explain xkcd - User contributions [en]

2064: I'm a Car

2018-10-26T14:19:22Z

172.68.90.46: /* Explanation */ add alternative explanation

{{comic
| number = 2064
| date = October 26, 2018
| title = I'm a Car
| image = im_a_car.png
| titletext = I'm the proud parent of an honor student, and the person driving me is proud, too!
}}

==Explanation==
{{incomplete|Created by A PROUD CAR. Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}

This comic shows a car with a {{w|bumper sticker}}, which is generally a thin rectangle piece of piece of plastic with a message on one side and adhesive on the other side in order to stick to a car. This allows the owner of the car to display a message they want to present to whoever is driving behind them or in their vicinity. Bumper stickers are usually used to express a viewpoint, whether personal or political, held by the owner or driver of the car. This comic makes literal the ones that include or allude to the personal pronoun "I" and its variations, i.e. {{w|Grammatical_person|first person singular}} statements. Of course the intent is that "I" is referring to the person who put the bumper sticker on the car, but as the sticker is attached to the car the more literal interpretation is that "I" is referring to the car. So the humor is derived by the notion that the car itself is making these statements.

The bumper sticker on the car in the comic is a variation of a sticker used to both encourage people to vote, as well as express their political part preference: "I'm a ___, and I vote" (where the blank is traditionally filled in with Democrat or Republican or some other party). However here it is attributed to an automobile which is not capable of voting. Alternatively, the comic could be referring to the growing intelligence of self-driving cars, such that one day they might be able to vote. See ‘Sally’ by Isaac Asimov.

The title text seems to be another [https://www.positivepromotions.com/proud-parent-of-an-honor-student-bumper-sticker-personalization-available/p/os-3360/ typical message] on a bumper sticker, saying that the driver is a "Proud Parent Of An Honor Student". However, this sticker is a bit longer, since it continues to state that "the person driving me is proud, too". Thus once again it is the car who is the proud parent. And thus maybe it is a car that is the honor student?

Of course this comic is also another way to try to get people to register for voting, as the [[Design_of_xkcd.com#Header|header text]] at the top of the xkcd page has recently changed to "Check your registration and find your polling place at [https://www.vote.org/ vote.org]." This is because the {{w|United States midterm election}} will be held on {{w|United States elections, 2018|Tuesday, November 6, 2018}}, 11 days after the release of this comic. Randall has an interest in getting as many as possible to register, see [[1756: I'm With Her]], since he most likely thinks that it is important to use the right to vote.

==Transcript==
:[The bottom right rear end of a car is shown with a bumper sticker next to the unreadable license plate.]
:I'm a Car
:''and I vote''

==Trivia==
This is the third comic displaying a bumper sticker, after the comics [[80: My Other Car]] and [[1033: Formal Logic]] that came out in 2006 and 2012 respectively.

Bumper stickers also are mentioned as a future milestone for self-driving cars in [[1925: Self-Driving Car Milestones]].

{{comic discussion}}

[[Category:Politics]]

1986: River Border

2018-10-24T15:30:35Z

172.68.90.46: /* Explanation */ duh

{{comic
| number = 1986
| date = April 27, 2018
| title = River Border
| image = river_border.png
| titletext = I'm not a lawyer, but I believe zones like this are technically considered the high seas, so if you cut a pizza into a spiral there you could be charged with pieracy under marinaritime law.
}}

==Explanation==
[[Ponytail]] explains to [[Megan]] that the Missouri-Nebraska state border is based on the {{w|Missouri River}} they are watching. And because the path of rivers mostly only change slowly these borders are typically adopted to that changes. But then she explains that the river once had changed abruptly by a {{w|meander cutoff}} and the border didn't move with it. That means that they are on a part of the Missouri side of the river that in fact belongs to Nebraska.

It then occurred to Megan that she could break the law in this area because she is under the mistaken impression that she is in an unclaimed area. Alternatively, she might think that the police can't reach her over the river and Missourian cops actually don't have jurisdiction. In fact, there are no bridges linking it to Nebraska so police would have to go through Missouri in order to get to that part of Nebraska.

The final panel shows Megan saying she's going to cut a pizza into a spiral, which while unconventional is by no means illegal, and she runs off to commit more things she calls crimes, likely similar acts to cutting a pizza in an uncommon way.

In the title text, [[Randall]] claims/hypothesizes the disputed region is probably considered like the {{w|International waters|high seas}}, suggesting the pizza case would then fall under {{w|Admiralty law|maritime law}}. "Pieracy" is a portmanteau of ''pie'' (another name for a pizza) and "piracy"; and pizzas are frequently made with marinara sauce, so "Maritime" law is rendered "Marinaritime". This is most likely a reference to {{w|The Martian}}, in which it was noted that Mars is technically international waters as well.

The region mentioned in the comic can be seen here at [https://www.google.com/maps/@40.5270132,-95.6954944,10627m/ Google maps] and is known as {{w|McKissick Island}}. In 1904, the U.S. Supreme Court confirmed in Missouri v. Nebraska that a sudden change of a river's course does not change any border. See: [https://supreme.justia.com/cases/federal/us/196/23/case.html Missouri v. Nebraska, 196 U.S. 23 (1904)].

===Riverine Boundaries in Common Law and Surveying===
This strip is alluding to the concepts of 'accretion' and 'avulsion' in boundary law.

Accretion is the gradual change of the location of a river or stream by erosion or addition of sediment through natural river processes. According to common law in the United States and elsewhere, if a river or stream location changes gradually, then the boundary line moves with the stream. In cases of pure accretion, it is possible for a parcel of land to be entirely eroded away on one side of a river, and have material be added to the opposite side of the river. In such cases, one property owner could lose all their land.

Avulsion is a sudden change in the location of a river or stream, often due to flooding. In times of flood, a river can cut a new channel through surrounding land, which can create islands and oxbow lakes. According to common law, an avulsive change will not change the boundary of the land, as it is likely that the property is unchanged except for the new channel.

In the real world, however, river systems undergo both accretion and avulsion multiple times over a period of time. This makes the determination of property lines along riverine boundaries one of the most complicated aspects of boundary surveying. An examination of a river boundary will require in-depth research of the local history of the river, including reviewing deeds, government survey plats, private survey maps, aerial photos taken over time, local landowners recollections, and local lore. In situations where there is disagreement over whether an avulsive or accretive change happened, landowners may have to go to court for a suit to quiet title.

Further in-depth reading may be found in the US Bureau of Land Management's 2009 Manual of Surveying Instructions, Chapter 8, specifically page 197-205. (See: [https://www.blm.gov/sites/blm.gov/files/Manual_Of_Surveying_Instructions_2009.pdf PDF (37.7 MByte)].)

=== Real-world examples ===
Often, borders defined by a river actually change. There are three methods to define a border:
*The border follows one of the river banks, often in reference to a low-water mark. The exact location of the border is defined in a clear way - but one of the territories will lose terrain through {{w|erosion}}. When the river bends, erosion occurs at the outer bank, and much less at the inner bank.
*The border follows the middle of the river.
*The most usual definition of a riverine border uses the {{w|talweg}}. The talweg (German for "valley path") always follows the line of the deepest points in the water body. Especially at river bends, the talweg is rarely in the middle of the river. Incidentally, the talweg also signifies the navigable zone of a river. In terms of {{w|natural border}}s, one counterpart of a talweg is the {{w|drainage divide}}, but these divides are hard to recognize on a map and rarely used to define a real border.

The Mexican-US-Border that follows the Rio Grande is one of the most prominent examples of an international border that needs meticulous regulation. Thus, the {{w|International Boundary and Water Commission}} was created. This commission was involved when the two nations rectified the course of the river, ceding equal amounts of land to each other. The Canada-US-Border is overseen by a similar commission. There is also a strange section on the border to Canada, which Randall mentions in this comic: [[1902: State Borders]].

The border between Delaware and New Jersey veers from the median and talweg methods such that Delaware's border includes all the way to the New Jersey shore where the {{w|Delaware River}} is within what is known as the {{w|Twelve-Mile Circle}}.

One of the causes of the {{w|Iran-Iraq War}} was the dispute on shipping rights on the {{w|Shatt-el Arab river}}, and because the border was defined as the low water mark at the ''eastern'' side of that river, Iranian shipping was severely restricted. So the Shah of Persia announced to ignore the 1937 treaty on shipping rights, saying that most riverine borders all around the world are defined by the talweg.

Between Switzerland and Italy, the border is, at most locations, defined by the actual {{w|drainage divide}}. Because the {{w|Theodul Glacier}} between {{w|Zermatt}} (Switzerland) and {{w|Breuil-Cervinia}} (Italy) is slowly melting, the drainage divide moves southwards, thus slowly enlarging the Swiss territory.

Most other national borders in Europe are defined today as ''fiat borders'' instead of following natural landmarks like rivers. If a river changes course now, the depicted situation would occur; however, most larger rivers have been rectified more than a century ago and thus don't change course often.

==Transcript==
:[Ponytail and Megan are standing on a grassy river bank, with the nearby part of the river shown above their heads. They are looking towards te river and Ponytail is gesturing at the river with her hand.]
:Ponytail: This is a cool spot.
:Ponytail: The Missouri-Nebraska state line follows this river. If the river's path changes gradually, the border moves with it.

:[A map is shown beneath the text spoken by Ponytail (off-panel). The map includes a bendy river shown in gray which is snaking its way from the left part of the panel down to the bottom. A dotted line indicates the old path of the river. It follows the gray river most of the way, but towards the bottom this line moves away from the current river extending to north-east, including a large chunk of land that the river used to encompass previously. Two arrows point to the gray section of the river with the dotted line, and another arrow points to the section of the dotted line not following the gray section. Both are labeled. On each side of the dotted arc, where it is farthest from the gray part of the river the state names are labeled, so the text follows the direction of the river (almost noth to south here).]
:Ponytail (narrating): But when it '''''abruptly''''' changes course, the border stays behind.
:Ponytail (narrating): This is a spot where that happened. We're on the Missouri side, but we're in Nebraska.
:River
:Old riverbed
:Nebraska
:Missouri

:[In a frame-less panel (with no background) Ponytail has turned to look at Megan who is holding a hand to her chin.]
:Megan: Wow.
:Megan: So...
:Megan: We can commit all the crimes we want here and the cops can't do a thing!

:[Megan runs away from Ponytail while she is holding her arm up in the air with a finger extended up.]
:Ponytail: What? No. Why would you even think that?
:Megan: I'm going to cut a pizza into a '''''spiral!'''''
:Ponytail: That's not even illegal!
:Megan: '''''Crimes!'''''

{{comic discussion}}

[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Maps]]
[[Category:Geography]]

2061: Tectonics Game

2018-10-19T21:40:37Z

172.68.90.46: Added tiny explanation of large igneous provinces

{{comic
| number = 2061
| date = October 19, 2018
| title = Tectonics Game
| image = tectonics_game.png
| titletext = They're limiting the playtesters to type A3 V stars, so the games will all end before the Sun consumes the Earth.
}}

==Explanation==
{{incomplete|Written by a Tectonics Developer. Do NOT delete this tag too soon. What do L_T etc mean?}}

This comic is to show similarity to many simulation games, which have various niche popularity. Similar to Maxis' {{w|Spore_(2008_video_game)|Spore}}, the game in question allows you to terraform entire worlds. However, in a typical Randall twist, unlike most simulation games, you could not speed up the progress of time to make world-changing endeavours occur in a matter of seconds. The game operates in real time, which means most of the user time-frame will be spent idly watching nearly non-moving continents, drifting at the real speed of continental drift, a couple of inches a year, which makes for very slow gameplay. Thus several millennia of play time is needed to reach a game {{w|Achievement (video gaming)|achievement}} of forming a kilometre high mountain.

Many {{w|computer games}} {{w|simulate}} to one degree or another real items and tasks, but often simplify them to fit into a game format -- to make them more exciting, to make them quicker, to advance a particular plot line or quest, etc. For example, a game about farming might allow you to grow corn, but whereas in real life corn takes about 90 days to germinate from seed and grow to maturity, in a game the growth might be instantaneous or measured by minutes, rather than by days/weeks/months.

In this game, especially, one would expect such shortcuts, given the extreme time frames required for {{w|geological}} events to be manifested. The joke is that this game is so realistic that it's played in "real-time", which means for every second or hour or æon something would take in real life, in the game it would take the same second or hour or æon to happen. Playing such a game where the events take longer than the person would be alive would likely be unsatisfying.{{Citation_needed}} A mildly less extreme example of a simulation game being played in real-time would be the {{w|Penn_%26_Teller%27s_Smoke_and_Mirrors#Desert_Bus|Desert Bus}} video game where you have to drive a bus from Tucson, Arizona, to Las Vegas, Nevada, in real time at a maximum speed of 45 MPH. The trip requires eight hours of continuous play to complete, at which point you score one point with the option to continue playing for additional points at the rate of one point per successful eight hour trip. The action consists almost entirely of just keeping the bus from veering off the road. It cannot be paused or sped up, and failure requires a tow back to the starting point at the same 45 MPH speed.

The frames show some elements of gameplay. The first frame shows a destructive plate margin in which an oceanic plate (grey) is being subducted under a continental plate (brown with a person standing on it) while sediments between the plates are compressed to form mountains. Clockwise from top left, the second frame shows: a cross section through the planet, Various statistics about the planet (CO2 levels of 840 ppm, solar irradiation of 1184 W/m2 and heat-flow through the crust of 91 mW/m2). Solar irradiation and heat-flow are similar to the Earth, but CO2 levels are raised. Bottom right is several stats titled LT and bottom left is a view of the planet showing the proportion covered by ice (3%) land (31%) and water (66%). It seems that the raised CO2 levels have reduced the amount of ice compared to the Earth. The final panel shows some of the achievements that can be unlocked, the first is 1 km mountain. Below that seems to be achievements in the formation of an atoll.

Large igneous provinces are suspected to be related to extinction level events and rapid climate changes in real life. Thus, they 'are the worst' in this game.

Type A3V stars are white main sequence stars. They have a shorter lifespan than the sun, hundreds of millions of years, compared to the 10 billion years lifespan of the sun. By starting the game now with an A3V star, there would be time to complete the game before the sun becomes a red giant and destroys the Earth.

This comic's number and content regarding simulations in real time may also be a reference to {{w|Arthur_C._Clarke|Arthur C. Clarke}}'s {{w|2061:_Odyssey_Three|2061: Odyssey Three}}, the third book in the {{w|Space_Odyssey|Space Odyssey}} series, in which {{w|Monolith_(Space_Odyssey)|monoliths}} are left throughout the solar system, manipulating environments to encourage the evolution of intelligent life.

==Transcript==
{{incomplete transcript}}
:[Cueball is standing behind Ponytail, who is sitting on the floor playing a video game on a TV which displays a diagram of tectonic plates.]
:Cueball: What game is that?
:Ponytail: ''Tectonics''!
:Ponytail: You steer chunks of crust around, rifting, subducting, and building and eroding mountains.

:[A view of the game screen is shown. It includes a large cross-section of the Earth with smaller charts around it.]
:Ponytail: You try to keep your climate stable and your biosphere rich. Avoid making large igneous provinces! They're the ''worst''.

:[Cueball holds his hand out.]
:Cueball: Cool!
:Cueball: Can I try?
:Ponytail: Sure!

:[Cueball plays the game.]
:Cueball: ...How do I unpause?
:Ponytail: It's not paused.
:Cueball: ...
:Ponytail: Continents can only move a few inches per year.

:[Cueball holds the controller in one hand, now uninterested in the game. The screen shows an achievement page with nothing completed.]
:Cueball: It's ''real-time''?
:Ponytail: Just 400 millennia to go until your first mountain achievement!

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Science]]
[[Category:Video games]]

1957: 2018 CVE List

2018-10-11T13:02:59Z

172.68.90.46: /* Explanation */

{{comic
| number = 1957
| date = February 19, 2018
| title = 2018 CVE List
| image = 2018_cve_list.png
| titletext = CVE-2018-?????: It turns out Bruce Schneier is just two mischevious kids in a trenchcoat.
}}

==Explanation==

{{w|Common Vulnerabilities and Exposures|CVE}} (Common Vulnerabilities and Exposures) is a standardized format for assigning an identity to a cybersecurity vulnerability (similar to the way that astronomical bodies are assigned unique identifiers by committees). Giving vulnerabilities a unique identifier makes them easier to talk about and helps in keeping track of the progress made toward resolving them. The typical format of a CVE identifier is '''CVE-[YEAR]-[NUMBER]'''. For example, the CVE identifier for 2017's widespread {{w|Meltdown (security vulnerability)|Meltdown vulnerability}} is [https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5754 CVE-2017-5754]. CVEs also contain a short description of the issue.

In this comic (released in February 2018), Randall presents a number of spurious predicted CVEs for later in 2018. Each CVE identifier is given as "CVE-2018-?????", reflecting the fact that they have not yet happened so we don't know exactly what their CVE identifier will be.

Following are short descriptions of all the ''vulnerabilities'' mentioned in the comic.

;Apple products crash when displaying certain {{w|Telugu language|Telugu}} or {{w|Bengali language|Bengali}} letter combinations.
:This refers to a real vulnerability in iOS and MacOS publicized a few days before the comic was released,<ref>https://techcrunch.com/2018/02/15/iphone-text-bomb-ios-mac-crash-apple/</ref> as well as past similar iOS vulnerabilities<ref>https://thenextweb.com/apps/2017/01/18/iphone-ipad-apple-text-ios-bug/</ref><ref>http://www.telegraph.co.uk/technology/2018/01/18/apple-text-bomb-can-crash-iphones-single-message/</ref>.
;An attacker can use a timing attack to extploit [''sic''] a race condition in {{w|Garbage collection (computer science)|garbage collection}} to extract a limited number of bits from the Wikipedia article on Claude Shannon.
:The reference to using a Timing Attack to exploit a race condition in garbage collection refers to Meltdown and Spectre CPU flaws that can be exploited in a cloud server like the ones in Wikipedia. {{w|Claude Shannon}} was an early and highly influential information scientist whose work underlies compression, encryption, security, and the theory behind how information is encoded into binary digits.
:
:This is not a security problem. However, since Shannon formulated how the amount of unique or actual information some entity contains is proportional to the number of bits required to encode it, retrieving only a few bits casts a dark perspective upon the significance of the Shannon article's content.
;At the cafe on Third Street, the Post-it note with the WiFi password is visible from the sidewalk.
:Cafés often offer free access to WiFi as a service to patrons, as a business strategy to encourage said patrons to remain in the building and buy more coffee. Some use a password, so that only patrons can use the WiFi, and may display the password on signage inside. Since anybody could go into the cafe to read the post-it, and then use the network from nearby, the ability to read it from outside is, at most, a trivial problem. For systems that are supposed to be secure, writing passwords in a visible place is a major security flaw. For instance, following the [[wikipedia:2018 Hawaii false missile alert|2018 Hawaii false missile alert]], the agency concerned received criticism for a press photo showing a password written on a sticky note attached to a monitor.<ref>http://uk.businessinsider.com/hawaii-emergency-agency-password-discovered-in-photo-sparks-security-criticism-2018-1?r=US&IR=T</ref>
;A remote attacker can inject arbitrary text into public-facing pages via the comments box.
:Describes a common feature on news sites or social media sites like Facebook. The possibility for users to "inject" text into the page is by design. This is a humorous reference to the relatively common security vulnerability "[[Wikipedia:Cross-site_scripting|persistent cross-site scripting]]", where input provided by a user, such as through a comment section, can result in dangerous content containing arbitrary HTML or JavaScript code being displayed to other users.
;MySQL server 5.5.45 secretly runs two parallel databases for people who say "S-Q-L" and "sequel."
:Some people pronounce "{{w|SQL}}" like "sequel", after SQL's predecessor "SEQUEL (Structured English Query Language)". The standard for SQL suggests that it should be pronounced as separate letters; however, the author of SQL pronounces it "sequel", so the debate is persisting (with even more justification than arguments about how to pronounce "GIF"). MySQL is an open-source relational database management system. The latest generally available version (at the time of writing) is MySQL 5.7.
;A flaw in some x86 CPUs could allow a root user to de-escalate to normal account privileges.
:{{w|Privilege escalation}} refers to any illegitimate means by which a system user gains greater access than they are supposed to have, and most hackers will seek to achieve this if they can. The most highly-sought privilege is that of the root user, which allows complete access to an entire system— a ''superuser''.
:
:The irony of this CVE presents the reverse situation: that a flaw inadvertently ''de-escalates'' a root user to a less privileged user, which would cripple the ''superuser'', they would be disallowed access or ability to accomplish their required tasks, or worse, cause such tasks which do not {{w|fail safe}} to have catastrophic side effects.
;Apple products catch fire when displaying emoji with diacritics.
:This is a reference to a common problem of modern gadgets catching fire (usually related to flaws in lithium-ion batteries), as well as to Apple products crashing when attempting to display certain character sequences. Diacritics are the accents found on letters in some languages (eg. č, ģ ķ, ļ, ņ, š, ž). These would not normally be found on emojis. ⌛️́ is an example of such an emoji.
;An oversight in the rules allows a dog to join a basketball team.
:This probably refers to the movie {{w|Air Bud}}, about a dog playing basketball. This has been a common theme in xkcd comics: see [[115: Meerkat]], [[1439: Rack Unit]], [[1819: Sweet 16]], [[1552: Rulebook]].
:In 2017, it was discovered that an oversight in the constitution of the state of Kansas may [http://www.kansascity.com/news/politics-government/article175956836.html permit a dog to be governor]. Shortly before this comic published, the Secretary of State's office ruled that [http://dfw.cbslocal.com/2018/02/13/dog-kansas-governor/ it could not].
;Haskell isn't side-effect-free after all; the effects are all just concentrated in this one computer in Missouri that no one's checked on in a while.
:{{w|Haskell (programming language)|Haskell}} is a functional programming language. Functional programming is characterized by using functions that don't have side effects because they can not change things accessible in other parts of the program, as in [[1312: Haskell]]. The joke here is discovering that it does indeed have side-effects, manifested via external alteration, not violating the internal alteration paradigm.
;Nobody really knows how hypervisors work.
:[[wikipedia:Hypervisor|"Hypervisors"]] are a tool for computer virtualization. Virtualization is implemented via various combinations of hardware and/or software, which requires a computer to completely simulate another computer, with its own unique hardware and software, and to varying degrees as to whether or not the virtualization is aware of or can determine whether it is being virtualized. Many IT professionals and businesses rely heavily on various forms of virtualization, but most of the individual employees would be hard-pressed to explain how it works. Programs running on other virtual computers, or on the real computer, may be able to access information on a virtual computer in ways which would not be possible with a single real computer. Consequently, understanding how the hypervisor works is important to assessing the security of a virtual server. Meltdown and Spectre are related to this.
;Critical: Under Linux 3.14.8 on System/390 in a UTC+14 time zone, a local user could potentially use a buffer overflow to change another user's default system clock from 12-hour to 24-hour.
:This joke is about arcane systems that are running Linux in exceedingly rare situations, meaning that reproducing errors would be incredibly difficult or inconvenient, and would only affect a very tiny user base (if any at all). {{w|IBM System/390 ES/9000 Enterprise Systems Architecture ESA family|System/390}} is an IBM mainframe introduced almost 30 years before this comic, which has a version of Linux. UTC+14 is a time zone used only on some islands in the Pacific Ocean (Primarily [[Wikipedia:Line_Islands|the Line Islands]]) and is also the earliest time zone on earth. Even if all of these absurd conditions were met, the resulting vulnerability would still be relatively benign: simply changing a user's preferred clock display format. Other xkcd comics make references to such obscure computer-time issues relating to time zones and time conversions, and how many programmers find these issues frustrating or even traumatizing.
;x86 has way too many instructions.
:The x86 architecture (used in many Intel and AMD processors) is very complicated. Processors typically implement such a complex architecture using programs (microcode) run on a set of hidden, proprietary processors. The details of these hidden machines and errors in the microcode can result in security vulnerabilities, such as Meltdown, where the physical machine does not match the conceptual machine.
:
:A more complicated instruction set is more complex to implement.{{Citation needed}} The x86 architecture is considered "CISC" (a "{{w|Complex instruction set computer}}"), having many instructions originally provided to make programming by a human simpler; other examples include the 68000 series used in the first {{w|Apple Macintosh}}. In the 1980s, this design philosophy was countered by the "RISC" ("{{w|Reduced instruction set computer}}") design movement - based on the observation that computer programs were increasingly generated by compilers (which only used a few instructions) rather than directly by people, and that the chip area dedicated to extra instructions could be better dedicated to, for example, cache. Examples of RISC style designs include {{w|SPARC}}, {{w|MIPS}}, {{w|PowerPC}} (used by Apple in later Macintoshes) and the {{w|ARM architecture|ARM}} chips common in mobile phones. Historically, there was considerable discussion about the merits of each approach. At one time the Mac and Windows PC were on different sides; owners of other competing systems such as the Archimedes and Amiga had similar arguments on usenet in the early 1990s. This "issue" may be posted by someone who still recalls these debates. Technically, the extra instructions do slightly complicate the task of validating correct chip behaviour and complicate the tool chains that manage software, which could be seen as a minor security risk. However, the 64-bit architecture introduced by {{w|AMD}}, and since adopted by {{w|Intel}}, does rationalise things somewhat, and all recent x86 chips break down instructions into RISC-like micro-operations, so the complication from a hardware perspective is localised. Recent security issues, such as the speculative cache load issue in Meltdown and Spectre, depend more on details of implementation, rather than instruction set, and have been exhibited both by x86 (CISC) and ARM (RISC) processors.
:
:This explanation has way too many words.
;NumPy 1.8.0 can factor primes in ''O''(log ''n'') time and must be quietly deprecated before anyone notices.
:Fantastically, this would be an unimaginable software threat, not to be confused with the even speedier, but future-bound, threat in hardware via {{w|Quantum computing}}.
:NumPy is the fundamental package for scientific computing with the programming language Python. ''O''(log ''n'') is [[wikipedia:Big_O_notation#Infinite_asymptotics|Big O notation]] meaning that the time it takes for a computer algorithm to run is in the order of log ''n'', for an input of size ''n''. ''O''(log ''n'') is very fast and is more usual for a search algorithm. Prime factorization currently is ''O''(''2''''n''n)). If something can find the prime factors of a number this quickly, especially a [[wikipedia:semiprime|semiprime]] with two large factors, it will enable attacks to break many crypto functions used in internet security. However, prime numbers have only a single factor, and "factoring primes" quickly is a simpler problem, that of [[wikipedia:Primality test|proving that a number is in fact a prime]].
;Apple products grant remote access if you send them words that break the "I before E" rule.
:Another joke on the first CVE and [[wikipedia:I before E except after C|a common English writing rule of thumb]], which fails almost as often as it succeeds. Possibly a jab at Apple's image, portraying their software as unable to handle improper grammar or spelling.
;Skylake x86 chips can be pried from their sockets using certain flathead screwdrivers.
:Skylake x86 chips are a line of microprocessors made by Intel. Some processors are soldered directly to a system board or daughter board, while others are attached to boards that plug into the system board by means of a socket (pins or connectors that make physical contact with receptacles or connectors on a system board). Some sockets, especially older ones, require force to insert or remove, and often require the use of a flat blade screwdriver or a specialized tool, but most modern ones use ZIF (Zero Insertion Force) techniques, often involving a lever or similar to tighten or loosen the friction/tightness of the contacts. No screwdriver is needed in this case. However, any processor ''can'' be forcefully removed from its socket with a screwdriver.{{Citation needed}}
;Apparently Linus Torvalds can be bribed pretty easily.
:{{w|Linus Torvalds}} is the {{w|benevolent dictator for life}} of the Linux kernel codebase. Normally it is hard to make changes because he has the last word, and because the kernel is replicated in all Linux installations. Linus made the news in January 2018 when, having looked at one of Intel's proposed fixes for the Spectre and Meltdown vulnerabilities, he declared "the patches are COMPLETE AND UTTER GARBAGE".<ref>https://techcrunch.com/2018/01/22/linus-torvalds-declares-intel-fix-for-meltdown-spectre-complete-and-utter-garbage/</ref> Presumably, it may be found that he may be successfully bribed to be less blunt and/or less critical of vulnerability fixes that are complete and/or utter garbage. If this were the case, this would be a severe critical vulnerability to all Linux servers and machines.
;An attacker can execute malicious code on their own machine and no one can stop them.
:The point of an attack is to make someone else's machine perform actions against the owner's will. Anyone can make their own machine execute any code if they have root access and the necessary tools, but this would usually not be described as an attack, except in the case of a locked-down appliance, such as a video game console, a John Deere tractor, or pay TV decoder.
;Apple products execute any code printed over a photo of a dog with a saddle and a baby riding it.
:This could refer to a CVE vulnerability of JPG files where JavaScript embedded within the image file is executed by some application. In this case, though, the code is visible on the image instead of invisibly encoded within the image file. The code is also only executed if the image contains a photo of a baby in a saddle riding a dog. It's unclear whether the photo would be a digital photo, a printed photo (i.e. as taken using a digital camera), or maybe both.
:Other than by some {{w|metadata}}, either internal to the image file, or embedded along with it, as in a web page, or a PDF or other container file, this "bug" would require the device to {{w|Hard AI|figure out}} specifically what the photo contains image-wise (something that's REALLY HARD for computers to do reliably), but would also require OCR (optical character recognition) code to convert the text superimposed on the photo into executable code. In other words, it's hard to believe in 2018 that such a bug could exist. Maybe in the future when such things are more routine...? As an example, OCR used to be hard to do reliably, but now it's a lot more routine and built into a lot of devices.
;Under rare circumstances, a flaw in some versions of Windows could allow Flash to be installed.
:Flash has been an integral browser plugin for decades, but has fallen out of favor in the 2010s, and eventually discontinued because of its notoriously abysmal security record. All security experts advise against installing it. Preventing installation of Flash would make systems more secure, but most versions of Windows do not prevent Flash installation. The joke here relates to the difficulty of keeping Flash up to date, or even installed properly to begin with. A common user experience, which is the subject of numerous jokes and memes, is the constant nagging notification to install or update Flash in order for web pages to display properly. Many IT professionals will bemoan the trouble they have experienced in the workplace due to these notifications and problems related to them.
;Turns out the cloud is just other people's computers.
:This refers to a meme that demands that "cloud" be replaced with "other people's computers" in all marketing presentation to CEOs and non-computer literate persons evaluating the security impact of using cloud services. Part of the humor here is that "the cloud" is, in actuality, simply a term for hosted services, or in other words computers being run by other people (typically businesses that specialize in this type of "{{w|Platform as a Service}}" or "PaaS" service model). Referring to "the cloud" as "other people's computers" is, at its core, entirely accurate, though it takes away the business jargon and simplifies the situation in such a way that it might cast doubt on the security, reliability, and general effectiveness of using "cloud" solutions.
;A flaw in Mitre's CVE database allows arbitrary code insertion.[[779|[~~CLICK HERE FOR CHEAP VIAGRA~~]]]
:Mitre's CVE database is where all {{w|Common Vulnerabilities and Exposures|CVEs}} are stored. This log message forms the punchline of the comic, as it implies that all of the exaggerated error messages above might have been inserted by hackers exploiting the vulnerability. To pour salt in the wound, they then included in a typical spam link purporting to offer inexpensive {{w|Viagra|brand-name Sildenafil}}.
;It turns out Bruce Schneier is just two mischevious kids in a trenchcoat.
:Appears in the title text. {{w|Bruce Schneier}} is security researcher and blogger. The "two kids in a trenchcoat" is a reference to the {{tvtropes|TotemPoleTrench|Totem Pole Trench}} trope. Shortly before this comic was posted, a [https://rare.us/rare-humor/two-kids-dressed-as-a-tall-man-to-get-into-black-panther-is-caught-on-video story went viral] in which two kids were photographed attempting this for real to get into a screening of ''Black Panther''.

== References ==
<references/>

==Transcript==
:[A heading is centered above a list of 21 vulnerabilities]
:<big>Leaked list of major 2018 security vulnerabilities </big>

:CVE-2018-????? Apple products crash when displaying certain Telugu or Bengali letter combinations.
:CVE-2018-????? An attacker can use a timing attack to extploit a race condition in garbage collection to extract a limited number of bits from the Wikipedia article on Claude Shannon.
:CVE-2018-????? At the cafe on Third Street, the Post-it note with the WiFi password is visible from the sidewalk.
:CVE-2018-????? A remote attacker can inject arbitrary text into public-facing pages via the comments box.
:CVE-2018-????? MySQL server 5.5.45 secretly runs two parallel databases for people who say "S-Q-L" and "sequel."
:CVE-2018-????? A flaw in some x86 CPUs could allow a root user to de-escalate to normal account privileges.
:CVE-2018-????? Apple products catch fire when displaying emoji with diacritics.
:CVE-2018-????? An oversight in the rules allows a dog to join a basketball team.
:CVE-2018-????? Haskell isn't side-effect-free after all; the effects are all just concentrated in this one. computer in Missouri that no one's checked on in a while.
:CVE-2018-????? Nobody really knows how hypervisors work.
:CVE-2018-????? Critical: Under Linux 3.14.8 on System/390 in a UTC+14 time zone, a local user could potentially use a buffer overflow to change another user's default system clock from 12-hour to 24-hour.
:CVE-2018-????? x86 has way too many instructions.
:CVE-2018-????? NumPy 1.8.0 can factor primes in ''O''(log ''n'') time and must be quietly deprecated before anyone notices.
:CVE-2018-????? Apple products grant remote access if you send them words that break the "I before E" rule.
:CVE-2018-????? Skylake x86 chips can be pried from their sockets using certain flathead screwdrivers.
:CVE-2018-????? Apparently Linus Torvalds can be bribed pretty easily.
:CVE-2018-????? An attacker can execute malicious code on their own machine and no one can stop them.
:CVE-2018-????? Apple products execute any code printed over a photo of a dog with a saddle and a baby riding it.
:CVE-2018-????? Under rare circumstances, a flaw in some versions of Windows could allow Flash to be installed.
:CVE-2018-????? Turns out the cloud is just other people's computers.
:CVE-2018-????? A flaw in Mitre's CVE database allows arbitrary code insertion.[~~Click here for cheap viagra~~]

==Trivia==

Randall has previously referenced diacritics in [[1647: Diacritics]].

Bruce Schneier was previously mentioned in the title texts of [[748: Worst-Case Scenario]] and [[1039: RuBisCO]].

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Charts]]
[[Category:Programming]]
[[Category:Computers]]

2001: Clickbait-Corrected p-Value

2018-09-29T13:57:09Z

172.68.90.46: /* Explanation */

{{comic
| number = 2001
| date = June 1, 2018
| title = Clickbait-Corrected p-Value
| image = clickbait_corrected_p_value.png
| titletext = When comparing hypotheses with Bayesian methods, the similar 'clickbayes factor' can account for some harder-to-quantify priors.
}}

==Explanation==
{{incomplete|Click here to learn more about the influence of Clickbait... But please first explain p-value. Most people don't know. And more wiki links.}}
This is yet another comic dealing with [[:Category:Clickbait|Clickbait]], and is satire mocking researchers/journalists/publishers for fudging research data based on what brings in the most advertising revenue. The topic of fudging research data in academia has also previously appeared in [[882: Significant]] and [[1478: P-Values]].

Clickbait is the practice of using deceptive or manipulative headlines to entice readers to click on a dubious news story, often with the purpose of generating ad revenue.

Hypothesis testing in statistics is a standard method to determine whether a particular hypothesis is supported by the data. For the topic given in this comic, a researcher might compare data on athletic performance with data on chocolate consumption by those athletes to determine whether the two trend together. By convention, the "null hypothesis" (designated H0) is that there's no correlation (that chocolate isn't correlated with athletic performance, in this case) and the "alternate hypothesis" (H1) is that they are correlated. (If the study consists of ''feeding'' chocolate to one of two identical groups and not the other, rather than tracking what they'd be eating anyway, then the alternative hypothesis can be strengthened to be that chocolate *causes* improved performance.) These sets are subjected to statistical tests which return a "p-value", which indicates the probability of observing the obtained results (or any more extreme value), when all assumptions of the test are true (including the null hypothesis). In layman's terms: the p-value is the probability that the researcher sees results as extreme or more extreme than the observed result given the null hypothesis is true; [http://www.perfendo.org/docs/BayesProbability/twelvePvaluemisconceptions.pdf the p-value is NOT the probability that the null hypothesis is correct]. Hence, if the p-value is low enough, the null hypothesis is rejected, and we conclude that the alternate hypothesis is supported by the data.

In this comic, the p-value is corrected by a factor that takes clickbait into account. This factor has the effect of increasing the p-value if H1 is more clickbaity than H0, and decreases the p-value if H0 is more clickbaity than H1. This suggests that whatever clickers of clickbait believe, the reverse is likely to be true.

Or, another interpretation could be that this factor corrects for a selection bias effect where the p-values for more clickbaity H1s tend to be lower than they should be and p-values for non-clickbaity H0s to be higher than they should be. For example, one explanation could be that for p-values that are on the cusp of significance, researchers may be more incentivized to fudge and adjust the data to get the p-value down if the H1 is highly sensational, since the H1 would make the research more likely to get published and attract attention. (See also [https://fivethirtyeight.com/features/science-isnt-broken/ FiveThirtyEight's article on p-hacking] and [https://stats.stackexchange.com/questions/200745/how-much-do-we-know-about-p-hacking-in-the-wild/200752#200752 this Stack Exchange question about p-hacking in the wild].)

As the statistical results now depend on people's beliefs about the hypothesis, this is as far from actual science as one can get. However, in a way, it is more in tune with a quote by Arbuthnot (one of the originators of the use of p-values) attributing variation to active thought rather than chance, "From whence it follows, that it is Art, not Chance, that governs." Randall applying that quote to the thoughts of the masses, bringing it in line with "Art".

[[1475: Technically|Technically]], the comic's depiction of null and alternative hypotheses is not entirely correct. As the alternative hypothesis (H1) predicts that chocolate will ''improve performance'' (i.e., a one-tailed, directional hypothesis), the null hypothesis (H0) should predict that chocolate will do nothing ''or'' make performance worse. In other words, the alternative hypothesis should be true if and only if the null hypothesis is false. For example, alternatively, if the H1 were to say that ''chocolate will change performance'' (for better or worse; i.e., a two-tailed hypothesis) then H0 should say that ''chocolate will do nothing''.

For the mouseover text: Bayesian methods start with a "prior", which is the probabilities believed before seeing new evidence (e.g. before conducting an experiment). Time spent reading clickbait would probably cause people to have unusual beliefs about what is likely before seeing evidence.

==Transcript==
:[Under a heading that says Clickbait-Corrected p-Value there is a mathematic formula. Below that is the description of the two used variables and what they mean:]
:Clickbait-corrected p-value:

:PCL = Ptraditional ∙ click(H1)/click(H0)

:H0: NULL hypothesis ("Chocolate has no effect on athletic performance")
:H1: Alternative hypothesis ("Chocolate boosts athletic performance")
:click(H): Fraction of test subjects who click on a headline announcing that H is true

{{comic discussion}}

[[Category:Clickbait]]
[[Category:Statistics]]

2050: 6/6 Time

2018-09-24T16:18:20Z

172.68.90.46: Category

{{comic
| number = 2050
| date = September 24, 2018
| title = 6/6 Time
| image = 6_6_time.png
| titletext = You know how einstein figured out that the speed of light was constant, and everything else had to change for consistency? My theory is like his, except not smart or good.
}}

The original image has a link to a previous comic [https://xkcd.com/1061/ 1061: EST] which is explained [[1061: EST|here]].

==Explanation==
{{incomplete|Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
Cueball: Under my time system, the sun rises at 6 am and it sets at 6 pm, as it SHOULD.

Cueball: The length of the second is different each day and night, and the current time shifts with your latitude and longitude.

Cueball: Today is one of the two days each year when my clocks run at the same speed as everyone else's.

Caption: Time standards are so unfixably messy and complicated that at this point my impulse is just to try to make them worse.
{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Physics]]
[[Category:Astronomy]]
[[Category:Time]]

1927: Tinder

2017-12-11T23:10:31Z

172.68.90.46: very unlikely this is a using-cell-phone-while-flying problem

{{comic
| number = 1927
| date = December 11, 2017
| title = Tinder
| image = tinder.png
| titletext = People keep telling me to use the radio but I really hate making voice calls.
}}

==Explanation==
{{incomplete|Do NOT delete this tag too soon.}}

{{w|Tinder (app)|Tinder}} is a social media/dating app. The main interface of Tinder shows photos of people using the app. Users swipe right for matches that they like, and left otherwise. The purpose of the app is to get dates, with the intent of a romantic relationship or sexual intercourse. However, in the comic, [[Cueball]] is trying to use it to get assistance flying a plane instead. This is bad, because it suggests Cueball is in charge of a plane he is unable to fly, and unless someone on board can fly, and matches with him, the plane will crash.

The title text implies that Cueball is doing this because he finds it annoying to use the plane's radio, which he finds too similar to making a phone call. The joke is about his bad priorities in using an ill-suited app which would be slower than asking for help on the radio. He is endangering the life of himself and any possble passengers, just to avoid the annoyance of having to talk on the phone.

This comic is similar to [[1897: Self Driving]], and as well as [[582: Brakes]], which also is about bad ways to get help in emergencies.

==Transcript==

:[An iPhone-esque device is shown with the screen facing the viewer. On the screen is the Tinder UI. The main photo is of Cueball, in the cockpit of a plane which appears to be tilting to the left, holding up a sign saying:]
:If you know how
:to fly a plane
:please swipe
:right ASAP

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Social networking]]

Talk:1791: Telescopes: Refractor vs Reflector

2017-01-31T01:48:47Z

172.68.90.46:

Nitpick: The refracting telescope, drawn correctly, has a mirror in the optical path (image inverter), but it is made with a special vampire reflecting material Ichorium. {{unsigned ip|162.158.74.219}}
:Doesn't the one in this image have a mirror too? at the bottom to make the image come out at the side instead of the end? [[Special:Contributions/162.158.89.187|162.158.89.187]]

That's a good point: as drawn, the refracting telescope still has a mirror and also wouldn't be able to see space vampires. However, the refracting telescope doesn't have to have a secondary mirror, and there are plenty that don't, so it is more the drawing that is wrong rather than the text of the comic.[[User:Cmancone|Cmancone]] ([[User talk:Cmancone|talk]]) 14:31, 27 January 2017 (UTC)

Typically refractors use a prism rather than a mirror at the end, though it does the same thing. Can vampires be seen in a prism? [[Special:Contributions/108.162.241.172|108.162.241.172]] 14:50, 27 January 2017 (UTC)
:Only if they're pink. [[Special:Contributions/162.158.74.219|162.158.74.219]] 14:57, 27 January 2017 (UTC)

Every time I press submit, it blocks me and makes me start over. Kynde, rather than making a small change every 30 seconds, perhaps you could do them all at once? -- [[User:Frankie|Frankie]] ([[User talk:Frankie|talk]]) 15:26, 27 January 2017 (UTC)
:Well I'm sorry, I had the same problem as you. So I did not dare read it all through before I submitted, and thus so tried to fix the errors I found afterwards. That was also why I did not make the section for the real problems a subsection to the explanation so it (as the transcript) could be edited without conflicting with the other sections. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 15:30, 27 January 2017 (UTC)
::Ah, it's {{w|network congestion}}. Sending small packets more quickly is indeed one way to get your message through, but it can lead to a tragedy of the commons. Everyone switching to larger packets is the optimal answer, but it's not a stable equilibrium. -- [[User:Frankie|Frankie]] ([[User talk:Frankie|talk]]) 15:39, 27 January 2017 (UTC)
Does anybody on the wiki HAVE a major in optics???? At least anybody who will see this page before MONDAY, when it will no longer be the latest??? [[User:Jacky720|That's right, Jacky720 just signed this]] ([[User talk:Jacky720|talk]] | [[Special:Contributions/Jacky720|contribs]]) 15:54, 27 January 2017 (UTC)

A telescope mirror typically would have no chromatic aberration, as it's a front-surface mirror. The light doesn't pass through the glass to get to the reflective material; the glass is on the back of the mirror for support. [[Special:Contributions/162.158.62.129|162.158.62.129]] 16:15, 27 January 2017 (UTC)

I think where the commentary says "This means most reflector telescopes make do with narrow apertures" it should be "refractor telescopes". [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 16:18, 27 January 2017 (UTC)

FYI: Randall updated the comic, so that the refracting telescope doesn't have a mirror.--[[Special:Contributions/162.158.74.111|162.158.74.111]] 16:59, 27 January 2017 (UTC)

I would think that the main reason for Refractors over Reflectors is that it would be easier to make one with adjustable focus, so you would not need to wear glasses and – more importantly – you might be able to use the telescope as a binocular for things like birds. I don't know of any Reflectors with a significant adjustable focus, but I'm not an astronomer either. [[Special:Contributions/172.68.51.28|172.68.51.28]] 17:31, 27 January 2017 (UTC)

Aren't there Space Vampires in Lovecraft somewhere? [[Special:Contributions/162.158.214.34|162.158.214.34]] 22:48, 27 January 2017 (UTC)
Not as such, but there are in the classic ''Queen of Blood'' [http://www.imdb.com/title/tt0060877/] and in the unfortunate "Lifeforce" [http://www.imdb.com/title/tt0089489/] . A refractor though should be able to see their interstellar umbrella [https://pluckyoutoo.files.wordpress.com/2008/08/lf17.jpg] [[User:Anthony11|Anthony11]] ([[User talk:Anthony11|talk]]) 07:05, 30 January 2017 (UTC)

An important advantage of refractors that keeps them popular is the very tiny amount of internal scattered light compared to reflectors. This really stands out when viewing planets and bright objects. Everybody loves that velvety black background field that refractors can provide. [[User:ExternalMonolog|ExternalMonolog]] ([[User talk:ExternalMonolog|talk]]) 09:59, 28 January 2017 (UTC)

Another issue with reflecting telescopes (though not pertinent to the joke) is that when used as a lens in photography, the bokeh, or unfocused highlights beyond the depth of field in an image, are rendered as circular 'doughnut' shapes, instead of the fuzzy points of light created by refracting lens systems. Run-on sentences, FTW. [[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 01:20, 29 January 2017 (UTC)

Strictly speaking, bokeh is the "quality" of the OOF areas, not the areas themselves. [[User:Anthony11|Anthony11]] ([[User talk:Anthony11|talk]]) 07:05, 30 January 2017 (UTC)

There can be no doubt that the original comic contains a *mirror*, not a prism. And a porro prism would not even work, because it reflects the projection by 180 degrees! Porro prisms are always used in pairs, to upright an image *without* changing the viewing direction! --[[Special:Contributions/162.158.89.43|162.158.89.43]] 12:26, 30 January 2017 (UTC)
::The lens of a refractor flips the image, so having a single prism would render it upright.[[Special:Contributions/172.68.90.46|172.68.90.46]] 01:48, 31 January 2017 (UTC)