explain xkcd - User contributions [en]

Talk:1946: Hawaii

2018-01-24T22:48:45Z

162.158.255.238:

OMG - so funny, so timely, so close to home. One of our modern fears, in a crisis what would happen if I forgot the password! [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 14:02, 24 January 2018 (UTC)

"Created by a TWITTER" [[User:Halo422|Halo422]] ([[User talk:Halo422|talk]]) 14:28, 24 January 2018 (UTC)

Based on the situation that xkcd is offering, it makes me look like I can't be any governor or an official, since I tend to forget my password very easily, especially my social media ones. RIP me.15:02, 24 January 2018 (UTC)

Most implausible explanation I've ever heard. Why not use something other than a Twitter account to notify people, apparently there's an entire system set up for delivering messages to people's phones, I'm not sure a tweet should be part of the official rollback process.
:Implausible, yet true. It was all over the news. Twitter is currently perceived as an appropriate way to communicate with constituents by many elected officials. I agree that a reverse-911 probably would have been far more effective, but the news would give more coverage to what's on Twitter, regardless (reaches more people, if less directly or immediately, than reverse-911).
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 18:09, 24 January 2018 (UTC)

As I am not a native Hawaiian or american, could somebody explain the nature of this warning system please? Does it work with a speaker / sirene system (as is common in Europe) or with text / CB messages? Why was it installed, what is the name of this system etc.
That information might give the uninitiated some background information needed to fully understand this comic. [[Special:Contributions/141.101.105.30|141.101.105.30]] 22:00, 24 January 2018 (UTC)

:The Hawaii state Emergency Alert system is multilayered. This event started with a text message, sent (in error) to phones. The text message was picked up by broadcast media (radio, television). There is also a siren system, reportedly a separate authorization is required to activate it. In some places, Honolulu especially, the sirens were sounded, apparently without the appropriate authorization. In others, such as Hawaii Island where I live, the sirens did not go off. Official channels did not retract the error until 38 minutes after the initial text. Though Governor Ige did not get his tweet sent, other officials, such as US Rep Tulsi Gabbard, did do so, to little effect. It's therefore an open question whether Ige's message would have made much of a difference.--[[Special:Contributions/162.158.255.238|162.158.255.238]] 22:48, 24 January 2018 (UTC)

1938: Meltdown and Spectre

2018-01-06T05:44:01Z

162.158.255.238: /* Explanation */ change explanation of specture and meltdown, quantum nothing to do with that

{{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.

Speculative execution is a technique used to speed up computer processors. Processors handle instructions in a series of steps, like an assembly line. The processor works on several successive instructions, each at a different stage in the assembly line. It may start speculatively executing instructions that follow a decision before the logic on whether or not they should be execute is finished. Once the decision is made, it keeps results from the selected path, and discards unnecessary processing. This allows it to keep doing useful work while some slower decision is made. Ponytail uses trolley tracks as an analogy for streams of instructions in a program.

The {{w|Trolley Problem}} is a thought experiment where an out-of-control trolley is heading to a switch which you control. Leaving the switch as-is will cause it to kill multiple people stuck on the tracks, but switching the track will cause it to kill one person; this creates the ethical dilemma of passively causing multiple deaths versus actively causing one. The Trolley Problem has gained significant memetic traction, helped in no small part by its inclusion in every introduction to philosophy college course.

The "quantum" aspect of this is that in some interpretations of quantum theory, quantum-level particles can be viewed as taking every possible path at once and the result is the sum of all of them. Or it might be related to some interpretations of {{w|Schrödinger's cat}}, in that the system can be regarded as being in both states until some event results in one of the states being selected.

Meltdown and spectre result from incorrect implementations of speculative execution, where the effects of speculatively executed instructions are not completely discarded. The phantom trolley driving through walls is an analogy for the computer instructions being able to access protected areas.

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.

The {{w|Row Hammer}} problem has been known for many years before this cartoon. A common form of computer memory is constructed from tiny capacitors organized in a two-dimensional grid of rows and columns. Capacitors store charge to represent information. By applying a pattern of memory access that rapidly changes a row of capacitors, you can cause charge to overflow to nearby rows and incorrectly change their states.

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 or change the behavior of your program, but these problems allow them to. This is particularly dangerous for time-sharing, servers and the cloud, where different programs, websites, or even companies can be sharing the same hardware.

Cueball took her explanation literally, and came to the conclusion that the cloud "is full of phantom trolleys armed with hammers". Instead of correcting him, Ponytail decides to accept his interpretation. (perhaps because she found this idea to be kinda cool)

The title text humorously states that as well as row hammer, computer servers also can be harmed 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. This would imply that the Rowhammer vulnerability is what inspired someone to try taking a hammer to a server. 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]]

1938: Meltdown and Spectre

2018-01-06T05:27:14Z

162.158.255.238: /* Explanation */ Quantum - schrodingers cat, speculative execution explanation

{{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.

Speculative execution is a technique used to speed up computer processors. Processors handle instructions in a series of steps, like an assembly line. The processor works on several successive instructions, each at a different stage in the assembly line. It may start speculatively executing instructions that follow a decision before the logic on whether or not they should be execute is finished. Once the decision is made, it keeps results from the selected path, and discards unnecessary processing. This allows it to keep doing useful work while some slower decision is made. Ponytail uses trolley tracks as an analogy for streams of instructions in a program.

The {{w|Trolley Problem}} is a thought experiment where an out-of-control trolley is heading to a switch which you control. Leaving the switch as-is will cause it to kill multiple people stuck on the tracks, but switching the track will cause it to kill one person; this creates the ethical dilemma of passively causing multiple deaths versus actively causing one. The Trolley Problem has gained significant memetic traction, helped in no small part by its inclusion in every introduction to philosophy college course.

The "quantum" aspect of this is that in some interpretations of quantum theory, quantum-level particles can be viewed as taking every possible path at once and the result is the sum of all of them. Or it might be related to some interpretations of {{w|Schrödinger's cat}}, in that the system can be regarded as being in both states until some event results in one of the states being selected.

[[Ponytail]] describes the two vulnerabilities as abusing the computer's solution to its trolley problem. The computer creates "phantom trolleys" down each of the tracks, and malware can take advantage of the quantum-esque prediction method to figure out the data the phantom trolleys are using by testing the speed in which results are produced.

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.

The {{w|Row Hammer}} problem has been known for many years before this cartoon. A common form of computer memory is constructed from tiny capacitors organized in a two-dimensional grid of rows and columns. Capacitors store charge to represent information. By applying a pattern of memory access that rapidly changes a row of capacitors, you can cause charge to overflow to nearby rows and incorrectly change their states.

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 or change the behavior of your program, but these problems allow them to. This is particularly dangerous for time-sharing, servers and the cloud, where different programs, websites, or even companies can be sharing the same hardware.

Cueball took her explanation literally, and came to the conclusion that the cloud "is full of phantom trolleys armed with hammers". Instead of correcting him, Ponytail decides to accept his interpretation. (perhaps because she found this idea to be kinda cool)

The title text humorously states that as well as row hammer, computer servers also can be harmed 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. This would imply that the Rowhammer vulnerability is what inspired someone to try taking a hammer to a server. 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]]

1938: Meltdown and Spectre

2018-01-06T04:29:16Z

162.158.255.238: /* Explanation */ junction -> switch

{{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 a thought experiment where an out-of-control trolley is heading to a switch which you control. Leaving the switch as-is will cause it to kill multiple people stuck on the tracks, but switching the track will cause it to kill one person; this creates the ethical dilemma of passively causing multiple deaths versus actively causing one. The Trolley Problem has gained significant memetic traction, helped in no small part by its inclusion in every introduction to philosophy college course.

Speculative execution in most CPU chips is where the processor, not knowing what the results of an operation will be, begins processing an instruction or instructions before the logic on whether or not it should execute is finished. Once a decision is made, it proceeds and discards unnecessary processing. This allows it to keep 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.

[[Ponytail]] describes the two vulnerabilities as abusing the computer's solution to its trolley problem. The computer creates "phantom trolleys" down each of the tracks, and malware can take advantage of the quantum-esque prediction method to figure out the data the phantom trolleys are using by testing the speed in which results are produced.

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.

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. By applying a pattern of memory access that rapidly changes a row of capacitors, you can cause charge to overflow to nearby rows and incorrectly change their states.

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.

Cueball misunderstood her explanation, and came to the conclusion that the cloud "is full of phantom trolleys armed with hammers". Instead of correcting him, Ponytail decides to accept his interpretation.
(perhaps because she found this idea to be kinda cool)

The title text humorously states that as well as row hammer, computer servers also can be "hacked" by regular hammers, which would destroy them. A zero-day vulnerability is an attack that takes advantage of a vulnerability that was discovered that day, and hasn't been patched. This would imply that the Rowhammer vulnerability is what inspired someone to try taking a hammer to a server. 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]]

Talk:1917: How to Make Friends

2017-11-20T05:58:28Z

162.158.255.238:

Please clarify: What are "friends"? [[Special:Contributions/172.68.58.95|172.68.58.95]] 08:18, 17 November 2017 (UTC)
: A friend is what you should treat people as - i.e. as a friend in themself, not as a means to a friend.[[Special:Contributions/141.101.105.156|141.101.105.156]] 11:36, 17 November 2017 (UTC)

Randall has obviously not read Stu the Cockatoo is New at the Zoo. [[User:Pmakholm|Pmakholm]] ([[User talk:Pmakholm|talk]]) 08:36, 17 November 2017 (UTC)

hairy is a jerk and unworthy of cueball's friendship. --[[User:Misterstick|Misterstick]] ([[User talk:Misterstick|talk]]) 12:56, 17 November 2017 (UTC)

"Go eat food" might be an effect of the post-"Thing explainer" simple English addiction, already mentioned in some other strip. In fact, the rest of his speech also looks a bit like that.--[[Special:Contributions/162.158.90.162|162.158.90.162]] 17:30, 17 November 2017 (UTC)

If I had a Tumblr, I'd set this as my profile picture. But the stigma of being "the kind of person who whines about vwxyzir disability on Tumblr" is bad enough that I don't wanna go there. [[User:Promethean|Promethean]] ([[User talk:Promethean|talk]]) 05:28, 18 November 2017 (UTC)

Seems like Randall likes to blame lonely people as being morally deficient and selfish... Must be easier than acknowledging the issues they face... [[Special:Contributions/162.158.255.238|162.158.255.238]] 05:58, 20 November 2017 (UTC)