Wikipedia:Reference desk/Archives/Computing/2008 June 14

= June 14 =

Problems with torrents and other P2Ps
I have been having a lot of problems with torrents and other p2ps forming a comection with peers. I think it has something to do with my port(s). How do I solve this problem. When I download a torrent I open it with utorrent and the availability is 0 even if there are a few thousand seeds. —Preceding unsigned comment added by Dalakoi (talk • contribs) 01:47, 14 June 2008 (UTC)

Networking is a complex field, particularly diagnosis & trouble-shooting of problems. Details of your environment, network configuration, applications used & their configuration (with regard to port(s) used), exact symptoms (including error messages etc.) would be of great help in order to offer some kind of assistance towards a solution. Unfortunetly, a vague description is not enough in order to provide anything more specific.

Pre-emptive suggestions: check the configuration of your applications, firewalls, routers etc. There should be a forwarding path from your external connection all the way to your application. Try testing with Wireshark. However, doing so may require reading/learning about networking concepts. Like I said; it's complex.

Don't be put-off by the title, there is a vast amount of useful information within: I kindly/gently point you to Eric Raymond's How to Ask Questions the Smart Way, which may help you in the art of asking questions which elicit useful answers. — Lee Carré (talk) 18:14, 14 June 2008 (UTC)


 * Perhaps your ISP has blocked your p2p ports. GoingOnTracks (talk) 18:00, 14 June 2008 (UTC)

2 questions, front panel connections pins, UPS
I had a hard time finding the correct front panel wires inside the chassis of my PC. I had to look behind the front panel to determine which is which. Now, although I have been able to recognise the right pairs of wires, I am not able to determine the correct polarity for each pair. Are they interchangeable? The manual of my motherboard specifies each pin of a pair for two LEDs. Like this: HD (IDE Hard Disk Active LED) Pin 1: LED anode(+) Pin 2: LED cathode(-) But I have no idea how I am to find which is anode and which is cathode. Can somebody help me? —Genuee (talk) 05:19, 14 June 2008 (UTC)

The White/Black one is the cathode, and the brightly coloured one is the anode. You can always do it the trial and error way though. --antilivedT 09:49, 14 June 2008 (UTC)


 * BTW, The wires on LEDs are not interchangeable. If you pass voltage the wrong way, in most cases they won't light. (Some bi-color LEDs will get the colors reversed.) JeremyMcCracken (talk) (contribs) 03:48, 16 June 2008 (UTC)

Second question is related to UPS. My UPS's manufacturer says that their product would support the computer only if there is a certain level of load. At least 100 Watts is the required load. In my case, when there is a power failure when the monitor is off/in sleep mode, the UPS will fail. Is this the case with all manufacturers? —Genuee (talk) 05:19, 14 June 2008 (UTC)

In response to your second question regarding your UPS: I have an APC Smart-UPS 1500 which does not exhibit this behavour. Personally I would consider the symptom you describe as a significant fault; there should be no minimum load needed for it to operate correctly. My UPS supplies power from battery no matter the load attached, even if there is nothing attached. The only reason I can think of for this sort of behavour is to preserve the battery when there appears to be no load (in which case the UPS should look for any load, rather than something greater than 100W). Batteries used in UPSes only have a limited life, governed mainly by the number of discharges, particularly if they are deep discharges. — Lee Carré (talk) 17:56, 14 June 2008 (UTC)
 * At my school, we have a rack to TV equipment and computers backed up by a 30amp TrippLite lead-acid UPS. About 1.5years ago, I determined that it did not require any particular load to discharge, as it sat there giving off a warning beep and powering a small test lamp while we went to lunch. While it may preserve battery life, I can't think of why 100w would be chosen as the load limit, especially when many small, but delicate devices would draw less than 100w. Freedomlinux (talk) 00:18, 15 June 2008 (UTC)


 * I've never heard of a UPS requiring 100 watts (that's quite a lot). JeremyMcCracken (talk) (contribs) 03:49, 16 June 2008 (UTC)

Non linear curve fitting in Matlab
I have been using Matlab for fitting a non-linear curve(the model is known for sure) which depends on three parameters and one variable: I have been getting results which look somewhat like this :

c =

General model: c(z) = newtransmittance(wav,ipow,opow,w,b,g,z) Coefficients (with 95% confidence bounds): b =       5.17  (-5.018, 15.36) g =         10  (-74.81, 94.81) w =      12.52  (5.814, 19.22) Problem parameters: wav =       1064 ipow =         90 opow =         80

gof =

sse: 0.007544015427389 rsquare: 0.824078213449844 dfe: 37 adjrsquare: 0.814568927690377 rmse: 0.014279086415046

As can be seen I am getting a large uncertainty in fit results. What shall be my approach to minimize the uncertainty in the coefficient values?The plot shape that I am getting seems to be descent enough.I have been trying to change the lower and upper bounds on hit-and trial basis which sometimes helps and sometimes not.

What should be my general approach while solving such ?I mean, how do I know which bounds will be giving me the best fits apriory? I am finding it very difficult to try hid and trial method (I have a lots of data )for finding the best bounds that suit my fit. Is there a better way?If, yes could you please help me out with the same?

I tried reading the Matlab documentation help, but couldn't find a good way to deal with such problem. Thanks in advance...


 * I've never used Matlab but have done curve fitting before, using polynomial parameterized arcs and splines. The higher the number of constraints you supply, whether point constraints, tangency contraints, or curvature constraints, the higher the degree of the arc needs to be for an exact match using a single polynomial parameterized arc (the degree has to be at least the number of constraints minus one to fit all exactly).  However, an arc with a high degree will also be "lumpy" and may bow out unexpectedly.  Therefore, you might want to lower the degree and accept more deviation from your constraints to ensure a smoother curve.  A similar effect also occurs when using multi-arc splines.  Alternatively, you might just want to remove many of the constraints, and only leave a few "representative" data points. StuRat (talk) 00:59, 15 June 2008 (UTC)

computer gives out continuous beeps and won't boot
I unmounted a Combo drive (DVD R + CD RW) from a computer. The drive was connected to an IDE cable along with a hard disk. After removing the Combo I connected the HDD at the end of the IDE Cable (It was connected to the middle connector earlier). When I switched on the system again, it gave out continuous beeps. The motherboard is Gigabyte. The continuous beep indicates power error according to the manufacturer's manual. I did everything I could do but the system wouldn't boot or enter setup, it just gives out continuous beeps. It did enter setup just once though, which gives the impression that the motherboard has no serious defect. I removed the SMPS and installed another one. Changed memory, removed and reset all connections,took out the CMOS battery to clear CMOS etc. but nothing helps. Any suggestion? --Genuee (talk) 11:51, 14 June 2008 (UTC)


 * Check out the jumpers on the back of your hard drive - there should be a guide to the jumpers on a label somewhere on the drive casing. If "CS" (cable select) is selected, you can't just move the drive to a different connector on the cable.  If this is the case and you still want to use the end connector, you have to move the jumper to "MA" (master).
 * A little background info: There's usually 3 sets of jumper pins, "MA", "SL" and "CS" (master, slave and cable-select).  Master is set to ID the first/primary device, Slave is set to ID the secondary device, Cable-select sets the drive ID (master or slave) based on which connector is used.  Occasionally, there's a fourth pair of jumper pins (sometimes labelled "SP") used to indicate to a master, that there is a slave present elsewhere - if the drive is the only device on the IDE cable, then the "SP" should be unselected.
 * Astronaut (talk) 13:19, 14 June 2008 (UTC)
 * It would help if you specify which motherboard you are using ("Gigabyte" doesn't quite cut it). Try disconnecting the power and data cables of everything that isn't required for the BIOS to run (that includes all hard drives) and making sure that what's left is connected properly. If it works, reconnect parts until the problem recurs. If the hard drive is the culprit, you need to mind the master\slave issues raised by Astronaut. -- Meni Rosenfeld (talk) 20:44, 14 June 2008 (UTC)


 * After a lot of fumbling the long howl has stopped. When I switch on the machine floppy drive is continuously lit and the DVD drive is checked. I can’t still enter the setup. The monitor shows nothing. Seems that no signal goes to the monitor. The keyboard is not recognized. No beep at all now. My board is GA-8I845GV of Gigabyte. The manual describes about auto recovery of corrupted BIOS from a special partition of the hard disk. I don’t have the hard disk this system used to have. I purchased a 160 gb and wanted to install OS. The board has two pins to short to clear the CMOS and go back to defaults. But there is no BIOS recovery as such. What can I do now? --Genuee (talk) 09:58, 15 June 2008 (UTC)


 * Do check the pins for primary/secondary on the drive, but the beeps and inability to get to setup sounds like you knocked a memory chip loose. Make sure they're seated right, and make sure all the cables are tight, and see if that fixes it. JeremyMcCracken (talk) (contribs) 03:52, 16 June 2008 (UTC)
 * I checked all connections and jumpers. Nothing wrong. The system turns on, looks up devices, first floppy drive, then DVD drive and after that HDD. But keyboard's led is never lit. Nothing on monitor. No BIOS beep. I removed memory and switched on. Continuous beeps. I had earlier tried another RAM to see if memory was the faulty bit. Does searching for devices mean the motherboard is OK? I tried writing a BIOS upgrade on a CD ROM. The manufacturer's manual vagues suggests recovering the BIOS from CD (when the attempt to recover from a hidden file in the hdd fails). However, the LED on the drive lit for some time and nothing happened. Expect more advice. Genuee (talk) 01:00, 17 June 2008 (UTC)

What type of connector is this?
Does anyone know what the connector shown in this picture: http://www.xanthos.se/~joachim/pmagb-b.jpg is? Thanks Rilak (talk) 12:10, 14 June 2008 (UTC)


 * I suspect it's some variety of RGB component video. —Steve Summit (talk) 15:41, 14 June 2008 (UTC)


 * A google search for "PMAGB-B" suggests that board is a DEC framebuffer video card, perhaps for a DECstation or AXP3000. —Steve Summit (talk) 16:32, 14 June 2008 (UTC)


 * You're right, this card is a frame buffer. I think the PMAG-B is called the CXT, or Color Frame Buffer. I have the specification document from Digital that I found at a ftp site for a BSD variant, but it mentions nothing about the connector type used. It is a variety of RGB component video connector, and the monitor side has three BNC plugs. But I want to know what the connector type is. I did some more searching and I think it may be a 3W3P, but other than that, I haven't found anything. Can anyone confirm this? Thanks. Rilak (talk) 06:48, 16 June 2008 (UTC)


 * This .PDF file from ITT Cannon will answer your question. Note that your connector is shown in the photo at the top of the first page. In much more detail, see page 49 of this catalog . Your connector is called a "3C3" in the "DA" style housing. You might also enjoy our article about the family of D-subminiature connectors.


 * Atlant (talk) 13:20, 16 June 2008 (UTC)


 * Many thanks! Rilak (talk) 06:59, 17 June 2008 (UTC)

disk image emulator
Is there a disk image emulator software for windows, which could mount simple hard disk images? There are programs, which can mount optical disk images and there are programs, which can mount encrypted hard disk images, but none of them mounts simple, unencrypted hard disk images. (Something analogous to linux loop device). -Yyy (talk) 14:22, 14 June 2008 (UTC)


 * See Daemon Tools. --Russoc4 (talk) 15:22, 14 June 2008 (UTC)


 * It was the first program i tried. (i also tried truecrypt) It cannot mount hard disk images. -Yyy (talk) 16:16, 14 June 2008 (UTC)


 * Try WinImage. It can't mount HD images, but it can edit them. --grawity 16:29, 14 June 2008 (UTC)


 * Acronis True Image supports mounting of hard disk images made by itself... There is also VMware Workstation, that can open some formats of hard disk images (it also supports real partitions) to run them inside a Virtual Machine... And there is also WinMount, that can mount lots of archives types (.zip, .rar, .iso, etc...), ... What do you mean by "simple hard disk images"? What program created those hard disk images? What are the types of files you want to mount? maybe then we can help a you little more SF007 (talk) 03:30, 15 June 2008 (UTC)


 * This image was created by ubuntu wubi installer (ext3 filesystem of ubuntu installation). Vmware workstation has image mounting tool for virtual machine disk images, but it works only on virtual machine disk images (i already tried)(i have not tried to attach this image to existing virtual machine). I will check out winimage and winmount. -Yyy (talk) 04:32, 15 June 2008 (UTC)


 * It was not possible to attach this image to VMware workstation virtual machine (vmware version 5.5.4)(it complained as it was an unrecognized format). Winmount (version 8.1) did not recognize the file (cannot open the file). Winimage (v6.1) could not open the image, but version 8.1 could and it was possible to extract files from image. Thank you for answers. -Yyy (talk) 06:31, 15 June 2008 (UTC)


 * Ah, it was created with Wubi, now it makes sense, yeah, that is one of the prolems with wubi: it is difficult to open the hard disk images created by it, since there seems to be no official tool for that... didin't knew WinImage would open that... Cool, have to try it some day... SF007 (talk) 13:58, 15 June 2008 (UTC)

Firefox text-search mystery
I've got one tab where command-G has stopped working. Command-F still searches for a string, but command-G won't search for the next occurrence of it. I wonder how that happened? (Command-G still works in other tabs in the same window, and other windows in the same session.)

(Firefox 2.0.0.14 under MacOS 10.4.9. When I say "command-G" I mean "apple-flower-key-G"; the rest of you can think "control-G".) —Steve Summit (talk) 16:11, 14 June 2008 (UTC)


 * I've had that happen a couple times before, but it is rare. I believe the only way I could get it to work again was to open the location in a new window, though I might have had to restart the whole browser (can't remember specifically, but it was one of those).  Mozilla/5.0 (X11; U; Linux i686 (x86_64); ; Alexa; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13  --Prestidigitator (talk) 17:24, 14 June 2008 (UTC)

X11
I have a black MacBook and when I downloaded the OS X 10.5.3 update, X11 and all the programs that used it stopped working. I tried downloading an older version but that didn't work either. Does anyone have any ideas on how to fix it?  J kasd  17:44, 14 June 2008 (UTC)

Ubuntu help
I'm the same guy as before. I managed to download the .iso Ubuntu file rather than buying a cd. I have a cd burner but no blank cds. Is it possible to install Ubuntu without burning the .iso file to a cd?

I've also been using Windows Vista for a few days now, and I don't know how to mess with partitions or anything. Regardless of the answer to my first question, how do I install Ubuntu without screwing up Vista or my files or anything? I also want to be able to access my files from both OS's if I can.--71.175.125.178 (talk) 18:32, 14 June 2008 (UTC)


 * I strongly suggest NOT doing this because it appears you are in a bit over your head at the moment... What you want is a dual-boot system with a shared file partition. So, you will need four partitions.  One will have Vista and likely be NTFS formatted.  Two will have Ubuntu and likely be ext3 and swap formatted.  One will be your shared file partition and will need to be FAT32 formatted.  That part of the process is difficult itself.  You need a program like Partition Magic to resize your current Vista partition and allow three more partitions.  The largest should be your shared file area.  Then, install Ubuntu using the ext3/swap partitions.  Once installed, both Vista and Ubuntu will be able to mount and work with the FAT32 partition.  As for installing from an iso, the difficulty is that you have to install from boot.  So, you don't have an operating system running.  Only BIOS is running.  I don't know of any BIOS capabilities that allow you to mount an iso off a hard drive.  You must put the iso on a bootable media (ie: a CDROM). --  k a i n a w &trade; 19:36, 14 June 2008 (UTC)


 * I would avoid PartitionMagic like the plague. Ubuntu's install has GParted built-in for partition purposes. -- Consumed Crustacean (talk) 19:40, 14 June 2008 (UTC)


 * Vista doesn't seem to respond well to partitioning. I have tried it using Ubuntu's partitioner (gparted) and Vista wouldn't boot. I also advise against using Partition Magic! It hasn't been updated since 2004 and it ruined an XP partition of mine. The best partitioning program out there is from Acronis and some have even reported problems partitioning Vista with that.


 * As for the ISO, it depends on your BIOS. My BIOS supports booting from a USB flash drive, so if you have one of those, that might be an option. Ubuntu will mount your Windows drive automatically and will allow you to modify files on it. To access your files on a Linux drive from Windows you will need to install a program like ext2ifs.--Hello. I&#39;m new here, but I&#39;m sure I can help out. (talk) 19:50, 14 June 2008 (UTC)
 * How can you tell if your BIOS supports booting from a USB flash drive?--96.227.31.211 (talk) 00:51, 17 June 2008 (UTC)
 * When I restart my computer, I press the DELETE key to access my BIOS settings. (You press one of the function keys on some other computers to do the same thing.) I then go to the screen for my hard disks and it lists my USB flash drive on the third line. So, it lets me make the USB drive the primary partition since I can move it to the first line.--Hello. I&#39;m new here, but I&#39;m sure I can help out. (talk) 19:04, 17 June 2008 (UTC)
 * FYI, Kainaw, Linux has native NTFS read and write (ntfs-3g) support now. --antilivedT 03:19, 15 June 2008 (UTC)


 * Try Wubi. No CD, no partitioning. -- Consumed Crustacean (talk) 19:40, 14 June 2008 (UTC)

Does your BIOS/motherboard use PXE? If so, you may be able to set up a server to host the ISO image for you over the network and boot it via PXE. Freedomlinux (talk) 00:23, 15 June 2008 (UTC)


 * Per User:Consumed Crustacean, just mount the iso using something like Daemon Tools and install Ubuntu through Wubi, nice and easy. -antilivedT 01:25, 15 June 2008 (UTC)
 * I think Wubi is a separate .exe file which is unrelated to the iso. I tried running it just to see how it works. The installer itself is tiny, and it downloads everything it needs when you run it (making the effort the OP invested in downloading the ISO go to waste). Unless, of course, it crashes, like it did for me. Somehow I don't feel comfortable having an unstable program mess with my boot loader. -- Meni Rosenfeld (talk) 12:39, 15 June 2008 (UTC)
 * Nope, he can use the ISO he downloaded. So long as he downloaded the Desktop version of Ubuntu (and he should have anyways), he just puts the ISO in the Wubi folder, runs Wubi, and voila. As for instability - I haven't noticed it; however, all Wubi does is puts in an extra entry in the boot.ini (or Vista's equivalent). Even if that's messed up somehow (unlikely in the extreme) it is easily fixed; Vista's setup CD has a bootup repair utility that's easy to use, and XP's setup CD has the fixboot command. 206.126.170.20 (talk) 22:14, 15 June 2008 (UTC)

Zelda DX
[This question moved from Wikipedia talk:Reference desk by Steve Summit (talk) 20:13, 14 June 2008 (UTC)]

Okay, so here's the story: I own Zelda: Link's Awakening DX, but I don't own a Game Boy Color or Advance. So I ripped the rom to the computer. I discovered a cool glitch that was enabled when I pushed 2 or more directional keys at once other than diagonal movement. I had a file where I was at level 8, but I couldn't find the fire rod, so I gave up and deleted the file. However, I'm now interested in that glitch again; one cool function was that it could launch the Hookshot in a half-parabola. I'm trying to find a SGM (save state) file compatible with VisualBoy, the emulator I'm using, preferably at the end of the game. The problem? I can't find one anywhere! Please help. 71.220.217.201 (talk) 19:44, 14 June 2008 (UTC)


 * Addressing your comments in order
 * 1) I'm interested in knowing how you ripped the cartridge without the gameboy. It can be done, but the only inexpensive ways I know to rip a gameboy cart involve a gameboy and a link cable. And even then, nowadays the special link cable probably costs more than the GBC itself!
 * 2) Yea, a lot of old games have weird glitches if you hold down opposing d-pad buttons. (Which can't easily be done on authentic hardware.) I don't recall which one, but one of the Zelda games allows you to fight Gannon in the first five minutes by this method.
 * 3) There are a couple of saves here. I haven't played the game, so I don't know how close these saves are to what you want. Hope it helps, though.
 * APL (talk) 18:03, 15 June 2008 (UTC)


 * I think, it was used on TASVideos but you must be lucky if the replay works on your ROM. With some (less?) luck you find the video on the internet (Youtube often has some). Else you can download the AVI as Bittorrent file here. --Constructor 18:38, 20 June 2008 (UTC)

Valve Sprays
I need help importing sprays to use on Team Fortress 2. I know that you need a .vtf file, but i don't know how to get it to work or how the game to regonize it. Also, I want to know how to convert JPEG's into .vtf. Any suggestions? --69.127.64.22 (talk) 20:50, 14 June 2008 (UTC)


 * I found this on the Steam tech support pages. Any good? CaptainVindaloo t c e 21:29, 14 June 2008 (UTC)
 * I don't know. I tried exactly that, and it doesn't work. Maybe the picture has to be in a specific folder? I don't know if the desktop counts. --69.127.64.22 (talk) 13:48, 15 June 2008 (UTC)
 * The desktop should be fine, just navigate to your desktop and open the file. If you are unable to work out how to navigate to the desktop from TF2, I suggest you try a different directory (folder). The easiest may be to create a new directory in C:\ called Temp and put the file there. Nil Einne (talk) 16:05, 15 June 2008 (UTC)

computer security ?
Is it possible for someone to "tap" a landline phone remotely. A friend of claims some guy on a AIM chat said he was tapping them. Or is that bs. --Rio de oro (talk) 23:45, 14 June 2008 (UTC)


 * Since all phone calls are routed through a great deal of equipment before they arrive at their destination, it's possible to tap the phone at any of those locations, or anywhere (cable or air transmission) in between. The US National Security Agency did such phone taps all the time, apparently illegally, since they didn't get a warrant first.  However, "some guy on AIM" isn't likely to have such access, or to brag about it if he does.  Therefore, it's the people who don't claim to be tapping your phone you need to worry about. :-) StuRat (talk) 00:26, 15 June 2008 (UTC)


 * That said, if you're using a wireless phone on your landline, you can be heard on a shortwave radio by your neighbors. If the frequencies are too close together, it may even be picked up by their baby monitor. With that in mind, you should always have sensitive discussions (such as credit card transactions) on a physical, corded phone. &mdash;  The Hand That Feeds You :Bite 17:40, 15 June 2008 (UTC)


 * Shortwave radio won't work for a DECT or other digital cordless. That said, usually digital phones are either not encrypted or have weak encryption. 206.126.170.20 (talk) 22:24, 15 June 2008 (UTC)


 * From back when I used my parents' AOL, I can tell you that you hear a lot of crap that people can supposedly do. Somebody told me once that they could kill my internet connection through a chat room. Knowing that they'd need my IP for that, and couldn't get it if I didn't give it to them, I told them to go ahead. Nothing happened. JeremyMcCracken (talk) (contribs) 03:59, 16 June 2008 (UTC)


 * Even if the attacker have your IP he can't do jack, with today's NAT and stuff. He might be able to pull of a DDoS attack but that requires way more than 1 computer. --antilivedT 04:24, 16 June 2008 (UTC)
 * Also what I herd from my friend that "guy" claimed he "can tap into the phone line, and charge your phone 10 bucks a min". Or something, that guy is probaly some wana be cyberpunk that lives with his mom --Rio de oro (talk) 16:52, 16 June 2008 (UTC)

Video file Conversion
I'd like to know how to convert video files (i.e. Windows Media or Quicktime) into a format readable by run-of-the-mill DVD players (not HD or Bluray). Please help. BeefJeaunt (talk) 23:56, 14 June 2008 (UTC)
 * You may want to try DVD Flick .  It will take many types of media files and produce an ISO image and/or burn directly to a DVD using ImgBurn. DVD Flick is only available for Windows, but the source is GPL and also available for download. I would highly recommend DVD Flick due to my personal satisfaction and its reliance on the stable ffmpeg and ImgBurn programs. Freedomlinux (talk) 00:28, 15 June 2008 (UTC)