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1500 questions
32
votes
3 answers
Has there ever been a pressed optical disc containing a computer virus?
I got 200 computer CD games here and I think checking them for viruses would be inappropriate. Also, when I bought software on CD I was always sure there is no virus.
I wonder if there ever was software or a game containing a virus on the optical…
zomega
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32
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5 answers
Does every retrocomputer and console with NTSC composite output have 'artifact color' ability?
Artifact color is heavily associated with the Apple ][, since that is the only method the machine had to produce a color display. I was looking at the fantastic demo for IBM PC + CGA, 8088MPH, and I vaguely understand how they managed 1K colors with…
Brian H
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32
votes
7 answers
Did any PC software floating point use non-IEEE format?
During the 1980s, prior to the 486 (well, strictly speaking, prior to the discontinuing of the 486SX in the nineties), IBM PCs and compatibles had hardware floating point only in the form of an optional coprocessor. Programmers responded to this in…
rwallace
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32
votes
1 answer
How did the various Soviet ZX Spectrum clones support Cyrillic text?
There may be no one single answer to this question, since the various clones might have done this all in different ways. And of course, some clones do not have the Cyrillic text support at all. I'm not aware of any, but if there were any clones also…
Omar and Lorraine
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32
votes
2 answers
Why did the Z80 break 8080 compatibility?
Although the Z80 is nearly fully backward compatible with the Intel 8080, there are minor differences such as the Z80 handling the parity flag differently with certain operations.
Why? Would providing full 8080 compatibility have interfered with or…
Paolo Amoroso
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32
votes
6 answers
Why did the monsters have "infinite invisible pillars" of hitboxes vertically in all versions of the DOOM engine?
Even in the last version of the DOOM engine, v1.9, used for Final DOOM, there is this strange limitation in which all the monsters have an invisible, infinitely tall "pillar" above and underneath them which blocks the player from, for example,…
Farrad
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32
votes
2 answers
Which computer system defined the IPv4 576 byte datagram limit?
The IPv4 specification requires that IPv4 devices must be able to reassemble a datagram with a length of a minimum of 576 bytes.
Looking back into the creation of the Internet...
RFC 791 in defining the IP protocol states:
Every internet…
user22965
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32
votes
3 answers
Does the video game Control (2019) depict a real computer system? What is it?
I was playing Remedy Entertainment's video game Control the other day. Inside the game world, I've come across several computers. (They all look extremely similar.) To me, it looks like some kind of DEC system. Now I'm wondering... is it just…
MathematicalOrchid
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32
votes
2 answers
What did Pete Stewart think he knew about efficient implementation of floating point denormals?
The most controversial part of the IEEE 754 floating-point standard is gradual denormals. Typically they trap to software rather than being implemented in hardware. In the common case where a workload has numbers that decline to zero, when they hit…
rwallace
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32
votes
2 answers
GameBoy Color games do not save any more
I have a Nintendo GameBoy Color with some games that support saving your game status and also have a real-time clock, like Pokémon Red and Pokémon Silver.
But recently the game does not save any more, the saved position is reset. Also the real-time…
Byte Commander
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32
votes
1 answer
Did DOS zero out the BSS area when it loaded a program?
As an example, say we have a DOS MZ EXE file that's around 20 KiB in size. The EXE header contains the value 0x1400 at offset 0x0A indicating that the program is requesting 5,120 paragraphs (or 80 KiB) to be allocated in addition to the space…
smitelli
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32
votes
6 answers
Why is the Amiga ROM at a high memory location, and RAM in low memory?
When a 68000 CPU powers up, it reads a few words at memory location zero to get the initial stack pointer and program counter. That suggests to me that a computer system designer would put the system ROM at memory location zero, where the 68000…
Richard Downer
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32
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2 answers
Why wasn't EBCDIC designed with contiguous alphanumeric characters?
Inspired by this question on ASCII, I have wondered similar things about EBCDIC.
At work we have an EBCDIC file that gets sent to a mainframe (I presume an IBM one) and to view it on my laptop I needed to run a command to convert it. dd…
Captain Man
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32
votes
3 answers
Was Dennis Ritchie being too modest in this quote about C and Pascal?
In his 1993 conference proceeding The Development of the C Language, Dennis Ritchie stated
Successors
C and even B have several direct descendants, though they do not rival Pascal in generating progeny.
Was Ritchie correct, or was he just being…
DrSheldon
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31
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6 answers
How did the BBC Micro stay cool?
The BBC Micro used the extended variant of the classic 'computer in keyboard' design; like the Apple II, the case went back far enough that you were encouraged to put the monitor on top of it.
All the electronics were in the back of the case…
rwallace
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