explain xkcd - User contributions [en]

1714: Volcano Types

2016-10-22T09:11:32Z

Jonsku99:

{{comic
| number = 1714
| date = August 1, 2016
| title = Volcano Types
| image = volcano_types.png
| titletext = It's hard living somewhere with antlions, because every time you find one of their traps, you feel compelled to spend all day constructing a tiny model of Jabba's sail barge next to it.
}}

==Explanation==
This comic presents a table of 12 different types of volcano. Split into 3 rows, the first 4 are authentic types of volcano; while the remaining 8 are parodies, one not even trying to represent a volcano but shows a real animal in its inverted trap cone.

Volcanoes have featured in many xkcd comics, [http://www.explainxkcd.com/wiki/images/d/d5/1608_Entire_Volcano_plateau_zoom_out_extra.png most prominently] in the left part of the world (the Lord of the Rings section) of [[1608: Hoverboard]]. This comic's volcano looks like it could soon turn into a Somma volcano...

===Real volcanoes===
* {{w|Cinder cone}}: small, steep-sided volcano formed of {{w|scoria}} and ash.
* {{w|Shield volcano}}: wide, rounded volcano formed of solidified lava flow.
* {{w|Stratovolcano}}: large volcano formed of layers (strata) from multiple eruptions.
* {{w|Somma volcano}}: new volcanic cone in the middle of an old collapsed volcanic crater.

===Joke volcanoes===
* Metasomma volcano: nested layers of somma volcanos i.e. a whole set of new volcanoes (three in this situation) formed inside of old ones. "Meta" is a prefix that often denotes recursion.
* {{w|Waffle cone}}: type of pastry that ice cream is served in, related to volcano cones only insofar as they are the same shape, but typically the waffle cones are turned the other way up to keep the ice cream inside... If the tip of the waffle cone is not filled with solid chocolate or similar, then the contents may very well melt and run out the bottom like the smoke coming out at the very tip of the Waffle cone volcano.
* Science fair cone: common elementary science experiment that is often used as a project for science fairs. A structure is built to resemble a model volcano and is filled with a mix of baking soda, vinegar, and sometimes food coloring. The reaction between baking soda and vinegar quickly produces a large amount of carbon dioxide, creating a foam that overflows and mimics a volcanic eruption. In this picture, there are people running away from the volcano that are much smaller than it. This is likely a reference to [[1611: Baking Soda and Vinegar]], either the scale-model people on the first volcano, or real people running from the baking soda supervolcano (in this case two [[Cueball]]-like guys and [[Megan]]).
* Doot cone: This may likely be a reference to the meme of the [http://knowyourmeme.com/memes/skull-trumpet skull-trumpet] where the trumpet playing skull [https://www.reddit.com/r/OutOfTheLoop/comments/39xnk2/what_is_this_doot_thing_with_the_skeletons/cs7jdsa produces the sound Doot] as a large part of the meme. Doot is also a fart sound, a doot cone could be just ejecting farts instead of lava.
** There has been some discussion about if this is likely, with someone referencing the [https://www.amazon.com/Florida-DOT-Approved-Traffic-Cone/dp/B009RUTKZA DOT cones], traffic cones approved by DOT or the {{w|Department of transportation}} in the US.
** Also there have been mention of ''{{w|Dot-com}}'' coming close to ''Doot cone''. The {{w|Dot-com bubble}} could be said to burst, just like this volcano bursts/erupts.
* {{w|Antlion}}: a burrowing insect that digs a conical hole to catch prey at the larval stage. Maybe a reference to {{w|Formica Leo}}, a small volcanic crater in the Reunion island named after the antlion. Also, a recurring boss villain in the video game Final Fantasy series. Also appears in the [https://en.wikipedia.org/wiki/List_of_Moomin_(1990)_episodes Moomin (1990) TV series] as a literal black lion.
* Inverse Volcano: as the name implies, a regular volcano but reversed. A real volcano consists of solid rock on the outside, magma on the inside and spewing lava from the top.
* Ghost Vent: cone with ghosts coming out of it. It may be a reference to {{w|Scientology}}, where part of the faith states that the souls of aliens were stored in a volcano from which they later escaped, as described in the story of {{w|Xenu}}. The ghosts could also refer to the {{w|Pac-Man}} video game.
* Pedant's Bane: the joke is that people sometimes confuse magma and lava, which are different names for the same heated liquid rock. Magma becomes lava when it emerges from a volcano. The Pedant's Bane volcano is therefore impossible by definition, but if it were possible, then a {{w|pedant}} would have met his [https://en.wiktionary.org/wiki/bane#Etymology_1 bane] (i.e. his downfall), because when he corrected someone's description of this volcano, the pedant would actually be wrong. Alternatively, the illustration itself could be Pedant's Bane because a pedant would be lured into pointing out how wrong it is. This is a direct reference to the pedant in [[1405: Meteor]].

The title text refers to a famous scene in ''{{w|Star Wars: Episode VI - Return of the Jedi}}'' where {{w|Jabba the Hutt}} intends to feed {{w|Luke Skywalker}} to the {{w|Sarlacc|sarlacc}}, an underground creature that builds a huge funnel trap similar to that of an antlion. [[wikia:c:starwars:Khetanna|Jabba's distinctive sail barge]] features prominently in that scene, and when Randall comes upon an antlion he can't help himself starting to build a scale model next to the antlions inverted cone. Given how small antlions are, this will be very difficult to do, see for instance [[878: Model Rail]].

==Transcript==
:[Twelve drawings in four rows of different "volcano" types, the first four real, and some not even volcanoes of any sort, real or fake. Below each panel is a caption with the name of the drawn volcano. Some of the volcanoes have labels or sound written inside the panel. Each of the volcanoes has a baseline for the ground going straight a short distance over the bottom of each panel. All 11 volcanoes lie on top of this line, but some show the inside of the volcano going further into the ground.]

:[Standard cone shaped volcano, with straight sides sloping up to a triangular shape, but with the tip of the cone cut off to form the central jagged edged crater. White smoke rises straight up and then drifts to the left forming three separate clouds.]
:Cinder Cone

:[Flat rounded shaped volcano, as a part of a circle. There is not a real crater visible but from the center a thin plume of smoke rises up, drift drifts to the left and forms a small white cloud.]
:Shield Volcano

:[This is the largest volcano. The tip of this volcano is similar to the first volcano, but with more uneven slopes and a bit smaller. The tip is clearly separated from the bottom section by a thin jagged line, and below the sides of the volcano decreases their slope, so they are less steep than the tip. Black smoke rises straight up from the crater and then drifts to the left in four thin lines.]
:Stratovolcano

:[A wide volcano spans the entire panel, with a large central crater, with a bottom baseline far above the ground level. Just left of the middle of this crater is a standard smaller volcano cone, very similar to the shape of the tip in the previous panel. Even the smoke from this cones small crater is similar to the previous panels.]
:Somma Volcano

:[The central part of this volcano is the same shape as the previous panel. This could be a zoom out, revealing that the large crater, is at the center on an even larger crater, which again is at the center of a crater that spans the panel. A plume of black smoke rises from the centeral cones crater, and drifts left as five white clouds.]
:Metasomma Volcano

:[A perfect cone-shape, triangular and steep, with checkered ice cone waffle texture, even with a line indicating where the waffle has been a folded. It looks like a road up the volcano. Black smoke drift up from the sharp tip, no crater, and drifts left forming a small cloud separated from the rest of the smoke lines.]
:Waffle Cone

:[Standard cone as in the first, but zoomed in so it fills the panel from left to right. The volcano's top has been cut much further down leaving a wide crater from which lava is pouring down the sides in large rivers of different width and length. To the left one long river has almost reached the ground. Cueball is running down the left side, and Megan is running after another Cueball with his arms up on the right side. There is a label with an arrow pointing to the lava:]
:Label: Baking soda and vinegar
:Science Fair Cone

:[Standard cone like the previous, but with more jagged sloped and crater. This volcano erupts with a large explosion with fire and smoke coming out in all directions above the crater. A large sound is written above the explosion:]
:Sound. <big>'''Doooooot'''</big>
:Doot Cone

:[This is not a volcano, but the inverse, a cone down into the ground, the ground level no above the center of the panel. The slope down into this cone hole is straight, the ground above is more jagged. At the bottom of the hole sits a small animal with six legs and an open mouth piece sticking up out of the hole. Its fat body is hidden under the ground along with its legs.]
:Antlion

:[Standard volcano cone like the previous volcano. It erupts and the central part shows how the erupting material comes up from below ground level (below the line at the bottom in which the cone it self stands). The erupting material is white rocks on black background. At the top several rocks is blown out of the crater top. The sides of the volcano is filled with blobs small and large, and stones rolling down the sides. There are two labels, each with two arrows. The first labels arrows points to the side of the volcano, the second labels arrows points to the erupting material inside and outside the volcano:]
:First label: Lava
:Second label: Solid rocks
:Inverse Volcano

:[Standard cone like the doot cone, with a crater that bends down in the middle. From this crater eight white ghosts with two black eyes are rising, like the smoke, drifting left. The highest ghost is just reaching the edge at the top left of the panel. The lowest ghost is still inside the crater with its wavy lower parts.]
:Ghost Vent

:[A standard cone like the doot cone. At the top there is lave over the outer edges, some of it running down the side. The inside of the volcano has been drawn like in the inverse volcano, so it is clear that the magma inside the volcano comes up from below ground level (below the line at the bottom in which the cone it self stands). There are two labels that contradicts the description above. The top label outside the volcano points to the lava with an arrow, and the bottom label inside the volcano points to the magma:]
:Top label: Magma
:Bottom label: Lava
:Pedant's Bane

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Multiple Cueballs]]
[[Category:Food]] 
[[Category:Animals]] 
[[Category:Star Wars]]
[[Category:Geography]]

1714: Volcano Types

2016-09-27T17:55:43Z

Jonsku99: /* Joke volcanoes */

{{comic
| number = 1714
| date = August 1, 2016
| title = Volcano Types
| image = volcano_types.png
| titletext = It's hard living somewhere with antlions, because every time you find one of their traps, you feel compelled to spend all day constructing a tiny model of Jabba's sail barge next to it.
}}

==Explanation==
This comic presents a table of 12 different types of volcano. Split into 3 rows, the first 4 are authentic types of volcano; while the remaining 8 are parodies, one not even trying to represent a volcano but shows a real animal in its inverted trap cone.

Volcanoes have featured in many xkcd comics, [http://www.explainxkcd.com/wiki/images/d/d5/1608_Entire_Volcano_plateau_zoom_out_extra.png most prominently] in the left part of the world (the Lord of the Rings section) of [[1608: Hoverboard]]. This comic's volcano looks like it could soon turn into a Somma volcano...

===Real volcanoes===
* {{w|Cinder cone}}: small, steep-sided volcano formed of {{w|scoria}} and ash.
* {{w|Shield volcano}}: wide, rounded volcano formed of solidified lava flow.
* {{w|Stratovolcano}}: large volcano formed of layers (strata) from multiple eruptions.
* {{w|Somma volcano}}: new volcanic cone in the middle of an old collapsed volcanic crater.

===Joke volcanoes===
* Metasomma volcano: nested layers of somma volcanos i.e. a whole set of new volcanoes (three in this situation) formed inside of old ones. "Meta" is a prefix that often denotes recursion.
* {{w|Waffle cone}}: type of pastry that ice cream is served in, related to volcano cones only insofar as they are the same shape, but typically the waffle cones are turned the other way up to keep the ice cream inside... If the tip of the waffle cone is not filled with solid chocolate or similar, then the contents may very well melt and run out the bottom like the smoke coming out at the very tip of the Waffle cone volcano.
* Science fair cone: common elementary science experiment that is often used as a project for science fairs. A structure is built to resemble a model volcano and is filled with a mix of baking soda, vinegar, and sometimes food coloring. The reaction between baking soda and vinegar quickly produces a large amount of carbon dioxide, creating a foam that overflows and mimics a volcanic eruption. In this picture, there are people running away from the volcano that are much smaller than it. This is likely a reference to [[1611: Baking Soda and Vinegar]], either the scale-model people on the first volcano, or real people running from the baking soda supervolcano (in this case two [[Cueball]]-like guys and [[Megan]]).
* Doot cone: This may likely be a reference to the meme of the [http://knowyourmeme.com/memes/skull-trumpet skull-trumpet] where the trumpet playing skull [https://www.reddit.com/r/OutOfTheLoop/comments/39xnk2/what_is_this_doot_thing_with_the_skeletons/cs7jdsa produces the sound Doot] as a large part of the meme. Doot is also a fart sound, a doot cone could be just ejecting farts instead of lava.
** There has been some discussion about if this is likely, with someone referencing the [https://www.amazon.com/Florida-DOT-Approved-Traffic-Cone/dp/B009RUTKZA DOT cones], traffic cones approved by DOT or the {{w|Department of transportation}} in the US.
** Also there have been mention of ''{{w|Dot-com}}'' coming close to ''Doot cone''. The {{w|Dot-com bubble}} could be said to burst, just like this volcano bursts/erupts.
* {{w|Antlion}}: a burrowing insect that digs a conical hole to catch prey at the larval stage. Maybe a reference to {{w|Formica Leo}}, a small volcanic crater in the Reunion island named after the antlion. Also, a boss villain in the video game Final Fantasy II at the bottom of a large cone of sand. Also appears in the [https://en.wikipedia.org/wiki/List_of_Moomin_(1990)_episodes Moomin (1990) TV series], as a literal, black lion.
* Inverse Volcano: as the name implies, a regular volcano but reversed. A real volcano consists of solid rock on the outside, magma on the inside and spewing lava from the top.
* Ghost Vent: cone with ghosts coming out of it. It may be a reference to {{w|Scientology}}, where part of the faith states that the souls of aliens were stored in a volcano from which they later escaped, as described in the story of {{w|Xenu}}. The ghosts could also refer to the {{w|Pac-Man}} video game.
* Pedant's Bane: the joke is that people sometimes confuse magma and lava, which are different names for the same heated liquid rock. Magma becomes lava when it emerges from a volcano. The Pedant's Bane volcano is therefore impossible by definition, but if it were possible, then a {{w|pedant}} would have met his [https://en.wiktionary.org/wiki/bane#Etymology_1 bane] (i.e. his downfall), because when he corrected someone's description of this volcano, the pedant would actually be wrong. Alternatively, the illustration itself could be Pedant's Bane because a pedant would be lured into pointing out how wrong it is. This is a direct reference to the pedant in [[1405: Meteor]].

The title text refers to a famous scene in ''{{w|Star Wars: Episode VI - Return of the Jedi}}'' where {{w|Jabba the Hutt}} intends to feed {{w|Luke Skywalker}} to the {{w|Sarlacc|sarlacc}}, an underground creature that builds a huge funnel trap similar to that of an antlion. [[wikia:c:starwars:Khetanna|Jabba's distinctive sail barge]] features prominently in that scene, and when Randall comes upon an antlion he can't help himself starting to build a scale model next to the antlions inverted cone. Given how small antlions are, this will be very difficult to do, see for instance [[878: Model Rail]].

==Transcript==
:[Twelve drawings in four rows of different "volcano" types, the first four real, and some not even volcanoes of any sort, real or fake. Below each panel is a caption with the name of the drawn volcano. Some of the volcanoes have labels or sound written inside the panel. Each of the volcanoes has a baseline for the ground going straight a short distance over the bottom of each panel. All 11 volcanoes lie on top of this line, but some show the inside of the volcano going further into the ground.]

:[Standard cone shaped volcano, with straight sides sloping up to a triangular shape, but with the tip of the cone cut off to form the central jagged edged crater. White smoke rises straight up and then drifts to the left forming three separate clouds.]
:Cinder Cone

:[Flat rounded shaped volcano, as a part of a circle. There is not a real crater visible but from the center a thin plume of smoke rises up, drift drifts to the left and forms a small white cloud.]
:Shield Volcano

:[This is the largest volcano. The tip of this volcano is similar to the first volcano, but with more uneven slopes and a bit smaller. The tip is clearly separated from the bottom section by a thin jagged line, and below the sides of the volcano decreases their slope, so they are less steep than the tip. Black smoke rises straight up from the crater and then drifts to the left in four thin lines.]
:Stratovolcano

:[A wide volcano spans the entire panel, with a large central crater, with a bottom baseline far above the ground level. Just left of the middle of this crater is a standard smaller volcano cone, very similar to the shape of the tip in the previous panel. Even the smoke from this cones small crater is similar to the previous panels.]
:Somma Volcano

:[The central part of this volcano is the same shape as the previous panel. This could be a zoom out, revealing that the large crater, is at the center on an even larger crater, which again is at the center of a crater that spans the panel. A plume of black smoke rises from the centeral cones crater, and drifts left as five white clouds.]
:Metasomma Volcano

:[A perfect cone-shape, triangular and steep, with checkered ice cone waffle texture, even with a line indicating where the waffle has been a folded. It looks like a road up the volcano. Black smoke drift up from the sharp tip, no crater, and drifts left forming a small cloud separated from the rest of the smoke lines.]
:Waffle Cone

:[Standard cone as in the first, but zoomed in so it fills the panel from left to right. The volcano's top has been cut much further down leaving a wide crater from which lava is pouring down the sides in large rivers of different width and length. To the left one long river has almost reached the ground. Cueball is running down the left side, and Megan is running after another Cueball with his arms up on the right side. There is a label with an arrow pointing to the lava:]
:Label: Baking soda and vinegar
:Science Fair Cone

:[Standard cone like the previous, but with more jagged sloped and crater. This volcano erupts with a large explosion with fire and smoke coming out in all directions above the crater. A large sound is written above the explosion:]
:Sound. <big>'''Doooooot'''</big>
:Doot Cone

:[This is not a volcano, but the inverse, a cone down into the ground, the ground level no above the center of the panel. The slope down into this cone hole is straight, the ground above is more jagged. At the bottom of the hole sits a small animal with six legs and an open mouth piece sticking up out of the hole. Its fat body is hidden under the ground along with its legs.]
:Antlion

:[Standard volcano cone like the previous volcano. It erupts and the central part shows how the erupting material comes up from below ground level (below the line at the bottom in which the cone it self stands). The erupting material is white rocks on black background. At the top several rocks is blown out of the crater top. The sides of the volcano is filled with blobs small and large, and stones rolling down the sides. There are two labels, each with two arrows. The first labels arrows points to the side of the volcano, the second labels arrows points to the erupting material inside and outside the volcano:]
:First label: Lava
:Second label: Solid rocks
:Inverse Volcano

:[Standard cone like the doot cone, with a crater that bends down in the middle. From this crater eight white ghosts with two black eyes are rising, like the smoke, drifting left. The highest ghost is just reaching the edge at the top left of the panel. The lowest ghost is still inside the crater with its wavy lower parts.]
:Ghost Vent

:[A standard cone like the doot cone. At the top there is lave over the outer edges, some of it running down the side. The inside of the volcano has been drawn like in the inverse volcano, so it is clear that the magma inside the volcano comes up from below ground level (below the line at the bottom in which the cone it self stands). There are two labels that contradicts the description above. The top label outside the volcano points to the lava with an arrow, and the bottom label inside the volcano points to the magma:]
:Top label: Magma
:Bottom label: Lava
:Pedant's Bane

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Multiple Cueballs]]
[[Category:Food]] 
[[Category:Animals]] 
[[Category:Star Wars]]
[[Category:Geography]]

Talk:1700: New Bug

2016-07-26T12:30:59Z

Jonsku99:

I'm new. For the explanation: A bug, as in a computer (programming) bug, can be reported and tracked, and many systems allow collaboration on the reporting and tracking of problems, or bugs, in code, and their solutions. Cueball reported a problem (bug) he found in the code, which presumably caused the server (program)—which he wrote as part of his project—to try to read the passwords as URLs before storing them. This exposes serious cross-site scripting attacks and other serious security vulnerabilities, and since handling password and user account information usually requires a lot of programming, this would be difficult to fix, which is why the character off-panel suggests burning the project down, as that would be much easier, and would solve any security problems, much more quickly than fixing the bug would. The comment text refers to Cueball's horrid solution to a horrid problem: Instead of solving the problem that is causing the server to read passwords as URLs, he can instead leverage a known problem in the programme which reads URLs which prevents it from reading a particular way of representing text in binary form, by adding a few characters to the user's password that the URL-reading program can't read. This would also "salt" the user's password, which is a security technique that makes passwords harder to figure out when they are stored properly. Cueball thinks this would solve the original problem, and two other problems at the same time, the second problem being the fact that user's passwords aren't salted (a security problem). The third solved problem is difficult to deduce. &emsp;[[User:Zyzygy|Zyzygy]] 05:40, 29 June 2016 (UTC)

: The third bug is the unicode handling, which would need to be solved in order to salt passwords with emoji since these are unicode only character. Although I'm not sure if salting with emoji really increases security since as a rule i'd say nobody uses emoji in their passwords. [[Special:Contributions/162.158.85.123|162.158.85.123]] 06:34, 29 June 2016 (UTC)

::Password: 👍🐎🔋Π [[Special:Contributions/141.101.98.131|141.101.98.131]] 10:11, 29 June 2016 (UTC)
:::That is a really funny password, [[936: Password Strength|but is it strong ennough?]] :-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:22, 29 June 2016 (UTC)

:Actually, nobody using emoji in their password would be reason salting with emoji is MORE effective. Salting doesn't really increase security of single password, but it does increase security of whole password database, because you can hash some string - like, [http://www.telegraph.co.uk/technology/2016/01/26/most-common-passwords-revealed---and-theyre-ridiculously-easy-to/ 123456] and check whole database for users having that as password. If every password is salted with different emoji, this strategy will not work, because while you KNOW which emoji is used - the salt is stored unhashed with the password hash - it's always different so you need to compute new hash for every line in password database. Hashing takes MUCH more time than just comparing strings. And how it's even more effective? Because someone might actually get multiple databases and search for entries with same salt, hoping there will be enough of them to be worth it. And salt with emoji likely wouldn't be so common ... -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 09:54, 29 June 2016 (UTC)

From 108.162.221.22 (long rant)
:Two comments: first, the explanation on password salting is incorrect. The current version says "Salting passwords increases security by adding random data to the passwords which primarily helps defend against dictionary attacks.". Password salting only protects against particular kinds of (common) attacks in specific situations. Most importantly, it is designed to protect passwords only in the event ofa database breach, when a malicious user has gained direct access to the database itself. Password salting provides no protection when brute force attacks (aka dictionary attacks) are directed at the application itself, as the application automatically takes hashes into account. Instead, proper password salting randomizes the hash for each password, ensuring that if two users have the same password, they will not have the same hash. This makes it much more difficult to guess passwords through attack vectors like lookup tables, reverse lookup tables, and rainbow tables. However, because the salt has to be stored with the password (otherwise the application would not be able to make sense of the hash itself), password salting does not secure passwords against dictionary attacks even in the event that a malicious user has managed to acquire the database itself. I will update the explanation with a brief description of what password salts do.
:Finally, I think there is a big misunderstanding throughout this explanation. In a web services context the "server" (referenced in the comic) is a very different thing than the application that a programmer builds. A server can refer to either the computer itself or the software that is responsible for responding to web requests and executing the actual application. In a professional context, the application (which is what cueball would be building) would never be referred to as the "server". It is possible that this is a mis-use of terminology on the part of cueball or Randall, but I suspect that the term was used properly and intentionally. The reason is because if cueball's application is crashing the *server*, it takes the level of incompetence up to completely new (and unusual) levels, in much the same way that he has done in the past. Normally the programming language used to build the application, the software hosting the application, and the operating system itself have a number of safe guards in place to ensure that if an application misbehaves, the only thing that crashes is the application itself. For cueball's application to break through all those safeguards and crash the server itself (either the operating system or the web server software) would require cueball to have developed a program that operates *well* outside the bounds of normal procedures. Just for reference, as someone who has been building web software for over 15 years, I wouldn't even know where to start to crash the server from within an application. It would probably have to involve either exploiting a previously unknown bug in the programming language or some *very* poorly designed system calls. [[Special:Contributions/108.162.221.22 15:11, 29 June 2016‎ 108.162.221.22]] (Rememeber to sign your comments)

::If you by 'server' means Apache it is not completely unexpected that a sloppy coded extension to Perl or PHP could crash part of the server – and I still maintain mod_perl code that does 'fancy' stuff. I wouldn't be surprised if Cueball still wrote web-application as he did when mod_perl was the hot stuff. Today it is a common setup to have a chain of servers. In the front nginx for SSL termination, maybe an application level firewall filtering out spooky requests, then Varnish for caching and load-balancing and finally the application server running the actual web-application – all layers implementing the HTTP protocol. Which of these are 'the server'? At least it is often easy for the application developer to make the last server in the chain unresponsive (i.e. crashed). [[User:Pmakholm|Pmakholm]] ([[User talk:Pmakholm|talk]]) 12:08, 1 July 2016 (UTC)

:::Writing an extension to your language of choice would probably be a good way of crashing the server, although I would say that writing extensions to the language itself is not a common thing for most people to do. I suppose I'm arguing from experience (which is not always accurate) but in years of PHP and python programming I've never once had to write a language extension, nor did I ever need to for my very complicated thesis work. So I would say that the general point still stands: if Cueball is crashing any part of the server, he is doing things very wrong or at least very different.[[User:Cmancone|Cmancone]] ([[User talk:Cmancone|talk]]) 12:58, 1 July 2016 (UTC)

:::: mod_perl (and it likes) are not language extensions (as they do not extend the language) but are plugins that extends the capabilities of the server (so as to be able to execute perl) [[Special:Contributions/162.158.255.113|162.158.255.113]] 22:03, 5 July 2016 (UTC)

Regarding those last two points: sorry for my long unsigned rant. Didn't realize I wasn't logged in. Still haven't figured out how to sign comments. Gonna try it this time. [[User:Cmancone|Cmancone]] ([[User talk:Cmancone|talk]]) 16:51, 29 June 2016 (UTC)
:You made it ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:22, 29 June 2016 (UTC)

Explanation says "There is no reason for password handling code to access urls" but that is somewhat wrong -- Password handling code frequently perform heuristics on the password to assess the strength, for example checking if part of the password is a dictionary word -- similar heuristics could be done to check thatthe password is not a URL, such as "xkcd.com" applying DNS and other internet resources as an extention of the concept of "dictionary". [[User:Spongebog|Spongebob]] ([[User talk:Spongebog|talk]]) 16:11, 29 June 2016 (UTC)

:I think http://xkcd.com/correct/horse/battery/staple/ would be a perfectly fine password, even though it is also an URL – but a heuristic that just looks at the length of the password and if it only contains alphanumeric characters would probably be fooled. Trying to detect the scheme used to generate the password could be helpful in choosing a relevant heuristic for deciding the password strength. Ont the other hand, I would consider it very bad to actually test whether the URL is resolvable in any way that leaks information about the password to the outside. [[User:Pmakholm|Pmakholm]] ([[User talk:Pmakholm|talk]]) 11:11, 1 July 2016 (UTC)

::leaking password information to the outside would be bad, but then again any implementation of a password URL resolving scheme would just add emoji salting [[Special:Contributions/162.158.255.113|162.158.255.113]] 22:03, 5 July 2016 (UTC)

Currently the explanation says: "Finally, emoji will often include unicode characters, which means that, if one can effectively salt passwords with emoji, then the passwords should be able to be stored in unicode (although that *probably* doesn't require anything outside the Base Multilingual Plane, so that might not need full unicode support after-all)." I'm fairly convinced that this doesn't make sense and is incorrect. Regardless of what character encoding the password is in, hashing will convert the entire thing into binary. This binary is then typically stored as a base64-encoded string in the database. Ergo, it doesn't matter whether the original password strings were in unicode or not: they will be stored in the database as ascii (or binary), not unicode. I'm going to go ahead and remove this comment from the explanation. I'm pretty certain that there isn't enough information in the comic to figure out why salting passwords with emoji would fix a unicode-handling bug in the URL request library. So I suspect that there is no explanation there: either Cueball is entirely confused and his statement makes no sense, or there is simply not enough information given to help us understand why this solution might fix the problem. However, I'm not going to make any updates to the explanation about this yet, because perhaps I'm missing something someone else will notice. [[User:Cmancone|Cmancone]] 12:50, 29 June 2016 (ETC)
:I suspect that the salting with emoji is to ensure that the password does not resolve as a URL (since the library cannot understand the encoding), and thus the issue of the crash is resolved, the issue of unsalted passwords is solved, and the issue of the unicode handling bug is "solved" by virtue of it now being a feature relied on by the system. [[Special:Contributions/173.245.56.68|173.245.56.68]] 20:50, 29 June 2016 (UTC)

I removed from the explanation the discussion about how Cueball's system might be checking passwords to see if they are resolvable URLs as a check against weak passwords. The problem with this explanation is that if that is where the crash was happening, then salting the password with emoji would not fix the crash. For salting to fix the crash (as Cueball suggests it will) requires that the crash be happening during the hashing process, not during password validation. The reason is because password validation is performed on the original password itself, while only hashing happens on the salted password. So for salting to fix the crash it must be happening during hashing, not validation. If the bug is happening while checking passwords for strength then Cueball's suggestion of fixing it by adding in a salt will not actually fix the crash at all. It could be that Cueball is simply completely wrong about everything, but I think it makes more sense to go with an explanation where the title text didn't just get everything wrong.[[User:Cmancone|Cmancone]] ([[User talk:Cmancone|talk]]) 13:12, 30 June 2016 (UTC)

In the nomenclature I am familiar with mailto:somebody@example.com is a URL. If you accept that mailto (and other protocols) are also URLs some of the description is untrue. Fortunately the untrue bits are also unnecessary and can be deleted or generalized.--[[Special:Contributions/108.162.219.11|108.162.219.11]] 04:51, 1 July 2016 (UTC)

Definitely a sequel to 1084[[Special:Contributions/108.162.221.92|108.162.221.92]] 08:27, 1 July 2016 (UTC)

The explanation of 'Resolveable URL' is very confusing and mostly wrong, it is mixing up technologies like HTTP and DNS and is confusing FQDN's with URLs. Though admittedly, the term 'resolveable URL' is a bit of a misnomer by itself. URLs are typically not resolved, they contain an FQDN that is resolved via DNS to an IP(v6) address and optionally port. The remainder of the URL can be used to identify a resource on that server, but how this is done and signaled is quite application/protocol dependent (and shouldn't be called 'resolving'). So if you hit a 404 the FQDN actually resolved but the HTTP resource could not be found. A non-resolveable URL would give a browser error like 'unknown host'. [[Special:Contributions/162.158.83.198|162.158.83.198]] 09:59, 1 July 2016 (UTC)
:Feel free to adjust the text as desired. I think in this case it is best to understand "Resolvable URL" as Cueball meant it, which (I think) is as any valid URL you might stick in your web browser. I don't think he meant any of the more technical possible definitions. In that sense a resolvable URL would be something that points to a server, potentially followed by a resource on the server. At least, that is how I would think to describe it. Feel free to give it a go. {{unsigned|Cmancone}}

Around the time this comic was published, Firefox linked on its start-page to https://advocacy.mozilla.org/en-US/encrypt/codemoji/2, where a webapp Codeempji is available. With this webapp one can use emojis to scramble messages with a Caesar-cipher like method. This might be the reason for the emoji reference in the title text.[[Special:Contributions/162.158.85.147|162.158.85.147]] 09:58, 4 July 2016 (UTC)

A good addition could be that the passwords were most probably stored in plaintext, which is even worse. [[User:Jonsku99|Jonsku99]] ([[User talk:Jonsku99|talk]]) 12:30, 26 July 2016 (UTC)

1637: Salt Mine

2016-02-01T13:55:24Z

Jonsku99: /* Trivia */ It is 'particle detectors' not 'particle physics detectors'.

{{comic
| number = 1637
| date = February 1, 2016
| title = Salt Mine
| image = salt_mine.png
| titletext = This one is a little bland. Pass the saltshaker?
}}

==Explanation==
{{incomplete|This is a summary, not an explanation}}
Ponytail has built a particle detector in a salt mine. Hair Bun Girl assumes that this is to block out cosmic rays, as is the case with the real life the {{w|Irvine-Michigan-Brookhaven (detector)|Irvine-Michigan-Brookhaven detector}} (IMB), started in Lake Erie in 1979. Ponytail affirms Hair Bun Girl's assumption; however, based on the wording of her response, it is clear that Ponytail knows about Megan and Cueball's ulterior motives, which is eating salt in huge doses.

The IMB detector was initially used to search for proton decay in very pure water kept in the mine. Although the IMB became famous for detecting neutrinos from a supernova 1987a, it never observed a single proton decay out of 10^31 protons. At the time, even a single observation would have contributed to the Grand Unified Theory, predicting that protons eventually decay. In the comic, when Ponytail says "Yes, That's definitely why" it could refer to the large expectations that such detectors had promised.

The title text is intended to be absurd, and thus humorous. Salt is normally used to add flavor to otherwise bland foods. However, the "bland" food that the speaker is eating is itself a chunk of salt, and they wish to season their salt with yet more salt. The substance they are eating could be bland salt rock (a mixture of rock and salt in raw form resulting in a lower salt content).

==Transcript==
{{incomplete transcript}}
[Hair Bun Girl, Ponytail, Cueball, and Megan are in a salt mine. Cueball and Megan are eating salt, while Hair Bun Girl and Ponytail talk in front of what appears to be a control console for a particle detector.]

Hair Bun Girl: So you've built this particle detector in a salt mine to block out cosmic rays?

Ponytail: Yes. That is definitely why.

Cueball and Megan [eating salt]: Homf Nomf Nomf

==Trivia==
*In real life salt mines are also used for exotic restaurants, such as the 'Wieliczka' Salt Mine, in Poland - a use for mines which is more rare than particle detectors. The Wieliczka mine contains a complete bar, hardwood seating, and gourmet chefs located 125m below ground. Dishes are seasoned with Wieliczka salt mine salt, and is used liberally in the selections. In the comic, Cueball and Megan and show as possible employees of the particle detector, but are instead eating something with salt, which could be a humorous reference to the lack of proton decay results.

{{comic discussion}}

[[Category:Comics featuring Hair Bun Girl]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Science]]

1636: XKCD Stack

2016-02-01T13:50:20Z

Jonsku99: /* Explanation of steps */ I added that some websites can break if an adblocker is enabled.

{{comic
| number = 1636
| date = January 29, 2016
| title = XKCD Stack
| image = xkcd_stack.png
| titletext = This site requires Sun Java 6.0.0.1 (32-bit) or higher. You have Macromedia Java 7.3.8.1¾ (48-bit). Click here [link to java.com main page] to download an installer which will run fine but not really change anything.
}}

==Explanation==
{{incomplete|Needs more detail. The table is great but should be corrected to not refer to a person's view or feelings. ''I think'' phrases are used more than once at the moment.}}

In software engineering, a tech stack is the set of technology platforms and tools that a company or app uses. A common tech stack is {{w|LAMP (software bundle)|LAMP}}, composed of a {{w|Linux}} {{w|Operating system|operating system}}, an {{w|Apache HTTP Server|Apache}} {{w|Web server}}, a {{w|MySQL}} {{w|Database}}, and the {{w|PHP}} programming language. In this comic, the XKCD stack is introduced. The technologies comprising it are either non-existent, unreliable, or outdated.

===Explanation of steps===
{| class="wikitable"
| | Layer
| | Explanation
|-
| |
EBNF/CSS
| |
BNF or {{w|Backus–Naur Form}} is a syntax used for describing {{w|context-free grammars}}.
{{w|Extended Backus–Naur Form|EBNF}} is "Extended BNF", it is the same thing as BNF with a few more syntactic constructs intended to ease its use in the most common cases. [[1343: Manuals]] mentionned EBNF.

CSS or {{w|Cascading Style Sheets}} are a language used to describe what a web page should look like. Web pages are usually written in {{w|HTML}}, which describes the ''structure'' of the page (i.e. divides the document into paragraphs, lists, etc.) complemented with CSS which describes the ''look and feel'' of the page (colors, fonts, margins, etc.). EBNF/CSS would suggest CSS with strange syntax.
|-
| |
Broken Java Applet
| |
In recent years it has become more difficult to run {{w|Java (programming language)|Java}} {{w|Applet|applets}} in several browsers. {{w|Google Chrome|Chrome}} 45 stopped supporting {{w|NPAPI}}, {{w|Mozilla Firefox|Firefox}} will drop support by 2016, and {{w|Microsoft Edge|Edge}} does not support NPAPI plugins at all. Furthermore, two days before this comic was published {{w|Oracle Corporation|Oracle}} (the developer of Java) announced plans to officially end support of Java applets in an upcoming version.
|-
| |
Archive.org Mirror
| |
{{w|Internet Archive|Archive.org}} is a website which archives websites, and created the {{w|Wayback Machine}}. It's ambiguous whether the "Archive.org mirror" would be a copy of the xkcd server or of Archive.org itself.
|-
| |
Hypercard.js
| |
{{w|HyperCard}} can be considered as a kind of predecessor for the world wide web developed at {{w|Apple Inc.|Apple}}. The file extension .js indicates that is was rewritten in {{w|JavaScript}}. A similar reference to JavaScript is found in [[1508: Operating Systems]]. The .js extension also refers to node.js, where most library names end in .js
|-
| |
QBasic on Rails
| |
A mix between {{w|QBasic}} and {{w|Ruby on Rails}}. {{w|BASIC}} is a programming language that was very widespread during the 80s. QBasic is an implementation of BASIC created by Microsoft in early 90s, that, among other things, added support for {{w|structured programming}}. QBasic, lacking several of the things present on modern computer languages, is known for its spaghetti code. {{w|Ruby (programming language)|Ruby}} is a rather modern language, often used with Ruby on Rails web application {{w|Software framework |framework}}. QBasic on Rails would likely mean a port of Ruby on Rails, replacing Ruby with QBasic. QBasic no longer runs on modern computers, however there are a couple of free {{w|open source}} implementation of QBasic, one being [http://www.qb64.net/ QB64] and the other [http://www.freebasic.net/ FreeBASIC], which are available for Windows, Linux, Mac, and Android. There also exists a webserver on BASIC called [http://www.runbasic.com/ RunBasic].

|-
| |
[Blocked by AdBlocker]
| |
{{w|Ad blocking}} software are extensions to browsers that try to remove ads from web pages, so the user is not distracted by them. [[624: Branding]] shows what "browsing without adblock" looks like. The joke is that AdBlocker is preventing us from seeing what makes up this portion of the stack, or completely breaking it which happens to some websites which have integrated content false positively recognized as ads and blocked. Additionally, some websites insert advertisements in the middle of their lists and tables, so an AdBlocker would remove such advertisements, leaving a blank space in the middle of the table.
|-
| |
MongoDB/Excel
| |
{{w|MongoDB}} is a modern {{w|NoSQL}} {{w|Database|database}} system, {{w|Microsoft Excel}} is a {{w|Spreadsheet|spreadsheet}} program from Microsoft, which is sometimes misused as a database system.

|-
| |
Some piece that works so nobody asks any questions
| |
Writing any non-trivial piece of software always require a phase of {{w|debugging}}, which consists in finding and fixing {{w|Software bug|bugs}}. With complex software, this is a long and tiring process, so when the product is finally finished no one dares to modify it any further for fear that it will fail in unexpected ways. After some time passes, it is even worse because nobody really remembers how the software was ''supposed'' to work, so the product becomes some kind of godlike treasure which must be treated with the utmost respect and reverence because, you know, if it stops working we're all doomed ([[1421: Future Self]]). After completion, {{w|Refactoring}} is the process of rewriting code for greater efficiency or reliability. However, if the performance is not 'too bad' (i.e. not unusably terrible in normal use) there is a great temptation to avoid this, in favour of the 'if it ain't broke, don't fix it' methodology. This could lead, for example, to a trained monkey and an abacus being used to crunch numbers. It works, but could be done far better. However, nobody wishes to change it, for fear of breaking a presently functional, if inefficient, system.
|-
| |
Triply-Nested Docker
| |
{{w|Docker (software)|Docker}} is a {{w|Operating-system-level virtualization|software container}}, which is a way that allows a complete operating system to run under different operating system (OS) (as long they share the same kernel, among other things). Triply-nested docker would mean OS A running under OS B running under OS C running under OS D (running under OS E?). That would likely be a performance and management nightmare
|-
| |
Paravirtual Boy®
| |
This is a reference to the {{w|Virtual Boy}}, a failed portable console created by {{w|Nintendo}}. It was [https://www.youtube.com/watch?v=MKKK6FH1vGw promoted as being a highly immersive, incredible experience], but the poor technology that it used caused to be [https://youtu.be/OyVAp0tOk5A?t=56s very criticized] for not meeting the high expectations. {{w|Paravirtualization}} is a way of virtualization, that requires cooperation of the guest operating system, contrary of {{w|full virtualization}}, on which the guest operating system does not require to do anything special and the host handles everything.
|-
| |
A dev typing real <nowiki>[sic]</nowiki> fast
| |
A dev is a {{w|Software developer|software developer}}. This is possibly a reference to [[341: 1337: Part 1]], where [[Mrs. Roberts]] edits the {{w|Transmission Control Protocol|TCP}} stream live while wearing oven mitts and baking cookies. Such a feat would require really
fast typing. It looks like the xkcd Webserver is not a computer after all -- we have a person manually replying to HTTP protocol queries. Such a feat would indeed require real fast typing.

|-
| |
Older version of our software
| |
People are often reluctant to switch to newer versions of software because, even though newer versions are supposed to have more features and fewer bugs, they end up confusing users. Users of older versions are used to doing everything with less features and circumventing old bugs. They don't know how to use the new features, which of course come with new bugs they haven't learned how to circumvent yet. It is also often the case that newer versions remove weird unused old features, breaking the workflow of users who actually did use such features and are left without a suitable replacement ([[1172: Workflow]]). Alternately, since higher parts of a stack are dependent on lower parts, this could also be a reference to how the consumer versions of Microsoft Windows (3.x, 95, 98, and ME) ran on the "older version" software Microsoft DOS until Windows XP. Paired with the previous layer, it could instead mean that the human is merely retyping the output of the older version.
|-
| |
Mystery Networking Horror
| |
Randall suggests here that the whole networking stuff behind the XKCD service is both mysterious (no one actually knows the details) and horrific (technically questionable architecture and implementation, or somehow tentacled and eldritch in nature).
|-
| |
Microsoft Bob Server®
| |
{{w|Microsoft Bob}} was a short-lived, failed attempt by Microsoft, around 1995, to provide a user-friendly interface for the {{w|Microsoft Windows|Windows}} 3.1x, Windows 95 and Windows NT operating systems. It consisted of a virtual "house" and "rooms", and the idea was that you could click on a pen and open the word processor. It was heavily criticized and was soon discontinued. Randall seems to be making the suggestion the Bob has continued to be developed and now there's a Bob Server, similarly to Windows server.
|-
| |
A giant {{w|Central processing unit|CPU}} someone built in Minecraft
| |
{{w|Minecraft}} is a popular sandbox game where you place blocks to build things. Since the introduction of Redstone objects (materials used to create basic electric circuits within the game) people have made many machines within Minecraft, including calculators and clocks. The most complex of these machines simulate simple computers, capable of storing several lines of code and performing basic mathematical operations such as division, which requires thousands of blocks and extremely complex designs.
|}

The title text contains several jokes about the Java programming language:

* First, it refers to Java both as {{w|Sun Microsystems|Sun}} Java and {{w|Macromedia}} Java. This is a pun on the fact that older documents refer to "Sun Java" where newer documents refer to "{{w|Oracle Corporation|Oracle}} Java", as if there were two different languages. The fact is that Java was designed originally by Sun and then bought by Oracle, so it "changed name" even though the language is the same. Macromedia was the company that developed Flash before it was bought by Adobe. Both Flash and Java were popular in the early WWW to have interactive web pages, but both are being deprecated in favor of JavaScript.

* Second, the version numbers: older software products used to have two version numbers: major and minor (e.g. in {{w|MS-DOS}} 6.22 the major number is 6 and the minor is 22). Newer products tend to have hundreds of minor revisions, all of them numbered, so a typical user may well find themselves updating version 6.0.0.1 to 7.3.8.1 without knowing at all the differences between both versions or which other versions are in between. The ¾ in the Macromedia Java version is a joke on complex version numbers, which (so far) have never included fractions.

* Third, the 32-bit or 48-bit version: The {{w|Intel 80386}} processor used an architecture known as {{w|IA-32}}, which implies the data bus is 32-bit wide and thus able to handle up to 4{{w|Gibibyte|GiB}} of {{w|Random-access memory|RAM}} memory. This was plenty for the early 1990s, when a typical home PC would have about 8MiB (this is 512 times less than 4GiB). However, about 10 years after that, a typical home PC could well use more than 4GiB of RAM, so several 64-bit architectures were created. These architectures are not compatible, so programs (including the Java Runtime Environment, or JRE) often have 32-bit and 64-bit versions. Furthermore, the JRE is heavily used by many web browsers, and for this to work the JRE and browser need to be the same "number of bits". This means that most people have installed both versions of the JRE to be able to use it with both 32-bit and 64-bit browsers. There's no 48-bit architecture (though some 64-bit processors including the {{w|x86-64|most common ones}} don't actually use all 64 bits everywhere, ignoring some bits so actual virtual or physical memory is smaller (in the case of the most common ones, 48bits virtual and 40bits physical), they simulate a full 64-bit environment to allow adding more bits later, so there are no specific 48-bit applications).

* Fourth, an application trying to let the user install a new version of the JRE should direct the user to the download page in the [http://java.com/ java.com site], not to the main page which deals with lots of issues with java and is not particularly helpful when trying to update the JRE.

* Fifth, and continuing with the joke of users updating from 7.3.8.1¾ to 6.0.0.1 and not knowing why they should, the new version is said to "run fine but not really change anything". This is the usual behavior for Java updates: they run fine (possibly in opposition to [[1197: All Adobe Updates]], where updating must be done several times and the user is never sure they have installed all the newest updates), but after finished updating the user can't see any difference with the previous behavior, and/or may still be told that an update is required. Considering that 7.3.8.1¾ is bigger number than 6.0.0.1, it can also refer to the fact that the test for upgrading is incorrect and 7.3.8.1¾ is actually newer version.

* Sixth, Macromedia was a multimedia software company in the 90s that originally developed Flash, a popular plug-in similar to Java. Adobe purchased Macromedia in 2005.

==Transcript==

:Introducing

:The XKCD Stack
:{| class="wikitable"
| |
EBNF/CSS
|-
| |
Broken Java Applet
|-
| |
Archive.org Mirror
|-
| |
Hypercard.js
|-
| |
QBasic on Rails
|-
| |
[Blocked by AdBlocker]
|-
| |
MongoDB/Excel
|-
| |
Some piece that works so nobody asks any questions
|-
| |
Triply-Nested Docker
|-
| |
Paravirtual Boy®
|-
| |
A dev typing real fast
|-
| |
Older version of our software
|-
| |
Mystery Networking Horror
|-
| |
Microsoft Bob Server®
|-
| |
A giant CPU someone built in Minecraft
|}

{{comic discussion}}

[[Category:Computers]]
[[Category:Programming]]
[[Category:Video games]]