This page includes trivia about computers, computer science, and infosecs.
No meme intended ;)
1. What is the use of tilde (~) in URL?
T.E.D and j08691 answered at the Stack Overflow:
Well, a webserver is free to use any character after the leading URI part for whatever purpose it wants.
That being said, the use of
~generally hearkens back to the early days of the web, when just about every web server ran on Unix. In the Unix world, systems supported multiple users, each with their own home directory. If you want to go to your own home directory, youcd ~. If you want to go to some other user likefred's home directory, that would becd ~fred.So when people started putting up web servers, they would generally let every user in the system have their own web space, which is accesible from the root of the webserver by using
~username.For example, a very old website of mine (now defunct) provided by an old ISP (Telepath) was at
http://www.telepath.com/~dennison/
binarym commented:
Damn, you forgot mentioning the "public_html" dir. ~user/ content was generally served from /home/user/public_html/ directory… Good old days :)
2. What does the "-ng" suffix mean in package names?
Short answer: NG stands for "Next Generation".
For example, aircrack-ng is a fork of the original Aircrack project, developed by Christophe Devine. But recently, people usually rename the project. A fork of tui-rs is ratatui, for example.
Sometimes if the original project has been deprecated, the "-ng" project omits the suffix. util-linux project can be an example, there was the original 'util-linux' and its development stalled. But there was a fork called "util-linux-ng", and it was renamed to "util-linux" at January 2011.
3. Why is 80 characters the 'standard' limit for code width?
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IBM punched card has 80 columns
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Typewriter and ISO standard papers (A4 etc.)
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Ergonomics and heuristics
For more information: Why is 80 characters the 'standard' limit for code width?
4. What’s the meaning of 'Roger' and how it became having a meaning of 'Okay'
If you’re familiar with radio communication, you might be heard of phonetic alphabet or phonetic code. If you make a phone call, it is quite hard to listen what the people actually said. Because the quality of signal and sound is bad and unclear, so you sometimes need to tell the listener each alphabets. Whiskey Tango Foxtrot! for example.
There are widely accepted way to read alphabet, which is called NATO phonetic code(alphabet). A for alpha, B for bravo. You might be heard of alpha, bravo, charlie squads in military movies.
R is Romeo nowadays, but it was Roger around 1940s, in the middle of World War 2. In radio communication R, Roger in phonetic code, was a sign of Received.
Like 'Hello' in phone call, the term 'Roger' became normal after the war.
Google 'Roger etymology' for details. You may find the term Roger had meaning of penis long ago.
5. Why most of "beeps" tuned to B?
Because beeps are tuned to 1000Hz. Let’s listen:
(The play 1000hz button is instant; Press F5 or refresh to load it again.)