Talk:Daemon (computing)/Archive 1

parent process
The article states "Daemons typically do not have any existing parent process, but reside directly under init in the process hierarchy (PPID=1)" so the net result is that "init" is the parent process.

On all the unix systems I have seen, "init" is a real process, consuming resources just like the rest of them. init also doesnt say much about inheriting processes.

As I recall, the theory of it all is that when a process dies, all of its orphaned children are given to the grandparent, who becomes their parent.

As best I can recall, init really really is their parent and it is nonsense to say otherwise. But, I'm wary of altering the text just yet, as the implications of parent/child arrangements revolve around signals (esp. SIGCHLD), and I'm not sure what "init" programs normally do with these inherited daemons. John Vandenberg 03:59, 6 February 2007 (UTC)
 * i just wikified "PPID" to Process identifier. Why is it "PPID", and not "PID"? --Jerome Potts 10:48, 1 July 2007 (UTC)
 * PID is "process ID", and PPID is "parent process ID". Unix/POSIX has both getpid and getppid system functions. — Loadmaster 15:10, 8 July 2007 (UTC)

Cron Demon?
I think we should mention the most common demon, the cron demon! I get e-mails every day from my Cron Demon telling me I have no viruses on my clarkconnect server! I know nothing about Linux, thats why i use clarkconnect, cuz its web configureable, but I do know that the cron demon likes to email me everything it finds. The cron demon is a anti virus program that runs in the middle of the night. It also handles scheduled deleting of cache from proxy. the cron demon is the heart of any Linux based system. Since Mac OS X is based on linux ( i know this becaus the terminals look the same and similar commands) then OS X should email out virus warnings too. —Preceding unsigned comment added by 71.201.151.133 (talk) 14:47, 28 January 2008 (UTC)

Feelings?
From the Mac OS section:
 * To the user, these were still described as, and disguised as, regular system extensions without any feelings.

Without any feelings? What is that supposed to mean? Maybe I'm missing something though. —Preceding unsigned comment added by 72.184.190.27 (talk) 21:33, 10 July 2008 (UTC)


 * Something along the lines of: "...regular system extensions without differentiating from them." 89.241.137.2 (talk) 10:18, 19 September 2008 (UTC)

/tmp or /var/tmp as "home" directory?
It's mentioned that daemons ought to use / (root) as home-directory to avoid blocking filesystems (thus preventing them from being unmounted).

However I've read that it's a good idea to use a publically writable directory (usually /tmp or /var/tmp) as home-directory for daemons, so that the daemon has a place to do things like drop core (if it crashes) or (I guess) write files if needed. Of course, if the daemon run as root, it can drop core anywhere, but it's usually a good idea to run them as someone less privliged.

Personally I thought the rationale to avoid blocking filesystems to be a bit wiered, usually daemons runs from boot-up to shut-down, and if you wanted to unmount an important filesystem (e.g. /var with /var/tmp), you'd probably take the system down to single-user and thus killing *all* processes (including daemons) anyway...

Any thoughts?

koppe Tuesday 20 March 2007, 16:25 (CET)

The rationale to avoid blocking filesystems is well-founded. If an admin needs to restart a daemon without rebooting (an extremely common action), he is likely to forget to "cd /" first. In fact, he's very likely to be on a filesystem that's quite inconvenient to block for unmounting, such as an NFS-mounted home directory. Changing the PWD to /tmp is an extremely bad idea, because an attacker could simply make a symlink named for the predicted core file name to a file to which the daemon has write-access and wait for the daemon to crash. Core dumps are typical on many OSs if swap space is exhausted; they don't even necessarily represent a bug in the daemon. This could be worth mentioning, but I didn't add it to the article because Wikipedia isn't really supposed to be a technical manual. -- Bilbo1507 (talk) 21:26, 8 October 2008 (UTC)

Daemon Wrappers / Daemonizers
What about a section on "start-stop-daemon" (debian) or "daemon" (rpm) which are utilities for daemonising an application. —Preceding unsigned comment added by 203.97.255.148 (talk) 09:34, 20 June 2008 (UTC)

Too specific. This article should cover all OSs or none at all. -- Bilbo1507 (talk) 21:28, 8 October 2008 (UTC)

I don't think info about a program that forks apps into a daemon process is important to the article at all. It also is OS independent so it can be compiled and run on any unix-based OS. Let's keep the article down to what a computer daemon is, and not list every single one out there. Nawcom (talk) 04:12, 12 October 2008 (UTC)

Day-man
Fighter of the Nightman! Master of karate! and friendship for everyone! —Preceding unsigned comment added by 167.7.17.3 (talk) 14:36, 16 January 2009 (UTC)

Windows services access
Corrected "Control Panel -> Services" to "Control Panel -> Administrative Tools", to conform to the Windows Service article (and to the XP box I'm looking at, although that's OR). If Vista has implemented a CP -> Services, then someone with Vista knowledge should add that both to this article and to the Services article, and make the distinction between the two systems. Also corrected the "Control Panel" link to the Windows-specific article rather than to the CP disambiguation page. Unimaginative Username (talk) 04:31, 13 February 2009 (UTC)

Simple English
This article should have a Simple English translation. 86.44.204.10 (talk) 17:34, 4 July 2009 (UTC)

Mailer-Daemon
How about the infamous mailer-daemon, folks???? Lots of people don't know what that is. (unsigned)
 * I have added Mailer Daemon (bounce message) to the 'See also' section. E-pen (talk) 12:42, 16 December 2009 (UTC)

Image copyright problem with File:Bsd daemon.jpg
The image File:Bsd daemon.jpg is used in this article under a claim of fair use, but it does not have an adequate explanation for why it meets the requirements for such images when used here. In particular, for each page the image is used on, it must have an explanation linking to that page which explains why it needs to be used on that page. Please check


 * That there is a non-free use rationale on the image's description page for the use in this article.
 * That this article is linked to from the image description page.

This is an automated notice by FairuseBot. For assistance on the image use policy, see Media copyright questions. --22:34, 10 February 2011 (UTC)

Correct pronunciation?
Anybody want to venture a pronunciation guide? My understanding is that the original CTSS folks pronounced it "de'men", like the mythical creature. Most of the younger folks I know use "day'men", presumably because that's how it "looks" like it should be pronounced.
 * JohnH 18:35, 30 August 2005 (UTC)

It is pronounced exactly like the equivalent word demon (i.e., deeˡ-men). The more recent pronunciation is due to illiteracy. See Æ for details. - Loadmaster 14:31, 18 August 2006 (UTC)


 * Pronunciation as dee-men, if anything, is due to illiteracy. Classical Latin and Greek pronounces Æ as 'ai'.  — Preceding unsigned comment added by 121.73.199.211 (talk) 22:40, 24 June 2011 (UTC)


 * Too many young kids have now watched too much STNG and its Ferengi daimons ;-).


 * Atlant 16:21, 18 August 2006 (UTC)


 * The Æ article says that in Classical Latin, the digraph was pronounced like "eye." I don't know anybody, young or old, who pronounces "daemon" like "diamond" without the D! MFNickster 01:24, 3 December 2006 (UTC)

I've done the IPA, and based on researches and the above have gone the "dee" route, changing what was on the page. --Slp1 03:18, 6 February 2007 (UTC)


 * This would also affect more commonly used words, like nebulae, antennae, formulae, Andromedae, etc., all of which currently have the "ae" pronounced as "ee". — Loadmaster 23:17, 5 July 2007 (UTC)

To add on as another resource, see Ae_(digraph). Final answer? The ae in daemon is commonly shortened to "demon" because that's how it's pronounced in english. The fathers of the computer daemon didn't decide to play off a latin word and pronounce it in a strange way. People are just in denial that it's the same word that some frown upon (crazy guess.) Nawcom (talk) 04:27, 12 October 2008 (UTC)

Be that as it may, the citation is disingenuous at best. The citation lists the 'demon' pronunciation as secondary to the 'daymon' pronunciation - further, it explicitly states that the pronunciation has drifted away from the original 'demon' form. The Jargon file is actually a reputable source (it's published in deadtree form, etc). Just because ae is properly pronounced 'ee' in English does not mean that the pronunciation of this word follows those rules. 98.212.62.219 (talk) 04:37, 1 February 2010 (UTC)
 * Just spotted the next two pronunciations with different citations. Note that the first (the 2009 m-w) is to an entry that does not pertain to this word but rather to its homograph.  Note that the second citation is 100% meaningless.  To demonstrate, observe the pronunciation of 'angel' with a similarly-formatted link:
 * http://www.merriam-webster.com/cgi-bin/audio.pl?demon001.wav=angel

98.212.62.219 (talk) 04:42, 1 February 2010 (UTC)


 * The prescriptivists at Oxford check in with and  exclusively – for the computing sense – and  alone for the supernatural sense. No support for.


 * (If you have a Mac or Kindle handy, it should have a New Oxford American Dictionary, which optionally displays IPA transcriptions, included in a dictionary app.) – RVJ (talk) 09:05, 24 January 2011 (UTC)

Daemon the novel
I have added a disambiguation hatnote because I landed here while looking for the Daniel Suarez novel Daemon, because it is a story about a computer daemon and not a mythological daemon. I figured this would be the easiest way to help other people who are also looking for the novel. Aardvark92 (talk) 16:20, 12 October 2011 (UTC)

BSD Daemon image copyright, again
I believe the File:Bsd_daemon.jpg image must be removed from this page for copyright reasons, should it? If so what can be done to keep it from coming back?

As near as I can tell this article does not meet the non-free-use rationale associated with the File:Bsd_daemon.jpg image. The article is not about FreeBSD and the image is not used in association with FreeBSD. I removed this image once already, some time ago, but it has returned.

(It's too bad the image cannot be used, because it's perfect. Such is life.)

kop (talk) 06:06, 12 January 2012 (UTC)

As there are no dissenting views, and the RFC tag has been removed, I will just take the image out :) --Errant (chat!) 08:54, 11 February 2012 (UTC)
 * At least as I read Kirk McKusick's reply as cited in the image page, the above is correct as long as you replace "FreeBSD" with "BSD" (Beastie could, for example, be used in a NetBSD or OpenBSD or DragonFly BSD page, or even in the Berkeley Software Distribution page - the daemon was, in fact, used for other BSDs in the past, as per one of Kirk's pages). Guy Harris (talk) 08:19, 12 January 2012 (UTC)
 * Concur, not appropriate here, as the article isn't specifically about the BSD daemon. Nobody Ent 15:31, 12 January 2012 (UTC)
 * I agree that this appears to violate WP:NFCC, particularly items #1 and #8. —David Eppstein (talk) 21:46, 16 January 2012 (UTC)
 * Sorry to be a spoilsport, but as I see it the question of copyright policy doesn't even arise; this demon is somewhat cute, but it has absolutely nothing to do with the subject. It might be an adornment, if the style happens to please the reader, but it illustrates nothing to do with any relevant concept. Why not a picture of a... Hey! A cute kitten! That should illustrate... something or other, anyway. I would not object to one of the various published pictures used to illustrate JCMaxwell's demon at work, though really, the concept strikes me as not needing illustration, but if anyone insists on a picture, I suggest that we either post a begging note for a candidate drawing uploaded to WM commons, or for a ref to a pre-1926 drawing of a Maxwell's daemon actually at work or something. But the current cutie is useless and out of place. JonRichfield (talk) 15:49, 27 January 2012 (UTC)
 * Delete Not appropriate in this circumstance. Quinn &#10048; BEAUTIFUL DAY 04:28, 1 February 2012 (UTC)
 * The image caption suggests the possibility of a valid NFCC usage - but then the article prose doesn't provide anything to back that up... if someone can write a reasonable paragraph for which the image is the subject then fine. Otherwise remove it (at the moment it is decoration). --Errant (chat!) 07:48, 9 February 2012 (UTC)

"Christian" demon
Will those trying to insist that BSD specifically adopted a Christian demon as their mascot, rather than a daemon and used Christian imagery in the artwork, please supply a source for this assertion? Anomie⚔ 10:40, 19 May 2013 (UTC)

Being stupid on the internet?
Daemon isn't an older word than Demon because they're the same word, "Daemon" is just an older spelling. Last I checked Modern English wasn't spoken until almost 2,000 years after Plato died. — Preceding unsigned comment added by 24.63.2.246 (talk) 01:23, 3 January 2014 (UTC)

Pronunciation
I stumbled across this article today, and noticed that the common pronunciation was not mentioned in the article; it seems 216.12.248.221 is insistent on denying despite all evidence that that pronunciation exists. The fact is, in the context of computer software the pronunciation has drifted such that both and  are acceptable, and arguments from English pronunciations of other Latin-derived words with the ae dipthong or the pronunciation in mythology or other contexts are irrelevant. Since we have a reliable source that clearly states that both pronunciations are acceptable in the context of computer software, removing it cannot be justified unless someone can find sources that specifically state that is not actually a common pronunciation in the context of computer software. Mainstream dictionary sources that merely omit the alternate pronunciation do not cut it, and a link to a page that can make any word seem to be pronounced "demon" is just ridiculous. I have edited the article accordingly, and I hope the IP user will discuss the issue rather than revert. Anomie⚔ 17:32, 12 March 2010 (UTC)

According to Garner's Modern American Usage, Third Edition, 2009, p. 220: daemon; demon. Both are pronounced /dee-mən/. The spelling daemon distinguishes the Greek-mythology senses of a supernatural being, indwelling spirit, etc. from the modern sense of devil's helper (demon). E.g.: "The daemon in him played the game just as it wrote the poems." Jeffrey Meyers, "Poets and Tennis -- Drop Shots and Tender Egos," N.Y. Times, 2 June 1985, § 7, at 24. Daemon is also a term of art in the field of information technology, referring to a background process or thread (primarily in UNIX). — Preceding unsigned comment added by 63.66.47.212 (talk) 15:50, 6 December 2011 (UTC)
 * Looks like a mainstream dictionary source that merely omits the alternate pronunciation, even though it does mention the computing definition. Anomie⚔ 18:07, 6 December 2011 (UTC)

What I don't understand is why some people insist on putting the pronunciation first, which in a dictionary implies it's more common, when it's clearly the less common version. For that matter, I suppose I wonder why this matters at all, given that Wikipedia is not a dictionary. Kerfuffler (talk) 08:08, 4 September 2012 (UTC)
 * when it's clearly the less common version Anomie⚔ 18:21, 4 September 2012 (UTC)

Anyone wishing to can follow the link to the Jargon File entry for daemon and find it telling us that the originators of the term used long-e and not long-a. As it is now pronounced both ways they should both be included, but as theirs is canonical it should go first. 68.2.82.231 (talk) 20:47, 26 April 2014 (UTC)

phantom
who the heck calls a daemon a phantom? --Eean 01:15, 2 Jan 2005 (UTC)
 * ditto --148.84.19.92
 * It was a name used at SAIL for non-invoked daemons. At MIT, the same use to be called a dragon. — al-Shimoni  (talk) 05:46, 20 October 2015 (UTC)

Here be dragons
Thought I'd mention FWIW that Harley Hahan (in his modest book entitled Harley Hahn ' s Student Guide To Unix claims that daemons are actually and originally a subset of "dragons", the difference being that dragons run automatically in the background, waiting for something to happen; daemons act the same, but must be manually invoked/started. --Gwern (contribs) 20:02 8 January 2007 (GMT)


 * Unix-like systems' daemons are generally either started by a script (rather than "manually" in the sense of a human explicitly starting them) or are launched on demand by inetd/xinetd, launchd, systemd, etc. when another process or a network client first requests a service from them. Guy Harris (talk) 14:55, 20 October 2015 (UTC)

Examples
It will be of a great help if someone points to HOW to build the "daemon" applictaions here, with elementary examples. — Preceding unsigned comment added by 80.64.34.252 (talk • contribs) 8:20, 15 April 2004‎


 * Under any Unix or GNU system, just call the daemon(3) function.
 * Teddy 80087 07:17, 17 Jul 2004 (UTC)


 * WP:NOTHOWTO. Guy Harris (talk) 14:57, 20 October 2015 (UTC)

"Services"
I'm confused by the following (from paragraph six)...

"On Microsoft Windows systems, programs called "services" perform the functions of daemons, ..." "There are "services" as well, but these are completely different in concept."

Was the second "services" referencing something on the Mac? — Preceding unsigned comment added by 12.24.201.155 (talk • contribs) 14:25, 6 April 2006‎


 * In Windows programs running in the background (ie. similar to daemons under Unix) are called "services".
 * In Unix, some daemons will provide network-*services*... like provide mail-services (SMTP, POP) or web-services (HTTP) - where "service" refers to the ability to handle some network-protocol (achived by having a daemon understanding the protocol listning on the port that protocl uses).
 * So in Unix "service" refers to what the program (daemon) provides, while it in Windows (also) refers to the actual program (of course many Windows "services" thus doesn't provide any services (as understood in Unix) at all, as they do other things than understanding network-protocols).
 * koppe Tuesday 20 March 2007, 16:40 (CET)


 * There's also a third NeXT/Mac form of services that are a sort of GUI pipe — Preceding unsigned comment added by 69.125.110.223 (talk • contribs) 13:07, 18 December 2007‎)


 * ...which are what's mentioned in passing in the "Implementation in Mac OS" section, with a link to Services menu. That has nothing to do with services in the daemon sense (which, as that section notes, are provided by things called daemons in OS X, OS X being a Unix system). Guy Harris (talk) 14:46, 20 October 2015 (UTC)


 * And, indeed, the full quote to which the original comment referred was


 * "On the original Mac OS similar systems were known as extensions. Mac OS X, being a unix-like system, has daemons. There are "services" as well, but these are completely different in concept."


 * so the second "services" was, in fact, referring to the NeXT/OS X "Services menu" services. Guy Harris (talk) 18:29, 20 October 2015 (UTC)