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...
> 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...
to divide power, compute.
- [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)
At the time, I thought "when an I ever going to use this stuff in real life?" Then I got into computers.
"Demons have the ability to cause people to see things that do not exist as if they did exist. -- Lactantius"
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.
unzip; strip; touch; finger; mount; fsck; more; yes; unmount; sleep.
It really is absolutely wild that it all works when you go to the absolute fundamentals and start working forward.
https://en.wikipedia.org/wiki/Daimon vs https://en.wikipedia.org/wiki/Demon
I've never found any significance to associate the unix term with Demons and consider it a mis-association.
In 1998 I started a new job, and my boss pronounced "URL" as "earl". That threw me for a loop, had to fight my way through our first conversation before I figured out what he was saying.
Eleven-year-old me was easy to entertain. Especially if rockets, robots, or science was involved.
I was mind-blown the first time I heard someone pronounce etc as "et-see".
et-see rolls off the tongue so much better than ee-tee-see that it makes perfect sense now.
Yep, that's what I meant to say with:
> … never noticed until I heard someone else say it with a long 'i' that that was obviously the logical pronunciation.
But maybe the sentence structure was too tortured for it to be clear what I was saying.
> Though I personally always use the short 'i'. I was going to justify that by saying it's the same as /usr/bin, but that's also short for binaries, so should also be an 'ai'.
Oh, shoot, even after I noticed the logical pronunciation of "lib" (long 'i') it never occurred to me that the same applied to "bin". I guess I just can't say any paths out loud any more.
The letter æ was used in Old English to represent the vowel that's pronounced in Modern English ash, fan, happy, and last: /æ/. Mostly we now spell that vowel with the letter a, because of the Great Vowel Shift.
When æ appears in writing Modern English, it's meant to be a typographic variant of ae, and is pronounced the same as that sequence of vowel letters would be. So Encyclopaedia or Encyclopædia, no difference.
Highly recommend the protracted arguments in the comments, that's a wonderfully pedantic StackExchange. Big shoutout to someone in 2012 defining "NLP" as an unusual word -- how the world has changed! It's only a matter of time before they open an AP/IB course in NLP...
Also, for those who try to pronounce everything rather than spell them out, where does it end?
I now have a newly discovered, morbid interest in how such folks say path elements like "selinux", "httpd", and "pgsql"...
The Great Vowel Shift indeed makes written English much more confusing than it perhaps should be. English is already a messy hodge-podge of a language, then our writing system started to get standardised (or standardized, if you're American!) right as pronunciation started to change, leading to the written version of words suddenly no longer being anything like the pronunciation.
But I pronounce the first vowel in aesthetic differently. For me, it's somewhat in between the vowels in "bed" and "bad" but closer to the former.
That's assuming you aren't trying to claw back more energy than you lose, I'm pretty sure that's not possible to reliably do without crazy hypothetical physics.
https://en.m.wikipedia.org/wiki/Maxwell%27s_demon#Criticism_...
As a fellow Californian, I’d say we have authority anyway - I was taught in school that Ohio has the least specialized dialect, but that’s based on newscasters and such. The 21st century is the Californian century!
…that is, assuming Brussels’ English is out of the running, I suppose ;)
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.
Tried to find the post again, but no dice :(
http://www.av8n.com/physics/thermo/entropy-more.html#sec-pha...
With 'entropy' being an obsolete term for (lack of) information, and
> “classical thermodynamics” is a contradiction in terms.
Also, I think I will risk opening my eyes now.
I think practically though, even before you hit anything "quantum", the requirement that you physically interact with the system is what dooms you.
The main requirement for the hole is that it's small enough that (with high enough probability) only at most one or a handful of molecules will make its way through.
And that size is completely independent of the size of your molecules, and only depends on how many there are per unit volume. There's a lot of 'empty space' between molecules in a gas.
One day I was at a restaurant explaining process control to one of my disciples. I was mentioning how we have to kill the children (child processes) if they become unresponsive. Or we can even set an alarm for the children to kill themselves. That the parent need to wait (wait3) and acknowledge that the child has died or else it will become a zombie.
The look of horror the woman sitting across had was unforgettable. I tried to explain it was a computer software thing but it was too late, she fled terrified, probably to call the police or something. I didn't really want to stick around too long to find out.
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.
> In the middle of the divider was a tiny gate, just large enough to admit one molecule of gas.
Still, that's quite a small hole relatively speaking. So you'd have to be fairly precise about both position and velocity. Potentially more than is allowed by Plank's constant. I dunno though, this isn't one of the counterarguments in the Wikipedia page, so probably you're right.
Searching for them did bring me to an interesting discussion :
https://www.lesswrong.com/posts/YSFRazdoWXKHgNakz/link-the-b... (2015)
and then to :
https://bayes.wustl.edu/etj/articles/second.law.pdf (1998)
Which confirms my suspicions, but also sheds lights on how old the confusion is !
There are a bunch of assumptions that are easy to make (because they almost always are true), but very hard to get rid of when they aren't :
- that entropy is objective/ontological rather than subjective/epistemic
- that entropy is equivalent to disorder
- that temperature can always be defined
- that entropy is extensive
(- I think there was at least another one, but I had to do something else in-between and I don't remember now)
- oh yeah, maybe it was that there's a difference between a distribution and a macrostate ? (not sure about it myself)
Now, I don't know what the Bayesian framework can bring to the table here (not being sufficiently familiar with it down to the nuts and bolts of calculations), but if it can prevent us (and future students) from making these mistakes over and over and over again, it would be real progress.
https://arxiv.org/abs/1508.02421v3 (updated, 2017)
They claim to fix the criticisms, see the section "The Bayesian arrow of time."
Who knows how well they did though.
As far as I can tell they're still making impossible assumptions, because certain Bayesian problems can't be calculated under a certain amount of energy, and some can't be calculated at all while embedded in spacetime (excepting time travel, and sometimes even then).
I think it's necessary to increase (on expectation) the entropy in a closed system when measuring, unless you take measuring to be magic and not a physical process.
"Professor Jerome H. Saltzer, who also worked on Project MAC, confirms the Maxwell's demon explanation. He is currently working on pinpointing the origin of the erroneous acronym etymology for daemon in this sense."
So all in all, a classic description would work reasonably well. (Remember that quantum uncertainty is related more to de Boglie wavelength than physical size.)