Wikipedia:Reference desk/Archives/Computing/2015 June 13

= June 13 =

Why are some YouTube links blacklisted and some not?
What is the difference between a YouTube addresses that contains 'feature=youtu.be' and the usual ones? The former may appear also as going to site youtu.be. And why is that one blacklisted by Wikipedia and the others not?

Here are examples:


 * 1) example 1 not blacklisted (example 1)
 * 2) example 2 blacklisted
 * 3) example 3 not blacklisted (example 3)

Note: because Preview doesn't tell you a link is blacklisted I had to save several times. Apologies for that.

Contact Basemetal   here  11:25, 13 June 2015 (UTC)


 * The justification given for this global blacklisting (see m:Talk:Spam blacklist/Archives/2010-12) is that URL redirection/shortening sites are redundant and can be used to circumvent existing blocks. This is consistent with WP:EL, which says that "URL redirection sites are not to be used on Wikipedia". Some discussion of this can be found at MediaWiki talk:Spam-blacklist/archives/December_2011 —Noiratsi (talk) 14:09, 13 June 2015 (UTC)


 * The difference is the domain only, not special links on the webservers. See "www.youtube.com" and "youtu.be". -- Hans Haase (有问题吗) 11:35, 15 June 2015 (UTC)

GoPro HERO 4 wifi streaming and getting internet at the same time
When you connect your computer to a GoPro HERO 4 via wifi to stream from it, can you still connect to your home wifi network to get the internet? In other word, if I want to stream from the GoPro HERO 4 and get internet via wifi at the same time, would I need to have two separate wifi adapters on my computer? I don't have GoPro HERO 4 yet so I can't test it out myself. My other car is a cadr (talk) 11:44, 13 June 2015 (UTC)
 * Wi Fi supports more than one device. So it should be possible.  However does your internet connection have enough capacity? A HD stream uses a lot of bandwidth going out from home, and many of these home internet services have a limited bandwidth for uploads.  So if you overload it it will be very slow for other uses. Graeme Bartlett (talk) 21:56, 13 June 2015 (UTC)
 * "Wi Fi supports more than one device" is a very ambiguous statement. You can obviously have a large number of devices on one wifi network but typically most devices/computers with one wifi adapter can only be connected to one wifi network at a time. I don't have a go pro but I have a canon camera that has wifi, it has 2 modes, it has ad hoc mode where you can connect directly to it (from a computer or phone/tablet) bit it also has a "network mode" where you first connect the camera to a wifi network and then a computer or phone on the same network (with the canon software) can connect to the camera. Maybe the go pro has a similar feature? having a very cursory browse, it looks like that might not be the case, i think gopro just creates its own adhoc network. Vespine (talk) 22:50, 16 June 2015 (UTC)

Encryption energy
If the WMF switch from HTTP to HTTPS is considered as a hypothetical, how much more energy would be consumed by HTTPS in a year (clients, transmission, and servers) compared with HTTP? All the best: Rich Farmbrough, 19:56, 13 June 2015 (UTC).


 * The impact, nowadays, is likely to be pretty trivial (see this blog post from 2010 by Google's Adam Langley). For some actual figures you could take a look at this 2003 research paper from Princeton: http://palms.ee.princeton.edu/PALMSopen/potlapally03analyzing.pdf —Noiratsi (talk) 22:05, 13 June 2015 (UTC)


 * From what I can gather from the raw data linked from Analytics/Data/Pagecounts-all-sites, all WMF wikis combined get a bit less than 10,000 connections per second, totalling a bit under 250 MB of transferred data per second. The blog post that Noiratsi linked says "Modern hardware can perform 1500 handshakes/second/core" (for RSA-1024, in 2010), and AES instruction set links a claim of 3.5 cycles/byte (i.e., around 1 GB per second) for authenticated AES encryption (also in 2010). So I'd guesstimate that the WMF's SSL overhead could be handled by the equivalent of one additional server, roughly. -- BenRG (talk) 04:32, 14 June 2015 (UTC)
 * Thanks! There is an information theoretic minimum too ref which would be even more negligible.  All the best: Rich Farmbrough, 17:55, 15 June 2015 (UTC).