explain xkcd - User contributions [en]

2114: Launch Conditions

2019-02-20T19:15:33Z

172.69.70.23:

{{comic
| number = 2114
| date = February 20, 2019
| title = Launch Conditions
| image = launch_conditions.png
| titletext = Though I do think the tiny vent on one of the boosters labeled "O-RING" is in poor taste.
}}

==Explanation==
{{incomplete|Created by a BOT. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

An image of a rocket with a progressively larger white cloud around it is shown, but no external object for scale is visible until the third panel.
It is then revealed to be a model or miniature by the relatively enormous size of Ponytail's head.
The dialogue confirms that it emits clouds of water vapour as a humidifier, which mimic the appearance of the exhaust plume of a full-size rocket.

This comic appeared the day after the death of Peter Cosgrave, who is known for photographing the launch of the space shuttle many times.

The title text references the failed o-ring that led to the explosion of the space shuttle Challenger and the death of all on board.
the failure of the o-ring was due to poor statistical analysis of the failure under launch conditions for that day causing the launch to be pushed forward at lower temperatures then what is acceptable.
For the humidifier to vent gas from this opening is indeed in poor taste, though the model does not resemble the shuttle.

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

{{comic discussion}}

Talk:2113: Physics Suppression

2019-02-18T17:12:37Z

172.69.70.23:

That's how mafia works. [[Special:Contributions/172.69.134.111|172.69.134.111]] 16:51, 18 February 2019 (UTC)
But White Hat didn't mention anything about a Mafia...? [[Special:Contributions/162.158.74.153|162.158.74.153]] 14:31, 18 February 2019 (UTC)
:No, but to suppress people publishing their results, a body like the mafia would be needed, is what Megan jokes about. And then takes an example (and one more in title text) about annoying results that did not get suppressed. Her example turned out to win a noble prize, the title text was later shown to be an error. But a mafia might have stopped both sets of results to have not been published. Basically proving that you can not suppress such results wether relevant or not. If White Hat's model is not taken serious it is probably because he has no data to back it up. Wild claims demands extraordinary well documentation. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:53, 18 February 2019 (UTC)
::A "mafia" isn't the only candiate. "Inquistions" have also worked well for suppression, but (AFAIK) have less of a history of intramural violence. I think the image of a cabal of cloaked physics monks torturing dark energy heretics into recantation would have been striking enough, but RMMV (Randall's Mileage May Vary). [[Special:Contributions/172.69.70.23|172.69.70.23]] 17:12, 18 February 2019 (UTC)

2108: Carbonated Beverage Language Map

2019-02-06T20:15:26Z

172.69.70.23: /* Explanation */ Added explanation for "Carbonated Beverage" and fixed "nonexistant" typo in "Aether."

{{comic
| number = 2108
| date = February 6, 2019
| title = Carbonated Beverage Language Map
| image = carbonated_beverage_language_map.png
| titletext = There's one person in Missouri who says "carbo bev" who the entire rest of the country HATES.
}}

==Explanation==
{{incomplete|Created by ONE GUY IN MISSOURI. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

In the US, people in various parts of the country refer to carbonated beverages by {{w|Names for soft drinks in the United States|different names}} such as Soda, Pop, Coke, etc. Generally, the West Coast and Northeast say "Soda", the South says "Coke" and the rest of the country says "Pop".

There are various maps of the name differences, including: [http://www.popvssoda.com/]

This map leverages xkcd's mockery-maps of regional and state-by-state differences or variations in the use of language and overlays the regional variances in the terms for soda pop (for example: https://laughingsquid.com/soda-pop-or-coke-maps-of-regional-dialect-variation-in-the-united-states/), as was made trending and popular in 2013. Not only are there far more terms than are actually used by Americans, many are terms for other drinks (mead), unrelated liquids (quicksilver), or copyrighted beverage names (Code Red) -- and in one case, something that's not even edible ({{w|cryptocurrency|"Crypto"}}).

{| class="wikitable"
|+Map terms (from left to right, approximately)
|-
|Fanta
|Name of a carbonated beverage line
|-
|Söde
|Presumably pronounced "soda" but spelled oddly
|-
|True Water
|Possibly a reference to True Blood, a fictional artificial blood substitute for vampires in The Southern Vampire Mysteries book series by Charlaine Harris, and the television series True Blood.
|-
|Crypto
|A term for encryption. Not drinkable
|-
|Yum
|Carbonated beverages are generally sweet, and therefore taste good
|-
|Sparkle Fluid
|Roughly analogously to how "sparkling wine" and "sparkling cider" are carbonated varieties of wine and cider, "sparkling fluid" or "sparkle fluid" would presumably be any carbonated fluid
|-
|King Cola
|Name of a carbonated beverage
|-
|Pepsi
|Name of a carbonated beverage
|-
|Crystal Pepsi
|Name of a carbonated beverage
|-
|Ichor
|several definitions (blood of a god) (watery discharge from a wound). None of them carbonated. None of them recommended as a drinkable liquid.
|-
|You-Know-What
|A phrase typically employed when a more specific term is considered unspeakable.
|-
|Tab
|Name of a carbonated beverage
|-
|Spicewater
|
|-
|Softie
|
|-
|Ohio Tea
|
|-
|Boat Drink
|
|-
|Melt
|
|-
|Fizz Ooze
|
|-
|Punch
|A drink typically found in the juice isle. Only sometimes carbonated.
|-
|Fun Wine
|
|-
|Diet
|Sometimes refers to a carbonated beverage. A common request in restaurants, as they often only have a single "diet soda" option for customers to pick. Ironically, "diet" sodas have been causally linked to metabolism related weight gain.
|-
|Refill
|The second glass of whatever you drank previously. Works for any drinkable liquid.
|-
|Tickle Juice
|
|-
|Bubble Honey
|
|-
|Sugar Oil
|
|-
|The Wet Drink
|
|-
|Code Red
|Name of a carbonated beverage
|-
|Mead
|An alcoholic drink. Traditionally not carbonated.
|-
|Canadian Ale
|
|-
|Aether
|Could refer to a highly flammable industrial solvent, also used as an anesthetic. Do not drink. Also, not carbonated. Alternately, could refer to the nonexistent fluid that was believed to carry light waves before electromagnetism was fully understood, or poetically to the sky; in either case it is not a drinkable liquid (or carbonated).
|-
|Carbonated Beverage
|Technically correct, but a bit of an awkward term due to its unnecessary length.
|-
|Mouthwater
|
|-
|Capri
|
|-
|Skim Shake
|
|-
|Kid's Coffee
|Somewhat accurate. Coffee is typically drunk by adults for it's caffeine. Carbonated beverages often have caffeine also, and are often consumed by children.
|-
|Regular
|
|-
|Tang
|
|-
|Formula
|Typically refers to baby's milk. Not carbonated.
|-
|Medicine
|Only sometimes a drinkable liquid. Never or perhaps almost never carbonated.
|-
|Broth
|Liquid in which bones, meat, fish, or vegetables have simmered. Often used as a soup base. Not carbonated.
|-
|Fool's Champagne
|Carbonated beverage is to champagne what fool's gold is to gold.
|-
|Sugar Milk
|
|-
|No word for them
|This region of the US does not have a word for carbonated beverages (according to Randall). Apparently they do not drink them at all.
|-
|Hydro
|A word for water. Carbonated water does exist, but this word means all forms of water.
|-
|Harvard Tea
|
|-
|Bubbler
|A nod to another popular map of the same type, exploring the regional dialects used to describe drinking fountains. This region of New England, as well as the eastern portion of Wisconsin are the only two locations where 'Bubbler' is commonly used to refer to drinking fountains.
|-
|Mouthbuzz
|
|-
|Brad's Elixer
|
|-
|Hot Water
|Not carbonated. Not even in Jacuzzi and hot tubs.
|-
|Fluid
|A word that means nearly any liquid in existence. Not accurate as a descriptor for carbonated beverages.
|-
|Coke Zero
|Name of a carbonated beverage.
|-
|Carbo
|
|-
|Quicksilver
|
|-
|Glug
|
|-
|Water Plus
|
|}

The title text may be a wry comment in light of the pocket of "soda" in the St. Louis, MO area.

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

A map of the United States divided into purple, red, green, blue, and yellow colored regions...
{{comic discussion}}

[[Category:Comics with color]]
[[Category:Maps]]

455: Hats

2019-02-04T18:18:15Z

172.69.70.23:

{{comic
| number = 455
| date = July 28, 2008
| title = Hats
| image = hats.png
| titletext = ...
}}

==Explanation==
[[Black Hat]] encounters a person who is wearing not one, but two black hats. Black Hat is not a person to be trifled with, but from his reaction, he apparently believes that Two Black Hats represents a considerable danger to him.

If a black hat is assumed to be akin to a badge of rank, then Two Black Hats certainly is superior to him in the capacity and willingness to do evil. Alternatively, and even more worrying, Two Black Hats could be someone who has the desire and the ability to acquire black hats, which he then wears like a badge of honor. With all this in mind, Black Hat edges away, keeping Two Black Hats in sight at all times.

This comic is also a metatextual joke about xkcd itself. Because of the comic's simplistic art style and characterization, Black Hat has only one defining physical trait, his hat, and one defining personality trait, his malevolence. Randall then implies that the two traits must be correlated, so that a black hat signifies malevolence, and accordingly two hats must signify even more malevolence -- an idea that wouldn't make any sense in real life, where a person with two hats would just be making an odd fashion choice.

The title text is simply "..."
This may represent the slow-motion pause during which Black Hat's nefarious life flashes before his eyes, as he considers his impending doom. It may also emphasize how the usually witty Black Hat is, for once, speechless. Or the title text is similar to that in [[412: Startled]], where Black Hat also becomes the little one (and with much focus on the black hat, as in this comic). As mentioned there, such a short title text could be due to the fact that it's a somewhat surreal comic, and any further commentary might have detrimentally brought it down to Earth. See also [[82: Frame]], with the same title text, but no relation to black hats.

Two Black Hats makes a reappearance in [[826: Guest Week: Zach Weiner (SMBC)]], down by the restrooms.

==Transcript==
:[Black Hat is walking.]

:[Black Hat stops in front of another man with two Black Hats, the uppermost hat tilted backwards.]

:[After two panels, the original Black Hat steps backward, shuddering slightly.]

{{comic discussion}}
[[Category:Comics featuring Black Hat]]
[[Category:Characters with Hats]]

2099: Missal of Silos

2019-01-19T20:34:56Z

172.69.70.23: /* Trivia */ added Malamanteau

{{comic
| number = 2099
| date = January 16, 2019
| title = Missal of Silos
| image = missal_of_silos.png
| titletext = Welcome to Wyoming, motto "We'd like to clarify that Cheyenne Mountain is in Colorado."
}}

==Explanation==
{{incomplete|Cremated by a BOB. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
{{w|Approximate string matching|Fuzzy, or approximate, string matching}} is a technique used for searching text for specified "strings" of characters. Normal string matching would only find results that fit the search exactly (searching for "''missile''" would find only occurrences of "''missile''"). Fuzzy string matching instead finds results that are "close enough" by some metric (searching for "''missile''" would find "''missile''" but also close variants like "''missal''" or "''missel''"). This is often used in search engines, as typos, misspellings, and inexact searches are commonplace.

{{w|Missile silos}} are often thought to be the first targeting priority in event of a nuclear strike, in hopes of preventing retaliation from the target. If a list of potential nuclear missile targets were stored, and a fuzzy search was looking for "missile silos", the {{w|Missal of Silos}} would most likely be returned as a result and could be made a target.

In Christianity, a {{w|missal}} is a priest's book of instructions, texts and music for the proper celebration of {{w|Mass (liturgy)|Mass}}. The Missal of Silos is an 11th-century missal from the {{w|Abbey of Santo Domingo de Silos}} in northern {{w|Spain}}; it is famous for being the oldest known {{w|paper}} document in Europe, written at a time when the usual writing material was {{w|parchment}}.

{{w|Cheyenne Mountain}} is a mountain in {{w|Colorado}}, which houses an underground compound (aptly named the {{w|Cheyenne Mountain Complex}}) designed to withstand a nuclear strike and host to the {{w|North American Aerospace Defense Command}}. {{w|Cheyenne, Wyoming}}, on the other hand, is the capital of {{w|Wyoming}}. The residents of Cheyenne, Wyoming would prefer their town not to be the target of a nuclear attack because of confusion with Cheyenne Mountain. However, Cheyenne, Wyoming is likely a listed target due to the nearby {{w|90th Operations Group}} at {{w|Francis E. Warren Air Force Base}} operating Minuteman III ICBMs from missile silos.

There have been several comics with nuclear weapons as a part of the plot. See for instance [[1655: Doomsday Clock]], where several other comics are mentioned in the explanation.

==Transcript==
:[A passage from the Wikipedia page for Missal of Silos is shown, with underlined heading and with links in the text in blue font. The last line is partly cut off by the comics panel, but can be read.]
:<big>'''Missal of Silos'''</big>
:<div style="border-bottom: 1px solid #bbbbbb"></div>
:<small>From Wikipedia, the free encyclopedia</small>
:The {{w|Missal}} of Silos is the oldest known {{w|paper}} document created in the Christian West; it is 11th century in date.<sup><span style="color: #0645AD">[1]</span></sup>
:The missal is held in the library of the {{w|Monastery of Santo Domingo de Silos}} near {{w|Burgos, Spain}}. It is one of a number of liturgical manuscripts...

:[Caption below the panel:]
:Spain would like to remind everyone not to use fuzzy string matching in their nuclear strike target lists.

==Trivia==
*The transcript of the Wikipedia article shown on the comic is accurate to the [https://en.wikipedia.org/w/index.php?title=Missal_of_Silos&oldid=857775302 revision made on 2 September 2018].
**This is because a spurt of editing took place on Wikipedia on the day of the comic, since xkcd and Wikipedia editing have similar target demographics.
**This "xkcd-Wikipedia effect" has happened before.
***One example of this revolved around [[878: Model Rail]], in which the alt-text mentioned that the debate over the title of the HO/H0 system was disturbingly long, and "coincidentally", the talk page debate got a little longer on that very day.
***And most famously, the comic [[1485: Friendship]], caused at least four Wikipedia pages to be vandalized, so these pages had to be semi protected.
***Of course, the canonical example of an "xkcd-Wikipedia effect" is [[739:Malamanteau]] [[https://xkcd.com/739/]] [[https://en.wikipedia.org/wiki/Talk:Malamanteau]]
{{comic discussion}}

[[Category:Wikipedia]]
[[Category:Comics with color]]

Talk:2086: History Department

2018-12-17T22:06:27Z

172.69.70.23:

The business about the 1750s probably has something to do with the British doing their changeover from Julian to Gregorian calendars then, but you can't look too carefully at the details. [[Special:Contributions/108.162.219.16|108.162.219.16]] 18:51, 17 December 2018 (UTC)

I'm confused. Is there any joke apart from the obvious "haha, studying history by fully covering time slices instead of topics"? [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 19:05, 17 December 2018 (UTC)
: There's also the joke about taking longer to study a period of time than that time took to pass. [[Special:Contributions/108.162.216.208|108.162.216.208]] 19:31, 17 December 2018 (UTC)
Two sides to the same coin? We normally think about historians studying time periods on the order of years, decades, or even longer periods (e.g. the Dark Ages), which naturally takes less time than the original era. Another joke is the idea that an entire department is devoted to such narrow periods, but maybe it's a really small college.
[[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 20:04, 17 December 2018 (UTC)

It seems to me that the humor is based on the incongruity of thinking in business-like terms of productivity and gains and losses in a history department.

Talk:472: House of Pancakes

2018-06-14T14:43:33Z

172.69.70.23:

My take on this (probably wrong in so many ways, especially as I'm British and obviously don't get some of the pop references that are obviously there), is that we are seeing this as if converted to a web-page (from a physical example that was scanned, with stains and marks and possibly even graffiti reproduced faithfully) and and given a number of hidden  by successive editors and reviewers of the material, except they're made visible for our benefit. It may even actually be a "wikified". I've seen worse ''actual'' examples. (Although the "Yvette's Bridal Formal", the epitome of bad web pages, had vanished last time I actually went and looked for it.)

"House" being in blue makes me think that this word has been globally 'linkified'.

Does the scribble "International" indicate someone trying to make it relevent outside the US?

This was to have been published on Blogspot, at some point, but some reviewer nerfed that.

Some of the footnotes sound a bit Lovecraftian, others somewhat as if Hunter S. Thompson had written them.

Footnote 19 points out the error (in my opinion, as well as the unknown annotator) of missing out the hyphen in "kids-only". The hyphen makes it a single compound term, which in this context isn't as necessary to remove ambiguity as it could have been, but still ought to be there. The editor concerned thinks this is related to the lack of the Oxford Comma (the one before 'and' in something like "foo, bar, and baz"), although I'm British and personally dislike that form of grammar (prefering "foo, bar and baz", the commas being "chained conjunction" replacers, the last of the conjunctions not being replaced so needing no comma) and don't actually think it's a majority UK grammatical feature. Except where the lack of it produces ambiguity, in which case I'd re-write it so it no longer had such ambiguity.

"The Big Steak Omlette" has been censored of some of its ingredients. Too thoroughly to work out what ''has'' been censored, so the joke may rely on knowledge of what they might have been.

"Mohawk Girls" is a documentary film. I only know that it exists (not even sure that this is the reference intended, rather than both items referencing something else) and have no idea about the relevence.

"Enough with your (God Damn) pancakes" as voiced by the graffiti stick-figures sounds like a meme, but is too obscure for me.

The title-text is the voice of a person unable to handle the mess (figurative and actual) all over the menu and deciding to try another eating-establishment.

I never knew about House Of Leaves, before now. This probably explains why this comic befuddles me. Checking out the description of it I see the stylistic link being made, although can't rule out that I'd remained befuddled (or even become much more so) even if/when I've familiarised myself with the book itself. :-) [[Special:Contributions/178.107.249.215|178.107.249.215]] 22:09, 11 June 2013 (UTC)
:Many thanks IP for your comments. I did start this page exactly because I need hints like that you gave. This comic is still incomplete so me and others have work on it.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:55, 12 June 2013 (UTC)

Should "House" in alt text really be colored blue? It's definitely not blue in the original, probably just because of HTML limitations, but still. [[Special:Contributions/172.68.11.53|172.68.11.53]] 02:11, 19 February 2017 (UTC)

I think this is the one example of an XKCD comic that had me completely lost. I knew nothing about the book in question, wasn't even able to infer its existence from the cues of the graphic itself. I was speculating that maybe Randall just hated IHoP or something, but that didn't seem right. Usually I come to Explain for some minor detail, or for one I do understand but am curious about others' reaction to. But in this case it was "I have no idea...please help me". I remember similar bemusement when it first came out. But I prefer Waffle House, anyway.
— [[User:Kazvorpal|Kazvorpal]] ([[User talk:Kazvorpal|talk]]) 22:49, 7 August 2017 (UTC)

I guess that this comic is outdated, now that IHOP is IHOb. [[Special:Contributions/172.69.70.23|172.69.70.23]] 14:43, 14 June 2018 (UTC)

Talk:1938: Meltdown and Spectre

2018-01-05T21:52:42Z

172.69.70.23: Sorry.

The "trolley problem" is the ethical dilemma thought experiment where an out-of-control trolley is heading to a junction (which you have control over) - to one side it'll kill one group of people - to the other, some others. Your moral dilemma is deciding which is the "best" outcome (eg, hitting a dozen five year old children or three Nobel laureats). This is like a software "if" statement. Speculative execution in most CPU chips is where the computer always takes both sides of a decision like this - explores what will happen down each path - and only causes the effects of the decision to happen when the decision as to which way to proceed is decided. This allows it to keep on doing useful work while some slower decision is made. The "quantum" aspect of this is that in some versions of quantum theory, quantum-level particles take every possible path at once and the result is the sum of all of them.

In a sense, the computer is exploring the consequences of the trolley problem in a quantum-like manner.

This would all be OK if it were not for the fact that devious black-hat hackers can come up with devious ways to see the information that should have been discarded in the "path-not-taken". So even though the computer will eventually decide that some piece of information should not be accessible - you can find out the value it would hypothetically read - even though it will soon decide that it should not access the information.

The "rowhammer" problem is something entirely different. Computer memories are organized as a two-dimensional grid of rows and columns - and are physically constructed from tiny capacitors. If you apply just the RIGHT pattern of rapid changes to one row of the grid, you can cause one of the capacitors on the next row to incorrectly change state. This is a design flaw in the memory chip - and it allows (in some circumstances) programs to change data in memory locations that they have no right to change.

[[User:SteveBaker|SteveBaker]] ([[User talk:SteveBaker|talk]]) 19:33, 5 January 2018 (UTC)

uhhh did you just copy and paste your entire edit into talk? [[User:DPS2004|DPS2004'); DROP TABLE users;--]] ([[User talk:DPS2004|talk]]) 20:19, 5 January 2018 (UTC)

: Pretty much. When I got here, there was no information about the comic at all. Since I'm unfamiliar with all of the other stuff that goes into an explain, I left it as a comment so someone else could use it...but after a while, nobody did, so I copy-pasted it into the explanation...with some tweaks! Sorry if that was a faux-pas of some variety! [[Special:Contributions/172.69.70.23|172.69.70.23]] 21:52, 5 January 2018 (UTC)

1938: Meltdown and Spectre

2018-01-05T21:49:28Z

172.69.70.23: /* Explanation */ More details.

{{comic
| number = 1938
| date = January 5, 2018
| title = Meltdown and Spectre
| image = meltdown_and_spectre.png
| titletext = New zero-day vulnerability: In addition to rowhammer, it turns out lots of servers are vulnerable to regular hammers, too.
}}

==Explanation==
{{incomplete|Created by an unpatched computer - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic was inspired by the {{w|Meltdown (security vulnerability)|Meltdown}} and {{w|Spectre (security vulnerability)|Spectre}} bugs in certain processors. These vulnerabilites were disclosed to the public the week of this comic. The bugs made big news because they broke the "walls" between programs, in some circumstances allowing malware to steal secrets from normal, bug-free programs.

The {{w|Trolley Problem}} is the ethical dilemma thought experiment where an out-of-control trolley is heading to a junction (which you have control over)—to one side it'll kill one group of people—to the other, some others. Your moral dilemma is deciding which is the "best" outcome (eg, hitting a dozen five year old children or three Nobel laureats). This is like a software "if" statement. Speculative execution in most CPU chips is where the computer always takes both sides of a decision like this—explores what will happen down each path—and only causes the effects of the decision to happen when the decision as to which way to proceed is decided. This allows it to keep on doing useful work while some slower decision is made. The "quantum" aspect of this is that in some versions of quantum theory, quantum-level particles take every possible path at once and the result is the sum of all of them.

In a sense, the computer is exploring the consequences of the trolley problem in a quantum-like manner.

Contrary to what the comic implies, in many cases both paths are not simultaneously taken during speculative execution. A {{w|Branch predictor}} may be used to select the most likely path, and the effects should be completely erased if the predicted path is incorrect. Both branch prediction and taking both paths, also known as eager evaluation, are considered speculative execution and are affected by these bugs.

This would all be OK if it were not for the fact that devious black-hat hackers can come up with ways to see the information that should have been discarded in the "path-not-taken". So even though the computer will eventually decide that some piece of information should not be accessible—you can find out the value it would hypothetically read—even though it will soon decide that it should not access the information. One way to do this appears to be to have the speculative code test the value of some illegal bit in memory and to perform some very slow operation if it's set, or to do something quick if it's zero. This speculative calculation can then be timed to determine which path it took. Since the timing data is still available after the speculative results have been discarded one may deduce which path the speculative code took - and therefore what the value of the supposedly secret bit was. By doing this repeatedly, one may extract the hidden data one bit at a time.

The {{w|Row Hammer}} problem is something entirely different. Computer memories are organized as a two-dimensional grid of rows and columns—and are physically constructed from tiny capacitors. If you apply just the RIGHT pattern of rapid changes to one row of the grid, you can cause one of the capacitors on the next row to incorrectly change state. This is a design flaw in the memory chip—and it allows (in some circumstances) programs to change data in memory locations that they have no right to change.

Ponytail mentions that we suck at building "shared computers" because Rowhammer, Spectre, and Meltdown all break down the security divisions built between programs and between users. A hacker running a separate program in a separate account shouldn't be able to access your secrets, but these bugs allow them to. This is particularly dangerous for servers and the cloud, where different programs, websites, or even companies can be sharing the same hardware.

The title text humorously states that as well as row hammer, computer servers also can be "hacked" by regular hammers. A zero-day vulnerability is an attack that takes advantage of a vulnerability that was discovered that day, and hasn't been patched. One might "patch" a server against this attack by plating it with stronger metal.

==Transcript==
:[Cueball and Ponytail are walking.]
:Cueball: The Meltdown and Spectre exploits use "speculative execution?" What's that?
:Ponytail: You know the trolley problem? Well, for a while now, CPUs have basically been sending trolleys down '''''both''''' paths, quantum-style, while awaiting your choice. Then the unneeded "phantom" trolley disappears.

:[Ponytail framed alone, facing left. They have stopped walking.]
:Ponytail: The phantom trolley isn't supposed to touch anyone. But it turns out you can still use it to do stuff.
:Ponytail: And it can drive through walls.

:[Cueball and Ponytail are standing, facing each other.]
:Cueball: That sounds bad.
:Ponytail: Honestly, I've been assuming we were doomed ever since I learned about Rowhammer.

:Cueball: What's ''that''?
:Ponytail: If you toggle a row of memory cells on and off really fast, you can use electrical interference to flip nearby bits and—
:Cueball: Do we just suck at ... computers?
:Ponytail: Yup. Especially shared ones.

:[They resume walking to the right.]
:Cueball: So you're saying the cloud is full of phantom trolleys armed with hammers.
:Ponytail: ...Yes, that is exactly right.
:Cueball: Okay. I'll, uh... install updates?
:Ponytail: Good idea.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Computers]]