Welcome to the computing section
of the Wikipedia reference desk.

Select a section:

WP:RD/C

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.

April 18

Difference between routers with repeater function and repeaters with router functions

I assume most of the capabilities are implemented as software and not as hardware. I see that the device case are different. The repeater is more a small squared device, that can be plugged directly close to an electric plug, maybe behind furniture. The router is more like a flat device, that has to be put on furniture. Is the difference mainly motivated by marketing? --Doroletho (talk) 09:09, 18 April 2018 (UTC)[reply]

Based on the way I understand it, the repeater does no actual routing in the definition of a Router being able to direct/translate traffic between networks, such as a LAN and the Internet. It simply repeats the signal it takes in back out again, the same as a normal amateur radio repeater for example. Here's my setup for example: I have a router hooked into my cable modem on one end of my house with a particular wireless SSID, and a repeater on the other end of the house with the same SSID. They do have different IP addresses and a particular setup within the repeater firmware to facilitate the operation, and the main router still serves as the gateway address regardless, however other devices will simply connect to the device with the strongest signal, be it the router or the repeater. RegistryKey^(RegEdit) 07:51, 20 April 2018 (UTC)[reply]

I think I have a repeater at home. I could not get a signal from my router in a remote part of the house, so I bought this NETGEAR AC750 WiFi Range Extender (EX3700-100NAS). It must be a repeater. AboutFace 22 (talk) 16:29, 20 April 2018 (UTC)[reply]

April 20

Desktop at Windows 10 Hewlett Packard

I have posted on this issue before. The answers were not to my liking. And what do I expect? I hope someone from Microsoft might pay attention to this problem and fix it. It is about the icons on my Windows 10 desktop. The hardware is HP Pavilion. After I purchased the machine, for the first 18 months or so I was placing the icons in convenient clusters and could find them there at will. Then one day, perhaps half a year ago I booted the computer and saw to my shock that all icons were clumped up on the left side of the desktop neatly arranged in about 6 columns. I moved them back to their old positions. After the next update which happen way too often, the icons migrated to the left again. I spread them across the desktop as my wont was. In short I did it a few times and finally gave up. I decided to learn their new positions clustered on the left and use them this way. It worked but a few days ago the Windows rearranged them all in that rectangle on the left and my learning came to naught.

What is the idiotic idea behind it? It is obvious that it is not a bug. It is by design, there must be a program that does it. Geometrically the icons are arranged perfectly well but what is it for me?

At work I have Windows 7 still. A month ago after an update I saw my icons clustered on the left also!! AboutFace 22 (talk) 16:45, 20 April 2018 (UTC)[reply]

The first thing to check is auto-arrange. Right-click somewhere on your desktop (not on an icon). A context menu with "View" should appear. If it doesn't, make sure you are using the right mouse button, not the left one. Make sure you are not clicking on an icon or a program or the clock or the start button. (You have no idea how many days of my life have been wasted trying to explain what "right click on the desktop" means. If you are reaching for your sharpie to write "click", just walk away from the computer.) Once you see the context menu, click on View. A submenu will appear. One of the options might be Auto arrange icons. If that is checked, Windows will keep automatically arranging your icons. You obviously don't want it checked. If it isn't checked, there is a different problem. 209.149.113.5 (talk) 18:07, 20 April 2018 (UTC)[reply]

I know the difference between right and left. The keyword "auto-arrange" gave me a clue, thanks. Then I went to the View as you said and a drop down menu opened. "Auto-arrange" option WAS NOT CHECKED there, however, another option: "Align Icons to Grid" was. I unchecked it. Now I have to do a weeks long experiment, to see if that was the culprit. What is the Grid though. Many thanks, AboutFace 22 (talk) 20:12, 20 April 2018 (UTC)[reply]

The grid is just a fixed width so that icons are not too close together. I always switch it off so that I can squeeze more in a row. Like you, I've had various versions of Windows reset both of these options for no apparent reason, though mine have now been stable for some time. If you do an improper shutdown, Windows always forgets recent changes because it picks up a reserve copy of the registry files. I used to know where these options were saved, but I can't remember now. It's somewhere in the files user.dat or user.nt depending on the version of windows. I expect someone else can tell you exactly where in the Registry it is stored. (If Windows were a person, I'd describe it as very stubborn and reluctant to learn my settings, but eventually it seems to settle down and submit to instruction.) Dbfirs 20:24, 20 April 2018 (UTC)[reply]

I definitely appreciate your help. Thanks AboutFace 22 (talk) 22:09, 20 April 2018 (UTC)[reply]

Cell phone signal strength

Is there a website to check cell phone carrier signal strength? I want to see if ATT or t mobile has stronger signal in my area, the signal coverage map I found shows them the same color so it is not helpful, I need strength not coverage.--User777123 (talk) 20:10, 20 April 2018 (UTC)[reply]

This site has some advice and a list of apps that you can download. Akld guy (talk) 20:55, 20 April 2018 (UTC)[reply]

April 21

Adobe Reaper help, Windows.

I've been receiving .PDF files of images where they blank out certain parts, like with a black square or rectangle.

How do you remove those?

When I 1st open the file, I see the image in it's entirety for a split second, and then the blank covering cover up.

I read in a newspaper there was a trick to remove them. :/

Thanks. 67.175.224.138 (talk) 03:37, 21 April 2018 (UTC).[reply]

You can look here and here. Ruslik_Zero 08:35, 21 April 2018 (UTC)[reply]

zip

I'm on Ubuntu and I'm trying to use zip to zip up these two files:

/home/user/target/a
/home/user/target/b

such that I end up with a zip file in /home/user/ containing:

target/a
target/b

One limitation is that I'm only given the absolute path of the input files, and I would prefer to keep using the absolute input paths to keep things clean. (I'm invoking zip from a script and not from a shell)

So far I've tried two approaches:

zip -r /home/user/result.zip /home/user/target

produces the following zip file, which is highly undesirable due to the excessive paths:

/home/user/target/a
/home/user/target/b

The second approach uses the -j flag to drop the paths:

zip -j -r /home/user/result.zip /home/user/target

But this creates a Tarbomb unfortunately, with the zip looking like this:

a
b

What's a good solution?

I'm open to using other compression utilities as well, as long as it's able to produce a zip file. Mũeller (talk) 13:31, 21 April 2018 (UTC)[reply]

Just drop /home/user:

  cd /home/user
  zip -r result.zip target/

--Wrongfilter (talk) 14:28, 21 April 2018 (UTC)[reply]

Thanks for the response. Yes, that would be the solution if I'm running the command in a shell. But I'm invoking zip from another program, so unfortunately I'm forced to supply absolute paths for everything. Here's the Python that I'm invoking zip with:

      process = subprocess.Popen( ["zip", "-r", "-j", filename + ".zip", filename] )

Of course I could have Python spawn a shell, have the shell navigate to /home/user/, then invoke "zip -r result.zip target". That would work, but I'd prefer to keep the shell out of it to keep things simple. Mũeller (talk) 23:53, 21 April 2018 (UTC)[reply]

If you're willing to use tar then try the following:

         tar cvf result.tar -C /home/user target/

--Wrongfilter (talk) 06:40, 22 April 2018 (UTC)[reply]

You don't need the shell to set a process's "current working directory". CWDs are a process thing managed by the OS on a per-process basis, not a shell thing. This says you can pass a CWD to Popen which I guess is equivalent to doing cd in a shell. 92.230.39.123 (talk) 06:43, 22 April 2018 (UTC)[reply]

Passing in the correct CWD solved the problem. Thank you very much for the help, you two. It's much appreciated. Mũeller (talk) 09:10, 22 April 2018 (UTC)[reply]

Similarly, if it was more convenient for the rest of the script, you could also choose to set the script's own CWD before starting the subprocess. I don't do Python, but in either Perl or C you'd do chdir("/home/user"); (and, of course, check whether it succeeded). --69.159.62.113 (talk) 20:50, 22 April 2018 (UTC)[reply]

April 22

Where would you upload some files useful for machine learning?

I have some extensive data files (user behaviour in e-shops, who orders, who contacts the shop, show sends items back and so on) that could be of some interest for some predictive model of machine learning. There's no software involved, just raw data. They are useful in the sense that they could be used to test some programs. There is no copyright issue involved, nor any private data in them. I don't care if they get some kind of open source license or are distributed free of charge. Main thing they are useful. --Doroletho (talk) 16:43, 22 April 2018 (UTC)[reply]

Possible places are Wikisource if it is in text, Wikiversity if it is educational, even original research, or commons if it is useful to several projects. Graeme Bartlett (talk) 01:51, 23 April 2018 (UTC)[reply]

Quick Turn-On for Outdoor Mode on Samsung ?

A Samsung Galaxy has a feature called Outdoor Mode, which increases the brightness of the screen so that it can be seen in bright sunlight. This can be turned on from Settings > Display ? Outdoor Mode, and stays on while the phone is in use. This is useful in running Google Maps as the navigation during the daytime (and as long as Maps continues to navigate, the screen stays bright).

However, is there a way that I can quickly turn on Outdoor Mode without having to bring up Settings, which may involve closing stuff? Is there a quick way to turn it on if I realize that it isn't in Outdoor Mode?

By the way, it is a Galaxy J7 and running Android 7.0. Robert McClenon (talk) 21:13, 22 April 2018 (UTC)[reply]

On my S7, if I held down the power/home button for a second, a menu would pop up that had common settings. It had a "full bright" option. See if the J7 has outdoor mode in that menu. 209.149.113.5 (talk) 14:55, 23 April 2018 (UTC)[reply]

April 24

Has anybody here tried the programming language called Lava?

Is anyone here familiar with the programming language and environment called Lava? The WP article was nominated for deletion once (result: no consensus). Notability aside, I don't find the article amazing. Has anyone tried the language? Is it worth checking out? Thanks. Basemetal 20:17, 24 April 2018 (UTC)[reply]

I've seen it suggested for a project. We went with Lego instead because most of the group felt that the children would prefer making Lego robots move around instead of just seeing some image on a screen wiggle. 209.149.113.5 (talk) 11:21, 25 April 2018 (UTC)[reply]

Don't think it's the same Lava. I mean this Lava This says there's another Lava (an extension of Java?) or even several other Lava? but the link provided is dead. But thanks. The Lava of the WP article was designed by this guy. But the mere fact that it's so hard to get any opinion shows that Lava would probably not be a safe choice for me at this time. Lego that's Lego Mindstorms? Basemetal 13:56, 25 April 2018 (UTC)[reply]

I was referring to the same Lava. It uses pictures to program instead of text. That is why we looked at it for kids. Mindstorm uses pictures as well, which is what we decided to go with. In my opinion (which isn't cool in modern time), if you are learning to program, learn C or C++. Then, you can pick up any other language by simply looking at a reference guide. Anecdote: I was asked if I could do a project in Ada. Sure. I then looked at a guide on Ada. I easily picked up the syntax and did the job. 209.149.113.5 (talk) 17:35, 25 April 2018 (UTC)[reply]

April 25

Having trouble accessing Forbes

When I try to access the website on my iPad via safari,all I get is a blank welcoming page: https://www.forbes.com/forbes/welcome/?toURL=https://www.forbes.com/sites/forbesagencycouncil/2018/02/08/three-best-practices-to-manage-your-online-identity/&refURL=https://www.google.ca/&referrer=https://www.google.ca/. I tried fixing the URL but it still does the same thing.

Try disabling all browser extensions and just use this URL: https://www.forbes.com/sites/forbesagencycouncil/2018/02/08/three-best-practices-to-manage-your-online-identity If that doesn't work, try a different web browser, such as Chrome or Firefox. TheMrP (talk) 00:26, 25 April 2018 (UTC)[reply]

Why two telephony networks, landline and cell-phone

Isn't the existence of a mobile and landline telephony network a waste of resources? Or does the cell tower connect to/need the landline network and cell-phones are just a kind of long range cordless phones? Are governments planning to deprecate landlines or, at least, not expand the network? --Hofhof (talk) 13:07, 25 April 2018 (UTC)[reply]

Land lines still work when there's a power outage; they're also usually much less expensive than cell packages. Matt Deres (talk) 13:15, 25 April 2018 (UTC)[reply]

Land lines work because there's a massive room full of lead-acid batteries in the telephone exchange. And that's there because regulators made the phone company have resilience during power outages (as the landline phones were an emergency lifeline service). This story discusses the regulatory environment in the US cellphone segment regarding power-fail resilience for mobile comms, now that cellular phones make the majority of emergency calls. These days, if a cell fails due to a power outage, that's a failure of regulation and infrastructure maintenance, not a real technical advantage of landlines. -- Finlay McWalter··–·Talk 13:54, 25 April 2018 (UTC)[reply]

And Matt's "expensive" is about cost to the end user, not necessarily the cost to install and maintain the network, which as Finlay says may be required by law. --69.159.62.113 (talk) 00:15, 26 April 2018 (UTC)[reply]

You might be interested by reading more on leapfrogging - in developing countries, landlines and wired internet networks are mostly inexistant, and likely to remain so, because cell phone technology has taken over. I have no good reference to suggest, but at a first glance "The distributional effects of leapfrogging in mobile phones" by J James looks like a good article. Tigraan^{Click here to contact me} 14:26, 25 April 2018 (UTC)[reply]

Readers used to reliable cell phone service availability everywhere they go might want to look at the map at https://www.telstra.com.au/coverage-networks/our-coverage . It shows how much of my country, Australia, is covered by cell phone service. Many people in those more remote areas (the gray bits) still depend on landlines. HiLo48 (talk) 01:12, 26 April 2018 (UTC)[reply]

Yes it is a waste of resources. The second network was car phone network which was very low capacity. The third and fourth networks 1G and satellite terminals started around the same time. 1G made car phones obsolete so there are three telephony networks now. CT2 worked like a cordless phone when you were at home and you could make only outgoing calls away from your basestation at home.
Sleigh (talk) 08:42, 26 April 2018 (UTC)[reply]

There's the matter of sunk costs. Building a landline network requires a large investment, but as most of the cables of the current network were already in place before the breakthrough of mobile telephony (about 20 years ago), that investment is irrelevant in western countries (but not in developing countries). But wired networks are still being rolled out in western countries, in the form of fibre to the premises. Whether it's because it can use optical frequencies, whereas wireless is stuck to radio, or because there are fewer devices per cable than there are devices per base station in wireless systems, wired has higher capacity than wireless. PiusImpavidus (talk) 09:17, 26 April 2018 (UTC)[reply]

Landlines almost never fail. In my county a few years ago, two people died stuck in a home elevator. They were unable to call for help. A landline is good for that use. With other things, you could be at risk if the power goes out, the internet is down, there is an error with the router, etc. Bubba73 ^{You talkin' to me?} 19:23, 26 April 2018 (UTC)[reply]

When I worked in the telecom industry in the early 2000's, pretty much everything past the MTSO (where the cell towers connected to) was on the same network as the landlines. I'm not sure how true that still is today though, since I've been hearing about mobile networks migrating to VOIP over the last few years. Random character sequence (talk) 21:00, 26 April 2018 (UTC)[reply]

April 26

Monitor energy usage.

28 Watt Acer Predator XB241H

65 Watt Asus ROG Swift PG248Q

Two monitors with mostly identical specifications (same resolution, screen size, panel type, refresh rate, response time, brightness, and contrast). Why does the latter use more than twice the amount of energy? Or generally, why, in certain cases, do two similar monitors use different amounts of energy? Is it because of a differing internal layout of components or that they contain low-quality parts or bad wiring etc? Th4n3r (talk) 16:30, 26 April 2018 (UTC)[reply]

The luminous efficacy of the LEDs will obviously play a factor, as will the efficiency of the driver and other power conversion equipment. I think talking about 'low-quality parts' or 'bad wiring' is misleading since efficiency is only one factor of a component. Nowadays there tends to be strong focus on it so often higher quality parts are more efficient but it doesn't automatically follow that a part if less efficient because it's 'low quality'. A significant point is that improving the spectrum of the LED is likely to reduce luminous efficacy but it may be desirable for a monitor for gamut and colour reproduction reasons. Also unless the power consumption figure is following some standard where all the conditions are the same, you may not even be comparing the same thing. Nil Einne (talk) 18:52, 26 April 2018 (UTC)[reply]

How to get youtube link at specific time without using the Youtube url shortner

The youtube tool that lets you copy at the time the video is uses the URL shortner however I found a video for a website i use (Not Wikipedia) but it is not the whole video or the beginning of the video but like 2 minutes into the video until the end of the 4 minute video so how would i be able to get the Youtube link at a specific time without using the URL shortner as URL shortners are banned on the website i use (not Wikipedia) but I do not want to violate copyright by copying the video and crop most of it Abote2 (talk) 20:43, 26 April 2018 (UTC)[reply]

Try adding #t= n m n s to the end of the youtube link. n is the value you add for the number of minutes and seconds into the video that you want to start at. Aspro (talk) 21:33, 26 April 2018 (UTC)[reply]