Wikipedia:Reference desk/Computing

Welcome to the computing section
of the Wikipedia reference desk.

skip to bottom

Select a section:

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

Want a faster answer?

Main page: Help searching Wikipedia

   

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

See also:

• Teahouse
• Help desk
• Village pump
• Help manual

May 2

IP address location

Where does WHOIS get location information for Australian addresses? https://whatismyipaddress.com/ip/49.198.51.54 shows me in Brisbane, but I'm really in Melbourne. https://whois-referral.toolforge.org/gateway.py?lookup=true&ip=49.198.51.54 says my "geolite2" is in Brisbane and my "geo_ipinfo" is in Melbourne. I guess whatismyipaddress might be wrong if I were in some remote regional area, but I don't understand why it's so badly wrong for an IP address from a major metropolitan area. It's not the physical address of my Internet provider, Optus, which is headquartered in Sydney. 49.198.51.54 (talk) 21:41, 2 May 2022 (UTC)

WHOIS doesn't have IP geolocation. Do you mean whatismyipaddress.com? Nil Einne (talk) 00:59, 3 May 2022 (UTC)

Anyway when I visit the above link, it says "Geolocation data from IP2Location." Confusingly [1] says "It came from the IP address geolocation service used to look at the IP address of wherever you were when you visited our site." I don't really understand what it's trying to say since I didn't and possibly you didn't visit a geolocation service when visiting their site. Maybe it means if you visit geolocation service that gets data from whatismyipaddress.com, it's forwarded to and cached by whatismyipaddress.com and this is what is displayed so it's possible they don't always get it from IP2Location. You can probably look a bit more on IP2 Location's site and here [2] for more info on the geolite2 IP database. In the absence of more info, it's generally difficult to say why a particular address might be inaccurate but I expect a common reason may be a geolocation change perhaps coming from the ISP moving their address space as part of their efforts of coping with IPv4 address exhaustion (which happened long ago but ISPs may still find it useful to move things around to manage things). You may or may not be able to use [3] and [4] to try and improve your geolocation on whatismyupaddress.com if you're willing to allowed your browser to provide it (and it knows).Nil Einne (talk) 02:06, 3 May 2022 (UTC)

I picked those links from Special:Contributions/49.198.51.54. I guess I thought that was what WHOIS consisted of? I've heard of badly wrong coordinates, like this story from America, but they tend to be all located at some central point for the company, not 1000km away from the company and 1500km away from the user, or they're in the centre of a region (like the American example) rather than being in another big city. And I think they're more often when a company has a ton of dynamic IP addresses and yours changes all the time, but I've had this IP address since 21 February. But it isn't a big deal (I don't want to try to get something fixed), so I was just curious. 49.198.51.54 (talk) 06:22, 3 May 2022 (UTC)

All I can say is the geolocation is sometimes wrong, which is why we have a choice of geolocation links (you can find many more scattered throughout various admin tools). Unfortunately there's only room for two links in that place, so we use the most agreeable (relatively accurate and spam-free) geolocation links. Several other sites will have it right.[5][6] The WHOIS link does indeed pull in data from separate databases - it is not a normal part of WHOIS, but something designed by one of us, for use by us. If you want standard WHOIS, try this Unlike WHOIS, there is no central registry of geolocations, and it comes from a variety of sources. Sometimes ISPs provide the info, sometimes it's based on user behaviour, or users, and sometimes there's a mix of proprietary databases and no one really knows where they get that from. And often geolocation will change as IPs get moved around. Australia in particular has a weird way of assigning IP addresses. Personally, I would be most persuaded by looking at "meb3.vic.optusnet.com.au" in your IP's hostname, where "meb3" and "vic" probably mean exactly what you think. -- zzuuzz ^(talk) 15:02, 3 May 2022 (UTC)

May 3

How to learn programing

How can I learn programing easily as a beginner, and what site may I use to learn? Makerman88 (talk) 11:28, 3 May 2022 (UTC)

Python.org has a page Python for Non-Programmers offering suggestions, and specifically links to free interactive courses. Learn Python is advertized as suitable for absolute beginners.  --Lambiam 14:24, 3 May 2022 (UTC)

I know there's also a website called "code.org" which teaches you coding using code blocks (However I Personally don't see how that's helpful since actual programming doesn't have code blocks for you to use), but I think that's Javascript (or is it Java?). ― Blaze Wolf^Talk_{Blaze Wolf#6545} 14:28, 3 May 2022 (UTC)

Hi @Makerman88:, the R-project has good manual to get started with R programming. There are multiple online free resources to learn it as well. I hope this helps. :) Nanosci (talk) 00:18, 4 May 2022 (UTC)

I've used code.org with school. Yes, you have blocks (I don't know if this is a certain code) but when you put the blocks in the right place, in the end, you can see the code you have written or see past levels you've done. So, you can learn coding in a really nice way and you can see what you have done so you can study it later. OK, I know that it can be seen a little bit childish at first because it was created in a funny way and to be closer for children too, but, it is a good way to learn coding, in my opinion. Also, it has helping videos to understand things easier. There are some levels that have to do with AI which I found really interesting. I would definitely recommend it for all ages.

Hope this helps :) - Fisforfenia (talk) 13:02, 5 May 2022 (UTC)

References

Restarting program/computer fixes some issues

Hello! So something people usually get told when something isn't working is to try closing it and reopening it or turning it off and then back on. Why exactly does doing this work? Isn't the computer just reading lines of code? Cause if that's true, then why would closing and reopening the program or restarting the computer change anything? For example, recently I was playing Snowrunner (insert a bunch of random, irrelevant details), I was using a truck with a crane attachment and the game had been running for a while. When I attempted to use the crane to pick up another truck, the attachment points for the crane were popping up (just white dots as a UI), however I wasn't able to actually select them and attach the crane to them. When I closed the game for the night and opened it back up the following morning, the crane and attachment points were working properly again. So why exactly did restarting the program fix the issue I was having? ― Blaze Wolf^Talk_{Blaze Wolf#6545} 18:18, 3 May 2022 (UTC)

Let's imagine a reason why Snowrunner might do this. Suppose when each truck is created, it is given an index number, and its attachment points are given numbers as well. How does the game identify which one has been clicked on? (I don't know whether selection in this game is actually done with a mouse click, but I'm imagining it is.) Let's suppose it uses a kind of chroma key: it maintains a whole second copy of the screen, which is mostly black, but has the areas you can click on drawn in solid colors. They might actually look very similar to black, that doesn't matter, because this private copy is for the computer, not for human eyes. The important thing is that each clickable item is drawn in a different color, which translates to its index number, the same way that for instance magenta is represented by hexadecimal code FF00FF (which equals 16711935). So let's say that the programmer chose to store both the index numbers and the translations of those numbers into color codes, which are very similar to the indexes, but which combine the truck index with its specific attachment point number into one number of the right format to be drawn as a color. These translations could be done every time they are needed, but instead the programmer decided to do them in advance and store them. OK so far?

Now, suppose in this game there are a bunch of other trucks around, and they come and go - and once in a while they leave the location altogether, or a new one arrives. So that means index numbers are leaving and new index numbers are arriving, right? And let's say the programmer didn't want the numbers to just keep getting bigger as a result, and for some reason didn't think of just recycling the numbers from trucks that have left, but instead chose to reassign the numbers of every truck whenever one leaves to keep the numbers as low as possible, without any gaps. However, this idiot forgot to write the part where the color code translation of the index number gets updated. So now what happens is that after a certain amount of seemingly unrelated background activity, the game gets into a state where the clickable items are producing codes that don't match up to any currently existing part of any currently existing truck. It reacts to this by doing nothing when you click on them. If you restart the game, however, every truck is freshly created, and assigned a fresh index number and a corresponding color code translation which matches correctly (for now). This imagined reason will turn out to be implausible if picked apart, but it could be something like that.  Card Zero  (talk) 19:38, 3 May 2022 (UTC)

That would make sense since I had been playing multiplayer previously so the person I was playing with was switching out the truck they were using (or just respawning their truck which I would assume would function the exact same). Probably not how it works exactly, but it does help understand. I always think of games and programs as just a bunch of lines of code that the computer is reading. And that's probably partially what it is, but clearly it's much more than that. ― Blaze Wolf^Talk_{Blaze Wolf#6545} 20:07, 3 May 2022 (UTC)

An analogy for this I read a while ago was: Imagine you are in a new city and you've been given a map. You walk around for awhile but suddenly get lost, and don't know where you are on the map. Would it be easier to either try and figure out where you are at your current location, or to return to your starting location and try again? It's generally the same thing with computers. ― Tuna + 13:41, 5 May 2022 (UTC)

@Tunakanski: Huh. Interesting. (kinda moot now since most maps are now online and don't lose where you are, but I still understand it) ― Blaze Wolf^Talk_{Blaze Wolf#6545} 13:42, 5 May 2022 (UTC)

May 4

Trouble installing Linux service (systemd)

Resolved

Systemd is so confusing. I created a file /etc/systemd/system/multi-user.target.wants/my.service with the following contents:

[Unit]

Description=My Service

Wants=network.target

After=syslog.target network-online.target

[Service]

Type=simple

ExecStart=/home/bin/my

Restart=on-failure

RestartSec=10

KillMode=process

[Install]

WantedBy=multi-user.target

Then rebooted the system but the binary /home/bin/my never loads. What am I doing wrong here? Come to think of it, is there an easier way than this whole manual config files route of setting things up? Earl of Arundel (talk) 06:51, 4 May 2022 (UTC)

systemd is a pain. Did you enable the service with the systemctl command? This article may help (it did when I created my own service) https://www.digitalocean.com/community/tutorials/how-to-use-systemctl-to-manage-systemd-services-and-units TrogWoolley (talk) 10:42, 4 May 2022 (UTC)

Thanks! It wasn't so hard after all. Copying the service file directly to the /etc/systemd/system directory, then starting the service via systemctl seemed to fix the issue. Earl of Arundel (talk) 17:39, 4 May 2022 (UTC)

Percent sign in link

The link gets messed up because of an invalid character. Where do I find a list of what I can replace invalid characters with?

The URLwikilink contains "{Bende egitilmek istiyorum}78.180.7.191 (talk)"— Vchimpanzee • talk • contributions • 19:32, 4 May 2022 (UTC)

Here's a URL encoding converter and reference. It's utf-8.  {  is %7B and  }  is %7D.  Card Zero  (talk) 03:34, 5 May 2022 (UTC)

The characters "{" and "}" in a URL are unproblematic; the link https://en.wikipedia.org/enwiki/w/index.php?title=Wikipedia:Teahouse&oldid=1060980341#{Bende_egitilmek_istiyorum}78.180.7.191_(talk) works just fine. How does the percent sign enter the picture? If you need to have a percent sign in the URL, for example to say "%20 indirim" (Turkish for "20% off"), you have to use "%2520 indirim", or else "%20" will be replaced by the space character.  --Lambiam 07:24, 5 May 2022 (UTC)

It's not working in a piped link, actually. Can anyone fix this?— Vchimpanzee • talk • contributions • 16:05, 5 May 2022 (UTC)

Okay, the percent encoding worked in a piped link. Thanks.— Vchimpanzee • talk • contributions • 16:47, 5 May 2022 (UTC)

Cool. By the way, I looked at the source of that talk page message, and it uses a template (?) called urlencode which can be used to produce codes like %7B by writing {{urlencode:{}}. This may be harder to use than just looking up the percent encoding, but it's good to know about. (It would go wrong with the closing curly bracket, unless there was something after it!)  Card Zero  (talk) 17:12, 5 May 2022 (UTC)

{{urlencode:}} is called a parser function. It's part of MediaWiki, documented at mw:Help:Magic words#URL data. PrimeHunter (talk) 01:47, 6 May 2022 (UTC)

The problem was an issue of wikilink syntax (see Help:Link § Disallowed characters), not of URL syntax.  --Lambiam 21:27, 5 May 2022 (UTC)

May 5

Why does UConn represent Wikipedia?

I put a link to a diff in an email to myself so I could find the diff again. For some reason, Hotmail (or at least that's the address, but I'm unsure how to define Outlook.com) puts a photo representing the web site below the URL. In many cases, it's a link to a photo I want to print out later, and the photo itself appears. In this case, for some reason, I got a photo of a female UConn basketball player.— Vchimpanzee • talk • contributions • 16:44, 5 May 2022 (UTC)

@Vchimpanzee: It was probably because Paige Bueckers was Today's featured article for April 28, 2022. Outlook.com likely crawled Wikipedia's main page on that day and took the first image on the page to represent the website. Yeeno (talk) 18:43, 5 May 2022 (UTC)

Formatting time in Excel

I have an Excel spreadsheet that lists time periods. I want them listed, in this format. For example, "4 hours and 38 minutes and 17 seconds" should be listed / formatted as 04:38:17. I want the leading zero in front of the "4" hours. In the cells, I did a "custom" format of h:mm:ss. This produced 4:38:17. There was no leading zero. I changed the "custom" format to hh:mm:ss (adding an extra "h"). This is what happened. When I looked at the spreadsheet, the hours were listed as 04:38:17 (with the leading zero, exactly what I wanted). All was fine. Then ... when I went to use the spreadsheet the next day, I noticed that the time was listed as 4:38:17 (no leading zero). I found this odd; I looked at the custom setting for the cell, and it said h:mm:ss (the leading extra "h" was missing). I tried this several times ... and, somehow, the custom format stays temporarily (the way I like it) ... and then, later, it somehow gets changed (automatically?) to the way I don't like it. What's going on? And how do I get the format I want? I also tried a custom format of [h]h:mm:ss ... with a bracket around the "h". Somewhere in the past, I was shown this method (and it worked). But, now, this custom format (with the brackets) made my Excel report an error in that cell. Thanks. Joseph A. Spadaro (talk) 17:13, 5 May 2022 (UTC)

Does the format change from hh to h every time you reopen the spreadsheet, or if not, when does it happen? (It seems [h] or [hh] is for hours which may exceed 24, by the way, so [h]h is a confusing thing to ask for.)  Card Zero  (talk) 17:42, 5 May 2022 (UTC)

It's odd. If I open up the spreadsheet one or two or five or ten minutes later, the "hh" is still there. If I open up the spreadsheet a few hours later or the next day, the "hh" has completely disappeared. As far as the brackets: I forget the exact scenario, but I believe I posted on a Wiki Help Desk some time ago. I was adding up cells with time in them ... the addition was not working correctly ... and I was told to use the brackets ... and it fixed my problem (the problem I had at that time). I think ( I don't recall 100% of the details ) ... I was trying to add 20 hours plus 7 hours ... I wanted a result of 27 hours ... but I was getting 3 hours ... or some such. The 24-hour (full one-day) period was being disregarded, I think. In any event, the brackets caused no problems or errors (at that time). Joseph A. Spadaro (talk) 17:53, 5 May 2022 (UTC)

For what it's worth. This was my "old" question ... from about a year ago ... about a different ( but, slightly related ) Excel scenario. This is where the idea of using "brackets" in the custom format was introduced. Wikipedia page: [7]. Thanks. Joseph A. Spadaro (talk) 18:11, 5 May 2022 (UTC)

Yes, and I expect [hh] will work here as well. I don't know if Excel will randomly change it to [h]. Possibly the change in format is triggered by Excel carrying out a calculation which exceeds 24 hours?  Card Zero  (talk) 18:15, 5 May 2022 (UTC)

Just curious ... is [h]h a valid syntax? Or does it need to be [hh]? Or do they mean two different things? Thanks. Joseph A. Spadaro (talk) 18:19, 5 May 2022 (UTC)

I have never used Excel (on purpose), I should warn you. But to my mind [h]h is specifying a two-digit number where the first digit can exceed 24, but the second can't. I suppose this would go 22, 23, 20, 21, 22, 23, 24, 25, 36, 37 ... where the "24" is composed of the first digit of 28 married to the second digit of 04. I'm not surprised that Excel refuses to do that.  Card Zero  (talk) 18:28, 5 May 2022 (UTC)

May 6

GnuPG v1

Is GnuPG v1 still safe?--2A02:908:422:9760:0:0:0:D631 (talk) 05:08, 6 May 2022 (UTC)

https://www.gnupg.org/download/ proposes to download 1.4 with the comment GnuPG 1.4 is the old, single binary version which still support the unsafe PGP-2 keys. This branch has no dependencies on the above listed libraries or the Pinentry. However, it lacks many modern features and will receive only important updates.

So, definitely don’t use the PGP-2 keys (unless you have read and understood all of International_Data_Encryption_Algorithm#Security, which I have not). Other than that, the absence of any other mention is weak evidence for the absence of any other significant vulnerability. Tigraan^{Click here for my talk page ("private" contact)} 08:42, 6 May 2022 (UTC)

May 7

Some kind of input device

In this unedifying diagram of event dispatching, what does the graphic in the bottom left represent? It will be a system or device producing input of some kind. It looks like an egg carton filled with bacteria.  Card Zero  (talk) 06:48, 7 May 2022 (UTC)

It's likely natural events, multiple organisms moving independently? WhoAteMyButter (📨_talk│📝^contribs) 07:37, 7 May 2022 (UTC)

None of the other input sources represent sensors, so indeed this Petri sixpack plausibly stands in for sensors (which could be sensing natural processes). It does not immediately evoke the association, but I'm not aware of any iconic representation that clearly signals "sensor".  --Lambiam 09:40, 7 May 2022 (UTC)

Kivy seems to be open source software, and so are the docs. That particularly image seems to be here [8]. It's possible exploring the history will give some clue what the image is about, or not. Nil Einne (talk) 12:39, 9 May 2022 (UTC)

Some examples of fiducial markers that can be placed on objects or in video for automated recognition and tracking, from a library called reacTIVision: project page, publication. --Amble (talk) 20:30, 9 May 2022 (UTC)

May 9

Mosaic killer

Mozilla, that handsome red beast, "has [...] been 'retired from active duty',^{[citation needed]} removed from official Mozilla branding" (says Wikipedia, which as we know is not a RS). And yes, it seems to have been. But why? -- Hoary (talk) 01:12, 9 May 2022 (UTC)

A (kind of) reason is found here.  --Lambiam 07:38, 9 May 2022 (UTC)

How much are intellectual property rights?

Hi there,

You probably don’t know me, but I am looking to form an IT company after I finish the degree I’m working on. I am looking to exploring several different areas that my company can work in, such as:

• Web Design
• Software Programming
• Game Development
• Composing music for people
• Buying franchises in a frozen dessert chain
• Reviving obscure games from yesteryear

That last point is the one that is relevant here. If I were to try and buy the rights to something, like Club Penguin, or the output of Humongous Entertainment, then how much money would it take to force these businesses to sign them over to my company? I’m even looking at some obscure Nintendo titles.

I hope to be the next big thing in IT services, and with my unique portfolio, I will hope to become as famous as Mark Zuckerberg or Bill Gates. With this newfound potential, I will invest in charity, welfare and other projects that will make an impact in the world. I also intend to take the mighty games of old, and using my handy-dandy intellectual property rights, make an official declaration to the effect that said articles are heretofore to be entered in to the public domain. As such, I expect to be dubbed a hero by hardcore fans of such properties, the very saviour that will free them, from the shackles of lawsuits by the likes of Disney and Nintendo, and will write my place in the IT and computer history books.

In other words, I’m trying to buy the rights to old games, to preserve them for the future and keep them safe from greedy corporate executives and lawyers.

I remain, yours sincerely,

D.R.Tennant, Student of Computing and IT, Open University

86.133.234.17 (talk) 20:03, 9 May 2022 (UTC)

Is this an entry in the "how not to write a CV" competition? Anyway, "Student of Computing and That" sounds better to me.2A00:23C6:AA07:4C00:EC93:EE2B:7F99:B899 (talk) 21:24, 9 May 2022 (UTC)

I corrected some mistakes. Also, to show how much of an IT genius I am, I’ve just changed my IP address, signed D.R Tennant. 2A00:23C5:B22E:7001:ECFA:C6E7:ACA7:EC99 (talk) 21:28, 9 May 2022 (UTC)

You can't buy the rights to games that companies aren't willing to sell.

In other words, unless Nintendo wants you to have it, you won't get it. WhoAteMyButter (📨_talk│📝^contribs) 21:37, 9 May 2022 (UTC)

That’s why I plan to try and figure out how much these games are worth and then offer slightly more than that. I would hope that a large wad of cash would convince them. That is why I need to figure out how much, then I can propose an offer and then see what happens. I plan to fight hard for these things. Hopefully my money and my charisma will win in the end. Obviously, since I haven’t attempted this yet, we don’t know what the status is of these games. For the remainder of this discussion, let us assume that the companies will accept my money.2A00:23C5:B22E:7001:ECFA:C6E7:ACA7:EC99 (talk) 22:12, 9 May 2022 (UTC)