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August 7

Lappy keeps shutting down

Does anyone here have any idea why my laptop shuts down at random without so much as a warning message or bluescreen? It is a Toughbook CF-48, running Windows XP, 256 MB RAM. The only two programs open both times I've shut down are Opera and KVIRC. —Jeremy v^_^v ^{Components:V S M} 05:34, 7 August 2011 (UTC)

Impossible to know. Take it to a repair shop. It could be a loose connection somewhere. Try removing the battery pack and any leads and then replacing then firmly.--Shantavira|^{feed me} 07:31, 7 August 2011 (UTC)

Not a connection issue. Still shuts down. —Jeremy v^_^v ^{Components:V S M} 18:07, 8 August 2011 (UTC)

For an old laptop a common reason is automatic shutdown due to overheating, which in turn is caused by dust blocking the airflow. Removing the dust fixes the problem. 98.248.42.252 (talk) 22:43, 7 August 2011 (UTC)

How would I be able to undust the fan? It's very small and, as far as I know, not very dusty... —Jeremy v^_^v ^{Components:V S M} 18:07, 8 August 2011 (UTC)

I had exactly this problem a fortnight ago. Remedy was to unscrew the case and open it, remove dusty hairball, and put back together. You /might/ be able to remove a dust blockage by blowing on the fan. It would be handy if you could ascertain that the fan or air-path is blocked before doing all of this. FWIW, I found that I could get access to the fan after removing the keyboard, and need not have removed a dozen and more screws from the bottom of the machine. --Tagishsimon (talk) 18:12, 9 August 2011 (UTC)

The fan is blowing hot air out of the back of the rig.. —Jeremy v^_^v ^{Components:V S M} 20:34, 9 August 2011 (UTC)

Note, however, that laptops are not designed to be user-serviceable. For example, when I opened up my IBM ThinkPad, the paper cable to the track point tore, and it became unusable. StuRat (talk) 18:28, 9 August 2011 (UTC)

"Go to a web site" displayed in Firefox address slot rather than the URL

Much of the time, although not always, I see "Go to a web site" displayed in the Firefox address slot rather than the URL of the page I'm looking at. I'm using Firefox 5.0 and WinXP.

Does anyone know how to fix this?

I've found this on the internet https://groups.google.com/group/mozilla.support.firefox/browse_thread/thread/b82e76ad30161d16/7f80d5c69fc11bcf which seems to blame openSUSE, but as I'm using Windows, not Linux, then I don't see how this applies.

How would I disable the openSuse thing in Firefox anyhow, if it is present even though I'm using Windows? 92.24.133.68 (talk) 15:14, 7 August 2011 (UTC)

MS Word - Highlighting

Is it possible to use Word's 'find' function to locate every instance of a word, and then highlight those instances in a colour I specify? For example, if I have a document with the phrase, 'the quick brown fox jumps over the lazy dog,' and I wish to highlight both of the instances of 'the', can I use the 'find' function to do it? Of course, with such a short sentence, I could do it myself. I am thinking about using this in a 20 page document, where I need all instances of the words that appear in an attached .xls glossary highlighted in the Word .doc I am working on. --KägeTorä - (影虎) (TALK) 19:07, 7 August 2011 (UTC)

The Search and Replace dialog has a "format" button (possibly hidden behind a "more" button) that allows you to specify all sorts of formatting in both the search and replace text. AndrewWTaylor (talk) 20:03, 7 August 2011 (UTC)

Ah, thanks - it turned out to be more obvious than that. There is a 'reading highlight' button, and an option to 'highlight all', and the highlights remain even after closing the 'find' dialogue, reopening, and then 'finding' all instances of a different word and highlighting them - just what I need! Cheers! --KägeTorä - (影虎) (TALK) 20:35, 7 August 2011 (UTC)

Batch renaming in Linux

In Linux, how can I batch rename a number of files with names such as oa0*.jpg (where the * part includes varying digits) to p80*.jpg, so that only the first two characters of the names change from oa to p8? JIP | Talk 19:25, 7 August 2011 (UTC)

You should be able to do: rename 's/oa0/p80/g' *.jpg. This assumes you don't have any files like baroa0.jpg the you don't want to rename.- Akamad (talk) 23:01, 7 August 2011 (UTC)

And if that doesn't work, try rename 'oa0' 'p80' oa0*.jpg (there are two popular rename applications out there). ¦ Reisio (talk) 18:36, 8 August 2011 (UTC)

The first one didn't work but the second one did. Thanks! The reason I was asking was that I had transferred image files from my brand-new Olympus E-620 camera but had accidentally set the filename to begin with "oa" instead of "p" and a digit/letter indicating the month. JIP | Talk 20:08, 8 August 2011 (UTC)

August 8

I need an old computing joke

• I know this is an inappropriate question.
• I know this is an inappropriate desk to ask it on.

But, I'm desperate, so here goes: there's an old joke, involving a king who calls upon an engineer and a software developer to design what becomes a toaster. The engineer comes up with your standard 1960's toaster (dial for darkness control, for example); the software guy determines it's way more than that, and it needs an object-oriented design, and a graphical user interface, and an operating system, etc, etc . . . and the punch line is something along the lines of "Wisely, the king took the software developer out back and had him shot."

Believe it or not, the joke perfectly illustrates a point I'd really like to make at a city council meeting Monday night.

I need a link to the (or an) original; you can post it on my talk page if you want to avoid polluting this desk. I've tried Google, and rec.humor.funny (yes, I'm that old), and all the other joke sites I can find; nothing so far. It's a computing joke (hence RD/C), it's gotta be out there somewhere. Anybody? --DaHorsesMouth (talk) 00:00, 8 August 2011 (UTC)

Googling "king toaster joke" I find one on this page and another on this page which look basically like what you want. There are lots of other pages with the same joke, if you use those search terms. --Mr.98 (talk) 00:27, 8 August 2011 (UTC)

Resolved

 – Ah, I see I used the wrong search terms. Thank you, sir!

Android - ability to sound alarm at regular intervals

Resolved: Thank you Magog the Ogre (talk) 11:45, 9 August 2011 (UTC)

I would like my Android phone to sound an alarm exactly once every six hours and fifteen minutes. It can deviate by only about seven minutes in either direction. Unfortunately, Android only gives a maximum of ten alarms that can be set to sound throughout the day, so I can't just create, say, a system where I set 27 different alarms throughout the week at an average interval of 6 hrs 13 1/3 mins (which would perfectly cycle after seven days).

Is there an app where I could do this? Magog the Ogre (talk) 00:54, 8 August 2011 (UTC)

Probably Nil Einne (talk) 09:32, 8 August 2011 (UTC)

You could probably setup your alarms in a calendar and sync/import to your android device, might be the simplest, short of having an app handed to you on a silver platter. ¦ Reisio (talk) 19:24, 8 August 2011 (UTC)

You want a stopwatch, not an alarm. There are many stopwatch apps. You want one that has a timer in it (many are called "stopwatch and timer"). Then, you set a timer for 6 hours and tell it to start. It will beep 6 hours later. You can set it on repeat to have it go off every 6 hours. -- kainaw™ 19:35, 8 August 2011 (UTC)

There is indeed an app called "Stopwatch & Timer" which has a paid version that will loop a countdown timer. The free version won't loop. The paid version is $0.99. (FWIW, I have the free version and don't have any complaints.) Dismas|^(talk) 06:46, 9 August 2011 (UTC)

SVG image appears incorrectly after uploading into Commons

I have an .svg image created using Inkscape. If I upload this image into Wikimedia Commons, the image appears incorrectly. It may be that some of the layers are missing. Is there any way to correct this without abandoning the .svg format? ike9898 (talk) 01:27, 8 August 2011 (UTC)

Quick question, are you saving it as a "Inkscape SVG" or a "Plain SVG"? I think the inkscape specific ones will glitch in some browsers. APL (talk) 02:44, 8 August 2011 (UTC)

I guess you're talking about File:Cheltenham PA township seal.svg. Some points to note:

• You've got text on a curve - the (rather old) renderer Mediawiki uses (which lags Inkscape and the libsvg renderer used by some browsers) doesn't handle this very well. That's why the "salubritas et erudito" part doesn't render.
• You're using fonts called "GulimChe" and "SimHei" (as well as the generic identifier "sans"). GulimChe and SimHei aren't installed on the render servers, so the renderer substitutes something else, with a different appearance and different font metrics. It's actually worse if I view it myself in Inkscape or Firefox, because I don't have these fonts either, yielding greatly different font metrics and some horrid overlapping. The list of fonts that are supported can be found at this page on meta.
• To fix both of the above, you should open the SVG on your Inkscape (with those fonts installed), select the curved texts, and do path->object_to_path. That will make what were curvey-text objects into just complex polyline objects. Then upload that.
• Browser foibles aren't really very relevant, because almost everyone who will view your picture will do so not as an SVG rendered by their browser, but as a PNG rendered by Mediawiki's SVG rasteriser. Most modern browsers have a better SVG renderer than Mediawiki, but it mostly doesn't come into play.

-- Finlay McWalter ☻ Talk 09:09, 8 August 2011 (UTC)

Qubbling with myself - the "ET" does render okay, because it's not text on a curve. -- Finlay McWalter ☻ Talk 09:13, 8 August 2011 (UTC)

Incidentally, shouldn't the last word of the motto be "eruditio" not "erudito" ? -- Finlay McWalter ☻ Talk 09:16, 8 August 2011 (UTC)

Thanks for the very insightful answer! Re: 'erudito', I think that's how the original has it, but I'll double check. ike9898 (talk) 11:41, 10 August 2011 (UTC)

Copying text from website with LOTS of links

So i have a website where you can send text messages to other people, and i want to copy all the information from it....

The problem is that the site has links to each message... So the main screen is a list of links with a "view next 20" or etc button...

So is there a way to copy the text on each page that each link points to without doing it manually? Ive googled for such things, but the nearest thing i can find is a Firefox plugin that copies the link text itself, and not text on the page the link goes to. Any help at all would be greatly appreciated, thanks!

74.117.245.62 (talk) 03:17, 8 August 2011 (UTC)

Sounds like you want a web crawler. Httrack would be my recommendation. Make sure you specify specific filters in the "Scan rules" so that it only downloads the parts of the site you actually want, rather than absolutely everything. AvrillirvA (talk) 09:47, 8 August 2011 (UTC)

hmmmm, seems close to what i need... but if i understand correctly Httrack will basically download all the pages so i can view them offline. This would basically create the same issue i have already, which is that i only want certain text from each page, not a bunch of links where i have to click them to see the text in each. In other words, this texting site im at stores each message of a conversation as a separate link on the main page. What i want is to be able to make a text file with the entire conversation on it. If Httrack downloaded the whole site into http files to a specific folder though, i might be able to write a script to open each file and get the required text based on certain info that is the same in each page?

I hope i have been clear here, i feel that what im looking for isnt exactly routine. 74.117.245.62 (talk) 11:03, 8 August 2011 (UTC)

An additional reason i dont think this will work: You have to log in to view the list of text messages, and the httrack thing says it doesnt do dynamic links, which these are i believe, because the messages are for my account and you cant just get them from going to the texting site. 74.117.245.62 (talk) 11:10, 8 August 2011 (UTC)

Chat site

Yesterday in yahoo chat, i was invited to join a site BuddyChatCams for live webcam chat. I have no prior experience in sites like this and want to know is sites like this safe and keep privacy of its members? Asking here to get serious answer. --Goblin 224 (talk) 03:47, 8 August 2011 (UTC)

Probably not safe, no. At the very least I'd expect them to put advertising pop-ups on your computer. StuRat (talk) 04:29, 8 August 2011 (UTC)

It is also known that there are some nodes that automatically tune in to video chat channels, and record everything they see. Comet Tuttle (talk) 20:42, 8 August 2011 (UTC)

Windows easy transfer

I am replacing a laptop for another person. I want to move all of his photos, music, and programs to the new one. He only has two programs installed beyond Windows 7: Microsoft Office and Nero. Does Windows Easy Transfer transfer the programs as well as the other files? I see that I can do a system backup instead. Will that allow me to restore Office and Nero to the new laptop? -- kainaw™ 13:59, 8 August 2011 (UTC)

No. Windows Easy Transfer was supposed to be expanded to do this, but the Companion was never released. Laplink PCmover appears to be able to transfer applications. PickMeApp is a free tool.[1] ---— Gadget850 (Ed) ^talk 14:21, 8 August 2011 (UTC)

Thanks. I expected that there would be resistance to allowing people the ease of not repurchasing everything they've already purchased. -- kainaw™ 14:28, 8 August 2011 (UTC)

Purchasing a second copy of software you already own would accomplish nothing. The install media would be identical. All you'd get is another license key, but the first key will work fine if you reinstall. The product licenses allow you to use the software on (at least) one machine at a time; it doesn't have to be the same machine forever. -- BenRG (talk) 20:08, 8 August 2011 (UTC)

The issue is that it isn't my laptop and I don't want to purchase a second copy of software for another person. It isn't reasonable for me to get the software from the owner (or ask if he owns a legal copy of it). I am just attempting to replace his laptop that my toddler destroyed and, since the harddrive was salvageable, copy over all his software. -- kainaw™ 20:15, 8 August 2011 (UTC)

Maybe you could just physically move the old hard drive to the new machine. -- BenRG (talk) 20:27, 8 August 2011 (UTC)

That'll only work if the version of Windows DIDN'T come with the laptop (OEM licences can't be transferred to another computer like retail licences and if there is a change in motherboard it'll deactivate and should refuse to reactivate.  ZX81  ^talk 20:40, 8 August 2011 (UTC)

You should be able to recover the licence keys using something like Magic Jelly Bean Nil Einne (talk) 15:39, 9 August 2011 (UTC)

Yes, a system backup and restore will transfer all installed software. Gadget850's "no" was for Windows Easy Transfer only. -- BenRG (talk) 20:08, 8 August 2011 (UTC)

Thanks. System backup fails as 99%. I found that I need to install SP1 to make it work. Tried that, but it locks up on Stage 1 of 2 at 8%. I'm going to try to move the files and registry manually. Hopefully I can get something to work on the new laptop. I may just pop the old drive into the new laptop and hope I can handle all the device driver issues. -- kainaw™ 20:17, 8 August 2011 (UTC)

http://www.virtualbox.org/wiki/Migrate_Windows#HardDiskSupport http://mark.koli.ch/2009/05/howto-whole-disk-backups-with-dd-gzip-and-p7zip.html
Or take this opportunity to switch to open source alternatives. ¦ Reisio (talk) 18:40, 8 August 2011 (UTC)

That won't work unless the new hard drive is precisely as large as the old one. I suppose you could make a partition of exactly the right size, then fill it with dd, then resize it to fill the whole disk, but it would be easier to use disk imaging software that has that functionality built in (which is to say, pretty much any disk imaging software except dd+gzip). Surely the best choice here is Windows 7's bundled backup software. -- BenRG (talk) 20:08, 8 August 2011 (UTC)

Personally I would try what you wrote, and put the old laptop's hard disk physically in the new one; or if the new one came with a significantly bigger drive, give him that benefit by using Clonezilla or Norton Ghost to make an image copy of the old drive over to the new drive. As noted above, there might be driver issues, but that ought to be solvable. Comet Tuttle (talk) 20:40, 8 August 2011 (UTC)

mouse pointers

how come the mouse pointer can go off the right and bottom sides of the screen but not the top and left?

The mouse's "hotspot", which is where the click is actually directed, is constrained to the screen. For the standard arrow mouse, this is the tip of the arrow, so the rest (whole) of the pointer can appear to go of the screen. For the hour-glass (busy) pointer, it is the waist of the hour-glass, so the hour-glass does not go off the screen. CS Miller (talk) 23:24, 8 August 2011 (UTC)

For the Windows Vista and Windows 7 circle busy-pointer, it is the center of the circle. Marthelati (talk) 04:32, 11 August 2011 (UTC)

August 9

Cell phone without a baseband processor

Are there cases of where a cell phone (smart or otherwise) does not use a separate processor/CPU for managing its radio (i.e., there would only be the application processor and no separate firmware)? --Melab±1 ☎ 00:47, 9 August 2011 (UTC)

Very early mobile telephones did not even have any software at all. Depending on what you want to count as a "cellular" telephone, many did not even contain digital electronics - for example, early "1G" technology was purely analog. (Okay - the pedantic details are nagging at me: 1G mobile phones probably had a computer and did have some digital signalling for network control - but pre-1G analog radio telephony did not have any digital or software-controlled signalling). The transition to modern multi-CPU computerized radiophones has been gradual. Nimur (talk) 02:45, 9 August 2011 (UTC)

I read on some forum that some of Nokia's phones running Symbian don't have a baseband processor (although whoever said it may have been confused; he referred to phones with a separate baseband processor as being "dual core"—maybe not the right terminology). Just to clarify this for anyone else who responds, when I say "without a separate baseband processor", I mean that the radio is controlled by the application processor; I am not referring to SoCs that have integrated baseband processors (they would still have a baseband processor). --Melab±1 ☎ 15:16, 9 August 2011 (UTC)

I think what you mean to say is "... the radio firmware and the application software reside in the same address space." It is also possible that you may mean "...the radio control software time-shares a single execution pathway with the application software." Conceivably, you may also mean "...the radio is controlled by electronics that are packaged in the same piece of plastic as the application software controller." There are certainly some devices that satisfy any or all of these criteria; but probably none are commercially available "cellular telephone" devices. This approach would be difficult to design using competitively-available electronics parts; and this design unnecessarily exposes the radio to serious fatal errors in application-software. Separation of function is more common. In any case, the radio is still controlled by the application processor; but, the commands take the form of higher-level software signals that are interpreted by the radio-control firmware. How else might you want to control the radio? Do you want to directly specify signal waveforms? (If so, no commercially available telephone device can do that). Nimur (talk) 18:32, 9 August 2011 (UTC)

The second option. The application processor is the only major processor (I consider the baseband a major processor, in this case). I read here that in the HTC Desire Z/T-Mobile G2, the baseband boots up first and operates independently of the Android firmware. My ideal setup is a single firmware installation controls everything. I would like this because you would be able to completely customize the software (depending on whether or not there are hardware-based signature checks). Also, I prefer a singular set of controlling firmware. --Melab±1 ☎ 01:01, 10 August 2011 (UTC)

Identify a satellite-view or bird's-eye-view image?

File:90 intersection.JPG is claimed as an own work, but it looks to me as if it's a screenshot of some website that provides bird's-eye views or satellite views. Any idea of the source? It's not Google Satellite or the bird's-eye-view on Bing; I don't have Google Earth, and I'm not familiar with other programs, so I can't give any more ideas. The location is 41°49′40″N 80°45′56″W. Nyttend (talk) 04:44, 9 August 2011 (UTC)

You can ask him. General Rommel (talk) 07:13, 9 August 2011 (UTC)

I'm pretty sure that's not satellite. That was taken from an aircraft. Have you considered the possibility that user:Route11 owns an airplane? It's pretty easy to take photos like that if you own a plane. APL (talk) 08:38, 9 August 2011 (UTC)

That was my initial thought (I was in a light airplane myself yesterday), but the image itself was very much unlike any photos I've seen: it has a vaguely computer-generated feel to it, similar to that of Bing's bird's-eye-view. Nyttend (talk) 12:55, 9 August 2011 (UTC)

Based on the positions of the cars its from Wikimapia ( http://www.wikimapia.org/#lat=41.827778&lon=-80.765556&z=16&l=0&m=b ) Kellhus (talk) 13:03, 9 August 2011 (UTC)

Actually, looking again its the same image that Googlemaps uses (cars are identical) its just been tilted Kellhus (talk) 13:06, 9 August 2011 (UTC)

That specific imagery is provided by DigitalGlobe (see the copyright on the mapping services pages). I seriously doubt that some random Wikipedia user owns the DigitalGlobe copyright and is releasing that copyrighted work to the public domain. -- kainaw™ 13:10, 9 August 2011 (UTC)

I marked the image as "disputed" and left a note with the author. -- kainaw™ 16:54, 9 August 2011 (UTC)

It was off google earth but, I did not know what to upload it under, so I uploaded under own work. I know I shouldn't of done that. Is there any way to upload it diifferent?SR11 (talk) 14:07, 10 August 2011 (UTC)

No. It cannot be uploaded. It is copyrighted by DigitalGlobe. Unless you get them to release it to public domain, they own it. Just because Google paid licensing to allow you to see it in Google Earth doesn't mean that you now have the right to distribute it to other repositories. -- kainaw™ 14:20, 10 August 2011 (UTC)

I've marked the image as a copyvio, and it is to be hoped that it will be deleted ASAP. --Tagishsimon (talk) 14:24, 10 August 2011 (UTC)

Starting programs via Run

In WindowsXP if I write "firefox" in the Run box in Start Menu, Firefox starts. Why? How can I do the same with Total Commander? — Preceding unsigned comment added by 109.74.50.52 (talk) 07:02, 9 August 2011 (UTC)

Firefox's executable is firefox.exe, which is in your computer's path. If you know TC's executable's name, then the same will (probably) work. For WindowsXP, start the task manager, select the Application Tab, click ONCE on TC's icon, right click and select "Go To Process". This will show the processes's name. CS Miller (talk) 08:00, 9 August 2011 (UTC)

You meant to link PATH (variable). I think it's more likely that firefox is not in the search path, but is listed in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths in the registry. Adding it to the search path might be a solution to the OP's problem. You can do this by pressing Win+Pause, going into "advanced settings" and clicking the "environment variables" button, finding the one named "Path" and double-clicking it, and adding C:\Program Files\Mozilla Firefox (or whatever) to the end separated by a semicolon. You may have to log out and in again to see the change. -- BenRG (talk) 17:47, 9 August 2011 (UTC)

This can help you set up any program to be accessible via Run AvrillirvA (talk) 11:41, 9 August 2011 (UTC)

Name of open internet group?

I remember seeing a video interview a while back with someone who was talking about his organization's efforts to promote the use of peer-to-peer and anonymity technologies to create a more open form of internet than the current government/corporate controlled system. I'm not sure about the technologies they intend to use, but the gist that I got was that instead of routing traffic through centralized telecom carriers, internet traffic would be routed via a p2p wireless mesh network. I'm trying to find the name of this group, or perhaps groups that are working on something similar. Anyone here ever heard of this group? What is the name of the organization? Thanks. -- Jrtayloriv (talk) 18:01, 9 August 2011 (UTC)

.p2p perhaps? --Melab±1 ☎ 18:25, 9 August 2011 (UTC)

Perhaps you heard about Tor (anonymity network) ? TheGrimme (talk) 19:22, 9 August 2011 (UTC)

functions of a function

Hi. In a computer algebra system such as mathematica or sage, suppose I define H() to be the Heaviside function, and the ask the system to evaluate $x=H(1+(f(3))^{2})$, where f() is a very complicated, massively expensive and difficult function. A human is clever enough to know straight off that x=1. But is mathematica or sage clever enough to know this without evaluating f()? Another example might be to establish whether $n=2^{10000000}-1$ is prime. I know that it isn't, but would a computer have to evaluate n first, *then* check it for primality? I am not sure exactly what I'm asking here; I guess I'm asking what the computer science term for "knowing enough about H() to avoid having to evaluate its argument exactly". Yours in confusion, Robinh (talk) 20:50, 9 August 2011 (UTC)

Formally, that is called short-circuit evaluation: recognizing that, due to the structure of a sub-expression, full evaluation is unnecessary. This saves a lot of compute-time, and is used by many compiler and optimization algorithms. I am not aware of any computer algebra systems that can deduce the specific sort of expression short-circuiting that you listed above; but I'm not a CAS expert by any means. However, I do know a bit about compiler internals, and I can tell you that the correct implementation of short-circuit evaluation is both (i) very ugly; (ii) prone to unintuitive side-effects, even if they are logically valid; and (iii) exacerbated by bugs in code and/or bugs in the compiler. Just yesterday I was reading the LLVM Blog, and came across "What Every C Programmer Should Know about Undefined Behavior", which contains some pathological examples of short-circuit evaluation of C code. C syntax is different from the allowable syntax of a CAS system input; consequently, the theory and practice of static analysis in C is much simpler than that of a CAS language. But the same general ideas apply: if the C-compiler / CAS interpreter determines that a sub-expression always evaluates to a known value, the evaluation code can be replaced with a hard-coded constant.

You may find Evaluation strategy and Formal grammar helpful in understanding how we design such "smarts" into an interpreter for a CAS. You might also find this list of other optimization techniques interesting; and in particular, Partial redundancy elimination (PRE), also known as "Expression Elimination" (EE); or the related, "Common subexpression elimination" (CSE). Nimur (talk) 21:06, 9 August 2011 (UTC)

There is no general approach to determining the properties of functions. For any interesting property a function expressed in a Turing-complete language can have ("interesting" can be defined quite broadly) it's not possible to decide whether a particular function has that property. Therefore, there is no general way to "examine" a function that is any better than just evaluating it.

Of course, there exist many optimizations that compilers can and do perform — the undecidability result just means that sometimes they'll miss a place where the optimization can be performed. But the properties are generally far simpler than things like "results in a value {above/below} x for input {above/below} y" (given that you need to figure out relevant values of x and y first). It's much faster to leave that stuff, which can really benefit from intuition, to the humans. Paul (Stansifer) 22:42, 9 August 2011 (UTC)

(OP) thanks guys, some interesting links. I like Stansifer's comment about undecidability above. But it strikes me that it might be possible to "catch" lots of short-cuts by "evaluating" subexpressions in the laziest (ie easiest) way possible. For example, evaluating $1+(f(x))^{2}$ sage would first observe that the answer is real, then non-negative, then positive, then greater than or equal to 1, then maybe some other result such as $\in [1,14]$, and only then proceed to actually find the exact answer. Then it could pass each result in turn to H() and find that the first two aren't good enough, but the third *is* good enough. So it stops there, never having to actually evaluate f() exactly. I see that no scheme can catch every possible simplification. But surely a system like this one could catch a good number of them, and save a lot of time. Or is this a hopelessly optimistic approach and even a rudimentary implementation would be AI-hard? Robinh (talk) 01:38, 10 August 2011 (UTC)

Yes, but you implicitly prioritized this set of properties: e.g., that the algebra system should bother to check whether the argument to the Heaviside function is real or positive. This is because you already know that having a real, positive argument will simplify the evaluation of H(x). You can therefore design the CAS system to check if those simplifying assumptions are satisfied. The hard part is knowing which set of assumptions will make a problem simpler. If your CAS hadn't already known the unique nature of the Heaviside function, why would it have bothered checking these properties of its input arguments?

Ultimately, it comes to this: a CAS system can be programmed to check for specific special cases. As I said above, I am not aware of any CAS that does contain special-casing logic specifically for the Heaviside function. I know that Waterloo Maple did start by assuming all functions might produce matrices of complex number outputs; and it began to narrow them down to vectors, and scalars; and restrict the domain to real numbers; and eventually, integers, or rationals, if possible. Similarly, range-checking can determine whether a arbitrary-precision arithmetic implementation is needed (e.g., should the function evaluate to a BigNum or 64-bit float?) So, range- and domain-checking are "special cases" of function properties that can be designed into CAS implementations. But no CAS can be expected to know every possible optimizable result in all possible scenarios for all possible functions. Such evaluation would be computationally more challenging than brute-force evaluation. From the practical standpoint, CAS systems are designed to simplify expressions when possible; and the algorithms that implement existing CAS systems probably prioritize optimizations that appear commonly during ordinary use.

Here is SymPy, an open-source CAS implemented in Python. You can read several of its special-case evaluation mechanisms, and see how they are implemented in program-code: SymPy Core Module documentation, Assumptions Module, and you can browse source-code that implements the symbolic assumptions module. As I mentioned before: this is nasty, complicated source-code; have a look at even the simple cases of basic number-theory assumption evaluation. Nimur (talk) 18:07, 10 August 2011 (UTC)

(OP) Thanks, Nimur. I'm beginning to see the deal. My little chain above did indeed make lots of implicit assumptions. Hmm. Although I can report that sage determined, instantaneously, that $2^{100000000}-1$ was composite. The source code you pointed me to was indeed complicated. Is there an "Idiot's guide to CAS" book that you could recommend? cheers, Robinh (talk) 20:07, 10 August 2011 (UTC)

Router gives wrong location

I just installed my brothers old router. He had it when he lived in a different city then where I am now. When I connect my cell phone to the wireless network, it shows my location on Google latitude, Grindr, and on the local weather to be in Cedar Falls, where he use to live. How do I fix this? I just upgraded to the newest firmware version also and Cisco won't provide support unless I pay, which I won't do. CTJF83 21:52, 9 August 2011 (UTC)

There is nothing wrong with your router. The problem is that Google, and many other companies, use a very unusual method to determine your location. They drive around on the street sniffing wireless networks; and they save the MAC address of every router they discover, storing it in a giant database that maps individual routers to individual GPS coordinates. Companies like Google then sell this data to third-party companies as part of a "location based service" data package. At some point, one of these services registered your router's WiFi MAC address and location; and any internet website (including Google) is now registering that outdated position as your current location. So, any website that uses that method is "auto-detecting" your location incorrectly. Some websites allow you to disable or override your "auto-detected" location. Firefox allows you to disable the voluntary submission of your location-data to websites. Nimur (talk) 22:20, 9 August 2011 (UTC)

So, how can I clear it out of my router, or redetect it? CTJF83 22:57, 9 August 2011 (UTC)

You might try changing the router's SSID or changing the MAC address that it reports. Or, you can disable location-services in your web browser, as I suggested above. Essentially, your web browser is (by default) set up to report its position to (e.g.) Google, and then relay that information to any website, on-request. For example, Firefox provides this "service" to track your location using Google, as a default option; and then, Firefox sends Google's best-guess for your location to any website who asks for it. Disable this system, by following the instructions here. Nimur (talk) 23:44, 9 August 2011 (UTC)

Many location services use Skyhook, which allows you to submit specific location data here. Once you've done that (and the change has propogated into their database), it should work correctly for everything that uses Skyhook as a backend. Of the services you list, at least Grindr does. gnfnrf (talk)

Ok...that's the one I most want accurate location for...thank you, I'll try that and let you know! CTJF83 01:38, 10 August 2011 (UTC)

August 10

Cannot access Windows Update

I need help. I need to access Windows Update, and I keep getting this error: "The website has encountered an error and can not display the requested page." I'm doing this on a computer that not only isn't mine, but is entirely in French, so I can't really navigate much due to my inability to read the language. Anyone who can help me out on this, please, I need your guidance. Windows XP Service Pack 2, if it helps. --70.29.252.46 (talk) 00:10, 10 August 2011 (UTC)

Well, the 1st update you should run is to install service pack 3, right? You can download the enire SP3 package in French here and install it manually. Vespine (talk) 04:25, 10 August 2011 (UTC)

Problem long solved, but thanks for the suggestions nonetheless. --70.29.252.46 (talk) 08:14, 10 August 2011 (UTC)

computers?

would it cost more to buy a computer or make one? what would be needed to make a computer? 70.241.16.91 (talk) 00:22, 10 August 2011 (UTC)

Commonly, computer hobbyists assemble a computer by purchasing pre-fabricated parts: a computer case, a power supply, a CPU and heatsink, a main-board, and a video card (for example). It is possible that this will save you money, but it depends on your skill as a shopper and your technical expertise. If you want to make a computer from more elemental parts, it will require far more expertise, and a lot more time and money. Nimur (talk) 00:34, 10 August 2011 (UTC)

There's heaps of websites that go into a lot of detail about what's involved with building your own PC. Yes it's typically cheaper but most people do it because it is fully customizable, you can put in only and exactly the components you want. I've never bought a pre-made computer, but if you've never even opened up a PC case and swapped a video card or upgraded a disk or anything, I would not recommend you start with building a whole computer, unless you have easy access to a friend who has built computers and is willing to help you. Things can go wrong and if you can't work out what it is, you'll be stuck with an expensive and large door stop. Vespine (talk) 01:49, 10 August 2011 (UTC)

I doubt if you'd save a great deal of money building a PC from parts, but it may well be worthwhile if you can reuse parts from old PCs. I managed to cannibalise two duff PCs to make a working one without too much difficulty - not exactly state of the art, but it cost me almost nothing, and enabled me to keep online long enough to afford a proper upgrade. As Vespine says, you'll need some backup from someone with a bit of experience to attempt a new build, so why not see if you can get hold of some obsolescent hardware first, to tinker with - too often, PCs get scrapped while they are still usable. AndyTheGrump (talk) 02:03, 10 August 2011 (UTC)

It depends on the type of computer you're looking for too. If you want a high performance "Gamer Machine" you may well find that you save a significant amount of money assembling it yourself, because the markup on those machines is rather high. But if you're looking for a "bare bones" cheapest computer you can buy, the price difference probably won't be significant. 76.28.67.181 (talk) 06:49, 10 August 2011 (UTC)

Also note that there are web sites that allow you to specify every component in the computer, and then they will assemble it for you. This provides the flexibility you might want without having to be an expert at computer assembly. Price-wise, though, it's in the same range as buying a computer off-the-shelf, although if you pick all premium components this approach will cost significantly more. StuRat (talk) 02:08, 10 August 2011 (UTC)

Another note not brought up above... If you are not in a rush and can plan well, you can save a lot of money by buying the parts you need only when they are on sale. I put together a computer that would normally run around $2,000 for $500 by purchasing each part when it was heavily discounted with large rebates. It took about 6 months. If you plan to do this, there has to be some order to your purchase. This is how I did it:

1. Buy a CPU. The CPU will limit what kind of motherboard you can use.
2. Buy a motherboard and CPU fan. The motherboard will limit the kind of memory you need, the power supply, and the case.
3. Buy memory, hard drive, and case at any time. Buy the video card (if you want a high-end one) next. That will put a power requirement on your power supply.
4. Buy the power supply.
5. At any time, pick out the monitor, keyboard, and mouse that you like.

Then, once you have all the parts, you are ready to go - except you don't have a Windows license. I don't use Windows, so I never factor that into my costs. -- kainaw™ 12:29, 10 August 2011 (UTC)

I see a couple problems with that strategy:

1) Your components may remain untested until after their warranty has expired, making it impossible to return any defective parts.

2) Technology improves and prices fall so quickly in this area that 6 month old components might cost more and do less than those purchased today. StuRat (talk) 14:37, 10 August 2011 (UTC)

Just because it irks me only a little, more then one person has now said buy a "cpu fan": If you buy a boxed cpu, you do not need a cpu fan, they come with a perfectly decent cpu fan. Today's CPUs are NOT the 100degC monsters of several years ago, pretty much all the stock coolers are perfectly fine.Vespine (talk) 22:59, 10 August 2011 (UTC)

Yes and no. Again, it rather depends on your PC. If you are building an overclocked gaming machine, you may well want a heatsink/fan combination the size of a halfbrick - if you look at the power consumption, even a standard CPU at stock clock speeds and voltages is producing enough heat for it to be worth looking at as a potential problem, so any extra (passive) cooling can't be a bad thing IMO. AndyTheGrump (talk) 03:05, 11 August 2011 (UTC)

Having built quite a few comptuers of various types including with aftermarket HSFs I agree with Vespine here. Any modern retail CPU comes with a HSF that is up to the job under normal settings and conditions. If the stock HSF isn't up to the job, the product is clearly defective and you should be entitled to return it in many countries. Obviously if you are overclocking or you find the HSF too noisy or for a variety of other reasons you may want to consider an aftermarket HSF. And similar if you buy a non retail CPU it probably won't come with a HSF. But for a retail CPU the stock HSF should be fine. Case cooling may need some consideration but that's a different matter. BTW, I would personally avoid any component other then perhaps HSFs and cases which come with only a 6 month warranty. Not saying I agree with the above strategy, in fact I would agree with StuRat's second point that most of the time it would be a mistake from a price standpoint (well for the HSF, keyboard/mouse, case and PSU it may be ok) but I've never lived in the US only Malaysia and New Zealand and we rarely have the sort of rebates that seem common there. Nil Einne (talk) 13:00, 11 August 2011 (UTC)

Yes and yes :P We ARE talking about a person here considering building their FIRST PC. They should not be thinking of building a pimped up overclocked gaming rig, and we should not be talking them into it. Once they become an ENTHUSIAST they will learn and consider aftermarket CPU cooling for themselves, it's a (completely) unnecessary complication and expense for a first build. As for noise, I've bought and build almost every intel CPU architecture since 486 days and since core 2 duo 4 or 5 yeas ago, the stock sinks have been very cool AND quiet. Vespine (talk) 23:13, 11 August 2011 (UTC)

o-p here, thanks for all the help! :) 70.241.16.91 (talk) 19:36, 12 August 2011 (UTC)

MS Office on a tablet

I should be very grateful if someone tells me can I open the MS OFFICE 2011 files in a tablet PC.I have many typing works and I want to know can I connect a bluetooth keyboard to a tablet? any proposal or answer is appreciated in advanc.--Chavosh (talk) 05:58, 10 August 2011 (UTC)

I've changed the title of the section to something more descriptive than simply "Question". As it says at the top of the page, things like Question, Query, or Problem are frowned upon. I'm sorry I don't have an answer for your question though. Dismas|^(talk) 06:07, 10 August 2011 (UTC)

It depends on the tablet. If the tablet runs MS Windows, then you can install and run MS Office. On an Apple iPad you can use applications such as Documents to Go and Apple's iWork[2] to view Office files, though they may not have the full functionality of MS Office. Various file viewers are also available for Android tablets. As for keyboard, the iPad supports bluetooth keyboards[3], and many other tablets will too, but you'll have to check for the specific tablet you have or are thinking of buying. --Colapeninsula (talk) 12:05, 10 August 2011 (UTC)

Hi-Grade ftp site for laptop drivers

I've been trying to help with somebody else's old laptop, which would be handy for using like a netbook. It works, but has no display adaptor installed, so it's stuck at an annoying resolution like 640x480. I assume it needs its drivers, which I assume are at the manufacturer's FTP site, linked to from this page: http://www.higrade.com/nqcontent.cfm?a_id=10956 (or the direct link is ftp://ftp.higrade.com/2010/Drivers/)... but the link never loads. I've tried just clicking it in Firefox, and I've also tried using FireFTP, and I've tried from two different connections (his house and mine). Is it just that their FTP server is down, or is there some way in? Is there another source of these drivers (for the Hi-Grade 4400) which has a moderate to reasonable chance of giving me the right files and not some malware? Is there some source of a generic driver which might be suitable instead?  Card Zero  (talk) 13:09, 10 August 2011 (UTC)

If you can find out what kind of graphics card it has, or the integrated card model / chipset it is, you might be able to find the driver from a different source. Is it Intel? TheGrimme (talk) 17:04, 10 August 2011 (UTC)

I don't have access to it right now, but I remember the processor is a Celeron, if that helps. Not sure what software to use to identify the make of the graphics card.  Card Zero  (talk) 20:34, 10 August 2011 (UTC)

OK, I got my hands on it again and found out:

GPU: SiS 315 Intergrated

Chipset: Northbridge: SiS 650

so I did the obvious thing and found the SiS site and downloaded the SiS 315 series GPU drivers for the right system, 32-bit XP, and ran the setup program ... and got the message "The setup program could not find a suitable driver, the setup program will terminate". Huh? Why on earth didn't that work? What else can I try? (Update) I found I could install the SiS 315 driver via the Windows control panels - it must be in a CAB file somewhere I suppose - but then I get "this driver cannot start" once it's installed. Perhaps the system profiler I used (Everest) got it wrong, and the GPU isn't SiS 315? I also tried hw32_384 and SiSoft Sandra (two other profilers) but couldn't get either to run (the first said something about missing setup files, and the second just triggers a reboot for some reason whenever I try to run it). Is there a simple way to find out what the GPU is?  Card Zero  (talk) 22:56, 12 August 2011 (UTC)

Got it! I didn't need the SiS 315 GPU driver, I needed the SiS 650 IGP driver. Sorted.  Card Zero  (talk) 23:52, 12 August 2011 (UTC)

undefined reference to vtable

I'm trying to compile a program I've been writing, for which I have received much helpful advice on this ref desk, and now it's almost done, I'm getting a compile-time error, "undefined reference to vtable". Needless to say, I'm using virtual functions, but there doesn't seem to be anything wrong with the program, and the error message seems to be from the underlying aspects of the compilation process (such as the linker). Ordinary compiler errors state a line number in the .cpp file, but here there are no line numbers, just a lot of weird information. Here's some of the info it dumps:

/tmp/ccTEIg2P.o(.gnu.linkonce.t._ZN4NodeC2Ev[Node::Node()]+0x7): In function `Node::Node()': diffs.cpp: undefined reference to `vtable for Node'

/tmp/ccTEIg2P.o(.gnu.linkonce.t._ZN4NodeD2Ev[Node::~Node()]+0x7): In function `Node::~Node()': diffs.cpp: undefined reference to `vtable for Node'

I'm using a rather old version of Linux (Fedora Core 4) and g++, with the compile command, g++ -Wno-deprecated -o diffs diffs.cpp. Is there a fault in my program, or is it g++, and can I get around it, or do I need to upgrade? Is there by any chance a free compiler around somewhere online, that can take text and produce an executable, as a temporary stopgap that will enable me to double-check it is the computer not me? Thanks again in advance, It's been emotional (talk) 17:23, 10 August 2011 (UTC)

Try defining the parent class functions as pure virtual functions, by specifying their definition this way:

  virtual void myFunction(int myArg) const = 0;

This is a common error. Make sure all virtual methods, including the constructor and destructor, are either pure virtual ( =0) or are defined. I find the = 0 syntax to be one of the most unintuitive aspects of the C++ language. Java uses the abstract keyword, instead of setting a pure virtual function to 0. Nimur (talk) 22:20, 10 August 2011 (UTC)

Thanks, because I never would have worked that out, and I don't think I ever would have found that link. I'm now getting a segmentation fault, which is glory, because I know how to deal with that one. It's been emotional (talk) 02:45, 12 August 2011 (UTC)

Different Voltage slower computers?

I have a Dell Studio laptop and I use it in North America with 100-110 V. Recently, I travelled to a country where the AC voltage is 240 V. After using my computer for a few days, the computer would freeze after been used for a few minutes and could only run properly in safe mode. My adapter says it can handle anywhere between 100-240 V voltage. After returning home to NA, the computer is running properly again. Could the AC voltage have had an impact on the performance of the computer? Acceptable (talk) 17:50, 10 August 2011 (UTC)

"Theoretically," the voltage should have had no effect on the computer. Typically, by the time the computer's internal ACPI power-supply sees the power, it's already been conditioned by the brick-shaped thingie in your cord (the AC/DC power supply). Analog circuitry inside the AC/DC supply should have produced a clean, standard DC current and voltage level (the same output, no matter what the input voltage); and the computer shouldn't have had any "knowledge" that its original input was 220 volt mains power.

In practice, if the AC/DC supply is imperfect (!), it may have supplied a different DC current or voltage when its input was 240 V. Any number of software or firmware level "glitches" may have occurred as a result: ACPI drivers tend to be flaky and can contribute to system instability. Nimur (talk) 18:13, 10 August 2011 (UTC)

I work in IT support and although I'm not a "hardware person", I think it is extremely unlikely that voltage had anything to do with your laptop being slow and crashing. It might have just been a coincidence, or maybe there is something else that you do when you are traveling that you don't do at home, like don't start up shut down properly all the time, or boot up not on your regular network, or something else. If it was a desktop computer, maybe you could convince me of some strange power filer effects or something, I've seen desktop power supplies cause "gremlin" issues, but on a laptop the adapter is essentially a glorified battery charger. Having said that, I'm not saying it's IMPOSSIBLE, I learned long ago never to absolutely rule out any hypothesis without solid proof, no matter ridiculous or implausible it sounds, but I would investigate other more likely things first, like look through your event log.. Vespine (talk) 22:55, 10 August 2011 (UTC)

And for reference, there's Power_supply_unit_(computer)#Laptops. It doesn't say much except to add that the power that comes out of the adapter is conditioned a second time by the laptop it self. Vespine (talk) 01:06, 11 August 2011 (UTC)

Mains voltages in the UK can legally exceed 250v, and do so regularly in country areas, but even this should not, in theory, change the voltage output within the laptop. (My "power brick" is designed for 100 to 240v AC and runs fine on 252v without causing problems.) As others have said, "shouldn't" doesn't mean "didn't". I would have thought that fluctuating voltages would be a more likely cause. My laptop behaves very oddly when I (foolishly?) try to run it in my car using a 12v to 240v inverter power supply. The two switch-mode circuits in series evidently interact in some strange way. Dbfirs 08:59, 11 August 2011 (UTC)

explicitly forbid a Windows 7 process from consuming more than 95% of the CPU

Sometimes, weird things happen where a weird browser plugin malfunctions and starts consuming 100% CPU. I've always wondered why OS developers let that sort of thing happen -- shouldn't it always allow for a "small reserve backup" to allow you enough CPU cycles to decently call up a process management program to kill to deal with the problematic process in question? Are there any rules you can implement that allow noncritical programmes to behave normally, but will never give them more than 95% of the CPU cycles? If not, why doesn't such a programme exist? elle _{vécut heureuse} ^{à jamais} (be free) 18:54, 10 August 2011 (UTC)

Windows' kernel allows you to set preemption properties: Scheduling Priorities. You can change your program's shortcut to always start with a certain priority-level. Here are some tips for different ways to set that up.

If you're asking the more philosophical question: why doesn't the Windows GUI (explorer.exe, or its child processes) forcibly preempt user-space programs? This is a design feature; Windows permits a user-application to use the entire system's resources. In certain other operating systems - most notably, a true Unix such as Solaris, your system administrator may specify hard preemption limits on specific processes (including the GUI or X Server). However, the details of making such a kernel-scheduling tweak are very complicated - undesirable side effects, like system instability and deadlock, may occur. For this reason, most computer platforms, such as certain Unix and all Linux and Windows, are designed to be "interactive with users." Their schedulers allow you to "pleasantly ask the Kernel to please preempt" a specific program. (No hard-guarantees). If you are a kernel engineer, you can easily design your computer system to never deadlock; but most users are not kernel engineers; so this is the better design-decision for a desktop computer. Technically, your computer never crashes when Firefox goes haywire - it's just sluggish. If your computer were a flight-control hardware for an airplane, it would be better to crash Firefox than to crash the plane because of sluggish response. Nimur (talk) 19:25, 10 August 2011 (UTC)

There is never a need to keep "spare" CPU cycles: at any given point in time the CPU might as well be doing something. There already exists a notion of priority in scheduling, which allows for programs like BOINC to soak up 100% of unused CPU time without affecting normal operations. The problem is probably, as Nimur said, that the UI just doesn't have high enough priority (looking at my Ubuntu system, it looks like X is running at normal priority, so the same thing can happen to it). I don't know enough about these issues to explain why this is the case, though. Paul (Stansifer) 02:45, 11 August 2011 (UTC)

There are still priority inversion-like scenarios on non-real time systems, even if CPU/IO priorities are being used. For example, a rogue process might allocate a lot of memory or access a lot of data on the disk, forcing the data of other programs and the UI, even if running at a higher priority, out of memory. When these programs are accessed again, their data needs to be read back from disk, and during that time the lower priority processes can continue to run (and perhaps make matters worse). See Thrashing_(computer_science). Unilynx (talk) 10:06, 13 August 2011 (UTC)

Where to find certificates in Windows 7?

Our application at work uses certificates for WCF authentication. My former boss made a great program which automatically creates a certificate, places it in the "My" store in the "LocalMachine" location, and writes its thumbprint in the WCF <serverCertificate> configuration. But my question is, how do I actually find this certificate in Windows 7 so I can view what it contains? I tried the Certificate Manager (certmgr.msc) and it found a certificate with the same subject name and creation date, so I guess it should be it, but neither the key ID or the thumbprint were anything like what my boss's program had written in the <serverCertificate> configuration. Yet the WCF service manages to find the certificate. How does all this work? Have I found the actual certificate in certmgr.msc? If yes, then why is its thumbprint different? If not, then where is it? JIP | Talk 19:51, 10 August 2011 (UTC)

August 11

Does lowering the volume on an MP3 player increase battery life?

If the volume is at 50% then does that mean that 50% of the voltage is going to the headphones and the other 50% is being wasted as heat in the resistors (or potentiometer) that reduce the voltage, making it use the same amount of electricity as if the volume was at 100%? --Codell (talk) 01:35, 11 August 2011 (UTC)

Yes. If you mute the sound, your MP3 player will consume a little little power for display and (maybe) internal data processing. Marthelati (talk) 04:29, 11 August 2011 (UTC)

It's not a direct answer to the question, but the actual decoding of the MP3 format is fairly CPU-intensive (and therefore battery-intensive). Fifteen years ago, your average desktop computer was too slow to decode MP3 in real-time, the way your portable player can do with ease now. This processing certainly consumes a lot of power, even at 0% volume. decltype (talk) 07:17, 11 August 2011 (UTC)

You are misunderstanding how a resistor works. Take a good look at Ohm's law. The resistor does not "burn off" the excess - it reduces the total current flow. Increasing the resistance of the potentiometer (turning down the volume) decreases the current flowing through it and subsequently through the audio amplifier and speakers. It is analogous to a half opened tap/faucet - the rate of water flow through it is less than when it is fully open. As other answers have pointed out the audio amplifier and speakers may however only be responsible for a small proportion of the total power consumption of the device. Roger (talk) 07:40, 11 August 2011 (UTC)

I'm not familiar with the circuit design of MP3 players, but I would have expected that most of them control the volume electronically, rather than with a potentiometer, so very little energy will be "burnt off" in resistors. A volume control built into the headphones is more likely to be a potentiometer with greater energy loss, but not the 50% you calculate. Remember that perceived volume is logarithmic (see decibel). A significant proportion of the energy from the battery goes towards producing amplified sound, especially at high volume, so the answer is yes, battery life is significantly increased when you turn down the volume, but not doubled if you reduce the volume by 50%. The exact percentage increase would depend on the particular model, and would require experimental data to determine because there are other factors such as battery capacity depending on current. Dbfirs 08:41, 11 August 2011 (UTC)

Resolved

 – Thank you. I was indeed misunderstanding how a resistor works; and have learned that the CPU consumes most of the power.--Codell (talk) 20:06, 12 August 2011 (UTC)

What? A METAL DETECTOR APP? (Android Marketplace)

Someone on a KurzweilAI forum said he had a metal detector app once, though he was sure it was a joke app.

I would believe that it was indeed a joke app.

On the other hand, what kinds of tech advances would be required of cellphone tech in order to create a real-working metal-detecting app??? --70.179.163.168 (talk) 05:39, 11 August 2011 (UTC)

Typical metal detectors work (roughly) by detecting interference in an antenna caused by the presence of metal. There's a bit more to it than that, but since cell phones do have antennas and can detect signal strength at least, it's not so difficult for me to believe that somebody might have been clever enough to write an app that interprets fluctuating signal strengths in such a way that it can act as a crude metal detector. Now, I don't know whether apps have that kind of access to the hardware, and I don't know whether patterns of changes of cellular signal strength are enough to actually make it work, so it very well could have been a joke. —Bkell (talk) 07:29, 11 August 2011 (UTC)

Many modern screenphones contain magnetometers, which they use to sense the strength and orientation of the Earth's magnetic field. This provides a basic compass function when the GPS and cell-based positioning systems aren't available. Data from the magenetometers is retrieved using the Android SensorManager and GeomagneticField APIs. I have a sensor monitoring app called GPS Status which shows a lot of the interesting information available to apps (GPS satellite constellation visibility, battery level, ambient brightness, pitch/roll/acceleration, and magnetometer data). If I put the phone on a wooden desk, or hold it in space, it reports a magnetic field of about 46 μTesla. Placed atop a steel filing cabinet it reports 193 μTesla, an effect that's noticeable out to at least 10cm. But it's hopeless at "detecting" anything smaller - any influence my watch or keys might have is less than the ordinary variation its sensor sees, even if held right under the phone. So strictly speaking it can detect very large steel objects that are very close to it, so it's nominally a metal detector, but (I expect because it's relying on the Earth's magnetic field, rather than generating its own and observing the changes in what it receives back) its so insensitive that it's useful only for novelty value. -- Finlay McWalter ☻ Talk 09:03, 11 August 2011 (UTC)

Android device with a USB Host port

Are there any Android devices currently on the market or "comming soon" that have a USB Host facility built in? So far all the devices I have seen (various phones and a Samsung Galaxy Tab) do not have a type A (or Micro-A) USB port and so are limited to only be a peripheral instead of controlling other peripheral devices. Roger (talk) 08:31, 11 August 2011 (UTC)

In the coming soon category (very soon according to most sources - a matter of days to weeks rather than months) there is the Lenovo Thinkpad Tablet, don't be put off by the fact that it looks like a netbook on the website - that's the optional keyboard dock. Equisetum (talk | email | contributions) 09:53, 11 August 2011 (UTC)

I know someone with a fairly cheap Android tablet (I think a Zenithink ZT 180 rebrand). It has an ordinary type A port and I presume has USB host facility because it can support memory sticks (I think) and definitely can support USB mice (keyboard too although can't remember if I tested that) and from memory of results during my searches some 3G and wifi dongles as well. However bear in mind unless you have good programming experience or there is a good modding community you may still be limited by whatever drivers available on the specific Android distro provided by whoever made your tablet (and whether the software allows access to the periheral supported by those drivers when rooted or whatever). E.g. for this friend's tablet USB bluetooth adapters don't seem to be supported from testing and searches this seems to be a common problem. Nil Einne (talk) 13:11, 11 August 2011 (UTC)

BTW, the Samsung Galaxy Tab 10.1 apparently doesn't have a USB A port, but it either has USB host functionality built in (requiring only a passive adapter) or has some other connectivity function that enables a stand alone USB host device (my guess is it's the former) sinc according to our article: "A USB host adapter was made available in June 2011. The dongle plugs into the 30-pin dock connector and allows USB compatible accessories such as keyboards, mice, and thumb drives, to be connected to the tablet." Nil Einne (talk) 12:14, 13 August 2011 (UTC)

Cheapo Android tablet battery life

I've just bought a no-name "seven inch" Android minitablet that's described as having "Rockchip 2818 1.0Ghz (ARM+DSP+GPU)", 256MB and (?) 4GB of memory (I mean, aside from and Micro-SD card), and Android 2.1. It was new, and cost very little over the interwebs. I wasn't expecting much, but I was expecting a battery life longer than fifteen minutes, which is all I get when doing something innocuous like attempting to view a PDF. ("Attempting", because zoom as I wish, it's too small. I assume that some other software will do the job.) Fifteen minutes is of course so short that the device is worthless. I'm now drafting a chilly message to the dealer, but I'm wondering what to say. It's obvious to me that anything like this should be usable for four hours, and that it's just this example that's a lemon, and I should ask for a replacement -- but I'm an Android ignoramus and maybe it's common knowledge that the charge capacity of batteries designed for these particular devices halves every three months after manufacture; maybe I should ask for a different model. What battery life can one reasonably demand of a new (but slightly old-stock) cheapo cheapo tablet? (The minuscule user's guide for this one talks of a charging time of five hours [ha ha] but says nothing about how much use you can then get out of it.) -- Hoary (talk) 09:19, 11 August 2011 (UTC)

The screen is what mostly determines the battery life - based on the batteries you have. Some batteries have longer life. Some have shorter life. The best you can do is get better batteries and dim the display on the screen. (Note: The following is heavily influenced by the excessive frequency of which coworkers bring me crap they've purchased on shopping networks and expect me to make it work as well as an iPad...) Basically, you feel it should be illegal to sell electronic devices with terrible battery life. Similarly, it should be illegal to sell diet drugs that don't work. It should be illegal to sell credit consolidation plans that don't work. It should be illegal to sell mosquito repellent bracelets that don't work. The key concept here is caveat emptor. There will always be some ass who slaps together some garbage and tries to sell it. If you go after the no-name super-cheap garbage, you will most likely get garbage that comes from a no-name company that doesn't care about you and, even though it was super-cheap, you will be out the money you spent. -- kainaw™ 12:59, 11 August 2011 (UTC)

Ah, screen brightness. Well, I can reduce that when I get my paws on the replacement. I'd assumed, perhaps naively, that low-power screen technology would have improved (or that better options would have got cheaper) during the popularity of netbooks: at a given brightness level, this screen might consume even 100% more juice than it should, but surely not 300% more.

One way in which this toy resembles the iPad is that both hide the battery. I've no idea of where it is or what size it is.

I don't know about your part of the world, but in mine the options are expensive iPad (of course from a company that has a huge ad budget), expensive Android devices from companies that have big ad budgets, and cheap Android devices from companies I've never heard of. I don't begrudge Apple its profits, and I've bought from Apple in the past. But I'll get something that will "satisfice" me until swish tablets with repeatedly tweaked OSes cost less than netbooks. -- Hoary (talk) 14:08, 11 August 2011 (UTC)

I didn't say this earlier since it was mostly OT. But actually in New Zealand where I believe the OP is from, the Consumer Guarantees Act requires goods are fit for their normal purpose [4] [5]. Because of limited resources and other factors, this and other requirements often aren't particularly well enforced in the computing field or particularly against low end retailers and unlike is sometimes done in Europe, there's usually little guidance on what it actually means. But unless the device was sold as basically requiring a permanent power connection with the battery only for brief emergencies, and presuming the OP isn't doing something wrong I have strong doubts a tablet with only a 15 minute battery life would qualify. I don't know if there have been any legal cases and I don't know if I'd go as far as the OPs 4 hours, but I would expect at least 1 hour. I strongly expect organisations like the Consumers' Institute of New Zealand or TV shows like Fair Go would agree with me and writing to them is sometimes a useful step. The Citizens Advice Bureau [6] could perhaps often some guidance whether there's ever been any cases. Ultimately taking a case before the Disputes Tribunal [7]. I'm presuming of course the OP has purchased the item from a retailer or something of that sort, not via an auction like TradeMe or even from overseas in which case they've elected (knowingly or not) to purchase something in a manner not covered by the extensive consumer protections of NZ law. Nil Einne (talk) 16:06, 11 August 2011 (UTC)

It very probably has a broken battery. Check with the manufacturer. Dmcq (talk) 18:48, 11 August 2011 (UTC)

Unable to create an Yahoo account.

I cannot create an Yahoo account, it said I answered the CAPTCHA incorrectly but it was correct. Windows 7 with Internet Explorer 9, help. Marthelati (talk) 13:16, 11 August 2011 (UTC)

How many times did you try? Nil Einne (talk) 13:19, 11 August 2011 (UTC)

Indefinitely many times. Marthelati (talk) 13:24, 11 August 2011 (UTC)

Did you check carefully that your upper and lower case characters were correct? Did you try loading a different captcha code? Did you try using the audio code instead? Are you sure that it was the the captcha code that was wrong, and not that you were missing some other piece of required information? Did you try reloading the page and trying again? These are generally pretty obvious, but I'm just putting them out there, cos there's not really much reason it shouldn't work. --jjron (talk) 15:28, 11 August 2011 (UTC)

The OP claims they tried 'Indefinitely many times' which I presume means they tried many different captchas. I do agree an audio captcha may be useful. Nil Einne (talk) 16:13, 11 August 2011 (UTC)

Is "an Yahoo" British English, or just plain wrong, like the use of "indefinitely" in place of "definitely" ? StuRat (talk) 17:31, 11 August 2011 (UTC)

My guess is English not first language or at least pretending to be. User has been blocked as an abusive sockpuppet so hopefully we'll never know Nil Einne (talk) 18:07, 11 August 2011 (UTC)

JDK, JRE, x86, x64

What I already know:

• JDK contains the JRE. There's no need to install the JRE after installing JDK.
• 32-bit version of JDK works well on 64-bit OS.
• Some well written programs check if other instance exists and refuses to install if there is any.

But I don't know:

• Does JDK x64 contain the JRE x86 and vice-versa?
• What is the purpose of 64-bit JDK, when I am writing a program for a virtual machine?
• I already have JRE installed. Now I installed JDK. Can JDK detect and not overwrite it? I know it depends on those who develop JDK, but does anyone know?

The Oracle website does not have any explaination at all (or because I haven't found it yet). -- Livy the pixie (talk) 14:16, 11 August 2011 (UTC)

What is the purpose of 64-bit JDK, when I am writing a program for a virtual machine? The compiler, virtual machine, etc are 64-bit native-code applications (not Java; written in C or C++), and hence can use the extra facilities of the 64-bit chip (it might even compile more quickly). The java byte code should be identical. --Colapeninsula (talk) 14:35, 11 August 2011 (UTC)

[8] suggests the compiler is written in Java although I presume as you said, it's usually distributed compiled to native machine code rather then Java byte code. In answer to the OP, I'm pretty sure the Windows x64 JDK as with the JRE doesn't come with the x32 JRE. You need to download and install that seperately if it's desired. Nil Einne (talk) 18:16, 11 August 2011 (UTC)

Linux Keyring prompt fix

According to this and this website, the issue i currently am having with a wireless network keyring can be resolved by deleting a default keyring file in a certain location. However, this file does not exist on my system.

From terminal:

  home@home-HP-Pavilion-dv9000-EZ458UA-ABA:~/.gnome2/keyrings$ ls
    login.keyring  user.keystore.AZNLQV  user.keystore.Q84TQV
    user.keystore  user.keystore.HD0RQV  user.keystore.WU8TQV

  home@home-HP-Pavilion-dv9000-EZ458UA-ABA:~/.gnome2/keyrings$ ls -a
    .   login.keyring  user.keystore.AZNLQV  user.keystore.Q84TQV
    ..  user.keystore  user.keystore.HD0RQV  user.keystore.WU8TQV

My guess is maybe i have a different version of the software? though that is rather more a stab in the dark than an educated guess. Should i delete one of these files which may operate the same as the intended default.keyring?

216.173.144.164 (talk) 14:48, 11 August 2011 (UTC)

It's hard to answer questions like this without knowing what Linux distro you are using. Looie496 (talk) 20:07, 11 August 2011 (UTC)

What computer manufacturer gives better warranty deals?

I believe I should move on from Dell with my next laptop/swivel tablet because some of their warranty deals are rip-offs.

I was promised year-long software warranty tech support for $239, then I learned that $239 covers just 4 incidents, then I was offered $110 for another 3.

I want warranty packages that are good for a period of time, period. Not for a period of time in a number of incidents.

So what competing PC manufacturer will offer better warranty packages (to include software warranties, not just hardware) than Dell?

(Also, this manufacturer has to allow me to choose my own parts/components like how Dell & Apple does when I shop for a new system on their websites. That would help me a lot. Thanks.) --70.179.163.168 (talk) 18:01, 11 August 2011 (UTC)

Why would a toolbar disappear?

I could have just changed computers at this library, but when I asked someone for help she asked if there was a mouse, and when I moved my mouse across the top of the screen the toolbar magically appeared. Then it disappeared. I should add that on Wikipedia, the sign-in link disappears if the toolbar is there, as do "My contributions".

Most of these computers are Internet Explorer, and another one said it was Windows XP. I don't know what this one is.Vchimpanzee · talk · contributions · 18:45, 11 August 2011 (UTC)

Don't take this personally, but I work in IT support and i'm really struggling to understand what you mean. I could have just changed computers at this library, don't understand what you mean by this. toolbar magically appeared. what do you mean by "toolbar"? What did it look like? Did it have menus or buttons and what did they say? "internet explorer" is not a kind of computer, it's just a program you use to browse the internet, it is the default browser installed on windows computers.

If I had to take a wild guess, maybe someone has dragged the task bar to the top of the screen and selected the "auto hide the task bar option"? Click this task bar image, does it sort of look like that? If it is, you can right click it, select "options" and un-tick the box that says "auto hide the task bar". If you are feeling adventurous, you can also try to drag it back down to the bottom of the screen. You have to make sure "lock the task bar" is NOT selected when you right click the task bar, then you have to click and hold on an empty part of the task bar and literally drag it down to the bottom of the screen and then let go of the mouse button. If it's NOT that, then I wrote all that for nothing lol.. Vespine (talk) 22:59, 11 August 2011 (UTC)

If I had to take a wild guess, press f11.--Shantavira|^{feed me} 07:29, 12 August 2011 (UTC)

You know, I looked all over the web and all over Wikipedia for the correct terminology (as well as a possible solution). When I say Toolbar, I mean there was no back button, no forward button, no place to type the URL. If I move the mouse across the top of the screen in just the right way, which sometimes is more difficult than it is at other times, because sometimes nothing happens, then all that stuff appears.

I'm no longer at that library but they need to fix it. And if I say a computer is "Internet Explorer" then you're supposed to know what that means. I don't think anyone understands how hard it is just to think how to explain a problem, much less do it in the exact way you want.

I looked up F11 and I guess that is the problem.Vchimpanzee · talk · contributions · 17:54, 12 August 2011 (UTC)

Networked printer problems

In the office I work we have 4 PC's connected to a networked printer all through a server, but every now and again one of the PC's won't print and what we have to do is go into Devices and Printers and un-install the printer and then re install it. Has anyone any ideas why this is happening as it has happened on the 3 PC's that are connected wirelessly but not the one that is directly connected to the printer by a cable, thanks. Mo ainm~Talk 21:37, 11 August 2011 (UTC)

Using VLC to add video effects/adjustments to vids

I use VLC on Ubuntu. You can easily add video effects and adjustments to videos (like changing the contrast, or rotating the vid) during playback but can you make those changes permanent? The Convert/Save menu doesn't seem to be able to do that, as far as I can tell (it's not the easiest thing in the world to use). TresÁrboles (talk) 21:47, 11 August 2011 (UTC)

I'd use ffmpeg or mencoder, but you might prefer using a GUI app, such as… (in no particular order) LiVES, CinePaint, Avidemux, Kino, CineFX, Kdenlive, PiTiVi, Cinelerra. ¦ Reisio (talk) 11:02, 12 August 2011 (UTC)

Tr0ub4dor&3 vs. correcthorsebatterystaple

Just some fact-checking. (that's from xkcd.com) Does the first password has 2^28 of entropy and the second 2^44? Is the second password harder for a computer to crack?Quest09 (talk) 23:46, 11 August 2011 (UTC)

For future reference, the relevant comic is #936. In practice the answer depends on the sizes of the dictionaries from which the two passwords (or their components) are drawn. -- Finlay McWalter ☻ Talk 00:02, 12 August 2011 (UTC)

And here's some discussion from Randall Munroe the cartoonist, of the bases on which he drew this particular cartoon. --Tagishsimon (talk) 00:06, 12 August 2011 (UTC)

Also of possible interest is the PGP passphrase faq, which advocated a similar strategy 18 years ago (see the answer to the first question). 130.76.64.116 (talk) 00:14, 12 August 2011 (UTC)

In the latter case it looks like he's using 4 dictionary words, so that's 44/4 == 11 bits each. That assumes a dictionary of 2^11 entries, which is 2048, which seems rather small. -- Finlay McWalter ☻ Talk 00:12, 12 August 2011 (UTC)

The author proceeds to only count certain bits: he assumes that the only relevant entropy is defined by the decision-tree as a passcode string is created per a specific recipe. For example, he counts the bit-length of a lookup-dictionary of known words. This is simply wrong. This methodology quantifies representations of abstract pieces of information with "bits" according to a known recipe for generating password sub-strings; but it then presumes that the attacker knows the recipe; and the author fails to account for any bits of entropy related to the fore-knowledge of the recipe. (Specific example: which words are in the lookup-dictionary? How long is the dictionary? Those pieces of information have entropy too!) If the method had any merit, it was lost at that point. I would tag this whole comic with ; the assumptions and conclusions may be suitable for a comic strip, but are probably not up to snuff for a cryptography or security-best-practices publication. Kudos to the author for bringing attention to the concept of heuristic-based password guessing, rather than pure brute-force iteration; but his math is off by a few orders of magnitude. Nimur (talk) 00:46, 12 August 2011 (UTC)

I think that it's correct to discount those bits; after all, a recipe is good precisely if it still works well when everyone uses it. Paul (Stansifer) 02:13, 12 August 2011 (UTC)

The latest (episode 313) Security Now podcast discussed this comic pretty well: [9]. They talk about it pretty early on in the podcast. - Akamad (talk) 01:58, 12 August 2011 (UTC)

The discussion of the comic starts at about 19:20 and ends at about 32:00, but I don't recommend it. Steve Gibson is one of those celebrity "experts" whose main skill is self-promotion. I'd even go so far as to call him a crackpot, based on his web site. Munroe clearly understands what constitutes a strong password; Gibson is clearly very confused. -- BenRG (talk) 10:40, 13 August 2011 (UTC)

Gibson does not claim that his little tool is a password strength meter. He just presents some metrics for understanding how many passwords can be created by combining a certain set of elements. 88.14.196.229 (talk) 13:53, 13 August 2011 (UTC)

"Temporarily" installing software

I'm looking for a way to only "temporarily" install a software on Windows 7 64-bit. The case is that I'm going to need to install a program which I'll really only need to use once, so I'd rather not have it install on my system and then uninstall it, as that will likely change some registry gobbledygook I don't want it to. I'd opt for using a virtual machine like VirtualBox, but all my previous operating system ISOs were on my (currently inaccessible) older computer. Preferably I'd like to install the program inside the virtual machine, let it do what it needs to, and then just delete the virtual hard disk. So, does anyone have an alternative solution to my query? Thank you and cordially, 141.153.215.55 (talk) 03:33, 12 August 2011 (UTC)

Ideally it should come with an uninstall script that will clear up all the registry entries when you remove it. This can be accessed under Add/Remove programs. If you don't trust that it will have this (or that it will work), do a system checkpoint before the install, then roll back to that point after the run. Note that any data file created might also be wiped out, so make a backup copy if you want to save it. StuRat (talk) 04:36, 12 August 2011 (UTC)

Either use Sandboxie, System Restore, or Windows XP Mode. 118.96.159.34 (talk) 11:17, 12 August 2011 (UTC)

Sandboxie is probably the easiest way. Just make an empty sandbox and run the program's installer in that sandbox, and to "uninstall" it, delete the sandbox (after extracting any files you want to keep). It's compatible with most applications, though not all. -- BenRG (talk) 10:46, 13 August 2011 (UTC)

August 12

Mouseover pop-up CHN-ENG translator for Internet Explorer?

Moved from Language Desk by Falconus^{p t c} 03:14, 12 August 2011 (UTC)

Hi everyone, I use the Perapera-kun add-on for CHN-ENG translation in Firefox. It lets you hover your mouse over hanzi to see the meaning. However, some sites in China don't work with Firefox (for example, certain online banks) and I was wondering if anyone knew of an add-on for IE with similar mouseover translation functionality. I haven't been able to find one... Thank you. — Preceding unsigned comment added by The Masked Booby (talk • contribs) 01:58, 11 August 2011 (UTC)

cropping jpg images

I've got an image with the .jpg file extension on a Linux machine. I thought maybe using ooffice to view it I could do some cropping. Hasn't worked so far. My other option my be finding something on some MS Windows machine in a university library and downloading the thing there. What should I do? Michael Hardy (talk) 04:31, 12 August 2011 (UTC)

Pretty much any image editor would allow you to crop a JPG. In Windows, Microsoft Paint works just fine. StuRat (talk) 04:34, 12 August 2011 (UTC)

A lot of Linux distributions include GIMP, which can do it. Looie496 (talk) 04:49, 12 August 2011 (UTC)

You could try an online image editor like this AvrillirvA (talk) 09:33, 12 August 2011 (UTC)

I do basic image editing in Linux using F-Spot Tinfoilcat (talk) 09:25, 13 August 2011 (UTC)

Note that the jpeg format uses lossy compression. By cropping in a general purpose image editor, you will decode and re-encode, thereby adding new artefacts to those that were created the first time the image was jpeg-encoded. To avoid unnecessary loss of quality, use a specialized cropping program that understands the jpeg format. Jpegtran is the grand-daddy, JpegCrop is a user-friendly windows interface. --95.34.139.175 (talk) 20:18, 13 August 2011 (UTC)

Google forces its localized domain on me

Why is it that when I attempt to change Google.ca back to Google.com, it just refuses to go to the US based domain? But when I'm the US, I'm perfectly capable of accessing the Canadian domain without the main one getting in my way? Yet funnily enough, I can access Google.fr, Google.co.uk, Google.de and so on from Canada with no issue, yet it has serious beef with me trying to access Google.com. Even when I sign into my Google account, I don't seem to have much of a say in my preference of which domain I want. Why is that? 70.29.252.46 (talk) 09:54, 12 August 2011 (UTC)

See this article. 118.96.159.34 (talk) 11:17, 12 August 2011 (UTC)

One of the problem is .com isn't really a US domain but a generic domain and when someone links to google.com they aren't necessarily intending to link to the US site in particular. I wonder whether www.google.us (which does work) also always takes you to the US site Nil Einne (talk) 12:40, 12 August 2011 (UTC)

I would've never guessed to do that. Thanks. 70.29.252.46 (talk) 15:47, 12 August 2011 (UTC)

Google problem

This morning, Google started acting weird on my Fedora 12 Linux system using FireFox 3.6. When I make a search that returns multiple pages of results, and browse to some page past the first one and click on a result, then when I click "Back" Google throws me back to the first page. If I click "Back" again then I get to the right page. This seems to happen every time. It does not happen on my work computer, which uses Windows 7 and FireFox 5. What the heck is going on here? JIP | Talk 15:03, 12 August 2011 (UTC)

Are you using the HTTPS everywhere extension? -- Finlay McWalter ☻ Talk 15:10, 12 August 2011 (UTC)

No. JIP | Talk 15:27, 12 August 2011 (UTC)

Also Google regularly inflicts random page tests and changes on random connections. (And they kind of suck at JS :p) ¦ Reisio (talk) 15:11, 12 August 2011 (UTC)

This stopped when Google thought I had searched too much for one day and asked me to fill a CAPTCHA. Then after I closed the browser window and did another Google search it started again. JIP | Talk 20:04, 13 August 2011 (UTC)

Screen Quality with Video Question/Concern

Hi, I just bought a new Dell XPS 17 laptop with a 17 inch 900p screen, I have another laptop that is 6 years old and runs 1280 x 800 with a 15 inch screen. Watching the same 720p and 1080p video on both side by side, I think the quality on the old laptop is better, the new one seems a little less sharp and slightly lower quality (the old screen is less reflective). Am I imagining it? Is it the difference in reflectivity? It is that the old screen is smaller? Or is there something I can do to fix this? Thanks for any help:-) 71.195.84.120 (talk) 17:10, 12 August 2011 (UTC)

The reflectivity or brightness are about the only things it could be -- the pixel size on the two systems is virtually identical. Looie496 (talk) 17:26, 12 August 2011 (UTC)

This is off topic, kind of, but I noticed that the results are near identical, if not slightly better, on the new screen with several other hd videos. Going back to the orginal ones I tested, I noticed that they are of a slightly smaller filesize, is it possible that the videos themselves are of varying quality and that the defects are more apparent on the newer display due to size and higher resolution?

The 900 -vs- 800 is not to big a diff, though they are the same vertical size, but width wise its 1600 to 1280; although the 1600 is on a wider screen. I'm not saying that you are wrong, just that I don't really know much about this and am not sure how to determine how big a difference there is/should be. Thank you:-) — Preceding unsigned comment added by 71.195.84.120 (talk) 17:41, 12 August 2011 (UTC)

720p is 1280x720. The old laptop can show it 1:1 without scaling, but your new laptop is apparently scaling it to 1600x900, and thus making the image fuzzier. 80.186.103.202 (talk) 17:51, 12 August 2011 (UTC)

Is native resolution the problem? Comet Tuttle (talk) 20:38, 12 August 2011 (UTC)

One other factor could be the refresh rate. If the new computer has a slower refresh rate, images could look choppy during movement, especially when looking out the corner of the eye. StuRat (talk) 19:45, 12 August 2011 (UTC)

Thank you for your answers :-) After using it for a bit, I'm starting to notice that a lot of hd videos play better, thuogh some still don't...I have two other questions. Would a lower res video play better on the smaller older screen or the newer, since the newer screen would require stretching it out and such? Second, I debated a lot between the 900p and 1080p screens and went with 900 because I think it would be easier to read off of (I have 10,000's of ebooks) and figured that at 17 inches and arms length away, the videos wouldn't look to diff on it; that and most of the video I have is 720p. That being said, I'm curious if I made the right choice? Honestly, I just want to get rid of (or justify) the nagging voice in my head that keeps telling me I could have got something better (I get a new computer every six years or so, so I'm going to have this one for a while) Any thoughts would be much appreciated; yes, I know, I'm probably over thinking this. Thank you :-) 209.252.235.206 (talk) 06:44, 13 August 2011 (UTC)

I'd say a larger screen with a higher resolution is the best choice. You generally want to display a video at it's native resolution to avoid any up-scaling or down-scaling of the image, which can distort the image, make it blurry, or introduce lag. With a large screen at high res, you do have the option to make the image window smaller than the entire screen. Unfortunately, some inferior video software doesn't seem to have the option to display at 100% resolution, and just goes with the current window size, whatever that happens to be. As for e-books, if they allow you to set the font, then again the largest resolution would let you use a larger font, which should have more resolution for each letter, making them clearer. StuRat (talk) 07:28, 13 August 2011 (UTC)

flickr

Hello. Are there any web archives or mirrors (accessible to the public) that have old pictures from flickr? I remember there was this beautiful landscape that a certain user had, CC-BY license, which is just the perfect resolution for my new computer screen, but which the user has taken down (waybackmachine has been rather unhelpful; flickr "doesn't allow frames", whatev that means). I have tried contacting the user, but he has been unresponsive. Thanks. 203.117.33.23 (talk) 18:25, 12 August 2011 (UTC)

And where was this top secret image? ¦ Reisio (talk) 19:54, 12 August 2011 (UTC)

I assume you know about archive.org? Comet Tuttle (talk) 20:20, 12 August 2011 (UTC)

Wayback Machine is part of Archive.org. So I think that's covered. --Tagishsimon (talk) 20:23, 12 August 2011 (UTC)

PS2 .STR Audio Files

I've got some audio tracks from a PS2 game copied to my hard drive, and I was wondering if there was a program out there that can play these tracks... and if possible convert them to .wav or .mp3

thanks 157.157.39.8 (talk) 20:11, 12 August 2011 (UTC)

Where's the security weakness?

I'm running XP Mode only for a scanner, so while I run Virtual PC I don't run it for more than a few minutes. I use a flash drive to store the resulting images, and "XP" has access to only the virtual HD and physical DVD-ROM drive. I have Firewall up but don't want to patch the "XP". I'm guessing then that any security weakness that would affect me would be in Virtual PC. Is that correct? 66.108.223.179 (talk) 23:25, 12 August 2011 (UTC)

Virtual PC could have bugs allowing the virtualised XP access to its host machine, but the likelyhood of malware targetting such a vulnerability would probably be small. However, if the XP machine were to pick up any malware that tries to spread itself further over the network, that malware is now on the wrong side of any router firewall you may have. It may still try to infect other machines on your network, including the hosting Windows 7 installation, if those are not properly secured. Unilynx (talk) 10:01, 13 August 2011 (UTC)

August 13

Video Enhancement and Programming

Hi, I've been wanting to write a program that would perform certain effects on a video, then output a modified copy. While I think I have sound ideas and am comfortable with programming, I do not know enough about video file formats and how they are played to get started and was hoping to get pointed towards some information regarding that. For example, any info on the following would help. 1.) Given a(n) wmv, mpeg, avi, etc. how would I extract an array of frames from it? 2.) If I play an a x b resolution video on a, say, 1080p screen, how does the player decide what values the extra pixels should have? 3.) More importantly, if I extracted an array of frames from an a x b res video, then added to them and increased the size to c x d res and built a video from that, would the end result be a c x d res video? For the 1st question I just need to know how frames are stored, I can figure the rest out. The 3rd sounds kind of obvious, but differences between screen resoultion and video resolution and lack of knowledge make me want to ask just to be safe. Thank you for any and all help :-) 209.252.235.206 (talk) 06:38, 13 August 2011 (UTC)

1) How the frames are stored is quite complex, due to various compression methods. For example, there are compression methods for each frame, but there are others for multiple frames (if an object doesn't move, there's no need to describe it in each subsequent frame). What I've done is used software that allows me to grab single frames and extract them as as PPM RAW ASCII format, which is human readable and uncompressed RGB values (each 0-255, typically). This makes the files huge, but it does make them easy to process with a program. I've then modified the frames and stitched them together as animated GIFs, but I imagine you can make other formats, too.

2) See video upscaling.

3) Yes, you can store the frames at a higher resolution, although I suspect that all frames in a single movie must have the same resolution. Also, there are limits on the max resolution for each format.

Something else I should add is that video rendering/processing is very slow. If you expect to, say, invert the colors on a full-length movie, I'd expect this to take many days to process, especially if you exceed the RAM of your machine and must go to paging space. StuRat (talk) 07:38, 13 August 2011 (UTC)

Here's a recent question we had on this desk where the format of a frame in PPM RAW ASCII format is described: [10]. StuRat (talk) 07:56, 13 August 2011 (UTC)

I'd consider using FFmpeg's libraries to handle the video format part, and working with the RGB frames it can provide. See eg http://dranger.com/ffmpeg/tutorial01.html Unilynx (talk) 09:53, 13 August 2011 (UTC)

Help with MS Access 2007 (VBA) to open a new instance of excel 2007 instead of excel 2003

I am writing a vba code in MS Access 2007 that creates and opens a new instance of MS Excel 2007 (have added the reference to MS Excel 12.0 already). Code for reference here:

Dim xlApp as excel.application Set xlapp = CreateObject("Excel.Application")

The problem here is that every time the code runs, it opens excel 2003 instead of excel 2007. I want it to open an instance of excel 2007 instead of exce l 2003.

Additional details: OS: Win 7 I have both MS Office 2003 and 2007 installed on my system. I have already tried 'Diagnose' in MS Excel (similar to detect & repair in MS Excel 2003 which makes it default for all excel files). Also, tried un-registering excel 2007 and then registering again but didn't help. — Preceding unsigned comment added by 122.173.224.151 (talk) 12:09, 13 August 2011 (UTC)

You might take a look at this article, especially the section on "automation" and multiple versions. It doesn't seem to be up to date for Excel 2007, but it does give some hints to look at (figuring out what the Excel 2007 class name is). --Mr.98 (talk) 18:44, 13 August 2011 (UTC)

How to make each excel files open in a same instance of excel 2007

Whenever i open an excel file on my system, it opens in a new instance of excel 2007. I want them to open in same instance of excel, how can i do t? Details: OS: Win 7 MS Office 2007 — Preceding unsigned comment added by 122.173.224.151 (talk) 12:12, 13 August 2011 (UTC)

On Excel 2003, you untick the box Show... Windows in Taskbar, under Tools.. Options.. View. I'd guess it's the same in 2007. --Phil Holmes (talk) 15:57, 13 August 2011 (UTC)

That doesn't make any difference in my Excel 2000. When I open from within the running instance, the new file opens in that instance, but if I open by double-clicking the file, the operating system (Vista) opens a new instance of Excel. Behaviour might be different in newer versions. Dbfirs 16:15, 13 August 2011 (UTC)

databases

does anyone have passwords to databses. i mean im doing reserhc project in schol and im not finding anything in the schol databses

so i hope someone can give me passwords thanks. i'd be nice to get a pasword for teh Harvard databses thanks all — Preceding unsigned comment added by 64.183.70.187 (talk) 15:21, 13 August 2011 (UTC)

You appear not to understand the purpose of a password. Suggest you read the article.--Shantavira|^{feed me} 16:19, 13 August 2011 (UTC)

Just FYI, to get access to the Harvard e-resources would require having a Harvard PIN, which would mean you would have access to all sorts of other Harvard student or employee services, information, etc., of whomever's PIN it was. Nobody is likely to post their PINs willingly. --Mr.98 (talk) 18:41, 13 August 2011 (UTC)

Obsolete or backdated website

If a website lacks current information and valuable data, then should it be called backdated website or obsolete website? thanks--180.234.82.244 (talk) 16:24, 13 August 2011 (UTC)

"Out of date" would be the phrase I'd use. But of the choices you present, "obsolete" makes more sense than "backdated". 82.43.90.27 (talk) 17:49, 13 August 2011 (UTC)

See Out-of-Date Websites Invite Problems | Branding and Marketing.

—Wavelength (talk) 18:05, 13 August 2011 (UTC)

How to find a lost iPhone

My iphone has been lost, and it could be anywhere in the city I'm currently residing in. I haven't downloaded MobileMe, iHound, or any of those things. Is there a way to locate it after it's already been lost? 70.179.55.4 (talk) 22:22, 13 August 2011 (UTC)