Wikipedia:Reference desk/Archives/Computing/2009 April 24

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April 24

Downloading

My torrent file of Forrest Gump has finished downloading.But out of 1.2 gb file I have got only 763 mb file that too broken.Should I wait till the uploading also also completes?It is now seeding.Is it necessary for seeding to complete?The ETA ishowing 18 hrs to complete!! —Preceding unsigned comment added by 121.246.174.130 (talk) 03:11, 24 April 2009 (UTC)

Is it just one file? What program are you using? You can usually force a re-check of the file by right-clicking the torrent in the program and selecting "Re-check". --wj32 ^t/c 04:22, 24 April 2009 (UTC)

You will in general never be "done seeding", since new peers will connect. If you are seeing a time until completion you are doing something other than seeding. Taemyr (talk) 04:38, 24 April 2009 (UTC)

In μTorrent, at least, there's an ETA displayed while seeding. It's the estimated time until you've achieved your desired ratio of upload to download. Algebraist 10:00, 24 April 2009 (UTC)

Common ancestor class in C#

Is there a way in C# to find the closest common ancestor of two classes? NeonMerlin 05:59, 24 April 2009 (UTC)

Here is something quick that I just threw together. It should get you pointed in the right direction. Modify as needed:

static IList<Type> GetTypeHierarchy<T>()
{
   IList<Type> hierarchy = new List<Type>();
   Type type = typeof(T);

   while (type != null)
   {
      hierarchy.Add( type );
      type = type.BaseType;
   }

   return hierarchy;
}

static Type GetMostCommonDerived<T, U>()
{
   IList<Type> hierarchyT = GetTypeHierarchy<T>();
   IList<Type> hierarchyU = GetTypeHierarchy<U>();

   Type t = null;
   Int32 minCount = Math.Min(hierarchyT.Count, hierarchyU.Count);

   for (int i = 0; i < minCount ; i++)
   {
      Type typeT = hierarchyT[hierarchyT.Count - 1 - i];
      Type typeU = hierarchyU[hierarchyU.Count - 1 - i];

      if ( typeT == typeU )
      {
         t = typeT;
      }
   }

   return t;
}

Then pass two types into GetMostCommonDerived. Regards, Bendono (talk) 06:51, 24 April 2009 (UTC)

Cell phone chargers

They show television commercials about how cell phone chargers are consuming power even when there is no phone connected to it. But how? There is no current in the charger when the phone is disconnected. There is nothing on the charger itself that consumes electricity. — Kjammer  ⌂ 09:53, 24 April 2009 (UTC)

Because it's not just a charger that connects your phone to the ac outlet, but also a transformer. See standby power and wall wart for more. 96.227.82.128 (talk) 10:05, 24 April 2009 (UTC)

It's certainly true that any kind of charger or 'wall-wart' consumes power when there is nothing connected to it. You can actually feel that they get a little warm all the time. Not as much power as when they are actively charging a phone - but yeah - you should unplug them from the wall when you're done with them. SteveBaker (talk) 14:42, 24 April 2009 (UTC)

Will switching them off at the wall have the same effect as unplugging them? Vimescarrot (talk) 18:02, 24 April 2009 (UTC)

If you turn off the electricity to the charger by any means, it will stop consuming electricity. I put mine on a power strip and flip the switch to turn them off. -- kainaw™ 18:07, 24 April 2009 (UTC)

Also note that some transformers will draw no real measurable wattage, with idle transformers typically drawing 0+ ~ 2.5 (I think 0.5~0.8 is pretty typical) watts from any info I've ever seen. IMO, it's insignificant compared to conserving energy when it matters, like switching from 60 watt bulbs to 13 watt CFLs, or turning down your AC, or not leaving the fridge door open, or leaving your computer on (way worse if running SETI/F@H), or... You get the point. --Wirbelwindヴィルヴェルヴィント (talk) 06:04, 25 April 2009 (UTC)

Screensavers

I have copied some screensavers to my System32 folder, but they don't appear in the Screensaver tab of Display. How can I fix this? 58.165.23.195 (talk) 11:52, 24 April 2009 (UTC)

Try copying them to the C:\WINDOWS folder (that sometimes works). Also try right-clicking the screensaver and clicking "Install".  Buffered Input Output 12:34, 24 April 2009 (UTC)

Wireless mice + keyboards

I've been asked to help a family member with some wireless computing advice; not using wireless myself, I don't feel I know enough about the security aspect. They'd be using a wireless mouse/keyboard up to 7 meters away, which rules out IR and suggests radio (RF) or bluetooth. The question I have is security and "ease of use" issues. I tend to be security conscious (wired ethernet, etc). They aren't using any other wireless devices. I need to consider:

• That they can switch from internal to wireless mouse/keyboard easily
• That the wireless is secure and doesn't expose them unduly to security openings, flyby hacking, scanning, whatever else can be done.
• That when they are using the internal keyboard in a public location, any open bluetooth/RF isn't posing a security risk.

So I'm after advice such as:

• Bluetooth or other RF?
• How secure it would be in practice? (both for malware/intrusion as a point of entry, and for data interception)
• Any particular configuration/s or "things to check" needed to maximize security?
• Is built in bluetooth low risk or should they use a removable dongle?

Any tips from someone technical much appreciated - thanks! FT2 ^{(Talk | email)} 13:25, 24 April 2009 (UTC)

Bluetooth is a bit 'iffy' at 7 meters. There are three classes of bluetooth gadget, Class I is good out to 100meters - but class II is limited to 10m and class III to 1m. At 7m, the class II devices are really rather unreliable - while they can reach 10m in theory, if there is any interference source or intervening walls or even heavy bits of furniture or many people - they don't work at 10m. So unless you have class I devices (which are rather rare), I wouldn't recommend it for this application. At 100m, bluetooth security is certainly a concern - and the bluetooth protocols really aren't very secure. They are designed for relatively trivial things like connecting headsets to cellphones and mice to computers where security is generally considered to be irrelevant - and the need for a hacker to get within a few meters of your equipment generally means that security is a non-problem. So I can't recommend bluetooth at all.

WiFi (802.11) keyboards and mice simply don't exist...your options are IR (which won't do 7m), USB (which needs wires) or BlueTooth (which I've already dismissed). So on the face of it, you're completely screwed! But you don't tell us precisely why they need to do this - but it sounds to me like they should be using a complete laptop as their "keyboard and mouse" and using WiFi (802.11) to talk to whatever computer needs the input. WiFi has more than enough range and is extremely secure when you use all of the encryption stuff correctly (which isn't hard - you just have to know how to do it). There are plenty of progams out there that'll let you drive one computer using the mouse/keyboard of another computer via the network - my son uses one all the time to do exactly this kind of thing - using a Windows-based laptop as keyboard & mouse for a Linux-based desktop computer. You can buy super-cheap WiFi 'sub-notebook' or 'netbook' laptops for a couple of hundred bucks these days - which includes your keyboard, mouse and WiFi stuff. Something like the ASUS Eee PC would fit the bill rather nicely. SteveBaker (talk) 14:31, 24 April 2009 (UTC)

It's going with a general-purpose laptop for a relative. They will use it sometimes "stand alone" on vacation (internal keyboard/mouse) but quite often (almost daily) for group discussions, or on the TV in their living room.

In those contexts the laptop would be next to and plugged into a TV (visible to anyone in the room) and the keyboard and mouse would be on a coffee table or the lap of whoever happens to want to use it, and passed around as needed. Some of the rooms concerned are small conference rooms up to 6 x 6 m, and the keyboard/mouse would regularly be used 3 - 5 m from the laptop where IR isn't viable. The security issue is because the laptop will contain their private documents as well - letters to hospitals, credit card companies, all the usual stuff people have on their main computer. (I can secure the machine generally, but I'm not familiar with wireless aspects which I tend to avoid personally.)

Realistically a maximum range of 5.5 m would probably be okay, and there will be little in the way; I figured up to 6 - 7 m to include some safety margin.

I can easily set "non-discoverable mode" and tell the user/s not to accept any strange "do you want to connect to this device" pop-ups, but they aren't hacker savvy, so I don't know if that would be enough. FT2 ^{(Talk | email)} 15:19, 24 April 2009 (UTC)

Bulk Mail in Outlook 2003

I am working on a project that has me sending out a lot of emails with a fax number for people to sumbit documents (each emIl only has one recipient). We're having technical issues and I want to bulk eMail people to give them a different fax number. I have all of the original emails I sent in an isolated outlook forward, so I was hoping I could just select a bunch of emails and hit "reply to all" or something but outlook wouldn't let me do that. Is there any function I can use to draw the eMail addresses out to bulk mail the new phone number? thanks --Shaggorama (talk) 15:06, 24 April 2009 (UTC)

How to adjust the 3d accelerator? And where...?

Hey, I have had some trouble with the graphics when playing a game. (presumably because it's a little old and my computer is new and strong with Windows Vista which means it's not entirely compatible) However, I found somewhere that I read that "turning on the 3d acceleration" will likely solve my particular problem. what does that mean really, or rather how and where do I turn it on?

I don't know, maybe that's not so much info and maybe it's difficult or even impossible to asnwer without more info?

Thank you for any answers, I'll come back soon to look for any —Preceding unsigned comment added by 84.49.121.115 (talk) 15:41, 24 April 2009 (UTC)

3D Acceleration is a function of the video card. First, to be very clear: Many video cards do not have 3D acceleration. Do not start from the assumption that your video card does have 3D acceleration and you just can't find it. Start from the assumption that if your video card did have 3D acceleration, it would already be turned on. Starting from there, if it isn't turned on, it will be an option in the video settings. I don't know where Vista moved it to. It used to be that you could right-click on your desktop and choose settings. I'm sure it is now hidden beneath a long series of left and right clicks or strange commands from the run menu now. -- kainaw™ 15:52, 24 April 2009 (UTC)

Thanks! Without more directions though I don't think I should start any mission impossible here trying to find it. I would need more guidance... but I am grateful for your answer —Preceding unsigned comment added by 84.49.121.48 (talk) 16:34, 24 April 2009 (UTC)

Be aware some games have a setting for turning 3d acceleration on and off. It may be presented as a choice between "SOFTWARE" and "OPENGL" (or "DIRECTX"), or it may just be a setting for "3d acceleration on/off". OF course, if you've got an older video card, or one designed exclusively for business use it may not have any 3d acceleration at all. APL (talk) 16:38, 24 April 2009 (UTC)

No I don't have a bussiness-use kind of card. It's a gaming machine so I suspect it should be 3d acceleration on it if this is normal on cards meant for gaming. But you mean that this might be an option in the configuration programme outside the game or in the Options-menu of the game itself while running the game? I see none... these were the first places I looked... hm.. —Preceding unsigned comment added by 84.49.121.48 (talk) 16:49, 24 April 2009 (UTC)

Just got a response from another IT guy... Go to start, then run, and run "dxdiag". You will see a window like this with 3d acceleration info. -- kainaw™ 17:52, 24 April 2009 (UTC)

If it's a setting specific to the game, then mentioning the game might help. Perhaps one of us knows it. APL (talk) 18:26, 24 April 2009 (UTC)

Dual-booting XP and Ubuntu; multiple hard drives

Hi all,

So I've been playing with Ubuntu through a Wubi install for a while. With the new release of Jaunty yesterday, I've decided that it's time to switch to Ubuntu as my main OS, but I will install XP as backup, and for a couple of apps that I use in XP that don't work in Wine well enough yet. So, I've found these instructions here: http://apcmag.com/how_to_dual_boot_linux_and_windows_xp_linux_installed_first.htm which are pretty straight-forward. Here's my question:

I have 3 HDDs: 35GB (currently my primary), 70GB (slave), and 300GB (external/USB) used for data storage (pictures, etc). Any reccomendations as to what do to, in terms of where to create the partitions? I'm thinking: use the 70 as the primary, for the Ubuntu install; use the 35 as slave, but with the Ubuntu swap and XP partitions on it.

What will happen when I try to install XP? Will it force me to install on the primary, or will it give me the choice to install on the slave? Any other thoughts/reccommendations?

Thanks! --richardmtl (talk) 16:00, 24 April 2009 (UTC)

Well, I just thought of something that may be easier. I can keep my setup as is, and delete the Wubi install. Then, I can install Ubuntu fresh, on the slave drive. I can alswo resize the XP partition on the primary, and use the freed-up space as the swap drive. This way, I also keep my current XP install, without having to re-install the programs that I need there.

2 questions, then:

1) Is it better to have the swap partitionon a different drive than the OS, as I plan on doing? Seems to me that it could give better performance, especially on a somewhat older machine like mine (Dell P4, 2.4 Ghz, 786 MB RAM)

2) is it worthwhile to have a seperate /home partition and/or /usr partition(s)?

Thanks! --richardmtl (talk) 17:15, 24 April 2009 (UTC)

It used to be that XP would not boot from a USB drive. I await others' responses with interest, since I could use the answer. EdJohnston (talk) 17:24, 24 April 2009 (UTC)

Swap: well yes, it's better for the swap to be on a different drive, and ideally a different interface, and ideally to be a particularly fast disk (like a solid-state drive). But don't think that "good swap" makes for "good performance". Swap is, for interactive applications and desktop machines, the epitome of >teh suck< ; once your (sum of) working sets has grown so big that it doesn't all fit in RAM and you need to be paging apps in and out, your user experience has degenerated to sitting listening to disks grind while looking at a screen full of unresponsive apps. If more apps were properly written to handle failed malloc() properly, I'd probably just disable swap altogether. Short answer: don't worry very much about swap (it sucks whatever you do). 87.112.75.169 (talk) 01:05, 25 April 2009 (UTC)

That 786 MB isn't a bad size (I've been using a 512Mb laptop for ages, without major issues), but more RAM (as much as you can get in there) is the best way to avoid the suckage of swapping. 87.112.75.169 (talk) 01:05, 25 April 2009 (UTC)

home partition: well yes, I guess so, but don't bother. People sometimes advocate /home be its own partition so that, if ordinary users totally fill their accounts so that the partition is totally full, you can still login as root and do stuff. But you can still login as root (if you enable that, which you don't need to) or anyone else (and su or sudo from there) even if the disk is full. If it's just you using it then you don't care (you'll be the only one to suffer), and if it's a truly shared machine then you should look at a proper quota scheme. People also used to advocate a /home partition because they used a partition based backup scheme (where the whole partition was replicated or tarred or whatever); you'll probably backup to DVD or by rsync to another disk, so that's not an issue. Short answer: don't bother. 87.112.75.169 (talk) 01:05, 25 April 2009 (UTC)

If you have two "Jaunty Jackalope" Ubuntu systems set up just the way you want them, one with /home in its own partition and the other not, but the two systems otherwise identical; and then next year you want to update the pair to "Leprous Lizard" (or whatever), wouldn't this be simpler on the one with a separately partitioned /home? (I don't know, and I'm asking as an Ubuntu computer will soon be on its way to me.) -- Hoary (talk) 16:07, 26 April 2009 (UTC)

Video Screenshots ?

Is it possible to take pictures/screenshots while playing a video?

Like when I'm watching a dvd, or you know, a private video or movie clip and such on my Windows media player, RealPlayer, Quicktime or VLC player or whatever, can I somehow pause the clip and take a screenshot, getting pictures in BMP or JPG formats or such? I have already tried the simple way, pausing my clip and pressing the button on the keyboard called "prt scn" (Print screen) but that didn't work obviously (Or if it did, I can't find where the pics was saved, but I really doubt it worked), so I was thinking maybe this is not possible to do... but I really hope so because I have some clips that would make for some good photos to have in our photo album

tnx

VLC player has this function. It's in the "Video" menu, under "Snapshot". By default, it saves a png file to the My Pictures folder. This can be changed in the video section of the preferences panel. Cycle~ (talk) 17:11, 24 April 2009 (UTC)

WOW! Thanks! I have been struggling to figure this out for quite some time. The VLC player is probably the only of the many players I have that I had not tried. Thanks alot, you made my day ;D Krikkert7 (talk) 17:31, 24 April 2009 (UTC)

The reason you can't normally is because the video is being played with hardware acceleration (your video card is beaming it directly to your monitor, skipping your operating system). You can turn off hardware acceleration under your display settings—dial it down to zero and you can take screenshots as usual. However hardware acceleration is a Good Thing so after you are done with your screenshots, you should turn it back up again. "Print Screen" takes a screenshot and copies it to the clipboard—so you've got to paste it somewhere (like MS Paint) before you can save it. --140.247.249.237 (talk) 17:41, 24 April 2009 (UTC)

mplayer has this function too, while playing press "s" key

Gom player can do this easily. And when you press shift-PrintScreen the image is saved to the clipboard and can be downloaded into Irfanview and another similar freeware picture editor I've forgotten the name of. 78.151.148.89 (talk) 21:55, 24 April 2009 (UTC)

iPod DST

I have a 3rd generation iPod nano. The features guide, [1], says that the DST option is in the settings>date&time menu. I dont have any sort of option for DST on the screen. What is the problem? Thanks. —Preceding unsigned comment added by 116.71.53.143 (talk) 18:17, 24 April 2009 (UTC)

What time zone are you set to? Perhaps the iPod has decided you don't have DST where you live? Nil Einne (talk) 12:00, 27 April 2009 (UTC)

Looks like your in Pakistan? From Pakistan Standard Time it appears DST is a bit adhoc in Pakistan so it seems likely that Apple has not properly implemented DST settings for Pakistan. You could try e-mailing Apple support and hoping a new firmware update will eventually fix it. Nil Einne (talk) 13:30, 27 April 2009 (UTC)

I can change my location in the time zone option on the iPod and see if that gives the DST option. And btw how did you know im from pakistan?

Couldn't get on Internet earlier, screen turned completely blue with no messages or anything

I don't remember how to find what kind of computer I have, but it was on this desk once before.

I know it's an HP Pavilion desktop.

I tried to get on the Internet when I turned it on, and the screen just stayed blank. The circle just kept turning.

The modem lights were working normally. The last time I told tech support this they said to do a system restore (though the lights on the back of the computer were working normally this time). So I pressed F11 and maybe selected the wrong option because the screen turned completely blue and I couldn't do anything or even turn the computer off. I could, however, unplug it. That didn't help, and furthermore, there was no more place for the URL and no buttons at the top. I pressed F11 again and the information at the top of the screen came back.

I finally realized unplugging the modem sometimes works. It did.Vchimpanzee · talk · contributions · 19:57, 24 April 2009 (UTC)

I figured out how to find my information. OS Name Microsoft® Windows Vista™ Home Premium Version 6.0.6001 Service Pack 1 Build 6001 Other OS Description Not Available OS Manufacturer Microsoft Corporation System Name System Manufacturer HP-Pavilion System Model KT369AA-ABA a6512p System Type x64-based PC Processor Intel(R) Pentium(R) Dual CPU E2200 @ 2.20GHz, 2200 Mhz, 2 Core(s), 2 Logical Processor(s) BIOS Version/Date American Megatrends Inc. 5.23, 4/21/2008 SMBIOS Version 2.5 Windows Directory C:\Windows System Directory C:\Windows\system32 Boot Device \Device\HarddiskVolume1 Locale United States Hardware Abstraction Layer Version = "6.0.6001.18000" User Name Time Zone Eastern Standard Time Installed Physical Memory (RAM) 4.00 GB Total Physical Memory 3.99 GB Available Physical Memory 2.15 GB Total Virtual Memory 8.18 GB Available Virtual Memory 6.13 GB Page File Space 4.28 GB Page File C:\pagefile.sysVchimpanzee · talk · contributions · 21:15, 24 April 2009 (UTC)

And on 7 August 2009 I was told to always say I HAVE A DSL MODEM.Vchimpanzee · talk · contributions · 21:51, 7 August 2009 (UTC)

How much do I use the Internet?

Several weeks ago Time Warner Cable was doing a test in which users in certain areas would be charged according to not only their speed, but also the number of gigabytes used. I was not a customer of theirs at the time I got the Internet and still don't get my Internet access from them, but if my Internet service provider were to do such a thing in the future, I'd like to know how much to cut back. One of the articles on the Time Warner test--which was cancelled after protests--said there's a web site you can use to measure your usage before the company does it for you and charges.Vchimpanzee · talk · contributions · 20:10, 24 April 2009 (UTC)

They (Time Warner) meant that there was an internal web site that offered users access to the tracking database (how nice of them!) so they could at least be aware of their usage before blowing past it on their way to a $150/month internet bill. Just to put this in perspective, from the article I saw they were going to cap their 6 megabit service at 40 gigabytes a month. This means that at full throttle it would take you 15 hours to burn through your 40 GB cap. Inversely, if you were to want to manage your bandwidth all month to stay under the cap, your average speed could not exceed 146 kilobits/sec. Now, to get to the meat of your question, how do you know how much you have used... There are a few mildly technical ways to do this. One is using a metric on your perpetually connected broadband device of choice, such as a cable modem. Chances are it has a web interface of some sort and a spot to report the cumulative bits/bytes/etc in and out. Using an old fashioned pencil and paper you could track this with mild accuracy, recording what the count is on given days. Be mindful that there is a chance the counter has a relatively low rollover point, for example 4.1 GB (if it is a 32 bit integer counting each byte). This is why frequent checking may be necessary. --66.195.232.121 (talk) 20:51, 24 April 2009 (UTC)

Thanks. No wonder I couldn't find the specifics in the article.

I never watch videos or listen to music not only to keep my computer safer and faster, but to avoid this possibility.Vchimpanzee · talk · contributions · 21:03, 24 April 2009 (UTC)

Download the free Networx utility from here http://www.softperfect.com/download/ and leave it running all day. It tells you maximum and average download speeds and gives hour by hour reports of your usage - down and up load speeds and quantity. It is interesting to reset the meter and watch it for specific downloads/pages. This will tell you which activity is using the most. A very low average speed does not mean modem failure; it means a time where you were reading a page (by eye), not actively downloading it. I have successfully used logs from it to prove my ISP was giving me less than a quarter of the advertised speed.KoolerStill (talk) 08:51, 25 April 2009 (UTC)

Another good (albeit commercial) tool is NetLimiter found here. In the free version, it will track usage and break down individual program usage over hours/days/etc. It also has the ability (in the paid version) to limit applications in order to keep under a bandwidth or transfer limit cap. --99.11.199.76 (talk) 13:43, 25 April 2009 (UTC)

I use NetMeter, which has all sorts of logging built-in. It can also display a scrolling graph of the roughly current upload and download, with an optional MAX download (mine right now says 82KB/s, which will update as the spike moves off the left-hand side). Oh, and it is free. The graph is also totally optional. Washii (talk) 22:07, 27 April 2009 (UTC)

A free easy to use database that learns

I've started keeping a record of all the food I buy (and eventually eat) with various nutritional details copied from the packaging. I want to enter these in a database so that I can calculate my average daily nutrition. But, when I enter the name of something I have already entered the details of before, such as 1 litre of skimmed milk for example, I want the database to fill in the details for me. Is there / are there any free databases that are suited to doing this please, and that are easy to use for a novice please? 78.151.148.89 (talk) 21:49, 24 April 2009 (UTC)

open office comes to mind right off the bat. While I'm sure there are good "single purpose" databases that may serve you better, and a search for "free, download, database, food" might be a starting point. openoffice is a good general free alternative to expensive software. — Ched :  ?  05:09, 25 April 2009 (UTC)

The problem is that what you're describing would not be hard to make if you were a database programmer, but if you're not... then the learning curve is steep. OpenOffice Base is free but not easy (even if you are a database programmer). -98.217.14.211 (talk) 15:18, 25 April 2009 (UTC)

Could MySQL do this please? If I'm going learn a database language, I would rather learn one that is widely supported. 78.149.215.89 (talk) 20:53, 1 May 2009 (UTC)

Want to download and check my online bank statements for regular payments

My bank provides online bank statements and in addition allows the data to be downloaded in two or three different formats such as comma seperated values and Quicken format (I have never used Quicken). I would like to be able to check automatically that some regular monthly or weekly payments to me have actually been paid, preferably by the programme dialling up and downloading the data itself. The amounts should be that same, the description should usually be the same, but the actual date of payment may fluctuate by a few days. Is there any software available that can automatically check or monitor these payments and alert me if they are overdue please? Rather than me having to do it manually. Proprietory, freeware, or any other licence will do. Thanks. 78.151.148.89 (talk) 22:07, 24 April 2009 (UTC)