Wikipedia:Reference desk/Archives/Computing/2015 March 1

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March 1

Manual for maven

I need to learn maven and I can find lots of tutorials. What I can't find is a manual. I would like to have a sound reference that explains the tags of a pom.xml by definition, not by fuzzy example. 93.132.25.201 (talk) 16:40, 1 March 2015 (UTC)

Generally, to find such things, you can search the name of the software and reference. So you've already the good term :)

For example here one of the first result on Google for maven reference is Maven: The Complete Reference, which seems to match your requirement. --Dereckson (talk) 23:08, 2 March 2015 (UTC)

Thank you, but I had seen that before. It is called a reference, but it is a tutorial. I'm afraid I have to inspect the maven source code, read many tutorials or play around a lot. 95.113.85.253 (talk) 19:32, 3 March 2015 (UTC)

Attempting to get best resolution

I have a PC set up on windows 7 that uses 2 monitors model number: NS-24E40SNA14. I connected one monitor to a HDMI to micro HDMI and then have that plugged into my PC in the micro HDMI port(I believe that's what it is called). The other monitor is connected with a HDMI to DVI cable (The DVI is on the PC end and the HDMI is on the monitor end its all one cable). I have fiddled with the monitor settings and Nvidia's control panel settings and I want to make each monitor display the best possible picture, color, contrast...everything. I want to know that the monitors are displaying the best they can, how can I do this? Extra information: I am not sure this is relevant or not but when I look in the Nvidia control panel in change resolution when selecting a resolution I noticed that the HDMI to DVI monitor is missing one option that the HDMI to Micro HDMI has, its "1080p, 1824 x 1026*" does this mean anything? My PC only has 2 DVI ports and one micro HDMI port. — Preceding unsigned comment added by 204.42.31.250 (talk) 16:57, 1 March 2015 (UTC)

Yes, HDMI is likely to give better results than DVI. However, given your ports, you seem to have the optimal setup for best resolution on both screen, assuming you have different images on each screen. If, on the other hand, you wanted to clone the display of one screen to another, then you might be able to split the signal coming from the HDMI port and send it to both monitors.

What resolution are you currently getting on each, and are there any display problems ? StuRat (talk) 17:18, 1 March 2015 (UTC)

I just edited the resolution in Nvidia control panel and now my monitors are both perfectly fitting in the screens, no underscan or overscan. They are displaying 1080p on both monitors. — Preceding unsigned comment added by 204.42.31.250 (talk) 17:39, 1 March 2015 (UTC)

I believe StuRat's claim '"HDMI is likely to give better results than DVI" is incorrect. DVI and HDMI are essentially the same signal. Please see Digital_Visual_Interface#DVI_and_HDMI_compatibility. Vespine (talk) 04:50, 2 March 2015 (UTC)

And with DVI, you get a ~50% discount on the cables.

Add to that that a DVI cable is a bit less flexible, thicker, and heavier than HDMI, so it doubles as a baton. - ¡Ouch! (^{hurt me} / _{more pain}) 08:30, 3 March 2015 (UTC)

The claim doesn't even seem to be close to correct. The cheapest DVI cable I can find is this 1m one [1] which is USD3.45 (I didn't look that hard since I'm not particularly interested in a DVI cable but I doubt it's far off). The cheapest 1m HDMI cable is this USD1.45 http://www. aliexpress.com/item/3Ft-1m-HDMI-V1-4-AV-Cable-High-Speed-3D-Full-HD-1080P-for-Xbox-DVD/2036678292.html (was USD1.42 when I bought it about 2 days ago). Or if you want eBay, this ~USD 1.60 [2]. Actually you can get a 1m HDMI to DVI cable for cheaper than the DVI [3] (~ USD2.37), also a short 0.3m DVI-A to VGA [4] (~USD 2.73, cheaper if you want female VGA [5] ~ USD2.43).

Even if you don't want to wait for delivery from China/HK, from Monoprice in the US for example, this 3ft DVI cable seems to be the cheapest at [6] USD4.31. The cheapest 3ft HDMI seems to be this [7] USD2.31. (Both seem to be similar in design, e.g. 28AWG.)

Locally here in NZ, I can get a 0.5m DVI-D for [8] $6.37, but a 0.5m HDMI is only $3.27 [9]. A 2m DVI is $7.48 [10] but the 2m HDMI is $4.29 [11]. (No 1m because I couldn't seem to find a good prices DVI, although the HDMI is between the 0.5m and 2m [12].)

I wouldn't exactly say any of this is surprising. HDMI is much more of a commodity item than DVI. Many TVs don't come with a HDMI cable at all and while not everyone may use one, enough will and combined with the popularity of TVs, there's a fair amount of demand. Most monitors still seem to come with at least one cable, be it VGA, DVI, HDMI or Display Port, and probably most people will just use it if they can, even if it's VGA. (Many people don't buy monitors seperately anyway and just use whatever their computer comes with.)

HDMI also only needs 19 wires, dual link DVI-D 23 or 24 I think. (Single link would be less, but it seems single link cables aren't so common, at least for ones you can buy now, as shown by the examples I used earlier where only 1 seems to be single link. I imagine the problem is that many people will buy dual link, even if they aren't ever likely to use it, so it's not necessarily worth it to stock a single link just because it slightly cheaper. Also, I imagine the bulky DVI plugs are more expensive than HDMI (more so given the HDMI's likely far higher quantities) or even VGA. Particularly for short runs.)

Of course the earlier point highlights another issue. Because HDMI cables are much more targetted at the consumer market, you will get wackily priced HDMI cables (Monster Cable and the like) but there's no reason to buy one.

I guess it's possible some sort of major retailer may have cheaper DVI than HDMI cables because they only stock the wackily priced HDMI ones, although I couldn't find that here in NZ since none of the ones I tried even had a DVI to DVI cable when I looked just now, and I think it's more likely they'll just have the cheaper HDMI cables more hidden away (but realisticly probably not much more than the DVI.)

I do agree with Vespine that it's fairly uncommon that HDMI will be better than DVI in terms of output options, except that you'll have audio presuming the monitor supports it.

Nil Einne (talk) 14:32, 3 March 2015 (UTC)

Whoopsy, old data.

Two years ago, the cheapest "good" cables were E10.99 (1.5m DVI-D) and E19.99 (1.5m HDMi), but maybe that's changed now that HDMI is the dominant connector in Europe. Prices were from 2 local electronics retailers, a quite limited sample on my part. There were some cheaper HDMI cables (around 18.00) but still DVI was much cheaper at the same quality.

That is, visual quality. The audio component is a good thing, tho, so the comparison was not 100% fair. - ¡Ouch! (^{hurt me} / _{more pain}) 13:23, 4 March 2015 (UTC)

How can you run Linux if you don't want graphics, guis and the like

How can you run Linux with only Browser + text editor? So, I don't have interest in anythng else that has guis. --Senteni (talk) 17:04, 1 March 2015 (UTC)

Not sure if it has no GUIs, but something like Damn Small Linux will have a much smaller footprint than full-feature versions. StuRat (talk) 17:12, 1 March 2015 (UTC)

Press Ctrl-Alt-F1 to get the first text login console (Ctrl-Alt-F7 should return you to the GUI). Login in, become root, and then use your command-line package manager to remove all the libx11 packages. This should remove all the GUIs from the machine. However, I'd suggest testing on the text console without removing libx11, to see if this is what you really want. Lynx is the normal text-only web browser. However, Lynx doesn't support CSS or Javascript LongHairedFop (talk) 18:12, 1 March 2015 (UTC)

Both solutions seem as something that could work, but I want to run a normal Linux installation, that normally has a GUI, without it. But I'd like to keep the possibility of running it as normal again. Damn Small Linux also has the additional problem that at a first glance it won't run in a 64 bit computer.--Senteni (talk) 18:27, 1 March 2015 (UTC)

Don't do the removal of libx11. Press CTRL-ALT-F1 to swap to console mode, on the next reboot Linux will return the to GUI, or (as I indicated above) press CTRL-ALT-F7 to return to it at any point. LongHairedFop (talk) 19:13, 1 March 2015 (UTC)

But how can I stop all the graphical programs, that appear to be running, even if I am in text mode? The idea here is also to extend battery life.--Senteni (talk) 19:54, 1 March 2015 (UTC)

They only normally only start when you log in, however Linux can be configured to autologin. If you want to stop the login program, then become root and run cd /etc/init.d/ ; ls *dm and then run ./kdm stop if kdm was listed, or similar for other dm (display managers). The Display Manager is the graphical login process. Stopping it will normally log out all logged in users. LongHairedFop (talk) 20:24, 1 March 2015 (UTC)

It depends on the distribution you're running, but if you're running the latest release of Red Hat, Fedora, or CentOS, you would just run this command as root and reboot your computer:

ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target

Then, your computer would boot into a text-only mode with networking by default. No graphical applications would start. If you wanted to switch from text-only to a graphical mode, you would type telinit 5 and press ENTER.—Best Dog Ever (talk) 02:09, 2 March 2015 (UTC)

You can see if text-only mode is usable for your purposes without changing the target in those RedHat-like systems that use Grub. When the system boots, you will see the versions of kernel available. Press whatever key it shows to edit the kernel (usually e). Then, find the line that begins with linux /vmlinuz... and alter the line by placing a 3 at the very end (it must be a 3 by itself, not touching whatever was already at the end of the line). That 3 will mean "boot into runlevel 3" which is text mode. If you like it, change the target to always stay in runlevel 3. 209.149.113.103 (talk) 18:38, 3 March 2015 (UTC)

I think a lot of this misses the point - "browser and text editor" looks like X11 and a GUI is indeed required, but with a light-weight window manager and not with a fully-featured desktop. One can browse the web with e.g. Lynx (web browser), but that's a bit painful even for old farts like me. Here is a description for how to install CentOS 6 with Fluxbox as a light-weight window manager, but there are many similar solutions (e.g. xfce, OpenBox). Slightly heavier are Xubuntu or Lubuntu. --Stephan Schulz (talk) 18:58, 3 March 2015 (UTC)

Sounds like either ChromeOS or Chromium OS is the thing for you. They are both based on Linux and have nothing but a tabbed browser running. You can open a regular shell in a tab inside the browser...which is a weird inversion of normality - but it works really well. I have ChromeOS running on an HP ChromeBook and for the kinds of thing you seem to be doing, it's perfect. SteveBaker (talk) 04:25, 4 March 2015 (UTC)