explain xkcd - User contributions [en]

2199: Cryptic Wifi Networks

2024-08-19T23:50:10Z

162.158.154.64: /* Removed some less plausible entries in the list of possible sources of cryptic WiFi networks. Note: if the world was a simulation it would not use WiFi. */

{{comic
| number = 2199
| date = September 6, 2019
| title = Cryptic Wifi Networks
| image = cryptic_wifi_networks.png
| titletext = They actually showed up on the first scan by the first WiFi-capable device.
}}

==Explanation==

In the comic, [[Knit Cap]] is on top of a high mountain in a remote location (second comic in a row with knit cap). Mobile devices frequently launch a popup telling users to choose a network to connect to. Knit Cap sees a WiFi network name listed on a handheld device, perhaps a cell phone. The WiFi network seems to be a Business that uses Toshiba. This is something you would expect in a city, but certainly not on a mountain top, hence the joke, that what produced these WiFi networks are unknown, but seems to be distributed randomly over the face of the Earth, disregarding nearness to technology.

Cryptic {{w|Wi-Fi}} (or WiFi) network names, called {{w|Service set (802.11 network)|Service Set Identifiers}} (SSIDs) are part of the joke about not knowing where the corresponding {{w|wireless router}} is located, suggesting they are unexplained phenomena instead of wireless radio devices. Some of the earliest WiFi devices like printers and {{w|internet}} routers advertised cryptic SSIDs, as do many of them today. [https://techtalk.gfi.com/the-31-funniest-ssids-ive-ever-seen/ Humorous SSID names] are not uncommon.

The SSID displayed is '''Toshiba-U2187-OfficeLink-Net46UHZ''' which is 33 characters long, unfortunately one character more than allowed. {{w|Toshiba}} is a multinational electronics conglomerate manufacturing many products including untold multitudes of different kinds of printers over the years. Such devices often have embedded {{w|wireless access point|wireless access points}} including the manufacturer name in the SSID. Many network names contain words like Net, Office or Link. The code might indicate a model U2187 device from Toshiba named (or having an interface program named) OfficeLink, which has a sub-model number or operates on a wireless network designated 46UHZ. That "Hz" is an abbreviation for {{w|Hertz}} suggests that designation may or may not have something to do with the frequency on which the transmitting device operates. U2187 could also be the {{w|Unicode}} character [https://www.fileformat.info/info/unicode/char/2187/index.htm code for the Roman numeral 50,000 spelled "ↇ"] or a serial number for a user or a utility pole. We don't know whether the SSID is connected to a network of more than one or is just one device. The padlock icon indicates that a password is required to communicate. The "join other network" option allows for manually typing SSIDs to attempt to connect with networks which are not configured to display their SSIDs.

While the most likely explanation in an office environment might be a printer plugged in somewhere nearby, other possibilities include a delivery drone, television, speaker, pacemaker, alarm system, [https://twitter.com/Theteamatx/status/1162762591677997056 offshore flying wind turbine,] fashion accessory, military base, hobby project, surveillance device, {{w|Loon LLC|balloon}}, malware-infested device, {{w|Starlink (satellite constellation)|StarLink satellite}}, [https://x.company/projects/foghorn seawater dialysis station,] telecommunication facility, {{w|Facebook Aquila|solar-powered drone}}, infrastructure element, [http://www.geekculture.com/joyoftech/joyarchives/2340.html ransomware worm nest,] or anything else in the Wifi {{w|Internet of Things}}. Sometimes, the {{w|ionosphere}} reflects radio waves, vastly increasing the distance that they can travel to and from remote locations, but this {{w|skywave}} propagation normally affects frequencies below 30 MHz, and never above 300 MHz, so they couldn't be the cause of receiving far away Wifi signals, which are 900 MHz and above.

The {{w|List of router firmware projects|software which produces SSID listings}} is administered by {{w|List of wireless community networks by region|network communities}} and depends on {{w|Wireless mesh network|mesh configurations}}. (Please see also [[1785: Wifi]].) Alternatives include [https://news.ycombinator.com/item?id=20861948 bluetooth mesh networks] and other {{w|wireless ad hoc network|''ad hoc'' networks}} to provide internet connectivity services.

The title text indicates that the first WiFi networking client interface displayed unexpected SSIDs. If true, this could potentially rule out all of the alternative explanations other than a software bug, rogue industrial espionage, hardware misconfiguration, or the supernatural. (It is worth noting that cryptic-sounding WiFi networks generated by a time-traveling alien entity as a trap was used as a plot device in the 2013 ''{{w|Doctor Who}}'' episode "{{w|The Bells of Saint John}}". Doctor Who is a [[:Category:Doctor_Who|recurring theme]] on xkcd.)



==Transcript==
:[Knit Cap (who has a backpack) is checking a phone at the highest mountain in a mountainous landscape, with 5 snow covered mountain peaks behind, and a smaller peak connected to and just below that one. There seems to be no snow on those two peaks. Above is a view of the phone's screen as indicated with a zigzag line from the phone's screen to the frame with text. There is also a wifi icon at the top left and a padlock icon at the end of the second line of text. The bottom line is a gray font.]
:Phone: Available WiFi Networks
:Phone: Toshiba-U2187-OfficeLink-Net46UHZ
:Phone: Join other network 

:[Caption below the panel:]
:Tech Trivia: No one actually knows what devices produce those cryptic WiFi networks. They just appear at random across the Earth's surface.

{{comic discussion}}

[[Category:Comics featuring Knit Cap]]
[[Category:Computers]]

2948: Electric vs Gas

2024-06-19T21:32:58Z

162.158.154.64: /* Explanation */

{{comic
| number = 2948
| date = June 19, 2024
| title = Electric vs Gas
| image = electric_vs_gas_2x.png
| imagesize = 284x385px
| noexpand = true
| titletext = An idling gas engine may be annoyingly loud, but that's the price you pay for having WAY less torque available at a standstill.
}}

==Explanation==
{{incomplete|Created by a HYDROGEN INTERNAL COMBUSTION ENGINE RUNNING A GENERATOR. Do NOT delete this tag too soon.}}

Internal combustion engines are the most common technology used to propel vehicles. In US vernacular, the most common motor fuel is known as "gasoline", or "gas" for short, leading to these engines being referred to as "gas engines".

Electric motors, which were long considered to be impractical for most forms of transportation, are rapidly rising in popularity, and now constitute 18% of all global vehicle sales. [[Randall]] has long been a strong proponent of electric vehicles.

In this strip, [[White Hat]] claims to be comparing the pros and cons of electric motors and gas engines. The joke is that every point he makes goes in favor of electric motors. Despite it being posed as a dilemma, it's very clear which side of the debate White Hat is promoting.

The strip offers the following points in favor of electric motors:

* "Cleaner and more efficient". Internal combustion engines produce and vent harmful combustion products, while electric motors produce no byproducts. The efficiency of both gas and electric motors vary, but the typical vehicle in the US converts around 25% of available energy into motion, while the typical electric vehicle is in the neighborhood of 80%. It should be noted that all of this refers to the motors only, and ignores how the fuel and electricity are produced. In reality, electric motors are far less efficient than internal combustion engines, requiring far more steps to convert chemical energy into kinetic energy.

* "More powerful". While this is misleading and objectively incorrect in the context of vehicles, electric motors are able to have a lot of power in small form factors, such as in toys and electric scooters.

* "Annoyingly loud". Internal combustion engines, by their nature, produce significant noise. Despite noise attenuation measures (such as mufflers), they contribute significantly to urban noise. Properly designed electric motors are nearly silent.

* "WAY less torque available at standstill". Internal combustion engines need to continually operate within a specific range of rotational speeds, which means that a complex system of transmission gearing is needed to convert this motion into the specific speeds needed at the wheels. When starting from a stand-still, this means that torque must be applied to the wheels relatively gradually to avoid stalling the engine. Electric motors, by contrast, generally produce their peak torque when at a standstill. This results in electric vehicles having significantly better acceleration and engine responsiveness.

It should be noted that White Hat is deliberately confining his arguments to electric vs gas ''motors'' rather than electric or gas-powered ''vehicles''. Doing so ignores the basic reason why internal combustion vehicles have long dominated transportation: hydrocarbon fuels are a very dense and fairly easy to handle form of energy storage. Providing electrical power to a moving vehicle requires a large number of high-capacity batteries, which was impractical until comparatively recently (other methods, such as fuel cells, have been proposed but remain experimental).

A more comprehensive comparison would include the cons of electric vehicles, including:

* Higher cost (primarily due to the cost of batteries)
* Long charging times
* Limited range
* Shortened range in hot weather
* Significantly shortened range in cold weather
* Limited charging infrastructure
* Lower reliability
* Higher repair costs
* Higher vehicle weight

Advancing technologies may change how serious these cons are, but they currently remain genuine issues.

White Hat's argument that electric motors are superior in every way is likely true, if we consider only the motor itself. This is evidenced by the fact that gas motors are virtually never used in applications where a reliable source of electricity is available to run an electric motor. However, if we consider the entire system of motor, power, power storage, and the costs of producing the vehicles and their power sources (i.e., refining the fuel or producing the electricity) the matter becomes significantly more complex.

==Transcript==
:[White Hat, with his palm raised, is talking to Cueball.]
:White Hat: Electric motors and gas engines each have their pros and cons.
:White Hat: On one hand, electric motors are cleaner and more efficient. On the other hand, electric motors are more powerful.
:White Hat: So it's hard to say which is better overall.

{{comic discussion}}

[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Cueball]]
[[Category:Climate change]]

2503: Memo Spike Connector

2024-06-12T07:56:49Z

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Talk:2896: Crossword Constructors

2024-02-19T22:36:18Z

162.158.154.64:

The top ten most common letters in the Concise Oxford English Dictionary, and the percentage of words they appear in, are:
E – 11.1607%
A – 8.4966%
R – 7.5809%
I – 7.5448%
O – 7.1635%
T – 6.9509%
N – 6.6544%
S – 5.7351%

source: https://www.rd.com/article/common-letters-english-language/

...

At least one of those "words" is already available
...oreta is a genus of moths: https://en.m.wikipedia.org/wiki/Oreta

Talk:2867: DateTime

2024-01-05T13:04:36Z

162.158.154.64:

Comics like this are why this wiki exists. [[Special:Contributions/172.70.100.172|172.70.100.172]] 23:30, 13 December 2023 (UTC)
:The time falsehoods gist linked above is a really good explanation about why a programmer might panic about calculating time. Especially the ones about calling "getCurrentTime()" twice in a row doesn't always mean the results are in the order you think they were called, or even different values. t2 might very well be the same or less than t1. It can be maddening. [[Special:Contributions/162.158.197.149|162.158.197.149]] 23:40, 13 December 2023 (UTC)
::The last item is the most important to me: ''Users prefer to use the local timezone.'' This causes so much frustration while browsing the web! [[File:PissedOff.gif]] --[[Special:Contributions/162.158.110.68|162.158.110.68]] 00:26, 14 December 2023 (UTC)
::Worth noting that events can take place over long periods. A sunspot or an illness or a relationship doesn't happen at a single point in time, it takes place over days or weeks or longer. When did it "start"? Who knows? Also I miss calling TI4-1212 here in DC. [[Special:Contributions/172.70.175.27|172.70.175.27]] 01:39, 14 December 2023 (UTC)
::Out of curiosity, could someone explain the item in that time falsehoods list that says "Months have either 28, 29, 30, or 31 days"? My guess is that it's a reference to their being more calendars in the world than Gregorian? But I'm not sure if there's more than that going on, there.[[User:ModelD|ModelD]] ([[User talk:ModelD|talk]]) 18:18, 14 December 2023 (UTC)
:::Isn't that true of Gregorian calendars? February has 28 or 29 depending on the year, AJSN have 30 and JMMJAOD have 31.[[User:Gavin|Gavin]] ([[User talk:Gavin|talk]]) 18:33, 14 December 2023 (UTC)
::::It's saying that "months have either 28, 29, 30, or 31 days" is a falsehood. The first one that comes to mind is the [https://www.timeanddate.com/calendar/julian-gregorian-switch.html switch from the Julian calendar to the Gregorian calendar]: "In North America, for example, the month of September 1752 had only 19 days, as the day count went straight from September 2 to September 14". [[Special:Contributions/172.70.43.108|172.70.43.108]] 21:03, 14 December 2023 (UTC)
:::: (Ninjaed, with an actual example! But retrying reply anyway as it had other details.) But how many days had <insert your choice of month(s) during which a given system changed from Julian to Gregorian>? I think possibly, without looking up when each and every transition occured, below 20 days is possible. (As in the ''n''th of one month to the ''n''th of the next is less than 20 days, for the right month and a number of ''n''s. For other ''n''s, you can only actually count from the month before to the month ''after'' (two full calendar months), the daycount for that being below the typical bimonthly stretch of 59, 60, 61 or 62 days (under more standard conditions)... [[Special:Contributions/172.70.90.48|172.70.90.48]] 21:07, 14 December 2023 (UTC)
::::: The shortest month might be February 1923 in Greece, which had only 15 days. The most recent such instance seems to be December 1926 in Turkey, which had 18 days. [[Special:Contributions/162.158.154.64|162.158.154.64]] 13:04, 5 January 2024 (UTC)

Related insanity on Computerphile with Tom Scott: https://m.youtube.com/watch?v=-5wpm-gesOY [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 03:54, 14 December 2023 (UTC)

Even with just Special Relativity, the question doesn't really make sense, because the answer will depend on the inertial reference frame. "Impossible to know and a sin to ask" is not a bad way to describe questions about non-invariants. [[Special:Contributions/162.158.154.189|162.158.154.189]] 08:09, 14 December 2023 (UTC)
:Is it even ''possible'' for two observers to agree on the answer and be sure that it's correct for both of them? [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 16:53, 14 December 2023 (UTC)
::In order to know if the answer to T2 - T1 is correct, you'd first have to know if T1 and T2 are correct. I'd say that's already impossible. [[Special:Contributions/172.71.99.134|172.71.99.134]] 11:53, 18 December 2023 (UTC)

I can see Randall's point, so for your average everyday programming I'd say "please use a library function instead of trying to do it yourself, or you'll end up like the guy in the lower frame..." --[[User:IByte|IByte]] ([[User talk:IByte|talk]]) 11:02, 14 December 2023 (UTC)

When I googled "DateTime" all I came up with was Python libraries, nothing about relativity or other effects. Is that what Randall's talking about? [[Special:Contributions/172.69.22.125|172.69.22.125]] 22:03, 14 December 2023 (UTC)
:Ideally, the standard library functions for a language would cover many of the "quirks" without the programmer having to worry about remembering the details. The required inputs for the functions would be sufficient to determine the necessary offsets. But programmers still have to be careful about some of the issues, and not all languages (and their libraries) are sufficient for all situations. When things like relativistic effects have to be taken into account, the usual languages (and their libraries) don't have the needed flexibility/complexity and precision. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 00:18, 15 December 2023 (UTC)
::I should clarify, I'm not saying the Python library doesn't have functions for those quirks. I'm just asking: what does Randall mean when he says "DateTime" (two capital letters, no space, as per the comic title)? Is he talking about the Python library? Or something else I didn't find yet?[[Special:Contributions/172.69.134.163|172.69.134.163]] 02:51, 15 December 2023 (UTC)
:::Doesn't matter. For one the usage of CamelCase in such cases is pretty much standard regardless of language and besides of that the problems he's talking about/implying are pretty much true for every language. [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 10:58, 15 December 2023 (UTC)
::::OP, I suspect your Google cookies/whatever are just too used to serving you answers to Python questions, as being the answers you most like to visit. I just added to the "it's definitely Python" explanation another three more (of an easy dozen or so, before I gave up) links that I found from searches for "DateTime library <language>", or equivalent. And even those that didn't give that exact wording in their actual modules tended to have "What's the standard DateTime library for <foo>..?" as an FAQ (including LISP, Forth, COBOL, even a few for one or other Assembler variant, which I tried just for laughs) because the concept of "DateTime" record is just too ubiquitous (whether stored as "seconds since epoch" a distillation of an ISO format or just "[yy]yymmddHHMMSS[.###]" pseudo-value/string) and goes way back before Python (1991+) as you can find mentions of one kind or other in my old Ada (c1980) and Pascal (c1970) manuals/references. [[Special:Contributions/172.70.162.206|172.70.162.206]] 15:47, 17 December 2023 (UTC)

:::The majority of libraries that provide time-calculation services call it something along the lines of DateTime. The reason you're getting Python results is because Python is currently the most popular programming language, especially for people learning to program. --[[Special:Contributions/172.71.150.154|172.71.150.154]] 19:51, 15 December 2023 (UTC)

The recently-added link for "hyperbolic" goes to a W'pedia page for "Hyperbolic motion (relativity)". This is obviously intended as a joke, but I'm not convinced that an unmarked joke like this is appropriate. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 16:04, 15 December 2023 (UTC)
:I highly doubt this was meant as a joke, I'm quite convinced this was genuinely added to be helpful and fail to see how this COULD be a joke. ??? If it's not the correct concept it's too subtle to be a joke. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 05:46, 17 December 2023 (UTC)
::It quite definitely was a joke. I will take the badges of 'too subtle' and 'inappropriate' and wear them both with pride. ;o) [[Special:Contributions/172.70.90.70|172.70.90.70]] 11:53, 3 January 2024 (UTC)

My first impression of the comic was that Randal was talking about romantic dates, and that participants may be too distracted to accurately recall when specific events occurred during them. [[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]]) 02:22, 17 December 2023 (UTC)