Wikipedia:Reference desk/Archives/Computing/2010 April 4

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April 4

Semi-unresponsive key

Resolved

I have a Macbook from c. 2007. And the r key is not as responsive as I would like. When I hit it directly, it types; but if I press down on the lower right corner of the key, it doesn't type. All other keys work fine when I press them that way. (As a result, I find that r often gets accidentally omitted while I'm typing.) What to do? --Lazar Taxon (talk) 01:43, 4 April 2010 (UTC)

Some options:

1) Try cleaning the old keyboard. First hold it upside down and shake it. If that doesn't do any good, pry off the key and clean the contacts with a cotton swab and alcohol.

2) Learn to live with it. (That's probably what I'd do.)

3) Buy a new keyboard. StuRat (talk) 01:47, 4 April 2010 (UTC)

As I said, this is a Macbook, not a desktop. As for removing the key, honestly I've never figured out how to do it on this computer. Any tips on how to do it safely? --Lazar Taxon (talk) 05:03, 4 April 2010 (UTC)

Can't be sure about a Macbook, but on a standard keyboard you can just pry a key off with a screwdriver or a nailfile, clean out any annoying gunk or crumbs, and push it back on. There won't be any contacts to clean at that level, though - to find those you have to take the back off the keyboard, and you're usually looking at two mazes of metal tracks on flexible plastic sheets which are pressed together at certain points by the keyboard action. These can get corroded, which might be cured by cleaning, but I expect (since it depends where you press) you've just got something stuck under the key. There might also be something mechanical displaced at an intermediate stage - often the key presses on a little rubber cup inside the keyboard, which acts as a spring and in turn presses the contacts together: this might have got shifted to one side a bit. 213.122.48.17 (talk) 05:37, 4 April 2010 (UTC)

I successfully removed the key and cleaned under it, and it appears to be better now. I was a little apprehensive about the Macbook keys because of their plastic scissor mechanism, but I figured it out. --Lazar Taxon (talk) 05:54, 4 April 2010 (UTC)

Glad it worked out for you. Had it been necessary to buy a new keyboard, this would mean an additional, external keyboard, in the case of a laptop computer. StuRat (talk) 13:04, 4 April 2010 (UTC)

You can replace MacBook keyboards without too much difficulty depending on the model. Some are rather simple things that are separate from the casing; some require you to replace the casing. Just FYI. Apple replacement parts are easily available through ifixit.com. --Mr.98 (talk) 20:17, 4 April 2010 (UTC)

Ugly DOS charset

One thing I've noticed on a laptop I have is that the extended ASCII characters display in a very ugly way. Is there any way to change the way the characters display? I'm in MS DOS 6.22 running on a Toshiba Satellite T2130CT. 76.117.247.55 (talk) 01:59, 4 April 2010 (UTC)

Can you describe these ugly characters ? On the usual ASCII code page, characters 128-255 give you lots of special characters for creating single line and double lined rectangles. There are also the card suit symbols (♠ ♣ ♥ ♦) and some other characters. Here it is: Code page 437. StuRat (talk) 02:07, 4 April 2010 (UTC)

They're all the normal ASCII characters, but the lines of the box drawing characters are offset and thicker (than usual) and letters that have descenders (p, g, q, y) seem to stretch like this:

. . . . . . .
. | . . . | .
. | . . . | .
. | . . . | .
. | . . . | .
. .=======. .
. . . . . | .
. = . . . | .
. .=======. .
. .=======. .
. .=======. .
. .=======. .

76.117.247.55 (talk) 02:26, 4 April 2010 (UTC)

Your example shows a 7×12 pixel character, which is pretty small. If you are using an MS-DOS command prompt window, you can set the size up to 13×22, which should look much better. (I don't think the small size is causing the problem you describe, but changing the font size will cause a new font to be loaded, and hopefully it will be OK.) StuRat (talk) 03:01, 4 April 2010 (UTC)

One possibility is that the BIOS (or whatever is controlling the screen display) is expecting a screen resolution of, say, 640×480, but the native resolution of the display is 1024×768 (or something else—I couldn't easily find the resolution of a Toshiba Satellite T2130CT with a Google search). So the image is being "stretched" to fit the screen, and it's being stretched poorly, by simply doubling some of the rows and columns of pixels. You might try to see if there's a BIOS setting that can be changed to fix it. I once had an IBM ThinkPad laptop that behaved similarly, and I discovered that there was a BIOS setting (if I remember correctly) to display 640×480 output, like MS-DOS, in a 640×480 rectangle in the middle of the screen rather than stretching it to fill the whole screen. —Bkell (talk) 02:47, 4 April 2010 (UTC)

I'm using straight up DOS and no option to change the size of the "window". I will try and find out how to get into the BIOS/CMOS setup if at all possible (I know it is somehow). 76.117.247.55 (talk) 00:52, 9 April 2010 (UTC)

Making a laptop a wi-fi hotspot

I need to make my laptop into a wi-fi hotspot so that my DS can connect to Nintendo WFC. Googling turned up several sites which said to create an ad-hoc wireless network, which I did. However, after locating the network, when I tried to test the connection on my DS, I got error code 51300. I confirmed that I'd entered the right WEP key, but it still wouldn't work. How do I set up a wi-fi hotspot using my laptop, without having to buy a wi-fi router, to which I can connect my DS? --70.129.184.122 (talk) 02:21, 4 April 2010 (UTC)

• i did try the same it did not work :(. —Preceding unsigned comment added by R.srinivaas (talk • contribs) 12:54, 5 April 2010 (UTC)

You don't write what operating system you use. If it is Mac OS X, I may be able to help you. I use my DS with my Mac Mini (with the built-in AirPort, i.e. without a separate, external router) and I should still have the link to the guide I used somewhere. Actually, now that I think about it, I remember having a similar problem so I just use no WEP key at all. Clearly, this is risky from a security point of view, so, I'm not sure I can recommend this. 83.81.42.44 (talk) 14:14, 5 April 2010 (UTC)

Finding accurate phone numbers online

How can I find accurate phone numbers for people online that are located in the USA? I tried anywho.com, whitepages.com, spokeo.com, and beenverified.com, but most the numbers are old and disconnected. Does anyone know of any other free or cheap unlimited web sites or services? —Preceding unsigned comment added by 76.94.253.121 (talk) 03:51, 4 April 2010 (UTC)

VirtualDubMod (abandonware)

Resolved

 – Thanks to Reisio. I needed to download a complete program package from SourceForge and now it runs.

I have installed this video program under Vista. It refuses to start and complains that it cannot find CORONA.DLL. I have tried reinstalling the program and also obtained a CORONA.DLL file which I placed in the same directory as VirtualDubMod. But still it says "The application has failed to start because corona.dll was not found". How do I get this program to run? Cuddlyable3 (talk) 09:45, 4 April 2010 (UTC)

http://www.sevenforums.com/software/72943-corona-dll-missing.html#post640586 ¦ Reisio (talk) 11:14, 4 April 2010 (UTC)

While I know this doesn't answer your question, why do you want to use VDM? If you just want to be able to load MPEG2 or ASF files, try the most recent version of VirtualDub with one of these plugins [1]. Nil Einne (talk) 13:09, 4 April 2010 (UTC)

AFAIK VirtualDubMod has features of VirtualDub plus some more. I have not yet found what I am looking for which is a free program to edit or convert .flv videos. Cuddlyable3 (talk) 17:11, 6 April 2010 (UTC)

Long time later (looking for something else) but VDM was very outdated then and more so now. It still has some featured VirtualDub does not but probably also lacks many features and bugfixes VirtualDub has. There is also a .flv plugin for VirtualDub which I think I've used before although I don't think that allows output to .flv (although not something I've ever cared about, I have used it to open flvs with some success IIRC) Nil Einne (talk) 04:31, 18 June 2011 (UTC)

Changing colours to a standard grey

Colours in digital photos are affected in appearance by how shaded they are. When measuring and comparing the RGB numbers for individual pixels, would it be possible to standardise the amount of greyness in the colour, so that you could remove the effects of shade and just see the colour without being distracted by the differences in shading or illumination? What would be the maths to do this? Thanks. 78.149.241.120 (talk) 11:03, 4 April 2010 (UTC)

How about changing it over to the HSV model, setting saturation and value to some standard amount, then going back to RGB ? StuRat (talk) 12:59, 4 April 2010 (UTC)

If you have PhotoShop, you can convert to CIELab and set the "L" channel to some constant value, which is theoretically mathematically better than HSV (though I don't know whether there's any actual practical advantage). AnonMoos (talk) 13:25, 4 April 2010 (UTC)

If you don't have Photoshop, a free and open-source alternative exists: GIMP, and the CIELab plugin for it. Nimur (talk) 15:12, 4 April 2010 (UTC)

I'm asking because in the future I'd like to be able to process images with software that I write myself. Would the procedure, to change a pixel to a standard grey, be getting the illumination (I) by (R+G+B)/3, then changing this to the required standard illumination (S) by multiplying each of the old R, G, and B by S/I ? Thanks 84.13.53.211 (talk) 10:58, 5 April 2010 (UTC)

(R+G+B)/3 is a very crude approximation to color-neutral brightness. One traditional formula (used in the JPEG format, and elsewhere apparently) calculates it as 0.299*R+0.587*G+0.114*B (see YCbCr). Once you go beyond a very few simple things, this is actually a somewhat complex area, which requires a fair amount of care and technical knowledge to really get things right, so you would probably be better off finding an appropriate library or API, rather than trying to reinvent the wheel... AnonMoos (talk) 13:45, 5 April 2010 (UTC)

P.S. I guess if you want a semi-quick-and-dirty method which doesn't completely ignore all accumulated past color science wisdom, then you could convert RGB to Cb and Cr using the equations in article YCbCr and/or the JFIF standard specifications document, assume an arbitrary value of Y, then use the inverse equations to convert these Y,Cr,Cb values to new R,G,B values. AnonMoos (talk) 21:06, 5 April 2010 (UTC)

Also, I don't think that method would work for all values of "S". Let's say a pixel is 0,0,255 (all blue). You would get an "I" value of 85. Let's say you want an "S" value of 100. This means you would need to raise the blue color above it's current level of 255, which is the maximum. So, you'd need to choose a level for "S" equal or below 85. StuRat (talk) 14:19, 5 April 2010 (UTC)

Bluetooth and WiFi

Is it possible to get a Bluetooth 1.1 compliant PalmOne Tungsten E2 to be able to talk to a Linksys WRT54G broadband router which, according to the side of the box, follows the following standards: IEEE 802.3, IEEE 802.3u, IEEE 802.11g, IEEE 802.11b? I've tried everything on the Palm side and no networks show up. Are these two things unchangeably apples and oranges? Thanks 71.161.45.84 (talk) 14:17, 4 April 2010 (UTC)

A direct connection will not work. Bluetooth is not the same as 802.11 (or any of its sub-types). (Briefly, Bluetooth uses a different kind of radio signal - at a different frequency, through a different analog layer, and with different digital encoding, and uses a different software network stack - in short, totally different technology implementation). 802.3 is simply wired ethernet. It might be possible to get a separate device, such as a personal computer which has both Bluetooth and 802.11 radios to act as a network bridge of some sort, but I'm not familiar with this procedure. I would guess it falls under Internet Connection Sharing if you are using Windows. Then, your Palm could conceivably connect to the PC using Bluetooth; and the PC could share its network connection. Nimur (talk) 15:06, 4 April 2010 (UTC)

IIRC, the Palm Tungsten E2 has a slot for a SD card, and I think Palm make (or used to make?) a 802.11a/b/g device that fitted in that slot and provided a wi-fi network link. Now I check the Palm Tungsten article where it says: "The Tungsten C has Wi-Fi and it is optional on the E2, T3, and T5 via the Palm Wi-Fi Card placed in their SD card slot". Unfortunately, the provided references are not much help, so maybe the WiFi card is no longer available; though you might be able to get one used - perhaps on eBay. However, I did come across this page which discusses who to use bluetooth to get wireless networking via the cell phone network (something have done on my T5). Astronaut (talk) 16:23, 4 April 2010 (UTC)

(or any of its sub-types). ..... at a different frequency - what? Both use (802.11 in some cases only) the ISM 2.4ghz band. If you don't believe me, Bluetooth "uses the microwave radio frequency spectrum in the 2.402 GHz to 2.480 GHz range". And you can see from List of WLAN channels that anything from 2.401 GHz to 2.483 GHz is possible depending on what's legal where you live (for b, g and n which is also capable of using 5 GHz). The possibility of mutual interference is an often discussed issue (CiteSeer^x: 10.1.1.21.8450 [2] [3]) with anedotal reports [4] [5] [6] although as illustrated in several of the earlier links, the frequency hopping characteristics of Bluetooth, it's low transmission power and a bunch of other factors means it doesn't tend to be a big issue. Electromagnetic interference at 2.4 GHz discusses the more general problem. They do of course use different channels so the frequency overlap isn't consistent but I think it's a little confusing to suggest they use different frequencies. None of this means they are in any way compatible or otherwise similar in design. Nil Einne (talk) 17:04, 4 April 2010 (UTC)

Nil Einne is probably correct; it's loosely used terminology anyway, though; because "the frequency" of a complicated digitally modulated waveform is poorly-defined. Both occupy the same frequency channel - a spread spectrum of frequencies near 2.4 GHz; but they use different carriers (with frequency-hopping, the concept of "carrier frequency" again gets stretched pretty far); overall, a different communication scheme, from the wireless link level all the way up to the software stack. Not compatible. Sorry for my loose terminology. Nimur (talk) 22:30, 4 April 2010 (UTC)

My CRT monitor has gone green.

The on-screen menu is colored normally, though. I can move the menu around the screen and the blue and red stay blue and red.

Is there still no hope? 67.243.7.245 (talk) 19:59, 4 April 2010 (UTC)

Check that the cables are firmly plugged in, for one. If so, well, it sounds like something has seriously conked out or gotten too loose on the inside. Don't try to service it yourself—there are nasty chemicals inside and there are electrical and vacuum dangers. Note that there are probably about 10 million CRT monitors on offer for cheap or free on Craigslist at any given time, since almost everybody seems to be converting to LCDs. --Mr.98 (talk) 20:11, 4 April 2010 (UTC)

Especially if it's a VGA cable, the most probable explanation is a loose cable connection on one end or the other. VGA transmits colors on separate wires, so if the cable is only plugged in "half-way," a full image can form, but some color channels may be missing or distorted. Other possibilities include a fizzled graphics card, a wonky video driver, or somebody mucking with software color settings at the operating system level. After checking your cable connection, check your control-panel or see this Windows color settings FAQ (if you're using a Windows system). Nimur (talk) 22:35, 4 April 2010 (UTC)

Try plugging into another monitor. That will tell you if it was a problem with the original monitor. Somehow I doubt it, though, I suspect it's the cable, the cable's connectors, or the graphics card in the computer. StuRat (talk) 01:58, 5 April 2010 (UTC)

Thank you all--you were correct. It was a connector that probably got loosened. I unplugged the VGA cable from the netbook and reconnected it, and all is fine now. FWIW, I had bought the monitor from Craigslist--not perfect, but it's only five years old. I had hoped that it wouldn't go out so quickly. Thanks again. 67.243.7.245 (talk) 15:15, 5 April 2010 (UTC)

My experience with CRT monitors is that they last almost forever. I've had some get a bit blurry, dark, or have colors off a bit, but never had one completely die on me yet. (I kind of wish they would, so I could justify a new flat-screen monitor. :-) ) StuRat (talk) 18:04, 5 April 2010 (UTC)

I wish I had your kind of luck. For some reason my CRT TVs die on me every few years. Everyone else I know have theirs for over a decade, it seems. And I've had one CRT monitor sent back to manufacturer, its replacement experiencing burnout several years later, and another hand-me-down going up in toxic smoke recently. Imagine Reason (talk) 15:18, 6 April 2010 (UTC)

Domino toppling in Blender

How long does it take to render a virtual domino chain reaction with 4.5 million domino stones in Blender? --84.61.146.104 (talk) 20:15, 4 April 2010 (UTC)

Are these two questions related? Which machine are you asking about? As far as rendering in Blender, the speed will depend on many factors - how did you design the scene? Are you computing physics, or simply running an animation script, for the dominos? How many dominos are on screen at any given time? What resolution are you going to render? How many textures, shadows, lights, and visual effects are you using? These are the sorts of things a 3D renderer is strongly affected by. The type of computer will also make a big difference; Blender can support hardware-accelerated rendering, so if you have a GPU, you may be able to process image data on that. The Blender Manual has a chapter on performance called "Rendering Big Hairy Scenes or Speeding Up Rendering" which you might like to read. Nimur (talk) 22:41, 4 April 2010 (UTC)

How large is the largest virtual domino chain reaction rendered with Blender? --84.61.146.104 (talk) 16:55, 5 April 2010 (UTC)

Mechanicaal engg

sir iam akshay i am studing mechanicaal engg.. —Preceding unsigned comment added by Akshay85 (talk • contribs) 21:24, 4 April 2010 (UTC)

my name is akshay.....i study mechanical engg...so my question is

i want to learn abt the machine ?wht i have to do? —Preceding unsigned comment added by Akshay85 (talk • contribs) 21:28, 4 April 2010 (UTC)

I have separated the above duplicated question from the Blender question above it. Comet Tuttle (talk) 02:14, 5 April 2010 (UTC)

I guess the best place to start would be machine and mechanical engineering. Can you refine your question? We're having a hard time understanding what you want to know. Nimur (talk) 03:35, 5 April 2010 (UTC)

Lost Picture

I accidentally erased a picture from my computer and emptied the trash can, not realizing the picture was among those erased. I would really like to get this picture back since it is irreplaceable. Is there a way to bring the picture back up-or is it gone forever? —Preceding unsigned comment added by 71.147.7.50 (talk) 22:05, 4 April 2010 (UTC)

If the picture was deleted recently and you have not done any disk-intensive tasks since then (such as downloading a large file), you may be able to recover the picture using a program such as Recuva (article). Good luck. Xenon54 / talk / 22:07, 4 April 2010 (UTC)

Yes, I use Handy Recovery for that. Ensure that you do backups in future! Sandman30s (talk) 22:33, 4 April 2010 (UTC)