explain xkcd - User contributions [en]

949: File Transfer

2022-10-26T23:14:01Z

172.70.135.224:

{{comic
| number = 949
| date = September 9, 2011
| title = File Transfer
| image = file_transfer.png
| titletext = Every time you email a file to yourself so you can pull it up on your friend's laptop, Tim Berners-Lee sheds a single tear.
}}

==Explanation==
[[Cueball]] is trying to help two people, his friend and his friend's cousin, exchange a 25 MB file. Most people know how to use email to send files through the internet, but (as of 2011 when this comic was published) 25 MB exceeds the attachment size limit of most email services. The reason there is a limit is because every email has to be transferred between several mail transfer agents, and each one has to temporarily store a copy of the email. Space constraints on those mail servers means that they must impose size limits, and an email with such a large attachment will therefore not be delivered.

The next option is to upload the file to an FTP server (FTP stands for {{w|File Transfer Protocol}}, as opposed to HTTP, {{w|Hypertext Transfer Protocol}}), used to transfer files between computers on a shared network, such as the internet. However, FTP servers are a touch more esoteric than a mere email attachment, and many internet users don't have access to one of their own.

Web hosting is simply the ability to create a website and store all the data for said website on a server which is connected to the internet. If Cueball's friend's cousin had the ability to do that, sharing the file would be as easy as putting a copy of it in an accessible directory and sending the link to the desired recipient.

{{w|Megaupload}} was one of many sites on the Internet that recognized most users' inability to host large files on their own, and so offers to host large files, sometimes for free, sometimes for a small fee. The payoff is that in order to make such a service profitable, many of these sites are cluttered with banner and pop up ads in a mad effort to squeeze as much ad revenue out of every page view as possible. It's not a dealbreaker for some, but Cueball seems to think it'll be too much for his friend's cousin to handle.

{{w|AOL Instant Messenger|AIM}} Direct Connect was a file sharing system on AOL Instant Messenger, which was already suffering severe drops in popularity by the year 2000. Clearly, Cueball is grasping at straws here: anybody desperate enough to invoke the name of AOL as a solution instead of a problem must be at their wits' end.

{{w|Dropbox (service)|Dropbox}} is a program with a web-based GUI that automates file sharing between two computers on the internet. But this solution also has its issues, as it requires that at least the sending party has a Dropbox account. Installing Dropbox software is not actually required, since Dropbox also provides a web interface for uploading and downloading files. At the time of the comic's publication, Dropbox was still relatively new and unknown, thus why it is not Cueball's first suggestion.

While Cueball is still explaining Dropbox, the friend's cousin has copied the file to a USB drive and physically transported it to the friend's house, circumventing the Internet entirely. It's not an elegant solution, but sometimes traditional methods are the most efficient ways to get something done.

When used to transfer files between computers in the same room or building, this same approach is referred to as {{w|sneakernet}}. This comic is also an illustration of what {{w|Andy Tanenbaum}} said in 1989: ''Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway.'' Sneakernet was examined in this [https://what-if.xkcd.com/31/ What If] article.

{{w|Tim Berners-Lee}} developed the HTTP protocol, the {{w|HTML}} markup language and the first web browser. Therefore he is considered to be the inventor of the World Wide Web. He envisioned originally an interactive web, where it would have been possible for the users to change a website directly using the browser, which would have made it possible to upload a file directly to a webpage:

:<q>Tim Berners-Lee's original vision of the Web involved a medium for both reading and writing. In fact, Berners-Lee's first web browser, called WorldWideWeb, could both view and edit web pages</q> (from Wikipedia [https://en.wikipedia.org/w/index.php?title=WebDAV&oldid=1006182171 WebDAV]).

In contrast to this, a static web ("Web 1.0") came alive, which developed then later to the interactive "Web 2.0" we know today. Wikis like [[Main Page| this website]], where the page content is editable via forms, are a perfect example for this "emulated interactivity". From the technical point of view, the webpage is still static and the browser is just a viewer for html pages with the limited possibility to send some form data to the server. Scripts on the server, which process this form data, then change the web page. This mechanism is a more complicated work-around for what Tim Berners-Lee originally planned.
Dropbox and the web interfaces of email providers are further examples of this "emulated interactivity". The title text assumes, that Tim Berners-Lee feels probably generally sad, that his invention developed into this unnecessary complicated way and misusing emails (maybe even via the web interface of email providers) for file sharing is therefore especially painful for what could have been so simple.

==Transcript==
:[Cueball stands near a computer, talking on the phone to another person.]

:Cueball: You want your cousin to send you a file? easy. He can email it to- ...Oh, it's 25 MB? Hmm...
:Cueball: Do either of you have an FTP server? No, right.
:Cueball: If you had web hosting, you could upload it...
:Cueball: Hm. We could try one of those MegaShareUpload sites, but they're flaky and full of delays and porn popups.
:Cueball: How about AIM Direct Connect? Anyone still use that?
:Cueball: Oh, wait, Dropbox! It's this recent startup from a few years back that syncs folders between computers. You just need to make an account, install the-
:Cueball: Oh, he just drove over to your house with a USB drive?
:Cueball: Uh, cool, that works too.

:[Caption below the panel:]
:I like how we've had the internet for decades, yet "sending files" is something early adopters are still figuring out how to do.

==Trivia==
This comic has a resemblance to both [[1810: Chat Systems]] and [[2194: How to Send a File]]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Computers]]
[[Category:Internet]]
[[Category:Comics featuring real people]]
[[Category:Email]]

Talk:2682: Easy Or Hard

2022-10-18T00:18:54Z

172.70.135.224: /* This whole "hair and baloon" thing */

For other people not in US: active ingredient of Tylenol is {{w|Paracetamol}}. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 12:51, 7 October 2022 (UTC)

"Now paleontologists have pinpointed during what time of year that millions of years event happened, all thanks to new fossil evidence" (from [https://www.youtube.com/watch?v=okOnVovooeM SciShow]) It is probably what's referenced in the "What time of year did the cretaceous impact happen?" [[User:Ppete pete|Pete Ratchatakul]] ([[User talk:Ppete pete|talk]]) 13:36, 7 October 2022 (UTC)

Paper cited in the title text: https://www.researchgate.net/publication/360674587_Derivation_of_a_governing_rule_in_triboelectric_charging_and_series_from_thermoelectricity
[[User:Victor|Victor]] ([[User talk:Victor|talk]]) 13:39, 7 October 2022 (UTC)
:AKA https://journals.aps.org/prresearch/pdf/10.1103/PhysRevResearch.4.023131 [[Special:Contributions/172.70.210.49|172.70.210.49]] 14:17, 7 October 2022 (UTC)

Papers related to the time of the year of the impact:

"... reveal that the impact occurred during boreal Spring/Summer, shortly after the spawning season for fish and most continental taxa." - [https://www.nature.com/articles/s41598-021-03232-9 Seasonal calibration of the end-cretaceous Chicxulub impact event]

"Here, by studying fishes that died on the day the Mesozoic era ended, we demonstrate that the impact that caused the Cretaceous–Palaeogene mass extinction took place during boreal spring." - [https://www.nature.com/articles/s41586-022-04446-1 The Mesozoic terminated in boreal spring]

[[User:Ppete pete|Pete Ratchatakul]] ([[User talk:Ppete pete|talk]]) 13:46, 7 October 2022 (UTC)

Isn't mechanisms of Tylenol well known?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4912877/
:No - that's still a fairly new theory and it isn't fully accepted yet, or confirmed that there isn't anything else going on. It's been an area of controversy for a long time - when I graduated it was still thought it was a cox-3 inhibitor and that wasn't that long ago. (I'm a pharmacist.) [[Special:Contributions/172.70.162.77|172.70.162.77]] 12:07, 9 October 2022 (UTC)

I can't vouch for the long-period accuracy of the software that I just used (nor have I cross-checked with any other list or interactive app), but my quick research shows that on 31st March 1889 (dignitaries were officially taken to the top of the Eiffel Tower), Mars was in Pisces, and that in-between then and 6th May (the public got to do the same) it had drifted through Aries (IIRC, forgot to note that explicitly!) and into Taurus, where it was still on 26th May (the lifts opened, and the journey didn't have to be by the stairs!). Although you would have been unlikely to get a good view of Mars as it was quite close to conjunction with the Sun, getting well past Mercury's furthest extent. (In mid-June, it was practically on top of (or over but behind, as it were) the Sun, out of sight for all practical purposes.) I'm sure someone can do a more thorough check than myself, before we set this down properly/succinctly, but it was the first thing I thought of checking for myself. [[Special:Contributions/172.70.90.245|172.70.90.245]] 15:56, 7 October 2022 (UTC)

Top right reminds of [[2501: Average Familiarity]]: I guess that for many people relativity and quantum mechanics might fall in the middle right cell, not the top right. [[Special:Contributions/172.69.3.238|172.69.3.238]] 16:07, 7 October 2022 (UTC)
:I agree. It takes some familiarity with physics to realize that reconciling them is hard. Lay people may not understand these things at all, but they might assume that they're known well enough by scientists that this is at worst a hard problem. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:28, 7 October 2022 (UTC)

Isn't there a category for these types of grids? There should be, he does lots of them. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:28, 7 October 2022 (UTC)

I got 2.125*10^-17 m/s^2, or 3.18*10^-18 N, for the gravitational force/acceleration from the Eiffel Tower on a baseball on Fenway Park. Someone might want to check my calculations, though.--[[User:Account|Account]] ([[User talk:Account|talk]]) 23:42, 7 October 2022 (UTC)
: How did you get those numbers? I was trying to figure it out (for shits and giggles), but I got a different number. What equations/calculations did you use? --[[Special:Contributions/72.138.76.186|72.138.76.186]] 14:04, 11 October 2022 (UTC)
: It occurred to me that the Boston to Paris gravity question might not be quite as easy as it seems, since the relevant distance would be not “as the crow flies,” but more “as the mega-gopher digs.” (I think?) [[User:Miamiclay|Miamiclay]] ([[User talk:Miamiclay|talk]]) 21:11, 9 October 2022 (UTC)
:: I already edited it away from the (implied) suggestion of Great Circle distance (as a trivial understanding of 'distance between', and probably what most searches for a value would turn up). But using latitude, longitude and radius (local, +altitude if you're into the detail) from a sufficiently accurate geophysical model (at least an oblate spheroid) as spherical coordinates leads quickly to true-ish straight-line length. And probably doesn't need to be sigbificantly further adjusted by the small dimple in spacetime that the Earth puts there, or even the fringe distortions of other tide-inducing (and therefore variable) gravitational bodies.
:: You might even get away with a mere spherical model (and altitude is surely less significant a factor than the difference between that and the spheroid), for a given necessary accuracy level. But I thought that was too much to explain, so left it a bit vaguer. But if further edits are needed, feel free! [[Special:Contributions/172.70.85.49|172.70.85.49]] 08:27, 10 October 2022 (UTC)
::: An oblate spheroid is probably overkill. The difference between the polar and equatorial radii is 20 km, about 0.3% of the radius. Certainly, if you're down to the accuracy where you care about the elevation above sea level, this is going to be important, but otherwise it's not going to change your result much to just use a sphere with the mean radius of the Earth. [[Special:Contributions/172.70.34.213|172.70.34.213]] 20:15, 11 October 2022 (UTC)

I can attest to the anesthesia one... Near the beginning of Covid I had to get my foot amputated, something they obviously would knock you out for. However, it was felt that it would be risky in light of Covid so they wouldn't, instead numbing me with a needle to the spine (as I understand it, same idea as the epidural women might get while giving birth). So I was awake and feeling nothing while getting a body part cut off me (both times, I had to get cut twice due to the first cut getting infected). Just shows how delicate even an anesthesiologist's understanding is. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:03, 8 October 2022 (UTC)

Is it actually a bigger medical mystery how Tylenol works than how general anesthesia works? I figure the latter has had more research dollars spent on it, at the very least. [[Special:Contributions/172.70.178.65|172.70.178.65]] 21:17, 10 October 2022 (UTC)

Calculating how much does the Eiffel Tower's gravity deflect baseballs in Boston is easy, but direct observation is insanely hard. [[User:Lamty101|Lamty101]] ([[User talk:Lamty101|talk]]) 02:09, 11 October 2022 (UTC)
:But just to observe the force, one only needs a {{w|Torsion_spring#Torsion_balance|torsion balance}} and some means of entirely relocating the tower to an equidistant point on the Earth's surface but on a plane at right-angles to that of the original vector (for comparative purposes)... ;) [[Special:Contributions/172.70.86.26|172.70.86.26]] 08:53, 11 October 2022 (UTC)

Why is the transcript marked as incomplete? [[Special:Contributions/172.70.238.143|172.70.238.143]]
:: Missing title text? New poster/editor didn't know/bother to remove the tag? [[Special:Contributions/108.162.241.51|108.162.241.51]] 15:19, 11 October 2022 (UTC)
::: If it has title text it is ''over''complete and TT details would need to be removed from it. Title text is already given verbatim. The Transcript is there to support access to screen-reading/text-searching of information only otherwise available in graphical form, and therefore does not do anything useful by providing the TT (and could be so eadily made to give a ''different'' TT). That's my general understanding of the evolved 'policy' on this, anyway. If it changes, I'd suggest that a <nowiki>{{Template}}</nowiki> be inserted below the initially empty Transcript (and above the Discussion insertion) that grabs the <nowiki>{{comic}}</nowiki> field of title text, on the calling page (or optionally another, by numeric parameter, if that would be ever useful) and repeats it verbatim. But, that aside...
::: If someone has an idea that they have now truly completed the Transcript, they can remove that tag. If someone else believes there are no further worthwhile improvements, they can remove that tag. But someone else might make it 'better', ''anyway'', two minutes or ten years later. And rather than worry about detagging the very latest comic (or even the prior couple, from within the last two) ASAP, I'd personally think about looking at anything untouched for a while from the older comics. And either tweaking (but leaving the tag a little longer for others to review, finishing the job a few days later if no further issues) or finalising as complete rather than polish the turd/gild the lilly.
::: But I know some people have blitzed all Incomplete tags, and many others clearly consider it not so clear cut and leave them in order to give the benefit of the uncertainty. – Between all our crowd-edits, there seems to be a fairly reasonable concensus, although vanishing Incompletes rarely get replaced by others who disagree but can't themselves (properly) Complete them so it probably biases towards more premature Completing. Which doesn't freeze it, and if the community-accepted 'transcript formatting' hasn't even been done yet it can still be done. (Perhaps the only time I'd reinsert the Incompleteness tag while "finishing" it.) [[Special:Contributions/172.70.86.26|172.70.86.26]] 18:09, 11 October 2022 (UTC)

== This whole "hair and baloon" thing ==

According to a fan theory, hair have a lot of microscopic imperfections like cracks, that tend to rub against things in "microrough" manner.
<br />Meanwhile, ballons, that are made of elastic matter, will have to interact with the hair's ... microscopic stuff.
<br />As a result, there will be quite a surface for interactions on molecular level to bump a lot of molecules one against another without scratching/damaging.
<br />Same thing in lesser proportions happened to me in 2009, when I magnetized my Philips screwdriver by revolving its edges against edges of holer in my PC case.
<br />So, in my opinion, "hair agaist baloon" is a good clue: it takes very little effort unlike revolving a 6mm screwdriver agaist 5 mm holes {{unsigned ip|162.158.203.40|Latest revision as of 13:10, 14 October 2022}}
:The big thing about balloon/whatever charge redistribution is (the last I heard) why charges preferentially travel in one direction upon rubbing. Given the complicated mix of surface-molecules, you can't ascribe it to ready-donor/ready-recipient tendencies, such as in an electrolytic cell specifically designed to promote electron/proton exchange from an amorphous mass. And, if nothing else, having been transfered then the force of newly accumulated charge syould want to flow at least as readily in the other direction upon more dynamic contact, so whatever 'incidental' bias from your particular choice of material-pairing (amber/cloth, latex/keratin, or however the charge differential is established in thunderclouds) there's going to quickly be a limit whereupon the charge-per-subunit is hit by diminishing returns (presumably intra-molecular charge distribution 'soaks' some chare distribution away frm the 'skin' of the respective substances).... So it's more complex than just the above, and definitely does [[2268: Further Research is Needed|need further study]], the last I heard. [[Special:Contributions/172.70.91.58|172.70.91.58]] 15:07, 14 October 2022 (UTC)

: FYI, the effect has a name. It's called ''triboelectricity'' (https://en.wikipedia.org/wiki/Triboelectric_effect). [[Special:Contributions/172.70.135.224|172.70.135.224]] 00:18, 18 October 2022 (UTC)