Origin of 'Daemon' in Computing (opens in new tab)

The *nix world is full of dark-but-fun terminology. Daemons run the system. New files get 666 (before the umask takes away unnecessary permissions). Parents kill their children before killing themselves. And sometimes you have to kill zombies.

> We also assume that this is the meaning behind the daemon.co.uk, host to many United Kingdom web sites

Not sure if it was the origin of the company name, but the domain was demon.co.uk not daemon. E.g. I had pretence.demon.co.uk with them for a few years.

https://en.m.wikipedia.org/wiki/Demon_Internet

I find the “a la mode” vs “au jus” discussion right under the daemon one very interesting!

I wasn’t familiar with both of these expressions but I looked it up and “a la mode” is an American culinary expression, meaning “served with ice cream”. And “au jus” is also an American culinary expression, meaning “gravy” or “broth”. Now, even though they are both derived from a French expression that is a prepositional phrase with à (meaning with), it does not matter any more when they were borrowed to English.

“A la mode” became a new adverbial expression meaning just that: “served with ice cream”. You can have pie a la mode = pie served with ice cream, but obviously not *pie with a la mode = pie with served with ice cream.

And “au jus” became a noun expression meaning “broth” or “gravy”. And you must say sandwich with au jus = sandwich with gravy and can’t say *sandwich au jus = sandwich gravy.

What is extremely interesting here is that it bothers the prescriptivist who wants language to be a certain way he feels it is supposed to be, also the author on that webpage.

"Warning: This paragraph is about science so, if this topic causes you undue alarm, please close your eyes until you've finished reading it."

Amazing.

Ha -- I read the title and said to myself, "gotta be Maxwell, right?" The jolt of pleasure I get from being right about things like this is unreasonable.

I remember learning about Maxwell's Daemon through the Apple II game Dr. Maxwell's Molecule Magic, in which you take the role of the daemon. You must toggle the barrier on and off in order to trap enough gas molecules at high enough pressure to launch a rocket ship. Once you think you have enough, you can then launch the rocket to see how well you did. If you were successful, the rocket would blast off the screen and an image would show of an astronaut on the moon saying "Hi, Mom!" (Speech was provided via PWM through the Apple II speaker.)

Eleven-year-old me was easy to entertain. Especially if rockets, robots, or science was involved.

Earlier threads:

- [2023] https://news.ycombinator.com/item?id=35283067 (24 comments)

- [2022] https://news.ycombinator.com/item?id=31069163 (127 comments)

- [2018] https://news.ycombinator.com/item?id=16299583 (46 comments)

- [2011] https://news.ycombinator.com/item?id=2691752 (45 comments)

Unrelated to the word "daemon", but related to the article, I was a bit surprised by this assertion:

> Eventually, though, the theory of quantum mechanics showed why it wouldn't work.

I was familiar with the information theory arguments (the same presented in Wikipedia[1]). Is that why they mean here by "quantum mechanics" or is there another counterargument to Maxwell's daemon?

1: https://en.m.wikipedia.org/wiki/Maxwell's_demon#Criticism_an...

Always thought it was because it denotes a process that stays alive and so is like a little living demon in your computer.

Of course it's not the origin of the usage, but I always found Lovecraft's quote from Lactantius to be pretty adequate:

"Demons have the ability to cause people to see things that do not exist as if they did exist. -- Lactantius"

I knew the origin of daemon from high school Greek philosophy courses.

At the time, I thought "when an I ever going to use this stuff in real life?" Then I got into computers.

I recall reading a mail exchange posted on some usenet group about, IIRC, some boss or similar higher-up being shocked to discover the UNIX systems they ran were full of demons, and as a devout christian wanted the sysadmin to put an end to that immediately. The sysadmin was repeatedly trying to explain that a daemon was not the same as a demon, without success.

Tried to find the post again, but no dice :(

Wonderfully written. “Warning: This paragraph is about science so, if this topic causes you undue alarm, please close your eyes until you've finished reading it.”

"Disk And Executive MONitor" does sound kinda cool, though.

Do you pronounce it as demon or like Matt Damon?

They rely too much on Professor Corbato's account:

Corbato confidently gives the reason but A) doesn't claim to have coined the term, and may not know what the coiner's thinking was; B) at the time may have had a different understanding than some other members of the group - it's not the sort of thing that people have a meeting about; and C) is writing about something that happened decades ago.

Corbato then cites Take Our Word's prior description - people who weren't present when the word was coined, and who openly say they have no idea: "This is so reminiscent of Maxwell's daemon watching his molecules that we can only assume that whoever dubbed these "system processes" had Maxwell's daemon in mind. Unfortunately, we have found no hard evidence to support this."

Then Take Our Word cites Corbato, creating a loop. The only evidence in that loop is Corbato's flawed (being human), prompted (by reading Take Our Word) memory of possibly limited knowledge from decades ago.

Saw this on a conspiracy theory subreddit recently, thought it was absolutely hilarious:

"Boy I love trapping demons in microscopic silicon megastructures to do my bidding, I sure hope nothing goes wrong"

I always wondered about this. Now I know. Thank you :)

Maybe we should have used `eudaemon` (happy spirit) to avoid alarming the common folk.

from PIE dai-mon- "divider, provider" (of fortunes or destinies), from root da- "to divide."

to divide power, compute.

Huh, I assumed: it does work whilst remaining unseen

Interestingly, Safari Reader View doesn't work on this page. Firefox's does.

Alternatively, here's a readable mirror: https://ei.cs.vt.edu/%7Ehistory/Daemon.html

And another: https://old.reddit.com/r/linux/comments/7w7914/the_origin_of...