Wikipedia:Reference desk/Archives/Computing/2014 July 24

= July 24 =

Burning CD
What is the problem when one tries to burn an hour music to an audio CD and when they are finished only 25 minutes have been burnt in?--85.74.103.132 (talk) 03:03, 24 July 2014 (UTC)


 * I think it has to do with it wanting to burn the CD at a certain rate, and if the PC can't supply the data at that rate it runs out of music to record and just records a blank from that point on. You can lower the speed at which it writes the CD, to try to prevent this.  However the CD you already recorded can't be saved, unless it's an erasable CD. StuRat (talk) 03:39, 24 July 2014 (UTC)
 * Also, make sure the source is on a local hard disk, I've seen this happen if you try to burn directly from a USB key or from a network drive, or even another CD drive. Vespine (talk) 06:41, 24 July 2014 (UTC)


 * What Stu and Vespine said.
 * Earlier HDDs could not reliably provide the data fast enough for the CD-R drive, at least in borderline cases with fragmentation etc. Today, HDDs are faster than CD-R drives, by orders of magnitude. Even at 24x, that'd translate into 3.84MBps, and HDDs provide sustained data rates in the triple or high double digits. So, today, almost any write speed is safe from a data rate POV (but there have been reports that no CD-R can take more than about 25x reliably due to thermal limitations?), as long as the source is on HDD. If the source is somewhere else, like a CD, USB flash drive, network drive, or teh internets. No matter how fast your drive/connection is, most of these media can experience hiccups, during which no data are delivered at all. This can be enough to kill your recording session. - ¡Ouch! (hurt me / more pain) 08:57, 25 July 2014 (UTC)
 * Proof of concept: the WP database had a minor hiccup several minutes ago. It got better.
 * Actually, I don't think we can reliably conclude the cause from the information given. It's true buffer underruns use to be a common problem in the very early days of CDRs (I remember dealing with them). However this hasn't been a common problem for a long time. It's not just because of faster HDs, but because of Optical disc recording technologies which began to become common place in 2001? or so. These mean, unless you disable them or the software doesn't know how to use them (which again hasn't been a problem for a long time), the recording should not outright fail because of a buffer underrun. Because of the small gap such protection results in, it's possible some standalone audio players will have playback problems with the CD. Although because the lead-out etc was written, worst case scenario they should work if you skip the track if that is the cause (of course some have problems with many CDRs). Definitely even with the limited EC, the writer should at worst have a small hiccup when reading that track, and it's the same for many CD-ROM drives (so probably including anything which supports MP3 etc). Note also many software support a secondary computer RAM buffer, and if you have a 4GB RAM computer, the whole 800mb or so of a 70 min CD could easily fit inside the buffer generally without causing issue for anything else if you choose to size the buffer appropriately. (It may work on a 2GB as well but if you're more likely to have problems if running something with high memory usage.)
 * It could also be your software failed for some reason. Perhaps a key point, if there was a buffer underrun, or some other burning problem, it should have reported this (as a recording failure) and only take the time for the 25 minutes. If it didn't, this indicates the software at least believes it burnt the whole disk or it's such a POS you should never touch it again. (IIRC some software will try and write the leadout even after a failure to try and keep the CD readable, but it should still clearly report the failure.) It's not clear from the OP's comment whether there was actually a reported recording failure or the OP just found the CD wasn't the expected length after burning. If there was a failure, logs should provide some clue of what happened if it did fail. (If there wasn't a failure, logs may still provde some clues.)
 * There are many other things that could go wrong or cause a player to have problems with the CD if the recording didn't fail. As I already mentioned, standalone players don't always like CDRs. Similarly media compatibility varies quite a lot both between players and writers. Some like the famous gold Taiyo Yuden may be better on average. But still if you're writer does a poor job with them, it may be some other CDRs will be better. (And contrary to what some believe, burning at a slower speed isn't necessarily better. To be fair, I'm not sure 52x ever produces the best results, but many modern CDR and modern drives definitely aren't going to produce good results burnt at 1x either.)
 * Then there could be a variety of mastering issues (both software and user caused).
 * At the very least, if the time playback time is very different from the recording time, you should be able to tell by looking at the CD whether roughly the expected size was recorded or not.
 * Nil Einne (talk) 18:44, 25 July 2014 (UTC)

Lang subcodes case sensitive?
In some of my websites I use the language code  which normally seems to pass the various validation checks. However I have now come across Powermapper which objects to this coding. After some puzzlement, I worked out that it would accept en-GB, with the subcode in upper case. Is this actually required by the standards, or is Powermapper being excessively pedantic? --rossb (talk) 07:57, 24 July 2014 (UTC)


 * For HTML4, the spec says "Names of character encodings are case-insensitive". HTML5's spec points us to IETF's BCP47 recommendation, which says "At all times, language tags and their subtags, including private use and extensions, are to be treated as case insensitive: there exist conventions for the capitalization of some of the subtags, but these MUST NOT be taken to carry meaning".  W3C's advice on language internationalisation says "Although the codes are case insensitive, they are commonly written lowercased, but this is merely a convention". The only place I see a requirement about case is where a document has both xml:lang and html lang= tags (where it's a transition from XHTML to HTML5) where the case is required to be the same in both formats. -- Finlay McWalterᚠTalk 10:38, 24 July 2014 (UTC)

hacking via php
I am a php beginner and on my first day my tutor hacked my gmail password using a small php script(approx 5 to 6 lines) and then he deleted it. i requested him to tell me for knowledge purpose but he didn't. i am wondering is hacking passwords so easy with php scripts?.i browsed on web but couldn't find anything reasonable. will anyone please clear that if something so easy exists in php or it was just a trick(may be he had some software installed on his laptop).182.18.179.2 (talk) 15:08, 24 July 2014 (UTC)

thanks for the reply Finlay Mcwalter, but i think i should have been more precise with the question the first time.actually, he wrote the code and saved in "htdocs" folder like normal procedure is and executed it in "localhost" then a page displayed with my username and password and he told that he had sent a request to "server".he also had a connection established to google and (through this) he tried to tell us that security depends upon coder's logic and not just this language is more secure and other not(between java and php here).182.18.179.2 (talk) 19:10, 24 July 2014 (UTC)


 * Things probably went something like this:
 * he copied the gmail login page (e.g. by downloading it with wget or curl)
 * he wrote a little PHP program that showed that page and waited for you to type your password
 * then he tricked you into accessing that site (maybe he just typed it in for you, maybe he messed around with the machine you were using to alter its DNS or proxy-server settings)
 * you didn't properly check that the connection was secure and signed by google
 * you typed your password in, and inadvertently sent it to his fake site
 * So he didn't hack Gmail with PHP, he hacked you with social engineering. -- Finlay McWalterᚠTalk 15:23, 24 July 2014 (UTC)
 * Well, Phishing to be exact.  Konveyor   Belt  16:24, 24 July 2014 (UTC)
 * As a general rule, one should never enter any kind of password into a machine that you don't trust (and for things that are really important - like banking - that you don't have total personal control over). He could have easily installed a keylogger, or could have altered the browser's settings (or its code) so that even if the site appeared to be an https connection properly signed by Google's certificate, it wasn't. -- Finlay McWalterᚠTalk 15:28, 24 July 2014 (UTC)


 * 182.18.179.2, you should reply at the bottom of conversations, rather than at the top. It sounds like your teacher may have made a simple proxy server which does what I described above. -- Finlay McWalterᚠTalk 20:27, 24 July 2014 (UTC)

@Finlay Mcwalter thanks and i will take care of it from now onwards.182.18.179.2 (talk) 17:48, 25 July 2014 (UTC)

text 'Chapter # ' missing before chapter in latex
I do not know much about Latex. I have written a thesis with the help of a sample thesis. But i have some problems. For example, the name my thesis first chapter is 'Preliminaries', But in table of contents only 'Preliminaries' is written rather than '1 Preliminaries' and first chapter starts with 'Preliminaries' rather than 'Chapter 1 'in next line 'Preliminaries'. base class of my thesis is 'book', I m using class file with no preamble file. — Preceding unsigned comment added by 39.35.150.202 (talk) 16:08, 24 July 2014 (UTC)
 * We may need more information about how you've set up your work. How are you adding the chapters? I presume you're doing something simular to me and not writting one big long document in one file. In my thesis to get the behaviour you are describing I used


 * \addcontentsline{toc}{chapter}{Abstract}


 * \input{Abstract.tex}


 * which gives the Abstract and no number in the table of contents, but for the main section I used


 * \include{Introduction}


 * which give 1 Introduction in the table of contents (As I named the chapter the same as the file but you can have different chapter headings). Dja1979 (talk) 19:08, 24 July 2014 (UTC)
 * I assume that inside  you used  ? OP, just an off-chance, but did you use   (notice the star) in your thesis? --Stephan Schulz (talk) 07:00, 26 July 2014 (UTC)
 * That'll teach me for not looking at my code properly, I had the  in my Abstract.text. Apologies for not being more carful befor given advise.Dja1979 (talk) 17:27, 26 July 2014 (UTC)

Right or Left alignment of filenames in Windows7 folder?
I have an open folder in Windows7 with "View Mode" set to "details"-view. Can I somehow get the filenames aligned to the right side instead of the standard left side of the column? Or toggle between Left and Right alignment of the filenames? -- 46.15.238.85 (talk) 19:01, 24 July 2014 (UTC)


 * I doubt it. You'd need another application to do that type of thing for you. StuRat (talk) 00:31, 26 July 2014 (UTC)


 * But, Both Hebrew and Arabic script is written from the right to the left, and surely those language versions of Windows7 must have right alignment as a default. So there must be some kind of environment variable, somewhere, which governs the current right or left alignment — and which could easily be toggled — don't you think so? -- (OP) 46.212.24.65 (talk) 21:50, 26 July 2014 (UTC)

Steelseries Apex keyboard media keys
I am interested in the Steelseries Apex keyboard, but I am concerned about the media keys to the right. According to some images on the Internet, there are previous/next track keys (|<<, >>|), while other images show rewind/fast forward keys (<<, >>) instead. I often use the previous/next track keys, but never the rewind/fast forward keys, so I am very interested to know what is actually the case. If the keys are the rewind/fast forward ones, can they be reprogrammed to act as previous/next track keys? --83.183.23.160 (talk) 23:08, 24 July 2014 (UTC)
 * The multimedia keys are standardized (at least de facto by Windows) and don't include rewind and fast forward, so I think that << >> is a variant labeling for the previous and next track keys. -- BenRG (talk) 04:56, 25 July 2014 (UTC)
 * Excellent. Thank you for your answer. --83.183.23.160 (talk) 18:35, 25 July 2014 (UTC)