Wikipedia:Reference desk/Archives/Computing/2011 July 23

= July 23 =

Sata power connector
I'm building a computer, and most of it is functional, but when it boots, neither the HD or OD are recognized. The light on the optical drive doesn't turn on, I can't eject either, and the hard drive isn't spinning, so I'm assuming it's a problem with the power somehow. The cable I'm using is a Cooler Master cable that looks like this. I tried swapping in a hard drive I know works, but that didn't work. I also tried switching the SATA power cable for a 4-pin molex, and using an adapter to change that to SATA, but that didn't work either. However, when that same molex cable is connected to the fans, it works just fine. How would I find the source of the problem? KyuubiSeal (talk) 02:36, 23 July 2011 (UTC)


 * Does the optical drive light come on if you unplug the data cable while leaving the power plugged in? Nil Einne (talk) 08:41, 23 July 2011 (UTC)


 * I suspect that the fan is more tolerant of power that's outside of specs, like low voltage. Those other devices might even have safety features to prevent operation (which might cause damage) using a defective power supply.  Try swapping in a new power supply. StuRat (talk) 14:12, 23 July 2011 (UTC)


 * I don't happen to have another power supply on hand. I do have a voltmeter though. Would it be safe to test the voltage and current on either cable while it's running? KyuubiSeal (talk) 14:35, 23 July 2011 (UTC)


 * Sure, that's easy enough for the Molex connector, but trickier for the SATA. Black->yellow should be 12V and black->red should be 5V; note that systems frequently draw maximum power for a few seconds as they boot, so watching the voltages as the system boots (rather than when it's quietly cruising along) can be instructive. That said, in my experience, when the drive-connector rails in a PC PSU are overtaxed the symptom is usually that a given drive starts, spins up, and then is depowered (sometimes a cycle of powerup/down develops). For neither device to even start to spin up would suggest the power isn't getting through at all, or at a very low voltage, suggesting either a bad connector somewhere or a defective PSU altogether. -- Finlay McWalter ☻ Talk 14:58, 23 July 2011 (UTC)


 * You were right, very little power was coming through. Also, a few minutes after we tested it, there was a huge spark, the fan stopped, and no power came from any port. Could have damaged something if we hadn't disconnected it to test it. Thank you so much! KyuubiSeal (talk) 02:11, 24 July 2011 (UTC)

Facebook - Exporting list of page fans ('likes')
Hi, does anybody know a straightforward way to export a list of people that 'like' a facebook page that you are an admin on? I've had a look through facebook, and range range of blogs and articles about it, and I cant seem to find an easy way to do this that appears entirely white-hat - We don't want to do anything that facebook or our fans might react poorly to.

In my case, I would need to be able to export the public names of several thousand profiles that 'like' the page. This isn't for any devious purpose, the place where I work operates a number of different internal and external digital social platforms, and we want to avoid bombarding people that may have accounts across several of those platforms with the same information. Ideally, if it is possible, I would like to be able to export as a CSV (or anything else easily compatible with Excel).

I can't find anything on facebook that forbids doing this, nor can I find anything that says it is ok to do this.

Facebook does appear to have a tool that allows you to do something similar for facebook groups, but hasn't rolled out a tool for 'pages'.

I keen to hear about any thoughts, experiences or tips you might have.

Thanks Computing helpdesk people. 86.182.254.23 (talk) 11:37, 23 July 2011 (UTC)


 * Enumerating "likes" certainly seems to be supported by the Facebook graph API (docs). -- Finlay McWalter ☻ Talk 11:46, 23 July 2011 (UTC)


 * Hi, thanks, I did have a look at that page, but I am afraid to say it mostly went over my head, and I wasn't sure if I could use it to do what I want. Given that you suggest I may be able to use that to pull out the details I'm after, I may invest some time in working out how to use the API properly. Thanks Finlay McWalter 86.182.254.23 (talk) 12:27, 23 July 2011 (UTC)


 * These APIs are intended for an audience of programmers, most of whom manipulate them through a wrapper adapter specific to whatever programming language they're using. The APIs show that, at least in theory, the information you want is accessible to programs (although I've not read the terms-of-service carefully; API users tend to have to be careful in that regard, lest they be treated as being not entirely white-hat). But if you're not a programmer, and don't have the help of one to hand, the mere evidence that an API exists which could allow a program to do what you want obviously isn't the same as actually having such a program.  You may need to recruit a programmer temporarily, if no-one else can find a pre-existing program that uses the API in the fashion you want. -- Finlay McWalter ☻ Talk 14:29, 23 July 2011 (UTC)


 * Hi Finlay McWalter, thanks for the additional reply. I can confirm that I am in no way what-so-ever a programmer, although, I do pick things up reasonably quickly. If I can't master the programming quickly (which I assume will be the case), I shall ask the powers-that-be how much they want to invest to pull in the data. I really do appreciate your additional advice, it is very helpful. In the words of my peers: "Cheers" (poet, didn't know it etc.), 86.182.254.23 (talk) 17:00, 23 July 2011 (UTC)


 * Facebook has created a Graph Explorer to walk the Graph (you will need to authorize the app using the 'Get access token' button there first), which might help you see if the data you want is available using that route. Click around a bit or type your page's ID in the input field there to get a bit of information. I haven't been able to find the Likes for a page using it yet though - if I enter a /likes, I get an empty list, although I am able to get a list of people liking a specific post by following /posts. 82.75.188.107 (talk) 18:27, 23 July 2011 (UTC)

relief map
i wasn't sure where to ask this question but is there any software by which i can make (imaginary) relief maps, very easily in a simcity like way?(i want it for a sci-fi story)--Irrational number (talk) 14:00, 23 July 2011 (UTC)


 * The scenery generator and fractal landscape articles list a few programs that can do this. -- Finlay McWalter ☻ Talk 14:04, 23 July 2011 (UTC)

Connecting subwoofer to receiver
I've recently upgraded from a plasma TV-based setup to a home cinema with projector, but I'm having trouble connecting my old subwoofer to my new receiver (it is this model). My subwoofer seems to use the same connection as my other speakers (here's a pic]) but there doesn't seem to be a port for it to connect to. Would I have to use some kind of adapter? doom gaze  (talk)  15:20, 23 July 2011 (UTC)


 * Your receiver has a line-level output for the subwoofer. You can use a powered subwoofer (that is, one with a built-in amplifier) with it. If you want to use your existing (non-powered) subwoofer, you'll need an amplifier to drive it. Try searching the web or your favorite shopping sites using "mono subwoofer amplifier" and variations of it. --98.114.98.196 (talk) 16:38, 23 July 2011 (UTC)


 * And you might find you can get a more modern sub-woofer for less than the amplifier will cost. That's what I did.  I got a decent 2.1 system (right speaker, left speaker, and powered mono sub-woofer) for $30. StuRat (talk) 18:11, 23 July 2011 (UTC)
 * Mm I was going to make that observation too, looks like I'll just replace the subwoofer. Thanks guys, doom gaze   (talk)  18:33, 23 July 2011 (UTC)

Missing edit links in Reference Desks
Wikipedia seems to a longstanding problem with sporadic disappearances of page and section "edit" links. Right now none of the Reference Desks has any edit links, either for the page or for individual sections. (I'm relying on a workaround to post this.) Does anyone know what the cause of the problem is? --98.114.98.196 (talk) 17:25, 23 July 2011 (UTC)


 * It seems to only be a problem for anonymous I/P's, like yourself. I suspect it's the lowest level of protection, to prevent spambots from plastering these pages with ads.  You can sign up with Wikipedia for free, to avoid this problem in the future. StuRat (talk) 18:02, 23 July 2011 (UTC)


 * There's zero evidence for that and it seems rather unlikely since the foundation doesn't tend to play nasty tricks. All evidence suggests it's a bug that no one has tracked down. The reason it only affects anons is likely because only they use the cached version. Nil Einne (talk) 18:56, 23 July 2011 (UTC)

It's still happening here too. Nothing seems to come of the threads on Village Pump either. Someone suggested filing a bugzilla report, I've no idea how to do that though. 82.43.90.27 (talk) 21:22, 23 July 2011 (UTC) I do like to call it as "fake protection" or "spoofed/cloaked protection". That means, the page seems to be protected and you cannot edit it, but actually can. Testor Ploa (talk) 04:05, 24 July 2011 (UTC)


 * No, no, it is not true that you cannot edit a page if the edit links of sections are not visible (simply press the Edit tab at the top), and missing edit links do not only affect anons. See Purge for the cause and the solution. --Espoo (talk) 16:08, 8 October 2011 (UTC)

Should routers make faint noises?
Should DSL routers with a DC input make very faint high pitched noises, audible only when you put your ears against them? What causes the to make this noise? Bahr456 (talk) 21:05, 23 July 2011 (UTC)
 * I often hear the flyback transformer in old television sets, and very often hear capacitors audibly squealing inside the switching power supply in a lot of small electronics. I particularly noticed a ~15 kHz squeal on the power supply of my old Linksys 802.11b wireless router.  Although such noises indicate a power supply whose design or manufacturing-tolerances were "imperfect," they rarely indicate a failure or imminent problem.  "Theoretically," acoustic resonance in a capacitor may reduce its expected lifetime, but I've never seen this in practice.
 * The root cause, in many cases, is a sort of 'piezoelectric effect' In the power supply capacitor. A signal is passing through the cap, which by design should (usually) be outside the audible range - say, 1 MHz, for switch mode power conversion.  Due to imperfect design, some signal may leak into an audible band.  Then, because the capacitor dielectric is subject to a mechanical force due to electrostatic attraction, the acoustic frequency electromagnetic signal can cause an acoustic vibration of the capacitor dielectric.  This can cause a faint audible buzz, hum, or squeal.
 * There are probably dozens of other possible root causes for faint squeals or hums in your router, but this one seems most common in my experience.  Nimur (talk) 04:16, 25 July 2011 (UTC)

screen recording device
Taking note that the people here are experienced with computers, could you please recommend to me some free software that records what you do on the screen that does not slow down the computer significantly nor advertise itself in the playbacked video? Thanks. --Thebackofmymind (talk) 21:32, 23 July 2011 (UTC)


 * CamStudio or VLC would be my recommendations. In VLC to record the screen go Media - > Convert / Save -> Capture Device - > Capture Mode -> Desktop. Both programs require some processing power to operate, which may slow down your computer. I don't think there's any way to work around that without upgrading your computer. AvrillirvA (talk) 23:15, 23 July 2011 (UTC)


 * Check out Comparison of screencasting software.
 * APL (talk) 06:11, 24 July 2011 (UTC)


 * To avoid a significant slowdown, you'd need a very low frame rate and/or resolution/color depth, or to give up on using the computer to record itself and use an external video cameras instead (or maybe clone the images going to the monitor and send half to another computer's video input, and have it store the images). StuRat (talk) 06:16, 24 July 2011 (UTC)