Wikipedia:Reference desk/Archives/Computing/2010 September 19

= September 19 =

Remoting into Ubuntu Desktop VM from Ubuntu Desktop Computer - Automation
I refer to my earlier question; Remoting into Ubuntu Desktop VM from Ubuntu Desktop Computer; is there a way to automate this process such that the Ubuntu Desktop Computer will, upon booting, immediately remote into the Ubuntu Desktop VM and then start the X-windows manager and make it display the graphical-desktop on the Ubuntu Desktop Computer, all without manual intervention? Thanks again. Rocketshiporion ♫ 05:14, 19 September 2010 (UTC)


 * Sounds like you want to turn your desktop computer into a thin client, or at least something similar. You might want to read up on the subject before re-inventing the wheel. :-) As previously suggested, Nomachine NX is a rather nice way of handling this. There are distributions like Thinstation that allow you to automatically fire up the X server and the NX client software straight after booting. -- 78.43.71.155 (talk) 09:38, 20 September 2010 (UTC)


 * It seems that ThinStation is just what I need for this project. Thank you! Rocketshiporion ♫ 03:52, 21 September 2010 (UTC)

"Locked" Micro SD Card
Greetings RD. I'm having an issue with my Micro SD card that I use in my phone to listen to music. The card and adapter are shown here. My issue is this: I downloaded new music I wish to listen to. However, whenever I insert the adapter/microSD into my PC's SD card drive and attempt to copy the files, it informs me that the disc is write-protected. How might I convince my computer that it is not?

FTR: Yes, there is a "Lock" switch on the adapter. Yes, it is in the "Unlocked" position. Yes, these files are totally legal. Yes, I am too lazy to log into my archaic WP account just to post this question.

Thanks for any help you can offer. 76.120.156.206 (talk) 02:23, 19 September 2010 (UTC)
 * Did you try changing the lock switch into the lock position? It could be mislabelled. Also have you tried fiddling around with the switch? It may be it wasn't properly engaged in the unlock position. Or the adapter could also be broken.Can you at least read files on he card (e.g. copy them to your HD)? It would likely also help to specify your OS. And what you're using to copy the files. I presume you're copying to the right location. And you mounted the card read-write (if that's relevant) Nil Einne (talk) 06:41, 19 September 2010 (UTC)
 * Clean off the microsdhc card contacts with a pencil eraser. They get crap on them all the time. 67.119.14.196 (talk) 09:25, 19 September 2010 (UTC)


 * RE: Nill Einne: Yes, I have tried it in both positions, no luck.  I can read/copy files from the card, just not to.  I am on Windows Vista, and I have no idea what you mean by "mounting the card read-write."
 * RE: 67.119: The contacts are squeaky-clean. —Preceding unsigned comment added by 76.120.156.206 (talk) 10:00, 19 September 2010 (UTC)
 * At some point you might just want to get a new SD card. They're like, what, 10-20 USD?  If the new one won't let you write to it, then obviously something's up with the computer.  If it does let you write to it, then you copy the contents of your old card over, copy the new material to it, and throw away the old card. Buddy431 (talk) 22:00, 19 September 2010 (UTC)


 * Some times it's the card reader not the card that's the problem. Try another SD card in the same card reader and see if you have the same problem. I had a similar problem with mine, where it would sometimes (which progressed to always) detecting an unlocked SD card as locked. In the end I took the card reader apart and soldered the detection mechanism so that it'll always detect it as unlocked. --antilivedT 04:44, 20 September 2010 (UTC)
 * Maybe local policies? Check that your account allows you to copy files to it, under the Security section of the Properties dialog of the SD card. If not, change your account to allow it. Sir Stupidity (talk) 08:05, 20 September 2010 (UTC)
 * I have a cheap card reader that will always allow reads but often refuses to write to some cards. Do check the reader before you buy a new card.  Do you have access to a different computer and a different reader to try writing to the card?    D b f i r s   08:38, 20 September 2010 (UTC)

Can anybody convert this Flash 8 file into a Flash 7 file?
It's very urgent. Damn incompatibilities. The file is at http://uploading.com/files/a9c5952c/Daylighting.fla/. Thanks,  ʄɭoʏɗiaɲ  τ ¢  05:05, 19 September 2010 (UTC)
 * That site is giving me errors "Sorry, you have reached your daily download limit. Please try again tomorrow or acquire a premium membership.". Upload it to http://www.mediafire.com/ 82.44.55.25 (talk) 11:06, 19 September 2010 (UTC)
 * I downloaded it and uploaded to mediafire . I don't know how easy it would be to convert it to Flash 7. Flash CS4 can only save as CS3. It can publish the file as a Flash 7 but I guess that isn't what the OP wants. I don't know how far back you'll need to go to save to Flash 7 (I presume 8 can) Nil Einne (talk) 14:07, 19 September 2010 (UTC)
 * Based on CS3, you can go back one version. Presumably Adobe did this on purpose as yet another blatently dickish commercialization technique. My assumption is that only someone with Flash 8 can do this. Thanks Adobe! -  ʄɭoʏɗiaɲ  τ ¢  19:18, 24 September 2010 (UTC)

Real-time shared comments on videos?
There are many video streaming sites on the web, and many players. But has anyone made a player or site where you can "heckle" the video - where there would be, for example, a screen directly under the video where comments can be placed so that they scroll on from the right at the exact moment in the action you choose to heckle, and steadily move off to the left afterward? I'm not talking about real-time chat (though that would be nice too), but chat precisely timed to the movie so you can suggest amusing alternative interpretations. Ideally there should be much vertical space to allow multiple heckles, and the heckles should be clickable to get links, or to "favorite" the poster so he appears when there are too many heckles to show, or to "ignore" him and yank him off stage with the cane. I think it'd be loads of fun to watch a movie that way. Wnt (talk) 05:09, 19 September 2010 (UTC)
 * You'd be wrong. 92.229.13.140 (talk) 10:25, 19 September 2010 (UTC)


 * Omnisio, a small Silicon Valley startup, provided this feature. It was purchased by Google, who merged them into Youtube and promptly disabled the feature (because it was incredibly irritating).  The technology lives on, in limited form, as YouTube Annotations.  Nimur (talk) 13:23, 19 September 2010 (UTC)


 * I was thinking of a stream of comments outside the screen space. Though I suppose there's no idea too obvious to patent and no patent too trivial for someone to buy and suppress... Wnt (talk) 22:18, 20 September 2010 (UTC)

Computer code
I want to do exercise,can u tell me about computer code.But i don't know that. How i to do exercise... —Preceding unsigned comment added by 119.15.92.234 (talk) 07:11, 19 September 2010 (UTC)
 * Do you mean tutorials so you can computer program?Sir Stupidity (talk) 09:09, 19 September 2010 (UTC)


 * We have an article on computer programming. And, because your IP locates in Cambodia and your English seems a bit shakey, you might find our article in the Khmer language, computer programming in Khmer, useful.  Nimur (talk) 13:42, 19 September 2010 (UTC)
 * Or to be more precise, Phnom Penh,Phnum Penh, Cambodia Sir Stupidity (talk) 07:59, 20 September 2010 (UTC)

Installing Ubuntu (dual boot) on a Windows machine with minimal disruption of Master Boot Record
I'd like to install Ubuntu (dual boot) on a windows PC (xp), which currently has one partition that spans the whole disk. I would like to do so without touching the MBR (or doing so only minimally, to reflect the repartitioning). This implies that I would have to install grub somewhere else. Is this possible? If so, I'd be grateful for advice on how to proceed. For starters, what is the safest tool for resizing the windows partition? Thanks, --NorwegianBluetalk 11:03, 19 September 2010 (UTC)
 * This page is a helpful reference. I've used qtparted before and it's part of the ubuntu repositories (I think that's the right one). Backup everything because things can go badly, of course. Depending on how your drive's laid out, you might be able to get enough space to put everything on the one disk. You could create a /boot directory on your first drive. You only need a few hundred mb (if that) for /boot. I don't think it's possible for you to not modify the boot-code of your MBR; it has to know where to point to bootstrap the rest of the OS. Right now windows is doing that on its own; there's no native way to make windows boot linux (unless you wanted to use a different boot medium for Linux startup). Shadowjams (talk) 19:18, 19 September 2010 (UTC)
 * Thanks! After doing a maximum paranoia backup (partimage+full dd-clone, sfdisk etc), I did the repartitioning with the ubuntu installer, and put the /boot directory on an SD-card. The repartitioning tool has an "advanced" button, which allowed me to put the grub-stuff that usually resides on the MBR of the first hard disk on the MBR of the SD-card (which I formatted as ext4). The laptop has a startup menu, reached by pressing esc during boot, which permits booting from the SD-card. So it seems that all the requirements are met. The only hiccup is that linux cfdisk complains (aborts) because of the third (swap) partition ending in the middle of a cylinder. However, both the Ubuntu disk manager and windows diskmgmt.msc agree that all partitions are healthy, so leave it as it is.
 * --NorwegianBluetalk 20:49, 19 September 2010 (UTC)


 * Glad you got it working. That cylinder warning is related to old dos-compatible partitions that had to end on a cylinder boundary, which modern OSes don't care about. Shadowjams (talk) 21:25, 19 September 2010 (UTC)


 * Another option would be to use Windows' boot manager as initial boot manager and let it pass control to GRUB when you want to boot linux. That way you don't need an SD card or other external media. This requires the use of GRUB4DOS / GRLDR, as previously suggested here on the reference desk (by me ;-)), so you should be able to find my earlier suggestion by typing "GRUB4DOS" into the search box :-) -- 78.43.71.155 (talk) 09:30, 20 September 2010 (UTC)

Is it possible to copy all the mails in a Gmail account to another account?
Or at least the inbox? —Preceding unsigned comment added by 59.189.216.70 (talk) 14:45, 19 September 2010 (UTC)


 * If you are using an email program, such as Thunderbird, to view your email. You can drag email from one account and drop it in another account easily.  Just select the emails that you want to move and drag them to the folder you want them to be moved to. --  k a i n a w &trade; 15:02, 19 September 2010 (UTC)

Another gmail account, or another email account on some other email service? I believe gmx mail has a feature for logging into gmail and copying all your emails 82.44.55.25 (talk) 19:41, 19 September 2010 (UTC)
 * Have a look at the gmail data liberation front.Smallman12q (talk) 02:59, 20 September 2010 (UTC)

From one Gmail account to another and all the emails at one go. Anyone have any idea how? Thanks in advance! —Preceding unsigned comment added by 59.189.216.78 (talk) 08:07, 21 September 2010 (UTC)


 * Enable POP for all mail (Settings > Forwarding and POP/IMAP > POP Download) for the account you want to copy from. In the account you want to copy TO, under Settings > Accounts and Import > Check Mail using POP3, click Add POP3 Email account. Enter the account and password etc. as directed. It takes some time to download all the messages, last time I did it. 209.89.177.187 (talk) 22:13, 21 September 2010 (UTC)


 * As stated above... Open both GMail accounts in an email program like Thunderbird. Select the email from one account.  Drag them and drop them into the other account.  Done. --  k a i n a w &trade; 15:31, 22 September 2010 (UTC)

Computer security certification
A friend of mine here in Ireland has a Bsc(Hons) in Computer Science but is finding it difficult to find work in the security field, I recommended getting additional certification and said a good starting point would be the Comptia Security+ but he feels this is a step down in certification. He inquired about CISSP but is getting told he needs 4 years experience to get this, has any editors any ideas what he can do to further his career in the computer security field, thanks Mo ainm  ~Talk  18:08, 19 September 2010 (UTC)


 * My favorite is the Certified Ethical Hacker (C|EH) test. The rest of the certifications are horrible, if you ask me. Bizarrely, CISSP is indeed the most prestigious, even though half of the material tested is meaningless strategy. And yes, Security+ is less prestigious than CISSP or C|EH, although it does test some important conceptual (not applied) material. Cisco security certifications emphasize router security, making them useless to 99% of security professionals.


 * He could also just learn a lot of real-world techniques on his own and then impress the manager in the interview. It's not as if the hiring manager will simply hire him because he has a certification. He will definitely ask him questions about computer security to test his knowledge. This course and this course would teach him far more applied material than he would learn to earn a certification. There are also quite a few books out there on the subject that are sold on Amazon.com. Read the reviews there and check some of them out, too.--Best Dog Ever (talk) 08:04, 20 September 2010 (UTC)

web archiving
If one were to take up web archiving, downloading entire sites and such, what is the best way to store the thousands and thousands of downloaded files (html and jpgs mostly)? Simply compressing them with WinRAR / 7zip? Or are there special archive compressing tools and formats which would be better to use? Also, is mhtml an acceptable format? 82.44.55.25 (talk) 19:39, 19 September 2010 (UTC)


 * I think you'll find MHTML will not yield particularly authentic copies. Compressing is a decent enough idea, but 7z or xz will be a much better idea than rar. ¦ Reisio (talk) 00:12, 20 September 2010 (UTC)
 * How so? Does it change the html / compression of images or something? 82.44.55.25 (talk) 11:21, 20 September 2010 (UTC)

If you're doing something serious, consider this:
 * http://www.digitalpreservation.gov/formats/fdd/fdd000236.shtml

For personal use, tarballs or the like suffice. 75.62.108.42 (talk) 08:04, 20 September 2010 (UTC)
 * Thanks. What programs use the arc format? 82.44.55.25 (talk) 11:21, 20 September 2010 (UTC)

Java
How can I check if a given BigInteger is a perfect square? --71.153.45.75 (talk) 19:45, 19 September 2010 (UTC)


 * By verifying that its square root is an integer. I don't think the standard Java library has much in the way of math functions for java.lang.Number and its descendants (java.lang.math works only for elemental number types), so you may have to either find an implementation of sqrt that works with BigInteger, or code one yourself - see methods of computing square roots. If this is classwork, I'd be pretty sure that what the examiner really wants is "implement sqrt for biginteger". -- Finlay McWalter ☻ Talk 19:55, 19 September 2010 (UTC)
 * It's not for classwork. I was trying to create a program that highlights all the squares in Pascal's triangle, but I had to use BigInteger because the entries get large very quickly. --71.153.45.75 (talk) 00:53, 20 September 2010 (UTC)
 * If all you need to know is if the BigInteger is a perfect square, not what its square root is, then one very simple algorithm is to keep squaring successive integers until you reach or pass your original BigInteger. If you reach its exact value, it's a perfect square, but if you pass it without exactly reaching it, it's not. This algorithm is very inefficient with large numbers though. J I P  &#124; Talk 12:18, 20 September 2010 (UTC)
 * You can trivially make that more efficient (though surely not optimal) by doubling (or even squaring) the candidate square root until you pass the original value, then applying binary search:


 * Written in Python (with its built-in bignum support) for brevity. --Tardis (talk) 13:02, 20 September 2010 (UTC)


 * Here's a more efficient version that uses only shifts and adds. It uses bit_length to compute the initial upper bound. The Java equivalent is called bitLength. I think that a base-10 version of this algorithm was once taught to grade-school students before the era of electronic calculators.


 * -- BenRG (talk) 20:42, 20 September 2010 (UTC)