windows 95 install disks and reformat it, but apparently those disks…
Mark
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15
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7 answers
New 6502 BASICs?
I sort of "have a thing for BASIC" right now, which has led to a couple of great exchanges here in RSE about the variations "back in the day". I'm wondering if anyone is aware of other modern BASICs for the 6502?
I'm ultimately interested in seeing…
Maury Markowitz
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