Wikipedia:Reference desk/Archives/Computing/2010 December 12

= December 12 =

Owning my own wireless network, how can I see what the others are surfing?
As many as 8 devices have connected to my wireless network, that I leave unpassworded for charitable purposes. But I wonder what those other devices look at through my signal, and whether they've been looking at what I look at.

So what software can I install that'll allow me to view what is seen from the other devices that use my signal? Thanks, --70.179.178.5 (talk) 00:27, 12 December 2010 (UTC)


 * Firesheep? 118.96.157.158 (talk) 00:29, 12 December 2010 (UTC)


 * Through your wireless router admin interface, you should be able to set up and look at usage logs. --Mr.98 (talk) 00:40, 12 December 2010 (UTC)
 * As a sidenote - there are risks associated with open wireless networks, you may (or may not) want to read Wireless Security Darigan (talk) 13:26, 13 December 2010 (UTC)

Just logging on to your routers admin interface (on a DLink router, you would just type htt://dlinkrouter/ in the address bar, other routers usually have an IP address to type there) will let you see what websites are being accessed without seeing the actual data being sent. unfortunately, it usually shows u the IP address, not the domain name, so you would have to type that IP address number in your own browser and hit enter to see the domain name. Another thing to note is that logging on to this admnin page of the router allowes you to change settings including adding a new password. the log on password for this page is usually blank or trivial like 1234. so if you are not going to add a password for your router, at least log onto this page and change the admin page password or someone else can and lock you out of your own wireless network....albeit you would just have to reset the router if you have physical access ot it. Roberto75780 (talk) 13:47, 15 December 2010 (UTC)

What should I use so that my programs can work with audio/video files?
I want to be able to perform some small changes to the audio and video of files (such as .mp4). These changes would be like setting the red value of each pixel to 0 or doubling the volume of the audio of a movie. I tried to work with ffmpeg, but I eventually gave up since there was very little documentation and examples. I understand that there is a way to do this with DirectX, but I have not really examined this yet. Does anyone know a good way of going about doing this that is well-documented and lightweight? I'm willing to work with any language (although preferably C++, C#, Java), and I only really care about a solution that works on Windows. 199.111.183.4 (talk) 00:53, 12 December 2010 (UTC)

Display of leading zeroes in Excel
Is there a way in Microsoft Excel (2007 Version) to control the display of leading zeroes in a numeral? For example, let's say that I want the numeral 58 to display as three digits with a leading zero (i.e., as "058"). I know that I can change the settings in Excel to determine the number of digits after the decimal point. What I am concerned about is getting the digits before the decimal point correct. I would like a certain amount of "leading zeroes" to display, so that my numerals are all displayed with the same number of digits in them. Is this at all possible? Is there any way to make this happen in Excel 2007? Thanks! (Joseph A. Spadaro (talk) 01:54, 12 December 2010 (UTC))


 * Select the cells in question, choose "Cell Format" from the menu (or right click and choose "Cell Format"), choose "Custom," and put as many zeros as you'd like there to be leading (so 000 if you want it to be 058; 0000 if you want it to be 0058). This page explains more about what you can do with custom formats. --Mr.98 (talk) 03:45, 12 December 2010 (UTC)


 * You can also ask Excel to see the cell as 'Text' in which case it won't edit out any zeroes at the beginning. This may have other drawbacks, obviously. FreeMorpheme (talk) 19:22, 12 December 2010 (UTC)

Or put an apostrophe before the number - e.g. '01. This shouldn't affect the calculation functions if my memory is any good (it's a very useful thing for when you want to 'show' a function but not have the whole excel spreadsheet show functions (or anything where you want it to ignore formulas). ny156uk (talk) 19:49, 12 December 2010 (UTC)


 * The apostrophe forces Excel to store the contents of the cell as a string (even though it looks like a number and would, by default, be stored as a number). Simple arithmetic (+,-,*,/) will still work - Excel converts the contents of the cell back into a number before processing the formula - but functions like SUM or AVERAGE will not work on such cells. Gandalf61 (talk) 16:36, 14 December 2010 (UTC)

SSH load balancing based on username?
Hi everyone, is there a FLOSS solution for my problem? I need to balance SSH logins between servers based on their usernames, so user1-user10 go to servera.example.com, user11-user20 go to serverb.example.com, etc. -- 78.43.71.155 (talk) 13:24, 12 December 2010 (UTC)
 * Obvious way to do it is to use a gateway machine. On the gateway set the user's shell to a script that ssh's them into their real server. Share a key between the server and the gateway, and this is almost transparent (ssh escapes will be confusing). CS Miller (talk) 14:51, 12 December 2010 (UTC)
 * I understand the part about the shell script, but could you please elaborate on the ssh escapes will be confusing part? -- 78.43.71.155 (talk) 16:05, 12 December 2010 (UTC)
 * See 'ESCAPE CHARACTERS' and the -e option in the ssh man page. Basically if ssh sees a - (minus) or ~ (tilde) as the first character in a line then they will have a special meaning. The user would normally escape them to send them to the remote shell. However, as there is another ssh running, this will then receive the - or ~, and will need to have it escaped again to send it to the real shell. Tilde-escaping can be blocked by using '-e "none"' as a param to the second ssh. I'm not sure how to disable minus escaping. CS Miller (talk) 17:16, 12 December 2010 (UTC)
 * Sounds like it's not going to be an issue in my specific case as the SSH connections are used for port forwarding / X forwarding and application calls like '/usr/bin/firefox' only. Thanks for the explanation. :-) -- 78.43.71.155 (talk) 17:25, 12 December 2010 (UTC)
 * If both ssh processes are started with -X then X-forwarding will work. I'm not sure how to get other port forwarding to work, as the ssh's need to co-operate. CS Miller (talk) 20:48, 12 December 2010 (UTC)

SD card refuses to work in cameras
Hello, I have an 8GB SD card I used to use in my Lumix camera. I put it into a Sony HDR camcorder the other day, and it worked fine. But then the Lumix wouldn't read the card. And now the Sony won't read the cvard. There's no option to format on either of the devices, they just won't recognise it. I would just imagine that the card is broken - but it still works in the card reader in my laptop. I have tried formatting it in there, both to NTFS and FAT32, but the cameras still wont recognise it. Anyone have any ideas? FreeMorpheme (talk) 19:25, 12 December 2010 (UTC)

(Daft idea but sometimes the daft stuff is true so worth a try) - is the 'lock' switch stuck either A) half-way between or B) on 'lock' mode? It may be that your cameras are picky about that but your computer isn't. ny156uk (talk) 19:46, 12 December 2010 (UTC)


 * Flash cards can either be formatted as
 * A hard-drive, where there is a partition table; there is one partition which occupies the full space of the card.
 * A floppy-drive, where there is no partition, but the disk extends over the full space of the card.
 * Windows will work with either method, but the normal formatting method is the former, and I'm not sure if cameras will understand both. It should be possible to use the Window's drive manager to check how the card is formatted, but I'm not sure of the details. CS Miller (talk) 20:53, 12 December 2010 (UTC)


 * It seems unusual that neither camera would have a format option. Try scrolling through all the options under Setup on the Lumix.  What are the specific model numbers?  -- LarryMac  | Talk  15:53, 13 December 2010 (UTC)

It's a Lumix LX3 and a Sony CX115EB. Since the laptop only recognised it I thought I'd let Windows 7 use the memory as extra - but that evening it began bluescreening under a Bad Pool Header warning. So I System Restored and took the card out - it has been languishing ever since. And no, the lock bit is firmly in the unlock position. FreeMorpheme (talk) 18:48, 14 December 2010 (UTC)


 * Given the error message from Windows, it sounds like the card may be corrupted in some way. Be that as it may, there are definitely format options on both devices, according to the manuals I found online.  If the card is corrupt, perhaps those options are not being displayed.    Here's the Lumix manual.  The format function is under the Setup menu, as noted on page 34.  For an SDHC card, it says to use FAT32 "in compliance with the SD standard", whatever that means.   And here's the Sony manual, which I think is saying that format is under the "Manage Media" menu, but it's not the best documentation I've ever seen, not least because it's attempting to cover at least four camcorder models.  Both manuals say that you should only format the card using the camera in question, formatting on a PC is right out.
 * Mmmm, well the problem there is that since they both refuse to admit there is a card inside them, they don't give the formatting option. Sad. FreeMorpheme (talk) 17:24, 18 December 2010 (UTC)

Merging or fusing two poor quality images
I have two different digital images of the same painting, both poor quality and different sizes. I would like to merge them together in the hope of creating a better quality image. Is there any software that can merge fuze or overlay two images automatically? By searching I have found something called "Merge" but its very difficult to get the two images to register manually. Is there any other software that can do this please? Thanks 92.28.249.229 (talk) 19:33, 12 December 2010 (UTC)


 * Perhaps Hugin (software)? The bottom picture there is "An image merged from multiple exposures with Enfuse". Not sure what Enfuse is, but it redirects to that article, so maybe it's part of Hugin. Wait, actually that's for doing HDR, isn't it. You want something more like what these people did, but with two images instead of millions. Hmm. 81.131.0.97 (talk) 20:35, 12 December 2010 (UTC)


 * If the lack of quality is caused by low resolution or graininess or blurriness, having just two images won't do much good. I could imagine that it would be possible to recover a sharp image from thousands of images like that, because together they'd have as much information as one sharp image, but I don't imagine that combining two images would reveal anything appreciable.  Paul (Stansifer) 06:16, 13 December 2010 (UTC)


 * I tend to agree. An exception might be if you had one grey-scale pic with excellent resolution, and one grainy, color pic.  It should be possible to get the resolution from the one and the color from the other, in such a case. StuRat (talk) 07:20, 13 December 2010 (UTC)

You could try GIMP, if you are prepared to take the time to learn to use it. You can place the two versions in different layers of an image, and then there are a vast number of things you can do to manipulate them and combine them in various ways. I have doubts that it will help -- mixing two different kinds of shit mostly just gives you a larger quantity of shit -- but you can always try. Looie496 (talk) 18:02, 13 December 2010 (UTC)

Registax can do the above. 92.28.254.198 (talk) 10:48, 17 December 2010 (UTC)

Securing files on my hard drive
I run Windows XP on my computer, and have an external hard drive. Can I password protect individual files or folders to keep the contents from prying eyes? (I have other files that do not need to be so protected.) Do I need third-party software to do so? Hemoroid Agastordoff (talk) 20:50, 12 December 2010 (UTC)
 * I recommend TrueCrypt 82.44.55.25 (talk) 21:01, 12 December 2010 (UTC)
 * TrueCrypt is good, but it's not terribly useful if you want to encrypt individual files, separately. Basically Truecrypt creates some sort of container that's encrypted (either a large file that acts as a folder when the password is given, or else an entire partition).  If you wanted to protect each file separately, you'd end up creating a small, encrypted container for each file, and putting the file in that; fairly time consuming (and a lot of passwords to remember).  If you're OK protecting all of your files with the same password (or even two or three different passwords, depending on who you want to be able to access the files), then TrueCrypt will work well. Buddy431 (talk) 00:58, 13 December 2010 (UTC)


 * I used to use PGP for this, which does encrypt individual files; but it turned into a proprietary, costly piece of software a number of years ago, so I have moved to using TrueCrypt. Comet Tuttle (talk) 18:30, 13 December 2010 (UTC)
 * How about Gpg4win? -- N Y  Kevin  @855, i.e. 19:31, 13 December 2010 (UTC)


 * If the drive supports NTFS, by far the simplest approach is to use Windows' own Encrypting File System. No extra software required, just right-click, Properties, General, Advanced, Encrypt... Mitch Ames (talk) 11:37, 14 December 2010 (UTC)


 * It's likely that the OP has XP Home, which doesn't support EFS. Also, I'd advise against using EFS unless you're sure you know what you're doing. It's easy to accidentally get a combination of no security (anyone can view the file without a passphrase, just as you can) and high risk of data loss (an innocent-seeming action like reinstalling Windows can make the file permanently unrecoverable). -- BenRG (talk) 21:13, 15 December 2010 (UTC)