explain xkcd - User contributions [en]

Talk:497: Secretary: Part 4

2018-06-08T17:51:51Z

LankyWhisper624:

The "pew" sound effect that Ron Paul fires back is also a joke -- go look up Pew Charitable Trust on Wikipedia: "Although today the Pew Charitable Trusts is non-partisan and non-ideological, Joseph Pew and his heirs were themselves politically conservative. The mission of the J. Howard Pew Freedom Trust, one of the seven funds, was to "acquaint the American people with the evils of bureaucracy and the values of a free market and to inform our people of the struggle, persecution, hardship, sacrifice and death by which freedom of the individual was won"."

Also, I am 99.9% sure that Tron was not based on a video game; any video games were based on the movie. {{unsigned|‎64.20.186.2}}

:It would appear the Light Cycles portion of Tron is based on a game called "Blockade". In fact, before Tron appeared, I fondly recall playing various versions of this game ([[wikipedia:Snake (video game)]]) on home computers before it became repopularised on Nokia handsets and what-not. Light Disc appears to be based on Pong, although the element of the player having a 2D field of movement was a cool touch. [[User:Thokling|Thokling]] ([[User talk:Thokling|talk]]) 08:04, 25 September 2013 (UTC)

I know this is a really old comic, but I'm wondering if it's possible that the 'gold' thing was a reference to Firefly? (I.e., "Jaynestown") Just because in other comics it's clear that Mr. Munroe is very familiar with that show (i.e., 577-581). [[User:Berets|Berets]] ([[User talk:Berets|talk]]) 00:12, 13 July 2017 (UTC)

I don't think that Cory's gun is a visual joke about Daleks; if it had been, I think Randall would have made sure to design Ron Paul's turret differently. [[User:OriginalName|OriginalName]] ([[User talk:OriginalName|talk]]) 23:50, 1 February 2018 (UTC)

Isn't the first panel a Star Trek reference? A common phrase right before battles is "Sir! the <Klingon or Romulan or Borg> ship is hailing us!"

1764: XKCDE

2018-06-04T21:03:24Z

LankyWhisper624: /* Fixed the citation needed tag */

{{comic
| number = 1764
| date = November 25, 2016
| title = XKCDE
| image = xkcde.png
| titletext = 4. They unplug the root machine but the thousands of leaf VMs scatter in the wind and start spinning up new instances wherever they land
}}

==Explanation==

Randall has created a theoretical software environment named XKCDE (a portmanteau on xkcd and {{w|Collaborative development environment|CDE}} (Collaborative Development Environment)), which relies on the user creating a series of nested virtual machines inside each other (creating sort of a digital version of the {{w|Droste effect}}), which would likely cause extreme strain on the resources of the machine running it. This strain is explained in [[676: Abstraction]], at least for the normal case.

"Virtual Machines" are software which pretend to be PC hardware so that a "guest" operating system can run inside of them, under a "host" operating system. Nesting VMs is the process of making a guest also be a host to yet another guest. Generally this is considered wasteful of resources, especially beyond one or two layers deep, and is not done except in a test lab for very specific purposes.

"Containers" are a lighter form of PC abstraction. Instead of emulating the entire physical hardware, they only emulate the software stack sitting on top of the kernel. A containerisation tool will have its own standard library, software-stack and installed programs, but delegates all {{w|system calls|system calls}} to the host kernel.
This is more efficient because no hardware needs to be emulated, but the disadvantage is reduced isolation between host and guest. A misbehaving guest can induce kernel crashes that take the host with them.
The most well-known example of container software is {{w|Docker (software)|Docker}}.

Randall derives humour from repeating the nesting ''ad absurdum'' in a never-ending fractal of nested VMs, thus trapping the follower of the instruction forever, in a form of [[Nerd Sniping]]: Any external observer, such as your boss, who sees you doing this is likely to fire you for wasting company time (An outcome which is undesirable, though still better than being hit by a truck{{Citation needed}}). [https://xkcd.com/356/]

A software environment which disables both the machine it runs on and the user that runs it could be thought of as a useless machine.

The title-text is a joke on the words {{w|Tree (data structure)|root and leaf}} as used in abstract data structures, drawing an analogy of cutting down a tree (unplugging the root machine) scattering leaves (the nested VMs).
A subtle pun is hidden in 'spinning': several tree species use {{w|Samara (fruit)|spinning leaves}} to scatter their seeds. The {{w|Autorotation (helicopter)|autorotation}} due to the special shape of the leaves helps the seeds travel farther on the wind from their parent tree. Randall mixes this meaning of 'spinning' with the act of "spinning up a VM", the colloquial phrasing for starting up a new instance of a guest virtual machine.
As a seed grows into a new tree where it lands, so apparently do the scattered VMs spin up new instances of themselves wherever they land.

In this case, a literal interpretation would be that turning off the computer the VMs are running on would make all the VMs without any VMs running in them propagate themselves through a network and install themselves on other computers, which at the end of the day would be a very inefficient method of creating a virus.

=== Real Life Practice ===
In 'normal' software development, spinning up a (single, non-nested) VM is a practice to ensure that the development environment is identical between developers, thus minimising hard-to-reproduce bugs due to local machine differences, such as [https://sourceforge.net/p/phpmyadmin/bugs/2343/#0e4a unmatching library versions], [http://www.moserware.com/2008/02/does-your-code-pass-turkey-test.html locale settings] or [http://askubuntu.com/questions/202857/cant-install-ati-proprietary-drivers-in-12-10 additional installed or missing software].
The single VM image is shared between all developers, who each spin up their own instance on their personal workstation.
In such cases, spinning up the VM is the first step in bringing up a local development environment, after which additional steps will usually instruct which programs to open, which configuration settings to change, etc.

Someone got [https://pcsteps.com/508-nested-virtualization 4 levels deep] with this.

==Transcript==
Installing the xkcd development environment

{| class="wikitable"
|
# Spin up a VM
# Spin up a VM inside that VM
# Continue spinning up nested VMs and containers until you get fired
|}

{{comic discussion}}

[[Category:Computers]]

1252: Increased Risk

2018-06-04T19:05:17Z

LankyWhisper624: /* fixed citation needed...again */

{{comic
| number = 1252
| date = August 16, 2013
| title = Increased Risk
| image = increased_risk.png
| titletext = You may point out that strictly speaking, you can use that statement to prove that all risks are tiny--to which I reply HOLY SHIT WATCH OUT FOR THAT DOG!
}}
==Explanation==
The panel satirises the common misunderstanding of the concept of percentage. Quoting a percentage change without mentioning the base probability that this ratio acts on is meaningless (outside of arithmetic for arithmetic's sake). Most everyday communication, however, succumbs to such incompleteness. In the aftermath of this ambiguity, people tend to conflate relative and absolute changes.

If the probability of a shark attack at the North beach is 5 per million, then the probability of shark attack at the South beach is still not more than 6 per million. The difference between these values is not enough to normally justify choosing one beach over the other, even though a "20% greater" chance sounds significant when stated out of this larger context.

[[Cueball]] parodies the concern by noting that by going to a beach three times instead of two, their chances of attack by dogs with handguns in their mouths (a ludicrous and unrealistic scenario as dogs cannot buy guns{{Citation needed}} and are not likely to pick one up off the ground) increases by 50%. If the chance of the dog attack is one per billion on each visit to the beach, then the chance of attack increases over multiple visits regardless; it's still one in a billion for any specific visit. This does not change the overall improbability of there ever being a dog swimming with a gun in its mouth.

[[Beret Guy]] misunderstands Cueball's probability, exhibiting the {{w|Gambler's fallacy}} by believing that since they haven't been attacked in their first two trips, the chance of attack by dogs with handguns is higher on their third outing.

This is a common misunderstanding of statistics. While the overall probability of an attack in three trips would be higher than in a single trip, it doesn't change the fact that in each individual trip, the probability is still the same; whether or not they managed to avoid being attacked in their first two trips, the results of these trips do not factor into the probability equation of the third trip.

This also can be illustrated by coin flips: if one flips a coin ten times in a row, no matter what the result of each previous flip is (even if it were nine heads in a row), the odds of getting heads on the tenth coin flip remains 50%. In other words, past experience does not impact subsequent flips.

The caption clarifies Cueball's point, but without sarcasm.

Then again, the title text objects to this point (that a tiny risk increased by 50% is still tiny). If this 50% increment is done repeatedly, the risk can get arbitrarily high, while the statement says that it is still tiny. This can be compared to the {{w|Sorites paradox}} (the "paradox of the heap"), which involves a "heap" of sand from which grains of sand are removed individually. If one assumes that, after removing a single grain, a heap of sand is still considered a heap of sand, and that there are a limited number of grains of sand in the heap, then one is forced to accept the conclusion that it can still be considered a heap of sand even if there is only a single grain of sand (or even none at all).

Being shot by a swimming dog with a handgun in its mouth is also specifically referenced in what if? 146, [https://what-if.xkcd.com/146/ Stop Jupiter].

==Transcript==
:[Three figures are standing around. Two have beach towels. Ponytail is looking at her cell phone. One of them is Beret Guy.]
:Ponytail: We should go to the north beach. Someone said the south beach has a 20% higher risk of shark attacks.
:Cueball: Yeah, but statistically, taking three beach trips instead of two increases our odds of getting shot by a swimming dog carrying a handgun in its mouth by '''''50%!'''''
:Beret Guy: Oh no! This is our third trip!
:Reminder: A 50% increase in a tiny risk is ''still tiny''.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Beret Guy]]
[[Category:Math]]
[[Category:Sharks]]

1252: Increased Risk

2018-06-04T19:03:50Z

LankyWhisper624: /* I fixed the citation needed tag */

{{comic
| number = 1252
| date = August 16, 2013
| title = Increased Risk
| image = increased_risk.png
| titletext = You may point out that strictly speaking, you can use that statement to prove that all risks are tiny--to which I reply HOLY SHIT WATCH OUT FOR THAT DOG!
}}
==Explanation==
The panel satirises the common misunderstanding of the concept of percentage. Quoting a percentage change without mentioning the base probability that this ratio acts on is meaningless (outside of arithmetic for arithmetic's sake). Most everyday communication, however, succumbs to such incompleteness. In the aftermath of this ambiguity, people tend to conflate relative and absolute changes.

If the probability of a shark attack at the North beach is 5 per million, then the probability of shark attack at the South beach is still not more than 6 per million. The difference between these values is not enough to normally justify choosing one beach over the other, even though a "20% greater" chance sounds significant when stated out of this larger context.

[[Cueball]] parodies the concern by noting that by going to a beach three times instead of two, their chances of attack by dogs with handguns in their mouths (a ludicrous and unrealistic scenario as dogs cannot buy guns {{citation needed}} and are not likely to pick one up off the ground) increases by 50%. If the chance of the dog attack is one per billion on each visit to the beach, then the chance of attack increases over multiple visits regardless; it's still one in a billion for any specific visit. This does not change the overall improbability of there ever being a dog swimming with a gun in its mouth.

[[Beret Guy]] misunderstands Cueball's probability, exhibiting the {{w|Gambler's fallacy}} by believing that since they haven't been attacked in their first two trips, the chance of attack by dogs with handguns is higher on their third outing.

This is a common misunderstanding of statistics. While the overall probability of an attack in three trips would be higher than in a single trip, it doesn't change the fact that in each individual trip, the probability is still the same; whether or not they managed to avoid being attacked in their first two trips, the results of these trips do not factor into the probability equation of the third trip.

This also can be illustrated by coin flips: if one flips a coin ten times in a row, no matter what the result of each previous flip is (even if it were nine heads in a row), the odds of getting heads on the tenth coin flip remains 50%. In other words, past experience does not impact subsequent flips.

The caption clarifies Cueball's point, but without sarcasm.

Then again, the title text objects to this point (that a tiny risk increased by 50% is still tiny). If this 50% increment is done repeatedly, the risk can get arbitrarily high, while the statement says that it is still tiny. This can be compared to the {{w|Sorites paradox}} (the "paradox of the heap"), which involves a "heap" of sand from which grains of sand are removed individually. If one assumes that, after removing a single grain, a heap of sand is still considered a heap of sand, and that there are a limited number of grains of sand in the heap, then one is forced to accept the conclusion that it can still be considered a heap of sand even if there is only a single grain of sand (or even none at all).

Being shot by a swimming dog with a handgun in its mouth is also specifically referenced in what if? 146, [https://what-if.xkcd.com/146/ Stop Jupiter].

==Transcript==
:[Three figures are standing around. Two have beach towels. Ponytail is looking at her cell phone. One of them is Beret Guy.]
:Ponytail: We should go to the north beach. Someone said the south beach has a 20% higher risk of shark attacks.
:Cueball: Yeah, but statistically, taking three beach trips instead of two increases our odds of getting shot by a swimming dog carrying a handgun in its mouth by '''''50%!'''''
:Beret Guy: Oh no! This is our third trip!
:Reminder: A 50% increase in a tiny risk is ''still tiny''.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Beret Guy]]
[[Category:Math]]
[[Category:Sharks]]