text:
Talk:Active camouflage

had an idea
I had an idea a while ago for this kind of thing, something made where on one side there was a tiny pinhole camera, and on the other side an lcd. These camera / lcd combos would cover the object at around 1 camera/lcd combo per centimetre. [maestro] 08:30, 9 Oct 2004 (UTC)

Merging
I disagree that this should be merged into camouflage. However, I think optical camouflage should be merged into here. Thoughts? -Joseph (Talk) 03:07, 2004 Oct 10 (UTC)

 * I think active camouflage should be kept seperate, but linked, of course. Optical camouflage, OTOH, should be merged and redirected to active camouflage. The article includes early experiments into the concept, while the later includes the Japanese experiments with X'tal Vision into developing optical camouflage. Optical camouflage should be included as a title, as the experiments use the name as the concept.--YoungFreud 05:18, 10 Oct 2004 (UTC)

 * Well, the main article on camouflage as it is now is quite brief and could be expanded nicely with this section. The main article already discusses adaptive camouflage, so this article could fit right in. Also, I think people looking for information on adaptive camo will go looking in the camouflage article, as there is no consensus really about naming this technology. If someone has a good idea of how to expand this article further then it might be good to keep it seperate, but right now I feel camouflage is shorter than it should be, especially if we remove the currently double information on active camo. -- Solitude 07:40, Oct 10, 2004 (UTC)
 * I agree. camouflage should have a linked reference to active camouflage and optical camouflage should be merged with active camouflage. I mean it's the same thing unless optical camouflage is considered a specific form of active camouflage. Either way I don't think they are distinct enough to warrant separate articles and they both cite the same fictional examples --FlooK 07:20, 31 July 2005 (UTC)
 * Another vote that active/adaptive/optical camouflage would make a nice subsection to the main page, which can only benefit from structuring it into sections of history / military / biological / active camouflage. It would be easier to manage the duplicate content. The active camouflage section should only contain the concrete or historical uses (and maybe their fictional equivalents) of active camouflage. Related technology demonstrations (such as the invisibility cloak, recent experiments, art projects, augmented reality, etc.) should have their own page where they can be discussed in depth and with pictures as they advance, without giving too much bulk to the main page. For example, I don't consider the surveillance suit image really essential to this article, but it would do nicely on a separate "computer mediated reality" (or whatever named) page, linked to from an introductory paragraph in the main article. Femto 13:05, 10 Oct 2004 (UTC)

octopuses/octopi (and chameleons)
Here I am, trying to come up with a witty but non-insulting remark about being misconceived or pedantic (their words, not mine, I swear), and you just tell me you were wrong (which it not necessarily wasn't, just unusual). Come here to be slapped in the face with a wet octopus!

By the way, the "Did you know..." section on the Main_Page suggests that chameleons change color to blend into their surroundings, which is another misconception, according to their article. Instead of change color and blend... like chameleons it should be change color like chameleons and blend... Can someone change it or tell me where to do it? Femto 15:08, 10 Oct 2004 (UTC)
 * Nice spotting that error, I've fixed it. For next time, editing the main page can be done here: Editing_the_main_page. -- Solitude 15:26, Oct 10, 2004 (UTC)
 * Thanks! Femto 16:06, 10 Oct 2004 (UTC)

Invisibility and holodeck technology are one and the same thing, but at different perspective viewpoints
I discovered that invisibility and holodeck type technology are both inverse forms of each other based on a well defined shared geometry. I have a webpage on Yahoo Geocities that details my work and explains what I am talking about,but i'm also new to Wikipedia.

Is posting personal webpages allowed in this forum?

 * No. And it's not a forum. It's a collaborative writing project. What's the address of your Geocities webpage? Arbo 17:23, 30 March 2006 (UTC)

I'm not selling anything on it I just explain my own contributions to the field of adaptive camouflage and immersion technology(as a by-product of adaptive camouflage)of which i've had figured out for over ten years now. I also developed a concept that I call Light-Interfacing, which I believe will make possible invisibility and holodeck type immersion technology.

 * Have you read the research done by MIT's Media Lab that gives astronomically-high (terrabit) figures for the data required just to create a single moment or frame for one hologram of one life-size person? I read this in Scientific American 15 years ago. The amount of data required for an active hologram of a moving human-sized figure is so great that even a roomfull of the processor and memory technologies we have now are inadequate for more one second of active movement, and the texture maps could not be generated on-the-fly; every possible rendering of 3D attitude and lighting angle would have to be ray-traced and stored in advance, with very efficient caching. You need a room full of Cray XM-P's for just one human figure, and any unexpected data to be simulated would be out of the question, ie: not generatable in real time. Even if you had all that, the hologram isn't going to look realistic as it does in Star Trek, where it is simply faked by actors. Instead it will look like your typical unconvincing flat-rendered textures in video games.

Data is just data, the storing and retrieval of which is subject to Moore's Law. What requires a room of Crays today will require a PalmPilot in a few decades. -Toptomcat 18:29, 12 June 2006 (UTC)

 * Good luck with your work. Arbo 17:23, 30 March 2006 (UTC)

Humans Didnt invent active camo
animals didn't invent it animals don't invent they adapt Dudtz 8/25/05 4:18 PM EST

 * Animals adapt to their environment/surroundings, and the cumulative process is known as evolution. I have changed "invented" to "evolved". Arbo 17:06, 30 March 2006 (UTC)

Philip K. Dick's role
The scramble suit, as presented in 'A Scanner Darkly', does not seem to actually be a form of active camoflage. When I read it, the focus seemed to be on keeping the wearer's identity completely anynomous rather than actually keeping them from being seen, making them 'vague' rather than invisible. This established, what IS the first appearence of proper active camoflage in science fiction? -Toptomcat 14:37, 2 November 2006 (UTC)

 * I want to say it was Neuromancer, but Gibson doesn't go into too much detail about it (from what I remember), although I remember it was an outgrowth of the same fabric Peter Riviera wears. I know the Ghost in the Shell manga was the first major work that demostrated it visually and broke it down somewhat technically, thanks to Shirow's footnotes. --YoungFreud 23:20, 9 July 2006 (UTC)

 * Predator demonstrated it visually before GITS, I think. Dosboot 21:16, 28 October 2006 (UTC)

Redundancy
Apparently as the result of a somewhat incomplete merger, the "Active camouflage or 'scramble suit'" section and the "Optical camouflage" section of this article are largely redundant with each other. They refer to the same movies and books as examples, etc. PubliusFL 15:49, 19 April 2007 (UTC)

Point of the photo?
The significance of the  is quite unclear, and its caption is unintelligible: Illustrating the concept, i.e. active capture and re-display, creates an "illusory transparency", also known as "computer mediated reality"  Can somebody rewrite that in English? Elphion (talk) 06:10, 13 November 2009 (UTC)

In Fiction --- with no sources ...
There were no sources at all in the following section, so I've boldly brought it here. If you can find sources for (parts of) it, feel free to add them and it back to the article. Chiswick Chap (talk) 09:01, 17 January 2012 (UTC)

"==In fiction== The active camouflage suit by name is credited to science fiction author Philip K. Dick in his 1974 novel A Scanner Darkly. Worn by the narcotics double agent Bob Arctor/Fred, the "scramble suit" is described as a flexible sheath covering the body of the wearer with a reflective/refractive coating on the inside surface that transfers the camouflaging pattern — projected by a holographic lens mounted on the wearer's head — onto the outside surface of the sheath.

Dick's invention has been copied many times in novels, films and video games to become a standard device in science fiction. Examples appear in the Artemis Fowl books as cam-foil and cham-pods, the Arnold Schwarzenegger film Predator, the James Bond film Die Another Day, the Doom and Metal Gear Solid video game series, the MMOFPS game PlanetSide, the Halo video game series, the Super Smash Brothers game series, the Crysis nanosuit, and within Japanese manga series like Ghost in the Shell and Gantz — cited as the inspiration for Tokyo University experiments into optical camouflage. A similar cloaking device is found in Star Trek, however this example does not achieve active camouflage in the same way. Active camouflage is also used by the Spy class in Team Fortress 2. An invisibility device is used by the Helghast Scouts in the Killzone series, similar to the Predator camouflage.

The "thermoptic camouflage" of Ghost in the Shell offers concealment in both the visible light and infrared spectra. It flickers or ceases to function upon contact with water or high humidity, or a harsh physical impact.

In the video game "Ace Combat X: Skies of Deception", Leasath forces use optical camouflage on the Gleipnir bomber and the advanced Fenrir fighter aircraft.

In the video game series Halo, active camouflage is a power-up that can be obtained. Certain variants of the game's alien race of Elites use this as well and are almost invisible, appearing as faint disturbances in the air where armor bends significantly that are difficult to detect. this can also be used in multiplayer mode. Active camouflage is also used by the spies in the multiplayer modes of Splinter Cell: Chaos Theory, making them harder to spot; however, it had a very limited power supply, making the suit only work for fifteen seconds, and contact with water will also short the system out.

The video game Red Faction: Guerilla has a stealth "backpack" which when used conceals the players character, except for a faint outline at close range. It can only remain active for a short while, before needing to recharge.

Active camouflage also appears in the video game Deus Ex: Human Revolution where it is called the Glass Shield Cloaking System, it also has a limited battery supply and when fully upgraded can only be used for seven seconds per energy bar, of which there are five.

Active camouflage, referred to as a "ruthenium polymer coating", is available to a variety of upgradeable vehicles, suits of armor, and weapons in the tabletop role-playing game Shadowrun.

The trailer of the upcoming video game Tom Clancy's Ghost Recon: Future Soldier shows four Special Ops Soldiers taking out two tanks with shoulder-mounted rocket launchers, before they turn on an active camouflage and vanish.

An additional fictional example of active camouflage in animals is the Gila-Munga, a race of extraterrestrial assassins appearing in Judge Dredd, a story serialized in the weekly British comic book anthology 2000 AD."

 * I added the Halo, Predator, Crysis and Deus Ex bits. A Scanner Darkly’s scramble suit isn't per se an active camouflage, as explained in chapter 2 of the book. Someone with a Shadowrun rulebook or the Judge Dredd's comic could add references for these part. Lunaramethyst (talk) 16:22, 28 July 2016 (UTC)

In animals, a remarkable capability, if true
Some fish (did the author mean in cephalopods?) can change color rapidly... "including mimicking stationary patterns (propagated backwards) while swimming forwards." They can? Prove it! I can't find any trace of this in the literature but by all means put it back in the article with a suitable citation. 14:55, 20 January 2012 (UTC)

Good stuff, but unfortunately not active
Removing this here just in case you can think of a use for it. Chiswick Chap (talk) 15:16, 20 January 2012 (UTC)

"In 2008, the University of California at Berkeley and the Lawrence Berkeley National Laboratory announced the creation of a metamaterial with a negative refractive index: light doesn't reflect or refract on it but bends around it. It currently works only at microwave frequencies but could work in the visible spectrum if further miniaturised. "

And this specimen is really pure WP:CRYSTAL, so it's landed here too. Chiswick Chap (talk) 15:21, 20 January 2012 (UTC)

"The Boeing Bird of Prey, a technology demonstrator aircraft built by Boeing's Phantom Works between 1992 and 1999, "pioneered breakthrough low-observable technologies" which may have included active camouflage; the press release however mentions only "radar-evading design". "   (breathless excitement, huh?)

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American English
first non-stub revision used "color"; this article is AmE  Red   Slash  17:18, 14 February 2021 (UTC)
 * All the camouflage articles are in BE. Chiswick Chap (talk) 08:50, 7 January 2022 (UTC)

title: Talk:Active camouflage


text:
Pincer

Pincer may refer to:

 * Pincers (tool)
 * Pincer (biology), part of an animal
 * Pincer ligand, a terdentate, often planar molecule that tightly binds a variety of metal ions
 * The Pincer move in the game of Go

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Pincer


text:
Talk:The Sleepwalkers: A History of Man's Changing Vision of the Universe

Failed deletion proposal
The Sleepwalkers was proposed for deletion. This page is an archive of the discussion about the proposed deletion. This page is no longer live. Further comments should be made on the article's talk page rather than here so that this page is preserved as an historic record. The result of the debate was KEEP

Advert for a non-notable book (contrary to the claims made in the article). Googling "The Sleepwalkers" gets over 5000 hits, many of which are not this book. Include the qualifier "cosmology" and the number reduces to 787 hits. SWAdair | Talk 08:32, 9 Oct 2004 (UTC) End archived discussion -- Graham ☺ | Talk 01:42, 16 Oct 2004 (UTC)
 * It appears I was wrong about this book. Dpbsmith, do you work for a book-finding service?  There's this book I've been looking for...  :-)  Keep.  SWAdair | Talk  22:59, 9 Oct 2004 (UTC)
 * Delete. That's a POV book review, not an article. —Rory ☺ 16:25, Oct 9, 2004 (UTC)
 * Keep. Retool. The book is notable. Googling "(sleepwalker OR sleepwalkers) Koestler" provides some 2400 hits, and they are meaty hits. --jpgordon {gab} 17:08, 9 Oct 2004 (UTC)
 * Keep. Or Merge into Arthur Koestler and redirect. I glanced at the VfD title, and I said to myself "If that's the Arthur Koestler book it's notable and I'll vote to keep." It is, and I do. It's certainly no ad, given that the book is out of print! Notability is arguable, of course (if it's so great why isn't it still in print?) A check of the local public library network shows that eleven out of thirty libraries in the network have it: ARLINGTON, BROOKLINE, CAMBRIDGE, CONCORD, DOVER, FRAM STATE, LEXINGTON/, MEDFORD, MOUNT IDA, NEWTON, WALTHAM. And for what it's worth, ten have it available but one of them lists it as "out," so someone is actually reading it. Article needs work, of course. [[User:Dpbsmith|Dpbsmith (talk)]] 17:34, 9 Oct 2004 (UTC)
 * Comment. For some reason, this book is hard to find in online indexes, perhaps because of variations in its long title. The library listings above, for example, were split between "The Sleepwalkers," "The Sleepwalkers: A History of Man's Changing Vision of the Universe", and "The Sleepwalkers/A History of Man's Changing Vision of the Universe" (slash instead of colon!) It is in print, "The Sleepwalkers: A History of Man's Changing Vision of the Universe," ISBN 0140192468. Amazon sales rank 44,179. I personally consider a rank better than 10,000 to be clearly notable and a rank worse than 200,000 to be clearly non-notable. [[User:Dpbsmith|Dpbsmith (talk)]] 18:05, 9 Oct 2004 (UTC)
 * Comment. The Columbia World of Quotations includes a quotation from the book: "If conquerors be regarded as the engine-drivers of History, then the conquerors of thought are perhaps the pointsmen who, less conspicuous to the traveller’s eye, determine the direction of the journey." I can't say that quotation really grabs me... More Googling turns up another quotation from [http://www.philosophers.co.uk/quotations/author_search.php3?author=Arthur%20Koestler&num=1 The Philosophers' Magazine Online: "Nobody before the Pythagoreans had thought that mathematical relations held the secret of the universe. Twenty-five centuries later, Europe is still blessed and cursed with their heritage. To non-European civilizations, the idea that numbers are the key to both wisdom and power, seems never to have occurred." Ah. Here's some paydirt. "More than four centuries after Copernicus’ death, writer Arthur Koestler claimed in his 1959 book The Sleepwalkers that nobody read De Revolutionibus when it first circulated." This claim inspired the current book, "The Book Nobody Read," by Owen Gingerich. [[User:Dpbsmith|Dpbsmith (talk)]] 18:15, 9 Oct 2004 (UTC)
 * Keep and cleanup. I'll have a go eventually if nobody else does, but need to find my copy in storage first. Enormously influential book, but like most of Arthur Koestler's stuff its detractors tried hard to minimise its impact, so you won't see it quoted by many contemporaries who just discuss and reject its ideas while carefully avoiding any reference to either the work or its author. Andrewa 18:29, 9 Oct 2004 (UTC)
 * Keep. It's a published book. Just because the article sucks doesn't mean it should be deleted. It just means it should be edited so it doesn't suck any more. CO GDEN  21:09, Oct 14, 2004 (UTC)

Questia.com's online library has the book available to read at: http://www.questia.com/PM.qst?a=o&d=59255222 -- although you can only read it in full with a subscription to Questia. —Preceding unsigned comment added by Chron (talk) • contribs) 16:56, 17 February 2006 (UTC)

Gingerich
I have removed a longish paragraph dealing with Owen Gingerich, almost word-for-word copied from the article on him, including the poor punctuation. I put a link to that article in the "See also" section. We hardly need two copies of the same verbiage on Wikipedia.

In addition to being redundant, the whole thrust of the paragraph missed the mark.
 * A similar cherished old belief backlashed on Koestler. In "II THE SYSTEM OF COPERNICUS", he stated on Nicolaus Copernicus seminal De revolutionibus: "The Book that Nobody Read - the Book of the Revolutions of the Heavenly Spheres was and is an all-time worst-seller." After finding a richly annotated copy previously owned by Erasmus Reinhold, a German astronomer in Prussia shortly after Copernicus' death there, Owen Gingerich was inspired to check Koestler' claim and research who had owned and studied the books. The decade long quest showed that books were in fact often richly annotated, and thus Koestler was incorrect. It was recounted in The Book Nobody Read, published in 2004.

Now the point that Koestler was making is that it took a surprisingly long time - over 65 years - for Copernicus' ideas to seep into the consciousness of the general public, and only with the discoveries of Kepler and Galileo. One aspect was the abysmal publishing record of De Revolutionibus. That Erasmus Reinhold, a young professor of astronomy at the University of Wittenberg, had a copy and made notes in it does not deal with the issue at hand, nor is it surprising. It is especially un surprising as the other astronomy professor at Wittenberg was Georg Joachim Rheticus who took a leave of absence to visit Copernicus, became his (only) disciple, and oversaw the publication of De Revolutionibus for the dying Copernicus. I have not read Gingrich's book, but I would lay long odds that Reinhold didn't even buy his copy, but was given it when Rheticus returned to Wittenberg.

That the few copies that were sold were "richly annotated" by the few professionals who read it, in no way refutes the claim that it "was and is an all-time worst-seller." B00P (talk) 07:43, 30 March 2008 (UTC)

I would strongly advocate putting the paragraph back in. I have read both a translation of De Revolutionibus, The Sleepwalkers and Gingerich's work, and Gingerich pretty much rips apart every piece of The Sleepwalkers. Koestler is quite simply just wrong in most what he writes, and it becomes very clear when you read Gingerich's work that he just simply never made any independent research. Gingerich's project is not just to survey a few copies of the book, he found them all, more than 400 copies. By just looking at De Revolutionibus, you'll notice that it is an extremely opaque book. It is a scientific treatise, not like "A brief history of time", which can be a best-seller, but a book that only a few professors and grad students at the time would have any interest in. I'd say 400 copies is a lot, and this mere fact contradicts central ideas of The Sleepwalkers.

The Sleepwalkers is notable, if not for anything else than the amount of stir it has caused, but no article about it is complete without the very substantial and well-founded criticism of it. --Kjetil Kjernsmo (talk) 21:35, 26 May 2009 (UTC)
 * Gingerich pretty much rips apart every piece of The Sleepwalkers - of course he doesn't; he doesn't cover the same ground William M. Connolley (talk) 19:17, 10 December 2014 (UTC)

Moved page
, The Sleepwalkers has not been moved properly, a primary page should not redirect to a disambiguated title. Incoming links look like they also need to be checked. Boleyn (talk) 09:49, 31 December 2014 (UTC)
 * As always, the reminder is most appreciated. Both the redirect and the links will be rectified within 24 hours. —Roman Spinner (talk)(contribs) 14:18, 31 December 2014 (UTC)
 * I moved it back. There was no need for the move in the first place William M. Connolley (talk) 17:19, 31 December 2014 (UTC)

Requested move 1 December 2017

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: page moved. Andrewa (talk) 03:47, 9 December 2017 (UTC)

The Sleepwalkers → The Sleepwalkers (Koestler book) – While Arthur Koestler was a major author, not every one of his books has an immediate claim to be the WP:PRIMARYTOPIC. There are 47 other entries at the Sleepwalker disambiguation page, including another book bearing this title, The Sleepwalkers (Broch novel). The Sleepwalkers should redirect to the Sleepwalker dab page in the same manner as Sleepwalkers, Sleep walkers, Sleep walker, The Sleep Walker, The sleepwalker, The Sleepwalker or Sleepwalk. —Roman Spinner (talk)(contribs) 05:56, 1 December 2017 (UTC)
 * Support, good call; no primary here. In ictu oculi (talk) 12:06, 1 December 2017 (UTC)
 * Comment. Even if a consensus develops to redirect the short title, The Sleepwalkers to the Sleepwalker disambiguation page, a form accepted in a recent RM may provide an alternative to the use of the parenthetical qualifier "(Koestler book)". At Talk:The Human Factor (Graham Greene book), an additional proposal to move The Human Factor (book) → The Human Factor (Kim Vicente book) was amended so that the title would be moved to its full form — The Human Factor: Revolutionizing the Way We Live with Technology. Analogously, the full form here, as indicated in the article's lead sentence and on the appended illustration of the book cover, is The Sleepwalkers: A History of Man's Changing Vision of the Universe. Taking a wider view, we already have numerous expanded titles of non-fiction books which would otherwise require a qualifier in their short forms:
 * Above and Beyond: The Encyclopedia of Aviation and Space Sciences
 * Alternative Energy: Political, Economic, and Social Feasibility
 * Beyond Fear: Thinking Sensibly About Security in an Uncertain World
 * Big Coal: The Dirty Secret Behind America's Energy Future
 * The Gift of Time: The Case for Abolishing Nuclear Weapons Now and many others. —Roman Spinner (talk)(contribs) 09:03, 2 December 2017 (UTC)

 * Support as proposed. Clear absence of a primary topic. bd2412  T 17:21, 2 December 2017 (UTC)
 * Support per nom. No clear primary topic. -- Necrothesp (talk) 16:36, 6 December 2017 (UTC)

 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

Requested move 5 March 2024

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: moved. – robertsky (talk) 13:37, 12 March 2024 (UTC)

– Per WP:SUBTITLE (When the most commonly used name is ambiguous, the full title and subtitle might be suitable to be used as a form of natural disambiguation), WP:NATURALDIS, and WP:NCDAB, natural disambiguation is preferable to parenthetical disambiguation. As pointed out above, many other non-fiction books use subtitles to disambiguate, and other moves of book articles, like this one that was closed very recently, also follow this pattern. Malerisch (talk) 02:40, 5 March 2024 (UTC) The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
 * The Sleepwalkers (Koestler book) → The Sleepwalkers: A History of Man's Changing Vision of the Universe
 * The Sleepwalkers (Clark book) → The Sleepwalkers: How Europe Went to War in 1914
 * Support per nomination. Enhanced main title headers of this nature are helpful to users. When such titles, with subtitles, are not forced, but appear on the book's cover or on the title page, their usefulness in disambiguating same-titled books should be taken into consideration. —Roman Spinner (talk • contribs) 17:06, 5 March 2024 (UTC)


text:
Category:Fictional aircraft

Aircraft that are fictional.

title: Category:Fictional aircraft


text:
Talk:Sexual network

Formating
Regarding emphasis in areas of this article: DO NOT UNDO! Important statistical information is relevant to sex education, and the prevention of VD’s such as HIV AIDS! Please keep formating for the sake of International sexual health information.

Please discuss proposed minor changes to formating here.

--Techrontech 12:54, 30 September 2006 (UTC)

Horizontal rules are not used for emphasis, they're used to differentiate between distinct parts of a discussion or article. The way in which they were used here — to separate paragraphs in a subtopic — is incorrect. I have removed them. I've also removed a hidden comment that was distorting the space between paragraphs, and a  tag that was broken anyway. If you are quoting something, indent the block using or the standard wiki formatting character ":", and use quotation marks, or italics. Don't center the block. --Canonblack 12:54, 14 October 2006 (UTC)

Other Edits, Touchups & Corrections
"There has been a decrease in the number of people having sex with animals outside of marriage." Seems like a pretty clear case of graffiti to me, so I deleted "with animals". JFS24.49.191.211 20:48, 13 November 2006 (UTC)

Thanks everyone for keeping up with the spell checks. When one uses a wordprocessor(sic!), not every spelling and grammar mistake is caught. Techrontech 18:25, 26 October 2006 (UTC)

Deleted
I removed "for example, it is impossible to catch a disease from someone who caught it after you have ceased to have sex with them, or after they have been completely and effectively treated in such a way as to entirely remove the causative agent of the disease." because it wasn't true. lysdexia 08:35, 9 Oct 2004 (UTC)
 * Why is it not true? -- The Anome 09:46, 9 Oct 2004 (UTC)

I see Anome's point actually. While rhetoricly the statement may seem in need of a slight alteration, Lysdexia is seemingly missing the whole point of this article (all though this conjecture, is, possibly and hopefully, untrue)!

While you cannot catch a disease from someone who caught it after you stopped having sex with that person, the disease can still be spread from that individual, to a new sexual partner of that individual, and through that person's sexual partner, or sexual partner's partner and so on, you may easily become exposed to that same strain and strand of VD. So, yes, you can a former partner's desease after the fact.

Further complicating things, and hightening your risk ractor beyond your control, (and don't bother making an accusation of homophobophobia or pull any other heterophobic antics) would be the existance of bi or homosexualism in your sexual network, simply because it would allow the network to easily skip a step at least once (and that is only if there is once instance of bisexualism). Think about it, because it's completely true.

--Techrontech 14:46, 30 September 2006 (UTC)

To be added
This article could possibly include a reference to the diagram which figures throughout the series The L Word. examples here: via

Great example. There are already many charts available that describe this same concept. The basic idea is if you have more than once sexual partner, you're exposing each one after your first partner with however many sexual partners your previous partners have been exposed to, and the only way to avoid this is to have only one sexual partner. The quick-fix straight solution: marriage.

To obtain a free copy of one of these charts (which I can't publish due to copyright laws), just call the Option Line at 1-800-395-HELP and ask about it. They can also give you info about sex and sexuality.

Techrontech 13:29, 30 September 2006 (UTC)

Do I detect a bit of politically conservative moralizing in this article? Let me offer a quick suggestion: Marriage is the legal (and possibly spiritual) union of two people. Sex often occurs in marriage, but often it does not and often there is more than one sexual partner involved. A better word for the quick-fix straight solution is not marriage but Monogamy: the idea of having one exclusive sexual partner. To defer the effects of sexual networking, the monogamist couple can review their sexual history and get STD/STI tested before having intercourse.

Marriage is not an option for all people. Monogamy is an option for all people as it is a personal choice by two individuals.

Wiseguy 12:11, 7 December 2006 (UTC)

I've now deleted at least the most blatent politically conservative moralising. It's been tagged since January with no sources been cited in response to that - for the fairly obvious reason that's its just point of view. 80.229.220.14 04:21, 20 February 2007 (UTC)

Rules
It is not necessary to make personal comments or conversation anywhere, principally those deemed unnecessary or uncouth. This can be done elsewhere in Wikipedia (such as in the User Talk pages, or areas in the Community Portal). Failure to follow these rules will result in immediate erasure of the text in question.

Sign your posts. Failure to follow this rule is annoying to your fellow Wikipedians, and makes it difficult if not impossible to follow a discussion or distinguish visitors from established Wikipedians (and by inference, how much value should be given to anything they say). And ((some would say that)) there is no place in Wikipedia for "...personal comments...deemed unnecessary or uncouth." --Canonblack 13:00, 14 October 2006 (UTC)

unwanted child
Where is the source that a monogomous sexual relationship cannot result in an unwanted child?Obina 23:19, 8 January 2007 (UTC)

Good point. This is clearly an absurd statement. We can all think of monogomous relationships - even marriages - into which unwanted children have been born. I've deleted this sentence along with some other unsourced conservative moralising. 80.229.220.14 04:22, 20 February 2007 (UTC)

Newer material
It seems that there must be resources from the past few years that the article can use.--John Bessa (talk) 17:38, 21 December 2009 (UTC)

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title: Talk:Sexual network


text:
Talk:OSF/1

"Intellectual property" can be a loaded word. Is there any reason we don't simply say "...now belongs to Hewlett-Packard."?

Also, I don't really care for the expression "became known as Digital Unix". That makes it sound like the users decided to call it that. IIRC, Digital simply renamed it. Is my memory right? Why not simply "and renamed 'Digital Unix'."?

 * Good points - I also tinkered to make it flow a little better; notabilities to lead, and more of a continuous narrative for history. Earlier writers probably found it hard to explain, because both OSF/1 and Dunix existed simultaneously. Stan 13:21, 9 Oct 2004 (UTC)

title: Talk:OSF/1


text:
Talk:List of English languages

Now that every local dialect is inflated to a language, where is Ebonics? Should Gullah be listed here? How about the fictional English language Newspeak? Wetman 08:37, 9 Oct 2004 (UTC)
 * Thanks for the tip. You can go ahead and add those to appropriate sections, if I don't first.  --  ℛ yan! |  Talk  08:44, Oct 9, 2004 (UTC)

title: Talk:List of English languages


text:
The Kiwi Party

The Kiwi Party was a political party operating in New Zealand between 2007 and 2011. Briefly known as Future New Zealand, it was a breakaway from the United Future New Zealand party and sought to carry on the tradition of Future New Zealand. The party was formed when MP Gordon Copeland left United Future after a dispute over support for the Crimes (Substituted Section 59) Amendment Act 2007. At the 2008 general election, the Kiwi Party was unsuccessful, and was not re-elected to Parliament. It did not contest the 2011 general election under its own banner, but the leaders and other members stood for the Conservative Party.

The party advocated more direct democracy through referendums and a return to the "Judeo-Christian ethic in democracy". On 8 February 2012, it requested that the Electoral Commission cancel its registration, which rendered it wholly subsumed into the Conservative Party. On its website, it announced that after holding an executive committee meeting in December 2011, the party had agreed to be 'wound up' and 'bring its existence to an end.'

Future New Zealand Party reformed
On 16 May 2007, list MP Gordon Copeland resigned from the United Future party, citing differences with party leader Peter Dunne over the latter's support of the child-discipline bill. Copeland announced his intention to re-form an independent Future New Zealand party with former United Future list MP Larry Baldock as co-leader. Copeland and Baldock acknowledged that the new party would face difficulties over issues like legal ownership of the party name, but were hopeful that they would be able to attract United Future's former conservative Christian voters. An inaugural meeting was held in Baldock's city of residence, Tauranga, and former United Future list MP Bernie Ogilvy became party secretary. Meanwhile, Brian Tamaki and his Destiny New Zealand party announced that it would contest the New Zealand conservative Christian vote at the next New Zealand general election in 2008.

On 14 June 2007 Copeland announced that Future New Zealand would "not work with, or be part of, a Labour-led government following the 2008 elections". Copeland also gave his proxy vote in Parliament to the National Party (except on matters of confidence and supply).

In June 2007, Copeland announced in his monthly "Copeland's Chronicle" newsletter that Future New Zealand had attracted the necessary five hundred members required for registration under the Electoral Act 1993. Baldock and Copeland were working on establishing a Board of Management and Board of Reference for their new party, still tentatively named "Future New Zealand." He also asserted his right to continue sitting in New Zealand's Parliament as a list MP.

Name change to the Kiwi Party
On 25 January 2008, it was announced that Future New Zealand was to be known as the Kiwi Party. Copeland stepped down as co-leader to focus on his Parliamentary responsibilities, leaving Baldock as the sole leader. The party applied to the Electoral Commission to register its new name, and was registered on 15 February 2008.

Policies
At the party's South Island conference in Christchurch the party outlined a number of policy ideas:

 * people should be able to direct $100 of their income tax to a charity of their choice each year
 * lift the adult minimum wage from the expected $12 an hour to $15 an hour
 * provide employers with a 100% tax rebate to cover the minimum wage increase
 * establish a Royal Commission to investigate the causes of family breakdown, family violence and child abuse.

2008 election
Going into the 2008 elections, the party had only one list MP, and no electorate MPs, in Parliament, and did not register significant support in national polls. Acting secretary Bernie Ogilvy apologised for not applying for free election broadcasting in time; Larry Baldock said "This does make our task just that much harder." The party fielded 25 electorate candidates out of a possible 70.

The party won just 12,755 party votes, or 0.54% of the votes cast, well short of the 5% required to gain list-only representation without winning an electorate. Baldock stood in Tauranga, winning 1893 votes, well behind National's Simon Bridges and his New Zealand First and Labour challengers. Copeland was similarly unsuccessful in Rongotai, winning just 515 votes. Despite this result, the party stated that they would contest the next general election, in 2011.

2008–2012
Gordon Copeland was elected as Party President in March 2009. The party contested the 2009 Mount Albert by-election, selecting Simmone Dyer as their candidate. Dyer came seventh with 91 votes. The party did not contest the subsequent Mana, Botany or Te Tai Tokerau by-elections.

Larry Baldock was one of the chief protagonists behind the 2009 referendum which attempted to repeal the Crimes (Substituted Section 59) Amendment Act 2007. The referendum passed with the support of 87.4% of voters, but was non-binding, and the government responded by promising a review of the law. In response, Baldock circulated a second citizens initiated referendum, calling for binding citizens initiated referendums in future debates. The proposed referendum petition fell well short of the required number of signatures to trigger such a referendum and lapsed on 10 December 2010.

The demise of the Family Party and New Zealand Pacific Party in 2010 left the Kiwi Party as the only conservative Christian-based political party within New Zealand politics. This was changed by the arrival of Colin Craig's Conservative Party of New Zealand in August 2011.

On 14 October 2011 the Kiwi Party announced that it would not be standing any candidates in the election, and that several members had joined the Conservative Party and would be standing for it. Party leader Baldock was number three on the Conservative Party list and stood again in Tauranga. Deputy leader Dyer was number 7 on the list and stood in East Coast Bays. Party president Copeland stood in Hutt South. No candidate was successful. Other members also stood for the Conservatives on their party list.

The party was deregistered at its own request on 8 February 2012, which marks the cessation of its independent political existence. Its former website URL is now also inoperative.

title: The Kiwi Party


text:
Talk:Separate Operational Purpose Division

Untitled
Why for all the confusion between Osnaz and Spetsnaz? It is a very straightforward matter. --Numerousfalx 08:38, 9 Oct 2004 (UTC)

OSNAZ is the obsolete term
"OSNAZ" term seems to be obsoleted in the 1970s or even in the 1960s by spetsnaz term. It is not (or almost not) used to refer to special forces of Russia. Please, adjust the article, Alpha Group, Vympel,etc. should not be here. Cmapm 00:59, 25 November 2005 (UTC)

OSNAZ is still the official MVD initialism used by the MVD. As it is still officially used it will stay.--Degen Earthfast (talk) 18:43, 26 June 2013 (UTC)


text:
Jules Germain François Maisonneuve

Jules Germain Francois Maisonneuve (10 December 1809 – 9 April 1897) was a French surgeon and student of Guillaume Dupuytren. Maisonneuve is notable as the first surgeon to explain the role of external rotation in the production of ankle fractures. The eponymously named Maisonneuve fracture describes a specific fibular fracture.

Publications

 * Maisonneuve, J. G. (1840). Recherches sur la fracture du péroné. Paris. France: Loquin & Cie.
 * Maisonneuve, Jules and Cunasc, Laurent (1847). La Société nationale de Chirurgie, ses travaux et ses membres. Th. Bonet. Paris.

title: Jules Germain François Maisonneuve


text:
Thomas Hancock (VC)

Thomas Hancock VC (July 1823 – 12 March 1871) was an English recipient of the Victoria Cross, the highest and most prestigious award for gallantry in the face of the enemy that can be awarded to British and Commonwealth forces.

Details
He was about 33 years old, and a private in the 9th Lancers (The Queen's Royal), British Army during the Indian Mutiny when the following deed took place on 19 June 1857 at Delhi, India for which he and John Purcell were awarded the VC: "9th Lancers. Privates Thomas Hancock and John Purcell

'The guns, I am happy to say,. were saved, but a waggon of Major Scott's battery was blown up. I must not fail to mention the excellent conduct of a Sowar of the 4th Irregular Cavalry, and two men of the 9th Lancers, Privates Thomas Hancock and John Purcell, who, when my horse was shot down, remained by me throughout. One of these men and the Sowar offered me their horses, and I was dragged out by the Sowar's horse. Private Hancock was severely wounded, and Private Purcell's horse was killed under him. The Sowar's name is Roopur Khan.'

Extract of a letter from Brigadier J. H. Grant, C.B., Commanding Cavalry Brigade of the Field Force, to the Deputy Assistant-Adjutant General of Division. Dated Camp, Delhi, 22 June 1857.)"

In a later dispatch from Brigadier-General Hope Grant, C.B. to Major H. W. Norman, Assistant Adjutant-General of the Army, on 10 January 1858, Hope writes:"I had the sincere gratification of naming two privates of the 9th Lancers, who had displayed signal gallantry in the fight - Privates Thomas Hancock, who lost an arm on the occasion, and John Purcell, who had his horse shot under him, and was, I regret to say, afterwards killed at the assault of Delhi. Sir Henry Barnard was pleased to recommend that the Victoria Cross should be conferred on both."

He later achieved the rank of corporal. He died in Westminster Workhouse, 12 March 1871, and was buried in a common (unmarked) grave in Brompton Cemetery. A memorial stone was subsequently placed over the burial plot on 15 October 2011.

title: Thomas Hancock (VC)


text:
Anthony Walton (politician)

Anthony John Walton (born 1962) is a former New Zealand political party president. He was leader of the Future New Zealand party, having previously been a prominent member of Future New Zealand's predecessor, the Christian Democrat Party. Before becoming president, Walton had been on the Christian Democrats' National Council since the party was launched in 1995. Walton championed Future New Zealand's merger with United New Zealand, creating the modern United Future New Zealand party in 2000. He was expected to take second place on United Future's party list but elected instead to pursue other career options. Walton is currently chief minister at the Olive Tree Church in Wellington. He is also associated with Zeal, an evangelical Christian youth enterprise and entertainment venue in that city. He has written on the subject of Christian apologetics and church formation. In 2001, he wrote a Christian apologetic's work (see below).

title: Anthony Walton (politician)


text:
Murray Elston

Murray John Elston (born October 8, 1949) is a former politician in Ontario Canada. He was a Liberal member of the Legislative Assembly of Ontario from 1981 to 1994 who represented the central Ontario ridings of Huron—Bruce and Bruce. He was a senior cabinet minister in the government of David Peterson. He briefly served as interim leader of the Liberal Party from July to November 1991.

Background
Elston was educated at the University of Western Ontario, receiving a Bachelor of Arts degree and a law degree. He practised law, working for the firm of Crawford, Mill Davies & Elston.

Politics
Elston was elected to the Ontario legislature in the 1981 provincial election defeating Progressive Conservative Gary Harron by 224 votes in the rural, southwestern constituency of Huron—Bruce. The Progressive Conservatives won a majority government under Bill Davis in this election, and Elston sat on the opposition benches for the next four years.

He was re-elected in the 1985 election. After the Miller government failed on a vote of no confidence, The Liberals formed a minority government with the support of the New Democratic Party and Elston was appointed to the high-profile position of Minister of Health. In this role, he was at the centre of the government's fight against extra-billing by doctors, an issue the government won after withstanding the province's first doctors' strike. Elston also announced subsidies for residents of Northern Ontario who needed to travel south for medical care.

The Liberals were re-elected with a landslide majority in the 1987 provincial election, and Elston was returned by a significant majority in the redistributed riding of Bruce. In the cabinet shuffle that followed on September 29, 1987, Elston was appointed Chair of the Management Board of Cabinet. He was also appointed Minister of Financial Institutions on August 16, 1988.

In the 1990 Ontario election, the Liberals were defeated by the New Democratic Party under Bob Rae. Many high-profile Liberals lost their seats, though Elston was returned in Bruce by a comfortable if reduced margin. Peterson, who had lost his own seat on election night, resigned immediately as party leader.

Interim leader and convention
The Liberals initially chose Robert Nixon as their interim leader, but he resigned on July 31, 1991, to accept a federal appointment. Elston was then chosen as interim leader in Nixon's place, though his time in this position was brief. He declared himself a candidate in the race to become the party's permanent leader, and accordingly resigned as interim leader on November 19, 1991. Jim Bradley took his place until the leadership convention.

Elston quickly became the favourite to win the 1992 race, gaining endorsements from such high-profile figures as Peterson, Ian Scott, and Sheila Copps. He led voting for the first four ballots, but lost to Lyn McLeod on the fifth and final ballot by only nine votes. The number of spoiled ballots from supporters of third-place candidate Greg Sorbara was greater than McLeod's margin of victory. Some political observers speculated that Elston appeared too much like a holdover from the Peterson era, as a time when the Liberal Party wanted to present a new image to voters.

Opposition
Elston remained in the legislature for two more years, and served as Opposition House Leader before resigning as an MPP on October 31, 1994, to enter the private sector. He was touted as McLeod's likely replacement when she resigned as Liberal leader following a poor performance in the 1995 provincial election but he declined to enter the race preferring to remain out of politics. In 1996, he was the most prominent supporter of Dalton McGuinty's ultimately successful bid to win the party's leadership.

After politics
From November 1994 until 1997, Elston was president of the Ontario Interlink Industrial Park. From January to October 1998, he worked for Engergreen Solutions Group. In November 1998, Elston was appointed president of Canada's Research-Based Pharmaceutical Companies (Rx&D).

From 2004 to 2009, Elston was president of the Canadian Nuclear Association, in order to lobby the Premier's office on behalf of the nuclear industry. As a former Liberal MPP, he had represented the riding of Huron-Bruce, which is home to the Bruce Nuclear Generating Station. Elston's lobbying was highly successful: on June 13, 2006, the McGuinty government announcement its commitment to rebuild all of Ontario's ageing nuclear stations as well as the construction of new reactors. He served as vice-president of corporate affairs for Bruce Power from 2009 until 2011.

title: Murray Elston


text:
User:Dr aamir

Hellow Respected sir, i am dr aamir from pakistan. i want to study or research in Norway plz  help me in this regard. i tried many times but failed. i beg to remain your good self  plz help me to fullfill my obses  in study  in Norway. dr aamir

title: User:Dr aamir


text:
Wikipedia:Articles for deletion/Male answer syndrome

Male answer syndrome
Neologism. Some of the websites I found while checking this one had me laughing and nodding my head in agreement (this one for instance). The concept is dead-on, but at under 600 hits, almost entirely from blogs, it's just a neologism. SWAdair | Talk 08:46, 9 Oct 2004 (UTC)
 * No vote yet, mostly bcz i think i've heard it used on Car Talk, which has a pretty good leverage for spreading cogent expressions. But even as edited, it is also 1) still PoV 2) orginal research and 3) wrong (C'mon, dump the "manly hunter" crap, this is about the sexual component of evolutionary selection, where the guy who does a good job of faking command of the situation bags the babe. Part of the whole "Look at the big brain on Brad" gambit, where being able to compose poetry or solve or pose riddles demonstrates general health and vitality, as surely as a peacock's tail does.), and if not deleted it needs to go to WP:CU. --Jerzy(t) 11:10, 2004 Oct 9 (UTC)
 * If deleted, i'd like to see it on a list of titles that i would call "Rising Notability Watchlist": titles of deleted articles that might soon become notable. --Jerzy(t) 11:10, 2004 Oct 9 (UTC)
 * Question: Is there a better, i.e. scientific and non-feminist word? Syndrome seems a bit harsh. Dunc_Harris|☺ 11:44, 9 Oct 2004 (UTC)
 * No vote -- but if it's a neologism, it's one that's been in use for fifteen years. No question it's a bit perjorative, but we're here to catalogue, not censor. --Metahacker 14:02, 9 Oct 2004 (UTC)
 * Keep. Not a neologism IMO, and a valid topic so it should either be an article, or a redir if a better name exists. Close to the border maybe but a clear keep is my call. Andrewa 18:21, 9 Oct 2004 (UTC)
 * I don't know if it should be kept or deleted, but I do know that if it's kept, it should be sent to cleanup, and then then sent back here to VfD if not improved. - RedWordSmith 20:44, 9 Oct 2004 (UTC)
 * Delete: The observation is common, but the usage is not stable yet. There will be a winner among the neologisms, but there hasn't been one yet.  Let the dust settle.  BTW, my girlfriend of long ago used to refer to the "Y-linked helpfulness gene," which causes any male to try to help a woman, even if they haven't a clue and the woman does.  A tissue paper kite is ripped up by a thorn bush in the park, and yet every man has to go try to "fix" it.  Anyway, a true observation, but not a notable or widespread term yet. Geogre 00:47, 10 Oct 2004 (UTC)
 * Delete. Neologism for a pop-psychology concept that is not supported by research. Rossami 03:58, 10 Oct 2004 (UTC)
 * Delete. There is a proper term, but I don't know what it is. --Viriditas 04:14, 10 Oct 2004 (UTC)
 * Keep -- or something -- are you giving any thought to the point of view of the person who hears it and looks it up? This is NOT science and it is not supposed to be.  It is an explanatino of a pseudo-scientific term that IS part of our language and culture, and BTW Rossami's change was NOT minor, having removed two thirds of the material. ;Bear 06:20, 2004 Oct 10 (UTC)
 * Google suggests its a deliberate humor piece originally attributed to Sam Hurt. You can find his book here.  In other words, it's a gag.  It should be merged and redirected to an entry for cartoonist Sam Hurt, but no such entry exists.  Should it be deleted and moved to BJAODN?  My answer is yes.  --Viriditas 07:04, 10 Oct 2004 (UTC)
 * Q. Why does it take 1.5 billion sperm to fertilize one ovum?
 * A. Because not one of them is willing to stop and ask for directions.
 * What do you mean, "part of our language and culture"?
 * It's called grasping at straws. I hereby throw in the towel and I hope everybody got a chuckle out of it. ;Bear 01:32, 2004 Oct 12 (UTC)
 * Consider that most of the Google returns (at least theso I checked) have to explain what they mean -- this implies that they don't expect their audience to have heard the term before. BJAODN and delete. --Aponar Kestrel (talk) 21:35, 2004 Oct 11 (UTC)
 * In case anyone's wondering what BJAODN is... - dcljr 21:52, 11 Oct 2004 (UTC)

 * Delete It's a not very funny joke phrase, like "retail therapy", based upon pop psychology. --Jll 12:54, 13 Oct 2004 (UTC)
 * I gather you're saying that "retail therepay" is funnier. That's rather POV, eh?  I do like that one, and have never heard it before.  Do we need anarticle on that?  How about a list? ;Bear 15:39, 2004 Oct 13 (UTC)
 * No - I was just using "Retail therapy" as an example of a similar phrase. I had heard that one before but not this one. I don't think either deserve an article! --Jll 12:32, 14 Oct 2004 (UTC)

 * Keep, I've heard the phrase from more than one source. — siro  χ  o  00:17, Oct 15, 2004 (UTC)
 * Delete - SimonP 19:09, Oct 16, 2004 (UTC)

It's been deleted now, the link has gone red. So why is that not explicitly mentioned here? ;Bear 00:18, 2004 Oct 17 (UTC)


text:
Talk:Mach (kernel)

Licensing
Under what license(s) might the Mach kernel be acquired? There's no indication of this in the article, and a cursory Google search has yielded no information for me. If someone has this information, it should be added. -- Apotheon 20:32, 19 May 2007 (UTC)

 * I had the same question. It appears to have it's own license, if you follow the links through to the official project page, but I don't feel comfortable add information about the license to the article, I don't think I have a great grasp on the material. Here's the link though, in case someone else can make sense of it and make the change. --Balleyne (talk) 22:35, 20 March 2008 (UTC)

 * There also appear to be some freely distributable (public domain) parts: . I added this info to the article, but we still need to figure out the license for Mach 4 from the University of Utah.  I suspect it might be public domain. -- Beland (talk) 15:11, 6 March 2009 (UTC)

Pronunciation
How is the word "Mach" pronounced? Like "match", or like "mac", or like "mash", or like German "Bach"?

This info is missing in this article. It should be included. In fact, there has been quite a bit of discussion about this question.

 * I've always presumed it was named after Austrian physicist Ernst Mach, and was pronounced the same as his name (like Bach). Qwertyus 16:13, 21 March 2006 (UTC)

 * I always figured it was pronounced as in "Mach number", which is pronounced like Ernst Mach's name. – Mipadi 16:21, 21 March 2006 (UTC)

 * But then some webpages say it is pronounced like "mack"? Any other opinions out there? Let us know.

 * I said I had   it was named after Mach. I'm not sure and have removed this unverified info from the page. It may also have been named after him indirectly, via the Mach number. That page says: "Mach number (pronounced "mack" in British English and "mock" in American English)". Qwertyus 00:06, 23 March 2006 (UTC)

 * Thank you, Qwertyus. OK! Now, is there anybody around who knows how (and why so) it is pronounced? Somebody should know! After all, one has to talk about it not only write.... :-) Thank you in advance.

 * I add here a link to the discussion on the pronunciation on the Mach number page. Maybe we get some info in that way.
 * Okay. I know for sure that in US English it is pronounced "mock".--[[Image:Nuvola apps kcmmemory.png|20px]]Mac Lover Talk 17:24, 10 August 2006 (UTC)
 * If it really is named after Austrian physicist Ernst Mach and/or Mach number (as for speed) then it should be pronounced with Hard ch same as J.S.Bach or Scottish 'Loch' —IEEE (talk) 01:23, 30 September 2008 (UTC)

I worked on the Mach project at CMU in the 80s. It's pronounced "mock." (Well, maybe more "mawck") When Rick was thinking about naming the system, there were a number of tentative names floating around, one of which was "muck." He was discussing real names with a colleague, Dario Guise, who has an Italian accent. Dario asked him what the working name was, and Rick said "muck." Dario said, "Ah, mach!" (mispronouncing it with his Italian accent), Rick loved it and it stuck. Other possible names were "Moose" (favored by Mike Young) and "Melange" (from Bob Baron, and which I was very fond of because Mach was in some sense a union of the old Spice project with Unix, "melange" was the spice from the Dune books, and "melange" means mixture). Since I'm an original source for this, I don't know if I should edit the page with it, so I'll just leave it in discussion for now.--Bill Bolosky —Preceding unsigned comment added by 131.107.0.77 (talk) 03:27, 10 February 2010 (UTC)

Here is a video of Steve Jobs pronouncing it as mock. Obviously there are other sources, too, that you may look up for yourself, for example 24C3: Inside the Mac OS X Kernel. Just thought it's worth mentioning. Dalba 10:14, 8 March 2016 (UTC)

Avie Tevanian, etc.
Perhaps we should mention Avie Tevanian here, too. ("Tevanian was an important figure in the development of the Mach kernel while at Carnegie-Mellon.") I think it's very interesting that two important Mach developers are now at top positions in Apple (Mac OS) and Microsoft (research).
 * Quite a few members of the Mach team came to Microsoft when Rick Rashid started Microsoft Research. Rich Draves, Joe Barrera, Alessandro Forin and me (Bill Bolosky), as well as Bob Fitzgerald, who'd worked on Mach's predecessor, Accent.

Is it still correct to state that the GNU Hurd is the biggest Mach project to date? Darwin's pretty popular as far as kernels in commercial OSes go. BonzoESC 00:04, 4 Dec 2004 (UTC)

 * I don't have an actual source, but didn't Apple say at one point that there were the biggest seller of desktop Unix now? AlistairMcMillan 02:12, 4 Dec 2004 (UTC)

 * The article actually needs a quite a bit of work. At one time it was thought that Mach would slowly take over the entire operating system universe, but this has not happened.  Except that the most popular operating system in use right now (Windows NT/2K/XP) uses a kernel based partially on the work done on the Mach project. AlistairMcMillan 02:12, 4 Dec 2004 (UTC)

 * I do not believe this is true. NT uses a classic monokernel, does not use IPC for much of anything, does not make extensive use of user-space servers, and is millions of lines long. NT was a development of VMS, not Mach. Maury 12:50, 23 Mar 2005 (UTC)

Is it true, that MACH stands for Microkernel Architectures Considered Harmful?

 * That's more of a [backronym] than anything else. That's like if FORD stood for Found On Road Dead, Fix Or Repair Daily, or anything that's not some dead dude's name.  BonzoESC 18:59, 23 Dec 2004 (UTC)

 * No, it definately is not true. Since Mach is a microkernel, it wouldn't make sense for that to be the acronym.  "Mach" isn't an acronym at all, and shouldn't be spelled in all caps.  See my comments on the name in the pronounciation section above.  --Bill Bolosky

BeOS
There is at least one more microkernel system that's left out of the article and that had decent performance: BeOS. Unfortunately I don't know much details, but the system had a real microkernel and servers like input server, application server, media server, net server, etc. In addition, it was and is very fast and responsive, in some cases faster than a Linux system. (Purely from user perspective.) It should be worthwhile to try and dig information about it, as it seemed to be a succesful microkernel based OS. --W-ber

 * the categorization of the BeOS kernel was discussed extensively on the Kernel article. The documentation describes it as a microkernel, while the developers described it as "modular monolithic." Eventually we reached a compromise and decided to place it under hybrid kernels unless a clear source shows otherwise. MFNickster

size of traditional kernels in lines of code

 * As the capability of computers grew, Unix became increasingly cluttered with code; while early kernels might have had 100,000 lines of code, modern kernels have much more. For example, Linux, a Unix successor, has over 33 million lines.

The comparison with Linux is off-key because back when the first Mach was released, Linux did not exist. We need a number of lines of code in a SVr4 kernel or similar. --Joy [shallot]   22:17, 18 Jun 2005 (UTC)

POV, confusing sentences, and historical information
I think the sentence The ultimate "classic" operating system is Unix, so any discussion of more modern systems must start with that one is useless and seriously POV. How does one define "classic" and "modern"? I don't want to enter the debate of what has Unix invented, but this claim is dubious; secondly, even if we admit that Unix is "the ultimate classic OS" (whatever that means, and I really have no clue what it means), it's not clear one can infer "any discussion of more modern systems must start with that one" from that. I suggest either rephrasing that as "Unix being one of the major modern operating systems, we shall start our discussion with it", or something along these lines. Or, we could simply remove this sentence, which IMO does not provide any information about the subject at hand.

Also, I don't understand what is meant by Another ongoing issue was properly handling computing resources: users spend most of their time staring at the screen instead of actually using their computers' resources, and the time share system should give the CPU time to an active user during these periods. What are these periods? To me, this sentence actually describes a non-timesharing system, and such description is unappropriate in this paragraph which is supposed to describe the problems of this era's timesharing systems.

And finally, I don't think that Unix invented pipes; ITS does have pipes (used by accessing the CLA, CLI, CLO and CLU devices), in all versions I have used, and they are described in the revised ITS reference manual, section 3.4.3 (July 1969). Unfortunately, I have been unable to determine from what version on pipes were implemented in ITS, so I cannot be sure which system had them first; anyway I seriously doubt ITS' pipes were implemented after seeing Unix's pipes; more likely the two systems developed pipes independently; oh, and note ITS's pipes worked across the network (since ITS's filesystem is nertwork transparent, it is not really surprising). Well, the article does not claim Unix invented pipes, but it does imply that the fact one can manipulate files through many little programs was invented by Unix; perhaps Unix was the first system to be described as having this philosophy, but one could and would definitely manipulate files using many small utilities under ITS, so I think this needs a rephrase. Sam 17:39, 29 December 2005 (UTC)

IPC performance
Roughly paragraph 10 under "Mach concepts" starts with a sentence that sounded weird and redundant the first few times I read it, "Performance of the IPC system was an initial performance problem..." It seems like the word performance shouldn't be in there twice. —Preceding unsigned comment added by 15.252.0.75 (talk • contribs) 18 april 2006 21:42

 * Fixed. Next time, please be bold! Qwertyus 23:55, 18 April 2006 (UTC)

Missing citations
Does anyone have sources for the citations that are missing from this page? There are a lot of statements that read as if they are facts but without citations who knows.

Long-winded, repetitive, and in some ways confusing
IMNSHO the entire article could do with an overhaul. It's long-winded and repetitive, particularly in the latter sections. Also, a better way to show the history of Mach (rather than writing it as a short story at the top) would be to display it in a table.

Also, am I alone in feeling that the article looks like it is going to come to some conclusion on whether or not Mach is a good thing? Reading through the article, I got the idea that the author had some sort of opinion, but it seems to flip-flop from criticising Mach for its IPC overhead through to enthusing about how the IPC bottleneck doesn't have to be that bad (e.g. for L4).

It's always read as a technical paper written by someone in the Mach community with it spending more time comparing Mach with other microkernels rather than just flatly describing Mach. This definitely requires fixing. --68.142.45.140 20:54, 16 May 2006 (UTC)

uname
Mach is said to be a UNIX kernel; can someone please edit its uname return-value into this article?--Jesdisciple (talk) 22:14, 13 March 2008 (UTC)

 * A description of Mach as just "a UNIX kernel" would be somewhat incomplete and misleading. There's a core Mach kernel, the kernel interfaces to which are described by the MACH Kernel Interface Manual, which provides (to quote the paper):

 * basic message primitives and support facilities,
 * port and port set management facilities,
 * task and thread creation and management facilities,
 * virtual memory management functions,
 * operations on memory objects.

 * It does not implement, for example, any file systems or network protocols, nor does it implement any UNIX system calls. Of those, the paper only says:

 * In addition to the facilities provided directly by the kernel, MACH also provides for complete emulation of all 4.3bsd functions as described in the 4.3bsd manual. This emulation is completely transparent to user programs and requires no special libraries or other utilities.  On all VAX hardware MACH is binary compatible with 4.3bsd.

 * In the original Mach, those were, I think, implemented by kernel-mode code that ran atop the Mach primitives; they could also have been implemented by, for example, user-mode servers making system calls that directly invoke Mach kernel primitives.

 * 4.3BSD didn't even have uname, as I remember; uname came from the PWB/UNIX strain of UNIX, not the Research Unix strain, and BSD came more from the Research UNIX strain. As such, I doubt there was a "uname return-value" in the original Mach. (Eventually, uname made it into the BSDs, etc., for compatibility.)

 * A number of Unix-like systems were built atop Mach; the "Operating systems based on Mach" section of the article lists some of them. At least some of them had or have uname, but the output isn't the same between, for example, Mac OS X and DEC OSF/1^W^WDigital UNIX^W^WTru64 UNIX.  I don't know whether NEXTSTEP had uname, but, if it did, its output wasn't the same as Mac OS X's output (OS X reports "Darwin" as the system name, but "Darwin" didn't exist, as such, before Apple bought NeXT).

 * In addition, some systems that weren't solely Unix-like, such as IBM Workplace OS, were built atop a (modified) Mach kernel; Workplace OS, according to the article, had a BSD personality, which might or might not have uname, but the MS-DOS and OS/2 personalities almost certainly didn't have uname, as the OSes they emulated didn't have uname.

 * So, unless the 4.3BSD-compatible Mach had uname - and, as indicated, I doubt it did - it's impossible for somebody to add its uname output to the article, as it didn't have uname output. Guy Harris (talk) 02:22, 14 March 2008 (UTC)

virtual memory management system
I found the quote:

 * The Mach virtual memory management system was also adopted by the BSD developers at CSRG

The problem I find with this quote is that there isn't enough information how Mach influenced today's BSD. Since Mach kernel is a microkernel, is the Mach's virtual management system really compatible to the monolithic BSD derivatives? I don't know but in the article there needs to be more clarification about the virtual memory management system in Mach and BSD. —Preceding unsigned comment added by Komitsuki (talk • contribs) 09:38, 4 June 2009 (UTC)

 * There's not much microkernelish about the lower layers of VM system - it has page fault handlers, data structures to represent address spaces and mappings, etc.. That's what was incorporated into 4.4BSD, with the topmost layer being based on BSD system calls such as   (first implemented "for real" in SunOS 4.0, and later adopted by non-BSD-derived UN*Xes as well) rather on Mach-style APIs. Guy Harris (talk) 00:54, 3 December 2014 (UTC)

Mach is a structure monitoring cpu-memory access. So apparently it's the other way around, Mach was the one influenced by BSD/Unix/Plan9, casting any all machine part to BSD-file, for monitoring all machine parts. So by casting cpu-memory resources to more single monolithic file-like point, Mach kernel practically completed the picture that's been covered by BSD-process cast, syscall, and hive-minded humanity traitors. — Preceding unsigned comment added by Dyk408 (talk • contribs) 22:57, 2 December 2014 (UTC)

Mach in a 64-bit environment
This article mostly discusses the performance hit in a Mach microkernel due to context switching. However, it makes no mention of a 64-bit environment in which context switching should no longer be necessary (for example, Snow Leopard running a 64-bit kernel can accommodate 32-bit/64-bit user apps plus the 64-bit kernel w/o context switching). Here's a link since I can't explain this correctly: http://www.appleinsider.com/articles/08/09/04/road_to_snow_leopard_twice_the_ram_half_the_price_64_bits.html —Preceding unsigned comment added by 173.206.4.117 (talk) 12:32, 9 November 2009 (UTC)

 * If I understand, there is less PMMU context switching necessary as there is more address space and the kernel VM space can be mapped in the same address space. It does not mean no context switch, but a lighter context switch.  This also does not solve the issue of syscalls where userland must trap (or use the special syscall instruction when available) for a switch to kernel/supervisor mode and stack.  I guess that yes, some microkernel IPC designs could benefit from a larger address space in some circumstances to reduce the overhead.  The overhead is still lower in a single unprotected address space though, as it was in AmigaOS (only need to switch messages among queues using node pointers).  Now consider the following scenario, on PMMU isolated components: some user task invokes a file system operation, sending a message to a file system task, sending itself a message to a block layer I/O and strategy task, itself sending a message to a HD device task... each possibly expecting an error back, so using synchronous messages for which a reply is expected.  You can probably understand the performance implications, comparatively to a syscall (a type of hardware-assisted synchronous message) on a monolithic-type kernel, with the internal operation consisting of direct function calls between all the internal layers (other than the interrupt service routines)...  Darwin (the OSX kernel) can be considered to be a hybrid kernel, with a Mach layer and a more traditional monolithic layer (similarily to running a Linux kernel under an L4 task).  These hybrid kernels can have components organized around a small microkernel, with the more complex systems provided by large tasks handling most other operations with less overhead.  76.10.128.192 (talk) 06:25, 1 July 2012 (UTC)

 * "Context switching" refers to switching from one running process to another. In any OS where each process has its own address space (which includes all the Mach-based UN*Xes), a context switch will involve an address space switch, whether it's in a 64-bit OS or not; 64-bitness doesn't change anything there.  It does not refer to switching between 32-bit and 64-bit mode, or switching between user mode and kernel mode.

 * And the performance hit being referred to is for operations in which one process requests a service that's performed not in kernel mode in the same process, but in user mode in another process. There is a significant amount of that in OS X, but that's mostly for graphics operations and servers such as coreservicesd, configd, and so on.  Network and file operations in OS X are done using the same system calls that are used in other BSD-flavored OSes, with the services performed by kernel-mode code in the same process. Guy Harris (talk) 01:39, 3 December 2014 (UTC)
 * And the speedup with a 64-bit kernel isn't eliminating context switches between processes, it's eliminating an address space switch within a process when making a system call or returning from a system call. The 32-bit Mac OS X kernel had a separate address space for kernel code and user code, so that user code could get a full 2^32-bit address space, which meant an address space switch when entering kernel mode from user mode or exiting kernel mode to go to user mode; the 64-bit kernel left the kernel in the same address space as user code (but not accessible to user code), so switching modes doesn't require an address-space switch.  Switching between processes, however, still requires an address-space switch, even with a 64-bit kernel. Guy Harris (talk) 23:51, 12 August 2022 (UTC)

Copy on write?
The sentence This offered a new solution to the port concept, using the copy on write mechanism used by VM. is very confusing. The previous sentences uses VM for virtual memory, but copy on write is a function of the operating system rather than the MMU. From what OS did copy on write find its way into Mach?--Shmuel (Seymour J.) Metz Username:Chatul (talk) 12:46, 12 July 2021 (UTC)

 * I read it as meaning the VM operating system, though I'm not familiar enough with its internals to know if it's a direct reference, just that VM pioneered a lot of stuff both in terms of virtual machines and virtual memory, especially with regard to efficiency (esp. compared to MVS, apparently...) --Vometia (talk) 19:35, 12 August 2022 (UTC)
 * I read it as meaning "virtual memory". I changed it to "virtual memory system" (not to be confused with VMS, which is one OS of many that have a virtual memory system), meaning both the hardware (MMU) and software (page fault/protection fault handling code) that implements virtual memory, speaking of "the copy on write mechanism provided by the virtual memory system" rather than "...used by...".
 * I.e., I don't think they're saying anything about the history of COW, they're just saying that the kernel can provide a COW mechanism in its virtual memory code, and that (plus mapping the same physical page into different address spaces) is what's being used by the Mach message system to transfer large blocks of data as part of a message. Guy Harris (talk) 20:19, 12 August 2022 (UTC)

title: Talk:Mach (kernel)


text:
Talk:Diamond dust

Untitled
I'm not positive that it was an actual occurrence of Diamond dust but my hometown experienced something akin to this the other night. Here is the link to the local newspaper article http://www.times-online.com/content/view/175533/60/ Calamitous (talk) 04:24, 10 February 2010 (UTC)

Hi, questions after reading the article: --69.212.100.126 08:48, 9 Oct 2004 (UTC)
 * what is "dynamic arrest"?
 * are there exclusive antarctic conditions that allow diamond dust only to appear there?
 * what's the difference bewteen diamond dust and ice clouds? if they are the same, and ice clouds aren't unusual, then isn't it a contradiction to state that diamond dusts are unusual?

 * (William M. Connolley 09:09, 9 Oct 2004 (UTC)) Not sure about the DA bit: I think its a ref to the fact that water supercools in the atmos and ice clouds don't form till it gets really quite cold: I suspect DA is the point at which supercooling always breaks down.

 * AFAIK there is no real diff between DD and IC, apart from DD being near the ground and very thin. But I'm not sure. DD is not at all unusual in the ant; it is elsewhere.

 * Thanks for the clarification. I changed the article to now mention that it's a near ground phenomena, and tried to add what I think DA means, in my own words. I'm sure I butchered it so if anyone wants to write it more elegantly by all means. --69.212.100.126 09:16, 9 Oct 2004 (UTC)

--Junglejob 22:18, 18 Feb 2005 (UTC) Interesting article but wrongly positioned: this kind of "diamond dust" is not an abrasive. But real diamond dust or powder is used as sanding or polishing media and would need a specific article.

Aside
Mildly interesting side note, clearly not worth putting in main article- Diamond Dust is the name of an ice based spell in the Playstation game Final Fantasy VII, which features a cloud of ice shards forming around and damaging your opponent. Sorry- I'm both a geographer and a gamer! Coyote-37 5 July 2005 12:33 (UTC)

Yes, its the main attack of the summon Shiva and not only in FF VII appears, too in VIII, IX and many others (Shiva can be called GF, Aeon, Totema, Eidolon as many FFs has diferent ways to call a summon)

What about diamond dust?
I actually came looking for information about the manufacture and applications of diamond dust (i.e., powdered diamond). Rather surprised there wasn't at least a link to such an article, much less a disambig. 71.11.242.156 17:42, 24 January 2006 (UTC)

Me too! Could be v. useful

 * A Google search for "Diamond dust" turns up a reference to Diamond powder as being the correct or preferred term for the dust of diamonds. It might be helpful if this was mentioned at the head of the article and on the disambiguation page, especially once the Diamond powder article is written. -- Cameron Dewe 08:29, 15 July 2007 (UTC)

Reference to Sandben Siberian Metereological phenomena book
A Google search for Sandben Siberian Metereological phenomena only returns the Wikipedia article. I suspect that the contribution by LambOfDog is a subtle attempt to compromise the integrity of Wikipedia, so I am removing the reference to:
 * Sandben, S.: Siberian Metereological phenomena (1991-1999), 2nd edition, Novotsky Press

If anyone can properly cite this work, please quote the ISBN and provide page references, or identify other works that cite the reference. -- Cameron Dewe 08:04, 15 July 2007 (UTC)

Pictures
19:37, 4 July 2009 edit removed a useful picture and video links, so these were recovered. YouTube videos were those posted by an original author.--Shimada22 (talk) 06:04, 5 July 2009 (UTC)

Now pictures and links to a picture and a video were added.--Shimada22 (talk) 19:46, 10 November 2008 (UTC)

A pic would really fit this article! 91.155.157.163 19:32, 3 November 2007 (UTC)

 * I just uploaded a video to commons that might enhance this article. It pretty accurately represents what I saw with my naked eye. --Kevinbsmith (talk) 00:39, 1 January 2018 (UTC)

WikiProject class rating
This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 09:48, 10 November 2007 (UTC)

External links modified (January 2018)
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title: Talk:Diamond dust


text:
Fusion tree

In computer science, a fusion tree is a type of tree data structure that implements an associative array on $w$-bit integers on a finite universe, where each of the input integers has size less than 2w and is non-negative. When operating on a collection of $n$ key–value pairs, it uses $O(n)$ space and performs searches in $O(log_{w} n)$ time, which is asymptotically faster than a traditional self-balancing binary search tree, and also better than the van Emde Boas tree for large values of $w$. It achieves this speed by using certain constant-time operations that can be done on a machine word. Fusion trees were invented in 1990 by Michael Fredman and Dan Willard.

Several advances have been made since Fredman and Willard's original 1990 paper. In 1999 it was shown how to implement fusion trees under a model of computation in which all of the underlying operations of the algorithm belong to AC0, a model of circuit complexity that allows addition and bitwise Boolean operations but does not allow the multiplication operations used in the original fusion tree algorithm. A dynamic version of fusion trees using hash tables was proposed in 1996 which matched the original structure's $AC^{0}$ runtime in expectation. Another dynamic version using exponential tree was proposed in 2007 which yields worst-case runtimes of $O(log_{w} n)$ per operation. Finally, it was shown that dynamic fusion trees can perform each operation in $O(log_{w} n + log log n)$ time deterministically.

This data structure implements add key, remove key, search key, and predecessor (next smaller value) and successor (next larger value) search operations for a given key. The partial result of most significant bit locator in constant time has also helped further research. Fusion trees utilize word-level parallelism to be efficient, performing computation on several small integers, stored in a single machine word, simultaneously to reduce the number of total operations.

How it works
A fusion tree is essentially a B-tree with branching factor of $O(log_{w} n)$ (any small exponent is also possible as it will not have a great impact on the height of the tree), which gives it a height of $w^{1/5}$. To achieve the desired runtimes for updates and queries, the fusion tree must be able to search a node containing up to $O(log_{w} n)$ keys in constant time. This is done by compressing ("sketching") the keys so that all can fit into one machine word, which in turn allows comparisons to be done in parallel. So, a series of computations involving sketching, parallel comparison and most significant bit index locator, help reach the required solution.

Sketching
Sketching is the method by which each $w$-bit key at a node containing $k$ keys is compressed into only $w^{1/5}$ bits. Each key $x$ may be thought of as a path in the full binary tree of height $w$ starting at the root and ending at the leaf corresponding to $x$. This path can be processed by recursively searching the left child of i if the ith bit is 0, and the right child if it is 1, generally, until all bits are scanned. To distinguish two paths, it suffices to look at their branching point (the first bit where any two keys differ). As there are a maximum of k keys, there will not be more than k-1 branching points, which means that no more than k-1 bits are required to identify a key. And hence, no sketch will have more than k-1 bits.

An important property of the sketch function is that it preserves the order of the keys. That is, $k − 1$ for any two keys $sketch(x) < sketch(y)$. So, for the entire range of keys, sketch(x0)<sketch(x1)<...<sketch(xk-1) because if the binary tree like path is followed the nodes will be ordered in such a manner that x0<x1<...<xk-1.

Approximating the sketch
If the locations of the sketch bits are b1 < b2 < ⋅⋅⋅ < br, then the sketch of the key xw-1⋅⋅⋅x1x0 is the r-bit integer $$x_{b_r}x_{b_{r-1}}\cdots x_{b_1}$$.

With only standard word operations, such as those of the C programming language, it is difficult to directly compute the perfect sketch of a key in constant time. Instead, the sketch bits can be packed into a range of size at most r4, using bitwise AND and multiplication, called the approximate sketch, which does have all the important bits but also some additional useless bits spread out in a predictable pattern. The bitwise AND operation serves as a mask to remove all these non-sketch bits from the key, while the multiplication shifts the sketch bits into a small range. Like the "perfect" sketch, the approximate sketch also preserves the order of the keys and means that sketch(x0)<sketch(x1)<...<sketch(xk-1).

Some preprocessing is needed to determine the correct multiplication constant. Each sketch bit in location bi will get shifted to bi + mi via a multiplication by m = $$\textstyle\sum_{i=1}^r$$ 2mi. For the approximate sketch to work, the following three properties must hold:

 * 1) bi + mj are distinct for all pairs (i, j). This will ensure that the sketch bits are uncorrupted by the multiplication.
 * 2) bi + mi is a strictly increasing function of i. That is, the order of the sketch bits is preserved even in x'.m.
 * 3) (br + mr) - (b1 + m1) ≤ r4. That is, the sketch bits are packed into a range of size at most r4, where r ≤ O(w1/5).

An inductive argument shows how the mi can be constructed. Let m1 = w − b1. Suppose that 1 < t ≤ r and that m1, m2... mt-1 have already been chosen. Then pick the smallest integer mt such that both properties (1) and (2) are satisfied. Property (1) requires that mt ≠ bi − bj + ml for all 1 ≤ i, j ≤ r and 1 ≤ l ≤ t-1. Thus, there are less than tr2 ≤ r3 values that mt must avoid. Since mt is chosen to be minimal, (bt + mt) ≤ (bt-1 + mt-1) + r3. This implies Property (3).

The approximate sketch is thus computed as follows:
 * 1) Mask out all but the sketch bits with a bitwise AND between x and $$\sum_{i=0}^{r-1} 2^{b_i}$$.
 * 2) Multiply the key by the predetermined constant m as calculated above. This operation actually requires two machine words, but this can still be done in constant time.
 * 3) Mask out all but the shifted sketch bits. These are now contained in a contiguous block of at most r4 < w4/5 bits.

Parallel comparison
The purpose of the compression achieved by sketching is to allow all of the keys to be stored in one w-bit word. Let the node sketch of a node be the bit string

 * 1 (x1)1 (x2)...1 (xk)

Here, all sketch words are clubbed together in one string by prepending a set bit to each of them. We can assume that the sketch function uses exactly b ≤ r4 bits. Then each block uses 1 + b ≤ w4/5 bits, and since k ≤ w1/5, the total number of bits in the node sketch is at most w.

A brief notational aside: for a bit string s and nonnegative integer m, let sm denote the concatenation of s to itself m times. If t is also a bit string st denotes the concatenation of t to s.

The node sketch makes it possible to search the keys for any b-bit integer y. Let z = (0y)k, which can be computed in constant time (multiply y by the constant (0b1)k), to make it as long as the node sketch such that each word in the node sketch can be compared with the query integer y in one operation, demonstrating word-level parallelism. If y were 5 bits long, it would be multiplied by 000001....000001 to get sketch(y)k. The difference between sketch(xi) and 0y results in the leading bit for each block to be 1, if and only if sketch(y) $$\leq $$ sketch(xi). We can thus compute the smallest index i such that (xi) ≥ y as follows:

 * 1) Subtract z from the node sketch.
 * 2) Take the bitwise AND of the difference and the constant (10b)k. This clears all but the leading bit of each block.
 * 3) Find the most significant bit of the result, to identify the exact index of transition from elements with sketch smaller than the query sketch to those greater than the query sketch.
 * 4) Compute i, the rank of the sketch, using the fact that the leading bit of the i-th block has index i(b+1).

Desketching
For an arbitrary query q, parallel comparison computes the index i such that
 * (xi-1) ≤ (q) ≤  (xi)

Unfortunately, this does give the exact predecessor or successor of q, because the location of the sketch of q among the sketches of all the values may not be the same as the location of q in all the actual values. What is true is that, among all of the keys, either xi-1 or xi has the longest common prefix with q. This is because any key y with a longer common prefix with q would also have more sketch bits in common with q, and thus (y) would be closer to  (q) than any  (xj).

The length longest common prefix between two w-bit integers a and b can be computed in constant time by finding the most significant bit of the bitwise XOR between a and b. This can then be used to mask out all but the longest common prefix.

Note that p identifies exactly where q branches off from the set of keys. If the next bit of q is 0, then the successor of q is contained in the p1 subtree, and if the next bit of q is 1, then the predecessor of q is contained in the p0 subtree. This suggests the following algorithm for determining the exact location of q:

 * 1) Use parallel comparison to find the index i such that  (xi-1) ≤  (q) ≤  (xi).
 * 2) Compute the longest common prefix p of q and either xi-1 or xi (taking the longer of the two).
 * 3) Let l-1 be the length of the longest common prefix p.
 * 4) If the l-th bit of q is 0, let e = p10w-l. Use parallel comparison to search for the successor of  (e). This is the actual predecessor of q.
 * 5) If the l-th bit of q is 1, let e = p01w-l. Use parallel comparison to search for the predecessor of  (e). This is the actual successor of q.
 * 6) Once either the predecessor or successor of q is found, the exact position of q among the set of keys is determined.

Fusion hashing
An application of fusion trees to hash tables was given by Willard, who describes a data structure for hashing in which an outer-level hash table with hash chaining is combined with a fusion tree representing each hash chain. In hash chaining, in a hash table with a constant load factor, the average size of a chain is constant, but additionally with high probability all chains have size $x < y$, where $n$ is the number of hashed items. This chain size is small enough that a fusion tree can handle searches and updates within it in constant time per operation. Therefore, the time for all operations in the data structure is constant with high probability. More precisely, with this data structure, for every inverse-quasipolynomial probability $O(log n / log log n)$, there is a constant $C$ such that the probability that there exists an operation that exceeds time $C$ is at most $p(n) = exp((log n)^{O(1)})$.

Computational Model and Necessary Assumptions
The computational model for the Fusion Tree algorithm is a Word RAM with a specific instruction set, including arithmetic instructions - addition, subtraction and multiplication (all performed modulo $p(n)$) and Boolean operations - bitwise AND, NOT etc. A double-precision multiplication instruction is also included. It has been shown that removal of the latter instruction makes it impossible to sort faster than $2^{w}$, unless it is permitted to use memory space of nearly $O(n log n)$ words (in contrast to linear space used by Fusion Trees), or include other instructions instead.

title: Fusion tree