Wikipedia:Reference desk/Archives/Computing/2015 June 24

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June 24

Can the Internet be interrupted by the government to broadcast emergency announcements?

In the same way TV and radio broadcastings are interrupted to send active alerts, in cases of inclement weather, natural disasters, or any emergency. The Internet has become the main medium of communication for many, taking the place that TV and radio were occupying in the past. It should be the medium of choice for important messages.--Yppieyei (talk) 13:19, 24 June 2015 (UTC)

The internet is not under the direct control of any single entity. It is not a broadcast medium. It is a request/response medium. So, no. With the current design and structure, the government cannot force a message to appear all over the internet... unless they post it on Facebook as an animated GIF with Deadpool riding Pinky Pie while making some statement like "There's a threat of severe thunderstorms with tornadoes over Oklahoma from 6pm to 10pm. Share if you love God. Like if you love your Mom. Ignore this if your are evil and want everyone to die, you scumbag!" 199.15.144.250 (talk) 13:52, 24 June 2015 (UTC)

Cell phone networks aren't broadcast networks either, but there are systems in place to send emergency alerts (such as Wireless Emergency Alerts in the US). The Internet protocol supports multicast which can in principle be used to efficiently send a packet to every Internet-connected machine (though with no guarantee of delivery). There could in principle be an RFC defining an IP-based emergency alert system. There just happens not to be. It has nothing to do with the design of the Internet. -- BenRG (talk) 18:26, 24 June 2015 (UTC)

That is not correct. Cell phone networks *ARE* broadcast networks. To function, your phone is always listening to the cell tower. Your computer is not always listening to the Internet. It only listens on a specific port to get an answer to a specific request and then it hangs up. 199.15.144.250 (talk) 18:40, 24 June 2015 (UTC)

Broadcast means that everyone gets the same data, not that everyone is always listening for data. Internet-connected computers do always listen for incoming packets. -- BenRG (talk) 07:31, 25 June 2015 (UTC)

I thought we were discussing networking. Broadcasting (networking) is not the same definition. You can rationalize that track data communications and packet data communications are one and the same. If you insist on believing that, there is nothing I could ever say to make you change your mind. Perhaps you will work on cell phone towers some day and realize how "broadcast" greatly differs from computer networking. 199.15.144.250 (talk) 13:55, 25 June 2015 (UTC)

Which government ? Which country ? Don't forget that the internet is a global infrastructure, not local or national. Can you think of any situation that would need a message to be broadcast to every person with an internet connection anywhere in the world ? Gandalf61 (talk) 13:54, 24 June 2015 (UTC)

That could be done in principle, because it is possible for internet service providers to intercept web browser requests and return any information they want to. But setting up a system would mean getting all ISPs to cooperate, in the same way that the Emergency Alert System requires all radio broadcasters to install and maintain the necessary equipment. I'm pretty sure no such system currently exists. Probably the most useful thing the government could do, if it felt such a system to be necessary, would be to ask for cooperation from Google and other search engines, so that they could return an emergency warning along with their search result. In fact such a system already exists, in the form of Google Public Alerts. Looie496 (talk) 14:35, 24 June 2015 (UTC)

Yes, it is theoretically possible, depending on the country, although the mechanism would be quite different than it is for broadcast media.

Look at this map (the site uses old data, but illustrates the point).

In the United States, it would be particularly difficult as it has far more ISPs than other countries (fewer now than in 2003, I imagine, but still more than anywhere else). On the other hand, many countries have only one, two, or three. In such a case it would be easier for a government to set up infrastructural interventions (which is why the Great firewall of China is possible).

The other way it could be done is on the level of personal computers or local networks. Take for example (using China again), Green Dam Youth Escort. The plan was to require any computer sold in China to have this content-control software on it that would monitor Internet traffic. Assuming an Internet connection, it would be pretty straightforward for there to be a centralized location that could send messages using such software (or other preloaded software). — Rhododendrites ^talk \\ 14:50, 24 June 2015 (UTC)

The question was about the Internet, not the Web. I interpret that as popping up a message on the desktops of Internet-connected machines even if they're using a word processor at the time. It would certainly be possible to do that, if there were a standard for it, and legislation forcing vendors to implement it.

Implementing an emergency alert system by spoofing web pages is a terrible idea, and I would hope no country would seriously consider an alert system that worked that way. -- BenRG (talk) 18:26, 24 June 2015 (UTC)

If you want to pop a message up on a desktop based on an Internet-based message, you *MUST* have a program running on the desktop that is always listening for the message. That means that you have to force everyone to install the alert client software (which must be programmed to run on a multitude of different desktop systems). Then, you have to have them constantly listening on the network - which computers do not normally do. The Internet is TCP/IP-based. It is designed to make a connection, send a request, get a response, and then hang up. It is not designed to listen forever and ever. So, you have three huge obstacles: 1) The software you want doesn't exist. 2) People won't want to install it and most will remove it if it comes on the machine. 3) Computers aren't designed to use the Internet in that way. Of note: There is one way in which this has already been developed and is in use: Bot networks. In a bot network, computer users ignorantly install the client on their computer. The client connects to the server and listens and listens and listens - forever. Then, the server sends a message to the client. The message causes the client to send out tons of spam or do a DOS attack on a server or something like that. So, in one way, you could ask: Why doesn't the government force everyone to join the Federal Bot Network or go to prison? 199.15.144.250 (talk) 18:49, 24 June 2015 (UTC)

This is partly true, but the problem isn't quite as hard as this makes it seem. Every computer that is connected to the internet and has an IP address is supposed to listen for Internet Control Message Protocol packets (which include a type of packet commonly known as a "ping") and respond to them immediately. This is part of the networking standard. In fact it is usual for networked computers to listen constantly to a set of "port"s -- that's the reason firewalls exist. There is actually one port, number 533, known as "netwall", that has been officially designated for emergency broadcasts (see List of TCP and UDP port numbers), though as far as I know no system makes use of it. So much of the functionality needed to set up something like this already exists. Looie496 (talk) 21:56, 24 June 2015 (UTC)

Netwall is not implemented in any OS I've used. Further, it is UDP. I'd make a UDP joke, but you probably won't get it. 75.139.70.50 (talk) 01:37, 25 June 2015 (UTC)

I got it, but it's become a TCP joke because I just said that MChesterMC (talk) 08:18, 25 June 2015 (UTC)

What is URL Canonicalization?

I want to know what is URL Cannonicalization? — Preceding unsigned comment added by Genelia.Abraham (talk • contribs) 13:34, 24 June 2015 (UTC)

It's a way of changing website addresses - mostly removing funny-characters - so they're more consistent. See URL normalization. 82.152.145.136 (talk) 13:58, 24 June 2015 (UTC)

It is more commonly called URL normalization. The purpose is to normalize the URL so you can compare two URLs to see if they are the same. Imagine if I tried to impress you by giving you links to twenty different sites, but with URL Canonicalizatin, you normalize them and find out that they all point to the same page. 199.15.144.250 (talk) 13:57, 24 June 2015 (UTC)

See canonicalization. The basic concept is that when there are different ways to write something, but the meaning is the same, one particular version is chosen as "canonical". In math, 5/2, 10/4, 2½, 2.5, and 2.5000 are all representations of the same number and are precisely equivalent (see note), but unless someone is trying to make a specific point they will use only one of those forms, the one they consider canonical (although I think different people will disagree as to which one that is). (Note: in science and engineering, forms like 2.5000 have a different meaning as they indicate that more significant digits are known. In math, numbers are presumed to be exact.) --70.49.171.136 (talk) 19:18, 24 June 2015 (UTC)

URL normalization and URL canonicalization are not the same thing. The issue is confused by the fact that before the Canonical link element was added to HTML, the two terms were often used interchangeably; I just corrected a couple of out-of-date Wikipedia pages.

URL canonicalization is It is described in RFC 6596 (2012). It specifies the canonical/preferred version of a web page[1][2][3] --Guy Macon (talk) 21:18, 24 June 2015 (UTC)

wordpress theme

1) I want a wordpress theme with home page which only contain different category widget with link to different article, just like apuzz.com ?123.238.96.132 (talk) 17:44, 24 June 2015 (UTC) — Preceding unsigned comment added by 123.238.96.132 (talk) 17:36, 24 June 2015 (UTC)

2) how to get good backlink for website for free ??123.238.96.132 (talk) 17:44, 24 June 2015 (UTC) — Preceding unsigned comment added by 123.238.96.132 (talk) 17:38, 24 June 2015 (UTC)

3) is it worth learning bootstrap ?123.238.96.132 (talk) 17:44, 24 June 2015 (UTC) — Preceding unsigned comment added by 123.238.96.132 (talk) 17:39, 24 June 2015 (UTC)

I added numbers to your Q's StuRat (talk) 19:11, 24 June 2015 (UTC)

• Woulda been even more useful to add section headers. —Tamfang (talk) 06:24, 27 June 2015 (UTC)

1) If you are using Wordpress, you really shouldn't be concerned with questions 2 and 3.

2) People will link to your website if it has something useful. Think about content before you think of design and marketing. For example, XKCD is popular because of the content, not because it looks cool and the owner paid a lot of people for backlinks.

3) Why learn Bootstrap if you are committing to using Wordpress? Just let the template writers do it for you and complain that the template doesn't meet your very particular requirements.

4) What happened to question 4: How do I get insanely rich by slapping together a Wordpress site and hoping everyone rushes to it and hands over gobs of money!? 199.15.144.250 (talk) 19:26, 24 June 2015 (UTC)

1 - are you using WordPress the software you install on a web server yourself or WordPress.com the blog-hosting site? They use different themes.

2 - the fields of search engine optimization (even though it's not strictly search engines you're talking about) and Internet marketing deal with that question quite a lot, and there's no single easy answer. the above response, while likely obvious, fits within the more ethical approaches

3 - depends what you want to do? If you don't already know html, css, and how wordpress works, you'll have a hard time doing anything with bootstrap. People do sometimes use bootstrap as part of some wordpress themes, but this article suggests it may not actually be a great fit (it's definitely popular though). If you do already know the basics, then learning Bootstrap would give you a transferable skill with applicability beyond wordpress.

(since it hasn't been linked here so far, here's our article on it: Bootstrap (front-end framework)) — Rhododendrites ^talk \\ 21:46, 24 June 2015 (UTC)

Hack for S3 galaxy mini to extract raw data from the camera sensor?

My smartphone software only saves jpg files, but obviously this is obtained from the raw data from the camera sensor that is not saved. However, it seems to me that it should be possible to hack the software that is involved in image processing so that the raw data from the sensor will be saved without any of the processing to produce jpg files. I could then download the data to my PC and do the demosaicing, noise reduction, color management etc. using my own programs which should yield much better results. But I didn't find any hacks for rooted S3 galaxy mini smartphones for this purpose. Count Iblis (talk) 22:09, 24 June 2015 (UTC)

This is sort of a Russell's teapot problem: rather than speculating that such software does exist, and asking us to find it... the onus is on you to show that such software does exist.

It has been my experience that most consumer devices are not user-friendly enough, nor fun enough, for enthusiast hackers to spend a lot of effort reverse-engineering. (I make this statement with full awareness that enthusiast hackers can be very skilled and very tenacious.) The complexity of a modern digital camera is just a few notches too high for amateurs or hobbyists to break into. A notable exception is the Nokia 900: but that one had commercial sponsorship, corporate cooperation, and a team of highly capable graduate-students!

On the flip-side, many programmable camera kits are available commercially at reasonable price points amenable to the various capabilities you can find on new hardware. Would you like help tracking down such a development board?

Nimur (talk) 23:13, 24 June 2015 (UTC)

Android has a programmable interface for accessing the camera[4] that includes a couple of raw type formats [5]. Though I do not know if S3 galaxy supports it. Graeme Bartlett (talk) 23:25, 24 June 2015 (UTC)

Samsung's Camera SDK - and the Google Android RAW10 ImageFormat - requires API Level 21 (first available in "Android Lollipop"); the S3 Mini does not support this API level.

In other words: the manufacturer has chosen not to expose "raw" sensor data to the users! This is probably why our OP is asking about "unofficial" mechanisms to access such data.

Nimur (talk) 00:21, 25 June 2015 (UTC)

If it was first provided in in Lollipop I don't know if you can say they chose not to expose raw data to the users so simply. Lollipop came out long after the S3 Mini release and Samsung had abandoned new firmware support for S3 Mini by the time of its release, as they and many other manufacturers do after 2 years or less. In other words, the decision not to provide Lollipop was likely for a whole host of reasons, raw support may not have been considered at all.

Now technically they could have provided their own API for raw support, as they did for a number of other things which Google didn't initially support and for some things which Google did support but they wanted to do via another method. So by that token you could say they choose not to provide raw sensor data, still it's a more subtle point when the framework of the OS they are using doesn't provide it already.

Anyway as is common with most popular phones, there are unofficial Lollipop releases for S3 Mini. Some of these even support the camera. E.g. [6]. Whether these provide RAW support I don't know.

Nil Einne (talk) 02:53, 25 June 2015 (UTC)

Hmm thought I posted this yesterday but guess I didn't save. I meant to say I'm not that sure the S3 Mini unofficial Lollipop releases would provide RAW support. While finding the right drivers etc for the camera with source is often problematic, hence why camera support is often an issue for unofficial releases, I'm not sure that whatever they do generally provides the low level access needed for RAW support. Also I didn't mention this but if you do want hackiness with phone cameras your best bet is probably to look for a phone known for the extremely high quality camera. These are the ones that tend to get enthuasist interest. Nil Einne (talk) 02:00, 26 June 2015 (UTC)

Thanks! I'll see if I can install the Lollipop release for the S3. Count Iblis (talk) 18:19, 25 June 2015 (UTC)