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1500 questions
102
votes
6 answers
Were there 8086 coprocessors other than the 8087?
The 8087 math coprocessor for the 8086 (and descendants) nominally added floating point and transcendental (trigonometric and logarithmic) instructions to the 8086. Contrary to naive expectations, the 8087 didn't "augment" the main CPU. It was a…
Euro Micelli
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99
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1 answer
Why did MS-DOS applications built using Turbo Pascal fail to start with a division by zero error on faster systems?
On faster MS-DOS systems, it wasn't entirely uncommon for applications built using Borland's Turbo Pascal to fail to start, and (before exiting back to the command prompt) to report a division by zero error immediately upon launch.
As I recall, this…
user
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96
votes
11 answers
What key factor led to the sudden commercial success of MS Windows with v3.0?
Microsoft Windows was originally introduced in 1985, ostensibly to compete with the Apple Macintosh, and other computers shipping with graphical shells by that time. However, early versions of Windows were not commercially popular, and MS-DOS…
Brian H
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96
votes
3 answers
Why does part of the Windows 98 Setup program look older than the rest?
When installing Windows 98, the part of the setup process where you enter things like product details looks... different. The scrollbars, buttons, title bar and such look more like they belong in Windows 3.1 or Windows 3.11, apparently using "ctl3d"…
Wander Nauta
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93
votes
7 answers
Why would a NES game use an undocumented 1-byte or 2-byte NOP in production?
Reading the NESdev wiki page on CPU unofficial opcodes, I see a few games use an undocumented 2-byte NOP instuction in production: Puzznic, F-117A Stealth Fighter, and Infiltrator use $89 #i. Beauty and the Beast uses $80 #i. Additionally,…
JAL
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92
votes
3 answers
How did Windows 3.1 implement multitasking?
Windows in its earliest days was simply a shell that ran on top of MS-DOS, which means that Windows 3.1 itself was actually just a standard MS-DOS application like any other.
Yet, MS-DOS is not a multitasking operating system, and at the same time,…
Mike Nielsen
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92
votes
10 answers
How much better was DEC Alpha than contemporaneous x86?
The DEC Alpha, released in 1992, seems like an early implementation of a fully 64-bit microprocessor architecture. Its release led to quite a bit of both marketing hype and genuine vendor support in the mid-1990s, which supported the conclusion that…
Brian H
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90
votes
20 answers
Have programming languages driven hardware development?
Programming language development has been influenced by hardware design. One example from this answer mentions how C pointers were, at least in part, influenced by the design of the PDP-11. Has the reverse taken place, where a construct provided by…
Nathan
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89
votes
9 answers
Why did modems have speakers?
Everyone who used early telecommunications services, not to mention the early dial-up Internet services, is familiar with the tones and hissing sounds of a modem establishing a connection. I recall all my home computer modems, from the early 1980s…
Brian H
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87
votes
9 answers
Why is the processor instruction called "move", not "copy"?
Many processors have an instruction called "move" (sometimes spelled MOV) which copies data from one location (the "source") to another (the "destination") in registers and/or memory. It does not do anything to the "source".
This is analogous to…
JoelFan
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86
votes
1 answer
How exactly does Sonic & Knuckles' 'Lock-On Technology' work?
The cartridge of Sonic & Knuckles is a little special. It flips open to allow you to connect another Sega Mega Drive (Genesis in US) cartridge to the top of it like so:
Click for larger images
I know why the Sega developers did this: with the time…
Robotnik
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85
votes
19 answers
Did any 8-bit computer system / OS have concepts for concurrency and multitasking like we know from today?
So, today all major OS support multitasking and concurrency in languages like for instance threading.
The Amiga seems to be the first home computer which has advanced concepts in this area. But had any 8-bit home-computer rudimentary capabilities…
Marco
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84
votes
18 answers
Why was BASIC built into so many operating systems?
There are a lot of retro-computers with BASIC as an integral part of the operating system. The IBM 5100 was one of the first computers with a separate memory space for BASIC, followed by the Commodore PET, Apple II and TRS-80.
But why was BASIC…
wizzwizz4
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84
votes
2 answers
Is there any code in Firefox (as of 2020) that comes from Netscape Navigator?
Inspired by comments on the previous question Is it true that Netscape Navigator eventually became Mozilla Firefox? (Answer: Yes).
In 1998, Netscape released a large amount of their existing source code as open source, and this became the basis of…
IMSoP
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83
votes
3 answers
Why does the Minus World exist?
In Super Mario Bros. for the NES and Famicom there exists a secret world, accessible by clipping through a wall to the first warp zone and entering the left-most pipe.
This pipe will take you to level " -1". In the NES release, this level is…
wizzwizz4
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