explain xkcd - User contributions [en]

1888: Still in Use

2017-09-11T22:30:21Z

Jonadab: The very specific wording "Still in use" is a direct quote from the OS error message; the safely-remove thing is unrelated.

{{comic
| number = 1888
| date = September 11, 2017
| title = Still in Use
| image = still_in_use.png
| titletext = 'Which one?' 'I dunno, it's your house. Just check each object.' 'Check it for *what*?' 'Whether it looks like it might have touched a paper towel at some point and then forgotten to let go.' '...' 'You can also Google to learn how to check which things are using which resources.' 'You know, I'll just leave the towel there and try again tomorrow.'
}}

==Explanation==
{{incomplete|Rough draft, can still use elaboration. Seems like there are two paragraphs more or less stating the same...? Do NOT delete this tag too soon.}}

Cueball is trying to remove the trash bag from his garbage can. However, the trash refuses to let him do so, citing that a paper towel in the trash is being used by some object in his home.

By itself, the comic is patently ridiculous; it is meant as a reflection of a common problem in computer use, specifically that of deleting currently-open files. One cannot delete a file in Windows while it's being used by a program, and Windows will also not tell the user which program it is. In technical terms, this happens on Microsoft Windows, specifically, because it was designed around FAT-type filesystems, rather than inode-based filesystems. Modern versions of Windows mostly use NTFS, which is significantly more advanced than FAT, but the added layer of indirection (called an "inode") that most filesystems provide between the directory entry for a file and its actual contents is not part of the paradigm that Windows uses, e.g., in its API. So when a program has a file open, it has a reference to the file's directory entry; consequently, the directory entry cannot be removed until the file is closed. On other operating systems, the program would have instead a reference to the file's inode, to which the directory entry points. The directory entry could be removed, decrementing the reference count of the inode and thus allowing it to be automatically deleted later when the program that has the file open closes it or terminates. In order to fix this, Windows would have to break backward compatibility, requiring all old software that runs on Windows to be updated to support a new API. (I am not sure whether NTFS would also have to change, or whether Windows could simply use it differently.)

The title text may be a reference to a simple solution to these sorts of problems: Wait a while, perhaps overnight, and see if the (unknown) application(s) close the open file(s). Alternatively, the user can shut down the system to make absolutely sure that nothing is using anything, and then remove the storage device. In some situations, this is the ''only'' way (at least in Windows) to safely remove an external hard drive from a computer.

Also, the title text may refer to the typical "solution" to the file deletion issue: waiting it out. Sometimes, while trying to delete the file, it could get so frustrating that many give up until the next day, hoping it'll fix itself.

This comic draws parallels between the act of emptying a physical rubbish bin and performing garbage collection on a filesystem, iconically represented by Microsoft as the emptying of a virtual wastebin on the desktop. It also may refer the growing trend of Internet of things, which is a concept that enables everyday objects to collect and exchange data. Sometimes when attempting to delete files the software may still have the file marked as in use, because the file is still marked as open by at least one process. The software will therefore prevent its deletion. This may be correct behaviour, as in when a document is still being worked on in a program, or it may happen erroneously, perhaps because the program has not closed the file properly, maybe because of incorrect behaviour. The user is then required to find the cause of the problem and rectify it before the file can be deleted. This may be difficult if the user is not familiar with the file in question, or the program that would have used it.

In the case of the physical bin, the absurdity of this is highlighted by imagining that a paper towel is still locked as "in use" and that the rubbish bin won't allow it to be taken out for final disposal until the household object that was "using" the towel has been identified.

==Transcript==
:[Cueball is trying to take out the trash]
:Trash: Sorry, you can't empty the garbage yet. A paper towel in here is currently in use by some object in your house.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Computers]]
[[Category:Programming]]

Talk:1196: Subways

2013-04-08T11:17:53Z

Jonadab: Some of those cities don't even HAVE a subway.

I think the comic is making fun of the ridiculous scale-inaccuracies found in public transport plans, including subway plans, which make it hard to estimate actual distances and travel times. {{unsigned|‎130.60.152.125}}

I think it's deffently a factor. <that one editor who always forgets to login>

What does it mean "(with respect to geography)"? As a non US citizen I don't know what is odd about this map. Is this actually how the lines connect up? Are these real stations/lines? Can you really go from san fransisco to new york on subway? {{unsigned|31.221.13.140}}
:Of course not. These are all different subway systems, only connected on this map because their official individual maps use the same colors for different lines. I expect this explanation will be updated to list all the different systems seen here, including Bay Area Rapid Transit (BART) and the New York Subway. [[Special:Contributions/75.37.205.50|75.37.205.50]] 09:30, 8 April 2013 (UTC)
:Also, the comic is using an extremely loose definition of "subway". (Chicago and Cleveland, for example, do not have anything that would fit a normal, dictionary definition of the word. And no, what they do have is certainly not connected in any case -- unless you count highways, in which case the map is ridiculously incomplete.) [[User:Jonadab|Jonadab]] ([[User talk:Jonadab|talk]]) 11:17, 8 April 2013 (UTC)

Hmmm, there is no mention of the 7 or so underground stations in Edmonton, Canada. It is classified as light rail as opposed to heavy rail but still meets the "pedantic rail enthusiasts" definition included under the comic.
Quote: For the pedantic rail enthusiasts, the definition of a subway used here is, with some caveats, "a network containing high capacity grade-separated passenger rail transit lines which run frequently, serve an urban core, and are underground or elevated for at least part of their downtown route." For the rest of you, the definition is "a bunch of trains under a city.[[Special:Contributions/220.239.66.60|220.239.66.60]] 10:10, 8 April 2013 (UTC)

1152: Communion

2012-12-26T12:21:53Z

Jonadab: /* Explanation */ Wikify that link.

{{comic
| number = 1152
| date = December 26, 2012
| title = Communion
| image = communion.png
| titletext = The local police, growing increasingly concerned about this church, ask parishoners to take a sip of wine and then spit it back out for DNA testing. It's blood, and it matches a 1970s murder victim.
}}

==Explanation==
This comic plays on the uniquely Roman Catholic doctrine of [http://en.wikipedia.org/wiki/transubstantiation transubstantiation]. This is the belief that communion bread and wine literally turns into Jesus' flesh and blood when consumed.

==Transcript==
:

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Danish]]
[[Category:Religion]]

1152: Communion

2012-12-26T12:20:57Z

Jonadab: /* Explanation */ link to Wikipedia argicle

{{comic
| number = 1152
| date = December 26, 2012
| title = Communion
| image = communion.png
| titletext = The local police, growing increasingly concerned about this church, ask parishoners to take a sip of wine and then spit it back out for DNA testing. It's blood, and it matches a 1970s murder victim.
}}

==Explanation==
This comic plays on the uniquely Roman Catholic doctrine of <a href="http://en.wikipedia.org/wiki/transubstantiation">transubstantiation</a>. This is the belief that communion bread and wine literally turns into Jesus' flesh and blood when consumed.

==Transcript==
:

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Danish]]
[[Category:Religion]]

Talk:1140: Calendar of Meaningful Dates

2012-11-29T02:51:57Z

Jonadab: Not controlled for day of the week.

Seeing how the (northern hemisphere) summer months are bolder than the winter ones, I remember that someone said that "historical things" like wars and battles used to occur during the good weather months. Same for e.g. romance novels - people date and love on those dates. {{unsigned|‎81.34.231.6}}

If the search included Spanish dates in English texts, May 5th would be larger. {{unsigned|214.4.253.121}}

I wonder if he took into account the month/day swap between the US and UK dating system (among other countries). [[Special:Contributions/76.122.5.96|76.122.5.96]] 14:22, 28 November 2012 (UTC)
:That's a good question. I entered [http://books.google.com/ngrams/graph?content=July+4%2CNovember+5%2C4+July%2C5+November%2CJuly+4th%2CNovember+5th%2C+4th+July%2C+5th+November&year_start=2000&year_end=2008&corpus=15&smoothing=3&share= July 4 and November 5 (Guy Fawkes Day) into Google Ngram], and the difference reflected in the calendar is only apparent when you put the month before the date.--[[User:Prooffreader|Prooffreader]] ([[User talk:Prooffreader|talk]]) 01:11, 29 November 2012 (UTC)

Interesting about the 11ths -- perhaps that correlates with low passenger loads on airplanes as well, and thus why the 11th was chosen for the attack (the month of September having been chosen for some other reason).[[Special:Contributions/50.0.38.245|50.0.38.245]] 15:33, 28 November 2012 (UTC)

I second the Spanish language date in English texts. May 5th is routinely routinely called Cinco De Mayo in English. Has Randall weighed in on how this was handled? [[User:Donglebaker|Donglebaker]] ([[User talk:Donglebaker|talk]]) 18:16, 28 November 2012 (UTC) JC

I also wonder about the difference between the 4th of July (Big 4) and November the 5th (small 5) as being the two "firework" days in US and UK! 4th of July peaks at 0.00003 July the 4th 0.0000001 November the 5th peaks at 0.0000006 and 5th of November peaks at 0.00001 so there are big differences and also whether you pick anything but English 2009. Reader in Invisible Writings --[[Special:Contributions/90.208.142.152|90.208.142.152]] 19:42, 28 November 2012 (UTC)

The transcript reads "[A regular Gregorian calendar laid out in a grid, with some numbers larger than others.]" In fact, there is no way to tell if this is a Gregorian or a Julian calendar; they both have the same months and days. The Gregorian calendar only differs from the Julian in its leap year rule (it has 3 fewer every 400 years).--[[User:Prooffreader|Prooffreader]] ([[User talk:Prooffreader|talk]]) 01:17, 29 November 2012 (UTC)

Certain days of the week tend to get their dates mentioned more than others. Since the sample data were from a small number of years, this may be relevant to the results (unless it was controlled for). For example, in the US, elections are always held on a Tuesday, and Thanksgiving is always on a Thursday (and the Friday and Saturday right after it also get mentioned a lot), but these would not be the same numeric dates every year. — [[User:Jonadab||Jonadab the Unsightly One]], 2012-Nov-28 9:45pm EST (GMT+0500)