Wikipedia:Reference desk/Archives/Computing/2013 March 28

= March 28 =

Vorbis codec for VLAN
An easy question, I hope; I just haven't found anything online (or rather, I've found too many things).

WP only takes ogg audio format, correct? I cannot convert in VLAN, because I lack the codec. Any idea where I can find one?

Thanks — kwami (talk) 07:23, 28 March 2013 (UTC)
 * http://ffmpeg.org hosts FFMPEG, including a codec library and a command-line tool that can re-encode. Nimur (talk) 09:24, 28 March 2013 (UTC)


 * Thanks, I'll check it out. Can one of them be imported into VLAN? — kwami (talk) 18:57, 28 March 2013 (UTC)


 * If VLAN means VideoLAN, it already ships with Vorbis, so I think your problem must be something else. There's a lot of other transcoding software out there. If you want a GUI application for Windows, foobar2000 is pretty good, and also ships with Vorbis. -- BenRG (talk) 16:15, 30 March 2013 (UTC)

palindrome in a palindrome ?
Hi

does anyone know how to solve this pushdown automaton?

l={w contains a,b,c,n>1,w=R{w}|w^n}

Thank you.Exx8 (talk) 13:24, 28 March 2013 (UTC)

Youtube - I can see but cannot hear
I'm having a problem with hearing youtube videos. My speakers are fine, and I can hear videos generally, but ones I access on youtube - complete silence. This has been happening now for about 2 weeks. I've tried everything I can think of; fiddled with every sound setting I know; looked on Help for similar problems, but all I see is a bunch of people with the same problem I have and nobody's getting any solutions.

Can anyone suggest what I can do to hear youtube videos as well as see them?

Thanks. --  Jack of Oz   [Talk]  13:38, 28 March 2013 (UTC)
 * Can we assume that you've tried everything at http://support.google.com/youtube/bin/answer.py?hl=en&answer=58132 ? If so, and if you have (or can download) VLC Media Player, you could try this. If the streams work through VLC, that pretty much narrows it down to an issue with Flash on your browser. - Cucumber Mike (talk) 13:57, 28 March 2013 (UTC)


 * Instruction 2 says "Adjust the volume control located in the lower left corner of the YouTube Video Player". I assume this refers to the screen I get when I access any utubular video.  It has a microphone icon at the lower left of the screen.  The only settings are Mute and Unmute.  I cannot adjust the volume any other way.  If I right click, I get a Settings tab, but it contains no options for volume control.  So, how come I'm missing this adjustment capacity?


 * I have the most recent version of Adobe Flash. Would uninstalling and reinstalling it do any good?   --   Jack of Oz   [Talk]  21:45, 28 March 2013 (UTC)


 * (Blush) Stop the presses.  Problem solved.  I'm too embarrassed to admit what I was overlooking.  Thanks for your help.  --   Jack of Oz   [Talk]  21:49, 28 March 2013 (UTC)


 * Ok, now I'm intrigued... - Cucumber Mike (talk) 21:52, 28 March 2013 (UTC)


 * OK, I'm not too proud. Allow me to bare my soul for your delectation.  When I hover over the microphone icon, there's a red scroll bar.  Immediately to its right is the digital clock counting away the seconds.  Because of that proximity, I misread that scroll bar as the same thing as the red scroll bar above, the one that shows how far into the video you're at, at any point in time.  I spectacularly failed to notice that the top scroll bar has a circle thing that moves along but the bottom one has a bar that never moves unless pushed by the user.  In fact, it didn't register with me that they were even different things.  In my so-called mind, there was just the one scroll bar, and it had nothing to do with volume control.


 * I comfort myself with the assertion that I cannot possibly be the first person to have made this mistake. Which means I fail Samuel Beckett's dictum: "To be an artist is to fail as no others dare fail".  But I have failed magnificently, and that shall be my solace any my consolation.  (You may now all cease your pathetic sniggering and get on with what you're paid for.) --   Jack of Oz   [Talk]  22:22, 28 March 2013 (UTC)

What algorithm do browsers use to interpret HTML colors?
I understand that the standard system of Web colors is a hex number with each pair of digits corresponding to red, green, or blue, and that there's also a set of color names you can use, like "limegreen". But I've found that any string can be put into bgcolor="COLOR", and not all such strings are the same color. For example, "rainbow" is a shade of green and "chris" is red. The results seem consistent across browsers. How is the browser determining the corresponding color? ± Lenoxus (" *** ") 15:35, 28 March 2013 (UTC)


 * Hmm, I didn't know that. Experimenting, it seems to work only on the body tag and only with bgcolor html attribute, not with a CSS background-color specification and not on another tag like a div. Further, it's not just picking out valid hex chars, and not the first few letters - it does seem to be some kind of summing algorithm. -- Finlay McWalterჷTalk 16:03, 28 March 2013 (UTC)


 * Per below, it is picking only hex chars, but it's doing so in a way that confused my simple test. -- Finlay McWalterჷTalk 16:51, 28 March 2013 (UTC)


 * I did some digging through the Firefox source code, and the relevant code seems to be NS_LooseHexToRGB in gfx/src/nsColor.cpp, which says it implements the WHATWG recommendation rules for parsing a legacy color value. The significant part is that it trims first from the right (up to 8 chars for each of the 3 components) and then parses leftwards, pulling out upper and lower case hex chars. -- Finlay McWalterჷTalk 16:42, 28 March 2013 (UTC)
 * What ho! NS_ASSERTION in Gecko source-code?  And all these years I had been taken in by the propaganda during the browser-wars, and the virulent rantings of pro-whatever-engine advocates, on the assumption that each rendering engine was somehow distinct!  Only to discover, on closer inspection, that WebKit and Gecko are mostly the same source-code?  At least I can rest assured knowing (speculating) that Internet Explorer's closed-source Trident uses a completely orthogonal code-base - after all, it would be unthinkable if NeXT had somehow hacked up COM+ for Unix, and  even more unthinkable if that source-code were still in use today in major commercial and open-source web browsers...  Nimur (talk) 14:35, 30 March 2013 (UTC)
 * NS stands for Netscape, which was the ancestor of Mozilla/Gecko as you may know. XPCOM was inspired partly by Microsoft's COM, but is used only in Gecko-based browsers and has no connection to NeXT. Nothing else that you wrote makes sense either. Were you confused about which layout engine is which? -- BenRG (talk) 17:40, 30 March 2013 (UTC)
 * Like many non-acronyms, "NS" doesn't stand for anything. But portions of the source-code in question is identical to portions of the source code released as OpenSTEP (circa 1994), and it very probably inherits the "NS" from NeXTSTEP, which also has identical source-code... and existed in 1988, predating Netscape (which incorporated, coincidentally, circa 1994).  I have no specific knowledge regarding whether that code was "copied" or "typed entirely separately by a different engineer at a different time, resulting in an identical sequence of characters."  Nimur (talk) 19:17, 30 March 2013 (UTC)
 * There is a WorldWideWeb → libwww → Mosaic → Netscape code lineage, but the NS prefixed symbols didn't come from there. I can find no evidence that they (as opposed to other NS prefixed symbols) are used outside the Mozilla code base. The OpenStep spec, for example, does not define NS_ASSERTION, which is what spawned this strange subthread. Can you please link the alleged duplicate code directly? -- BenRG (talk) 16:07, 31 March 2013 (UTC)

For other striking examples of letters that don't stand for anything, NS also doesn't stand for NeXT/SUN, even though these corporations cooperated to create the library and API; for that matter, SUN Microsystems never stood for the Stanford University Network microterminals, even though that's what they originally were; the SPARC doesn't have anything to do with a collaboration between SUN/Xerox PARC; SRI hasn't been Stanford Research International since the 1970s, and even though Siri was invented there, her name has no connection with any acronym; similar-sounding non-acronym SGI merely acquired Silicon Graphics, Inc. but is a distinct company; and in case any conspiracy theorists want to bring oil companies into this, Esso, despite being marketed by the direct patrilineal descendent of Standard Oil, is just a meaningless but marketable brand name, and is not an acronym. GNU actually stands for "GNU is not Unix. COM+ stands for "Common Object Model and Microsoft Transaction Server."   Nimur (talk) 19:43, 30 March 2013 (UTC)
 * Half of this seems to be wrong as well. -- BenRG (talk) 16:07, 31 March 2013 (UTC)


 * Thank you, Finlay McWalter and others! ± Lenoxus (" *** ") 22:42, 31 March 2013 (UTC)

How does bitcoin work?
Hi,

Can anyone explain me simply how does bitcoin work?Exx8 (talk) —Preceding undated comment added 16:04, 28 March 2013 (UTC)
 * The best start is to read the intro to our article on the topic Bitcoin, and then to read the Bitcoin wiki FAQ ( although we don't link it in the article and the site seems to be down right now; google has a cache of it though) which is a good introduction. If you have questions after that, ask them. There are 3 or 4 distinct concepts going on so tackling each in turn is the best way to start. Shadowjams (talk) 16:11, 28 March 2013 (UTC)


 * A very short explanation for someone just trying to wrap one's head around the basics of it, as I understand it. To make sense of Bitcoin, first you need a slightly better-than-average understanding of what a currency is in the first place:
 * All currencies can be considered representations of value. A dollar bill is just a piece of paper with writing on it, but because other people are willing to say it has value, I can use it as a currency and exchange it for something else of value (say, a piece of candy). The value of currency is not always stable — fifty years ago, I could have bought a lot more candy for a dollar than I could today. If everybody turned around tomorrow and said that the dollar has no value at all, then it would just be paper again.
 * Most currencies are backed with something else. It used to be, for example, that a dollar's value was backed by a given amount of gold in a bank somewhere. (Currently, the US dollar is a fiat currency, backed only by the assertion that the US government says it has value.) Why gold? Because there is a limited amount of gold in the world, and it is difficult to get, and it is pretty stable as far as worldly objects go. For these reasons gold (and silver, and other precious metals) have long been the basis of currency regimes. If it turned out, tomorrow, that there was an unlimited amount of gold in the world, and it was easy for anyone to get it, gold would lose value very quickly, and be a bad choice for currency.
 * OK, if you're with me so far... the idea behind Bitcoin is to use information as a means of backing a currency. The Bitcoins themselves are based on mathematical problems that are hard to solve. So the effort it takes your computer to solve these problems is equivalent to the effort it would take to mine gold. So the answers to the problems are more or less the backing of the currency. There are other aspects to it (e.g. it uses peer-to-peer networking as a means of exchanging and verifying the value of the information, instead of a central bank, and making sure that information isn't counted twice), but that's kind of the basics.
 * So why should anyway value the answers to these mathematical problems? The same question can be asked for why you would value gold, or value pieces of paper with the word "dollar" written on them. They have value so long as people are willing to say they have value. If you have three Bitcoins, and someone is willing to give you something else for them, suddenly they are equivalent to any other form of "money" you can imagine.
 * So will Bitcoins retain value? Is investing in them a good idea? Can they really be used as an alternative to national currencies? Nobody really knows at this point; there are lots of opinions pro and con as to what the long-term prospects are. At the moment they seem to have value to some people, but that doesn't mean they will tomorrow. There are lots of questions by real economists about whether this can really work out. --Mr.98 (talk) 16:44, 28 March 2013 (UTC)
 * That's a good overview of the currency aspects. The technical aspects involve solving these core problems:
 * How do you stop people from spending the same money twice
 * How do you stop someone from spending someone else's money
 * How do you create money in the first place (in a way that inspires confidence)
 * One and two are easy (or easier) with physical currencies. When you give it away it's gone, and when you have it nobody else can give it away. The third is the reason we have banks, and more specifically central banks. Bitcoin addresses the first problem with what it calls a "block chain" which is essentially a giant transaction log of every bitcoin ever spent, and who currently owns it. The second is addressed through public key signatures, when you send money you do so by signing a transaction that says I give x bitcoins to y. Everyone else uses the block chain to make sure you own the bitcoins you're giving to y, and then checks the signatures to make sure only you signed the transaction. The third is done through "mining." Put simply, as the block chain gets created, people randomly are given coins (not actually randomly, it's more of a lottery and your odds are proportional to how much computing time you dedicate to mining).
 * Any one of these points, and some others along the way, have more technical pieces to them. Shadowjams (talk) 17:37, 28 March 2013 (UTC)

Windows 7 problems
I recently upgraded from Windows XP to Windows 7, and I found a few things that give me problems with it.

1) I use mIRC 6.2, which was released before even Windows Vista came out, because I like prefer it over more recent versions. As far as I know, user data from applications programmed to "recognize" it will put their data in C:\Users\ \AppData, but since 6.2 is pre-Vista, it still stores its data in C:\Program Files (x86)\mIRC (in my case, x86). Now, mIRC stores its logs within its subfolder, and when I recently went to find that folder, it was not there. Unhiding hidden + system folders did not help. However, I remembered that WinRAR could see hidden folders on my XP machine by default, so I browsed there with it, and voila, there it was. Why is Win7 completely hiding the logs folder from my view? Is it because it's not in the AppData folder?

2) Windows 7 changes (Windows/File) Explorer and file select/save dialogs in many ways that I do not like over XP. I use Tab all the time to navigate over various selections. For example, in XP, if you pressed Shift-Tab in the area where you would type in the file dialogs, it would go directly up to the file list (where I would then use the arrow keys or type in the beginning of the file name). In 7, it goes up to the "Date modified" column. Is there any way to change this back so that it goes directly to the file list?

3) Windows 7's search (bar) is useful in some places, but not in others. Is there a way to restore or emulate the way XP used to do its search? In addition, is there a way to remove the "Search programs and files" textarea from the Start Menu? (I used to browse the Start Menu with my keyboard, which is now impossible without hitting Shift-Tab first, small, I know)

4) Is there a way to restore the Favorites menu-bar item in 7? That's the way I used to use to primarily get around my system (again, keyboard and typing; in this case I would type Alt+A [brought up Favorites], then type the letter of the shortcut in my Favorites that I wanted to go to).

5) In XP, using Backspace would go up a directory. In 7, you need to do Alt+Up. Is there a way to change this back?

Thanks! -- 143.85.199.242 (talk) 16:33, 28 March 2013 (UTC)


 * 1) I suspect the logs are really in the VirtualStore directory, and you will see them in Explorer if you look there. 2-5) Classic Shell can fix a lot of Vista/7 UI regressions, but I don't know whether it can fix the ones you mention. You can also use a program like AutoHotkey to set up convenient keystrokes to replace the missing built-in ones. -- BenRG (talk) 22:43, 28 March 2013 (UTC)


 * Classic Shell will probably address most of these. (Disclaimer: I haven't used it myself.)
 * You can turn off and thus remove the Search completely from Windows 7 by using "Turn Windows features on or off" (in Control Panel, Programs and Features - or just run OptionalFeatures.exe). Mitch Ames (talk) 08:16, 30 March 2013 (UTC)

Medieval Toal War (original)
How can I get another cd/dvd of this game??? I played mine so much I wore it out! It won't even load anymore... — Preceding unsigned comment added by 24.117.101.191 (talk) 18:34, 28 March 2013 (UTC)


 * Getting a new disk: You can contact the company that made it (we didn't) and ask them (might work), or you can buy a new copy from Amazon or eBay.
 * BUT I'm pretty suspicious that you in fact could have "wore out" the CD/DVD, unless you physically damaged the media (e.g. scratched it). Disks don't really get "wore out" through repetitive usage. Disk drives might, though even there it seems pretty unlikely unless you are on ancient hardware. And there are other software-based reasons that software can fail. Unless you've physically damaged the disk (easy way to check: try it on another computer), pursue other avenues of figuring out what is wrong. --Mr.98 (talk) 03:40, 29 March 2013 (UTC)
 * Unfortunately DVDs do wear out. See DVD rot. Most of the older DVDs that I rent have dead spots on them, despite a thorough clean before they go into the player.--Shantavira|feed me 12:19, 29 March 2013 (UTC)
 * I'm curious about the risk of ultraviolet light damage. The DVD rot article only mentions it in the lead and doesn't say anything else. Viriditas (talk) 12:36, 29 March 2013 (UTC)
 * They decay, but that's not the same thing as wearing out. Wearing out implies there is a correlation between use and failure, as opposed, say, to just age and failure. I've never heard DVD rot ascribed to use, though I don't claim to be an expert on the phenomena. --Mr.98 (talk) 16:55, 29 March 2013 (UTC)


 * Apparently you can also download games directly onto your computer now? might solve the problem of the CD getting damaged. My friend tells me that if you bought a CD and it broke, you're allowed to download a free copy from various 'piracy' websites, but I don't know whether there's any truth to that, might be better to just buy another copy. Or even do what I did when my Rome, Total War got damaged, buy a whole box-set of them, it was barely more than the cost of one CD. Kitutal (talk) 18:46, 29 March 2013 (UTC)


 * There is no such allowance in the law for downloading pirated versions if your original version broke, even if one considers that to be a totally just interpretation of things. (It's debatable, let's not debate it.) --Mr.98 (talk) 21:37, 29 March 2013 (UTC)