Wikipedia:Reference desk/Computing

Welcome to the computing section
of the Wikipedia reference desk.

skip to bottom

Select a section:

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

Want a faster answer?

Main page: Help searching Wikipedia

   

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

See also:

• Teahouse
• Help desk
• Village pump
• Help manual

September 18

Folder Overwrite upon Installation

I had a folder dedicated to saved in-game files copied to my new computer before I installed this game onto the new computer. I think the folder may have been replaced with a new one because they had the same name. Is that possible that all my old custom files were deleted upon installation of the game and replaced with an empty folder? 128.101.184.181 (talk) 00:07, 18 September 2013 (UTC)

Yes, quite possible. Better install programs will prompt you to either "replace all old files from previous installs", or "install a new version, preserving the old version". However, many install programs don't bother. StuRat (talk) 03:30, 18 September 2013 (UTC)

Yeah; it's always a good idea to make backups of important files like this. Though it wouldn't be a problem if all installers took into account the fact that the game/program/etc may have been installed before by the user, or some old files may be present on that computer. Strangely, a really interesting glitch in the AVG antivirus program caused the files of the older version to be retained when the user updated to the latest version. This caused the two sets of files to conflict, and made the AV go haywire and identify every single incoming file as a virus. --.Yellow1996.^(ЬMИED¡) 03:39, 18 September 2013 (UTC)

Turing thesis

Does Turing thesis entail that every algorithm must have a "starting point", i.e. a first step starting that algorithm? 84.229.81.123 (talk) 06:39, 18 September 2013 (UTC)

The definition of algorithm already implies that. --Stephan Schulz (talk) 06:50, 18 September 2013 (UTC)

When & Why does Win 7 Re-arrange Desktop Icons?

Recently I booted up my Toshiba Satellite L750 (PSK2YA-05210) laptop PC from sleep mode and found that my desktop Icons had all been re-arranged. They were previously spread out in groups across the desktop as I wanted. Now they are in a row of 3 down right across the top, and 3 across on the left side of the desktop. Even a few desktop gadgets (weather, clock & calendar were pushed up on top of each other into the top right hand corner. The icons don't seem to be in any particular order i.e. not alphabetically, or by file type. Thus about half the screen on the centre & lower right is now completely clear.

I occasionally have to force a re-boot by powering down without shutting windows first, and might have expected strange results, but the icons always seem to stay where I left them.

Is there a set of conditions where Win 7 will automatically re-arrange the desktop? € 220 of ^Borg 12:35, 18 September 2013 (UTC)

I've experienced something similar when gaming occasionally. If the screen resolution is changed then things do get moved like this. Could that explain what you experienced? Thanks ツ Jenova20 ^(email) 12:39, 18 September 2013 (UTC)

Actually, while I had that problem in previous Windows, that changing the screen resolution, then changing it back, would leave your icons all messed up, they seem to have fixed that in Windows 7. Presumably it now stores the icon layout at each screen res and restores the layout when you return to that res. However, if you change the icon layout at the new resolution, it might no longer return to the original layout when you return to the original screen res. StuRat (talk) 12:58, 18 September 2013 (UTC)

(edit conflict) I know what you mean Jenova20 & StuRat, but I haven't changed the resolution and haven't been playing any games for a while. I Just un-slept the PC. ю 220 of ^Borg 13:08, 18 September 2013 (UTC)

I've experienced this kind of behavoir, certainly on Windows Vista and maybe on Windows 7 as well. As far as I can tell, it gradually collects various icon layouts (and a few other parameters too) per user, per screen resolution. I think it sometimes has a hidden default, one that might not be owned by the currently active user, when it is unable to find one that it already knows about, eg. when in sleep mode for the first time. The good news is that as it collects more, the problems will eventually go away. Astronaut (talk) 14:09, 18 September 2013 (UTC)

I've had this happen with several versions of Windows and it happened to me yesterday with Windows 8 when I restarted. I don't know why it happens. But it moved only ones that had been recently added to the desktop. Bubba73 ^{You talkin' to me?} 15:04, 18 September 2013 (UTC)

I had this problem until I installed Fences (software).--Shantavira|^{feed me} 18:41, 18 September 2013 (UTC)

I've seen this on XP and 7, but not Vista. More specifically, I have a switch which allows me to go back and forth between an XP computer and a 7 one, with one monitor. Sometimes, whenever I'd switch back to 7 from XP, this would happen. There was pretty much two variations to this; the first being that all the icons would be rearranged (as you saw.) Or, the resolution would be drastically altered so that the icons were about four times their normal size; and - once I had fixed the resolution back to it's normal ratio - the desktop icons would be rearranged due to "shrinking" from the overlarge incorrect size back to their usual "smaller" size. Then I would have to manually rearrange them. --.Yellow1996.^(ЬMИED¡) 01:11, 19 September 2013 (UTC)

Eureka!

Now I remember that the only odd thing I did recently was activate the "Tablet PC Input Panel". (Right click on "Taskbar/Toolbars/Tablet PC Input Panel", in Win'7). Wonder if that may have moved my icons? Yes it seems so, all the icon were moved up ↑ above the On-screen keyboard, when I docked it at the top, they moved down ↓. So another example of Microsoft Genius. A 'feature' that stuffs up my desktop, but isn't smart enough to restore it! >:-( Maybe if I re-boot my PC?-∑-220 of ^Borg 06:52, 20 September 2013 (UTC)

No such luck !

Well I seem to have found out the trigger event for the desktop icon re-arrangement. Unfortunately when I eventually re-booted (after a few days[5?], I use hibernate a lot) the icons did not return to their 'correct' positions. :-(
• So I am still at a loss for the 'exact' set of conditions that trigger a desktop re-arrangement.
• In fact they moved again later, into ≈7 columns of 8 icons on the left hand side of the desktop. 220 of ^Borg 05:01, 26 September 2013 (UTC)

September 19

Bad Javascript extension?

I posted the following request for help at WP:VPT, but it got archived without any suggestions on how to resolve it.

IE8, Windows 7, Monobook. In the last few days, occasional pages have started not to appear: I go to a page, the elements appear as they're downloaded, but as soon as everything's downloaded, the screen goes white. Completely white, as if the page had no code on it at all! At the same time, I know that things are downloading and not simply cached, since the little bar at the bottom right of the browser says "Downloading imagenamehere.png", "Accessing http://en.wikipedia.org/wiki/pagenamehere", etc., until it displays "Done" once completed. I can view the history page and the edit page fine (although I have to go directly to the URLs, since the tabs don't appear), but if I preview an edit, the screen goes completely white. I have no clue what's causing this, because it's rare — I've only encountered this on four pages, and all of them are just in the last few days:

• Commons:COM:ADMIN
• Commons:COM:VP
• Norway
• CAT:CSD
• Japanese yen Added at 02:26, 10 September 2013 (UTC)

At first, I thought it was something weird at Commons, so I asked for help at their VP (using Firefox, which didn't have a problem with either Commons page) but was given a snarky response and nothing that helped to resolve the problem. Now that I've encountered it on two vastly different pages here, I have no clue at all what's happening. Nyttend (talk) 23:57, 9 September 2013 (UTC)

These are the typical effects of a document.write statement being used somewhere in an async executed Javascript. You hardly have any JS installed on this wiki as far as I can tell, so my suspicion is a broken browser extension (which are also JS normally). —TheDJ (talk • contribs) 08:48, 10 September 2013 (UTC)

Other pages have started not appearing, such as mouse (computing), train station, and France. Whenever I try to load one of these three pages, I get a long message at the bottom (where the browser tells me what it's loading) immediately before the screen goes blank. With France, I first get Downloading picture data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA4AAAAgCAMAAAAVMLmlAAAAA3NCSVQICAjb4U/gAAAACXBIWXMAAA3X [the string is longer, but it gets truncated here because it's too long to fit in the bar], and after that I get Downloading picture https://bits.wikimedia.org/static-1.22wmf16/extensions/TimedMediaHandler/MwEmbedModules/EmbedPlayer/resources/skins/kskin/i [again, truncated for length]. Any idea what I should do to fix the situation? Changing to a later edition of IE isn't possible for various reasons. As far as I know, since this started happening, I've not upgraded my browser in any way, except for installing any routine updates from Microsoft that might have come along. Nyttend (talk) 06:25, 19 September 2013 (UTC)

Have you had a look at the javascript console. You might see the javascript errors there? (You might need to get hold of the developer toolbar to inspect the javascript).--User:Salix alba (talk): 09:08, 19 September 2013 (UTC)

Your comments are meaningless: not because you've said gibberish, but because I don't know enough to be able to follow your advice. I'm sorry for my ignorance! Could you please give a For Dummies-style explanation that I could follow? Nyttend (talk) 05:56, 20 September 2013 (UTC)

To see the javascript errors you will need to use the F12 developer tools. These come ready loaded in IE8 and can be accessed by pressing F12. You can read the full instructions here go to the debugging javascript section. Hopefully when you run the javascript debugger you will see which extension is causing problems.--User:Salix alba (talk): 06:38, 20 September 2013 (UTC)

Thanks for the simple instructions. I decided to follow them on a page that was exhibiting problems — but to my surprise, all of these pages load without problems! I'm completely unable to explain why they seem to be working without problem now; I've made absolutely no changes today. They still display weirdness when downloading (other pages don't give the complete upload.wikimedia.org/etc.etc.etc. link for every image that gets downloaded, but they're still doing this), but the pages all end up loading properly. Nyttend (talk) 21:55, 20 September 2013 (UTC)

What might have happened is by using the developer tools you are using a debugger version of javascript which does not have the bug which caused the problem in the first place. The alternative is that some code has changed on wikipedia. Anyway glad its working.--User:Salix alba (talk): 22:31, 20 September 2013 (UTC)

Windows Vista Media Player

It used to display the time, but I've lost it somehow. How can I get it back? Clarityfiend (talk) 08:42, 19 September 2013 (UTC)

For clarity ;-) do you mean the 'time left'/ 'time played' display to the left of the controls? (in 'Now Playing' view: Ctrl + 3). I'm using Media Player Ver.12 under Win.7. -Λ-220 of ^Borg 19:21, 19 September 2013 (UTC)

Hmmm... I'm in Vista and I'm not seeing that (Ctrl+3 doesn't do anything) though I may be using WMP11 (I use VLC, so don't update media player anymore.) Is the display time completely vanished (ie. is there a blank space next to the "turn shuffle on/off" button)? Try clicking in the blank space... that might work. Generally you click there to switch between displaying the time:elapsed, the time:left-over, or the time:elapsed/overall:time. --.Yellow1996.^(ЬMИED¡) 22:22, 19 September 2013 (UTC)

I'm looking to restore the elapsed time. When I click where it used to display, it toggles between a line of about 8 dots, two musical notes tied together, and a button. Clarityfiend (talk) 01:00, 20 September 2013 (UTC)

Sounds like something weird is going on here. 8 dots, musical notes tied together and a button... seems to me like maybe something's been corrupt. Which version of WMP are you using? --.Yellow1996.^(ЬMИED¡) 02:56, 20 September 2013 (UTC)

11.0.6002.18311. Clarityfiend (talk) 07:54, 20 September 2013 (UTC)

@ Yellow, yes I'm not surprised that shortcut doesn't do anything on Vista. They made a lot of changes in Media Player when they went to Win7. The sequence of times you give seems right. Though in my case time:left-over precedes time:elapsed.-π-220 of ^Borg 06:21, 20 September 2013 (UTC)

Concur with Yellow. Suggest that ClarityFiend download and re-install the entire Media Player again.
• Second thought 'CF', you haven't installed a new skin have you? Or just had an OS 'update'?-Θ-220 of ^Borg 06:21, 20 September 2013 (UTC)

MS tech support says that "reinstalling" would entail doing a system restore. I haven't done anything manually out of the ordinary; there have been the usual automatic patches of course. Clarityfiend (talk) 07:54, 20 September 2013 (UTC)

A 'system restore' would be bitch to have to do. Is there a Media Player entry in the 'install' or "Uninstall or change program" utility or Vista equivalent. If so does it have a 'repair' or 'Change' selection when you right click on it. You might be able to fix it using 'repair'.
I assume you don't have original Windows Vista discs from where you could possiblt extract the exe file/s, and have to restore from a HDD partition, or a 'Restore' disc?-∞-220 of ^Borg 09:25, 20 September 2013 (UTC)

Well this is interesting. When I widened the window, the time showed up, along with some other information I didn't have before. Thanks, everybody. Clarityfiend (talk) 15:41, 20 September 2013 (UTC)

Ah - I see! (I just got access to my Win7 desktop earlier, I see the differences.) Glad to hear it all worked out in the end, though! :) --.Yellow1996.^(ЬMИED¡) 03:12, 21 September 2013 (UTC)

Resolved

DVD write problem

when i try to write a new dvd it fails and shows Invalid block address F: HL-DT-ST DVDRAM GSA-T20L. — Preceding unsigned comment added by 14.99.144.221 (talk) 08:42, 19 September 2013 (UTC)

The possibilities:

1) Bad DVD. Try a new one to see if that's the problem.

2) Bad DVD burner. Try another one with that type of DVD, if you have spares.

3) Incompatible DVD and DVD burner. It's possible you may be able to use that burner to read from that DVD type, but not to write to it.

4) Bad driver for DVD burner. If it's a DVD burner in your PC, versus a standalone DVD burner, then this is more likely.

5) Bad cable/connection. If the DVD burner is getting the data to write via cable, then that could be the problem, too.

So, please describe your setup for us, so we can eliminate some of the possibilities. StuRat (talk) 02:14, 21 September 2013 (UTC)

Could not connect to system event notification service

I have a PC running Vista Home Premium, with 1 admin login and 2 user login accounts. Today it refused to allow users to logins, reporting "Windows could not connect to the system event notification service service". The admin login still works, but without Aero. How can I fix this? I googled this error and found sites that tell you to use netsh via a command line to winsock reset. However this returns "This command requires elevation", whatever that means. Looking in the event log shows no errors that are unique to today. 121.215.151.4 (talk) 10:10, 19 September 2013 (UTC)

UPDATE: I have since realised that "elevation" means elevate in privilege level, ie requires admin level. I forgot that when you invoke the command line when logged in as admin does not automatically mean the command line has admin rights. You have to explicitly tell it (right click). I fixed the problem by running sfc /scannow. Thanks. 121.215.151.4 (talk) 12:51, 19 September 2013 (UTC)

Color reduction of a pic with one just one pixel to every color on 24bit pallete

RGB color cube

I was reading about http://en.wikipedia.org/wiki/Color_quantization.

Anyway, lets imagine someone made a big picture with every colour from 24-bit pallete, each colour having just one pixel and then reduced it to a 256 colours pallete how this pallete would be? And the 16 colours one? — Preceding unsigned comment added by 201.78.138.193 (talk) 14:07, 19 September 2013 (UTC)

Well, it depends on the quantization algorithm that is used, but basically you end up with colors distributed more or less evenly throughout the color cube. Looie496 (talk) 14:56, 19 September 2013 (UTC)

Android Chrome browser history

How can you access browser history on Chrome in Android (4.1.2)? Entering "chrome:history" or "chrome://history" in the address box as suggested by various websites just opens a page of Google search for the term which is essentially identical to the search results that told me to do so in the first place. And yes I am being very careful to type it into the address box not the search box. 70.91.135.89 (talk) 16:09, 19 September 2013 (UTC)

I have an Acer Iconia A1-810 tablet running Android 4.2.2. The settings are similar to Chrome V29 on Win' 7 except there are 3 'dots' (not 3 bars) in the top right hand of the window. Select that and the fifth item is "History". --220 of ^Borg 17:06, 19 September 2013 (UTC)

I should have said under the X (The "Close" window 'button') or just right of the Bookmark 'star', so not at the very top of the browser window! --220 of ^Borg 17:33, 19 September 2013 (UTC)

I also tried both your suggested methods and both worked for me. The first one seemed to trigger 'auto-complete' so that it ended up the same as your second 'code'. Check that you are not accidentally entering a semicolon ";" rather than a colon ":". Probably easy to do on a small screen. :-/ --220 of ^Borg 17:31, 19 September 2013 (UTC)

Tabs open automatically in Firefox?

FF23 here. Basically there's a few sites that I check every time I'm on my laptop. I'd like it so that as soon as I start up Firefox, these sites open in separate tabs automatically. I'm sure I used to know how to do this but now I can't remember. Thanks! --.Yellow1996.^(ЬMИED¡) 22:30, 19 September 2013 (UTC)

1. Open the tabs you want.

2. Go to Tools, Options, General.

3. Under the Home Page field, click Use Current Pages. (It fills in the Home Page field with the addresses of each tab seperated by |.)

--Bavi H (talk) 23:26, 19 September 2013 (UTC)

Worked perfectly! Thanks again! :) --.Yellow1996.^(ЬMИED¡) 03:01, 20 September 2013 (UTC)

September 20

KEY BOARD FUNCTION KEYS

One of my friend bought an 'HP PAVILION 15 Notebook PC 15-E016TU' model laptop recently. There some additional keys (such as 'fn') and he wants to know the meaning(functions) of those keys. Where can he find the details of the keys and functions? Thank you.175.157.16.32 (talk) 01:56, 20 September 2013 (UTC)

User guide here. [1] Fn key usage is on page 26. AndyTheGrump (talk) 02:11, 20 September 2013 (UTC)

Microsoft office need to close message comming of office 2007

Dear

Iam using microsoft office 2007

every time i am getting Microsoft office need to close message sorry for the inconvenience message

i ready i uninstall and install several times please post the solution — Preceding unsigned comment added by 27.251.31.210 (talk) 09:17, 20 September 2013 (UTC)

More details are probably needed. What version of windows for example, and the circumstances under which it is happening. "every time i am getting Microsoft office need to close message" is not particularly clear. Is this during install, or when you first try to open an office program? ◅ 220 of ^Borg 09:36, 20 September 2013 (UTC)

They're probably getting it when editing/writing documents, as that's the only time I've ever seen that. Suprising though that uninstalling and reinstalling did nothing... but without further information, we can only speculate. --.Yellow1996.^(ЬMИED¡) 03:31, 21 September 2013 (UTC)

I think the IP is referring to the "(Application) has (Microsoft-specific euphemism for "screwed up") and needs to close" crash message. I don't know about that specific case but usually, if a program keeps crashing after a reinstall, you have to uninstall, remove the remaining files and folders, and remove the "HKEY_Local_Machine/Software/(Corporation)/(Product)" registry branch. In that case, it would pobably be HKEY_Local_Machine/Software/Microsoft/Office 2007.

Unfortunately, Microsoft keeps adding layers of confusion. It could be a corrupted DLL, too, or even a corrupted .NET framework, which is harder to fix. - ¡Ouch! (^{hurt me} / _{more pain}) 08:53, 23 September 2013 (UTC)

Using an inkjet printhead.

If I were to buy and old (working) inkjet printer and remove the print head - how hard would it be to drive it from (say) an Arduino. I have plenty of software coding skills and I can wire up simple logic gates and such.

What I guess I'm wondering is how much "black magic" goes on in the software/firmware of a printer to make the ink come out of the nozzles? Do they just set a logic level for each color and each nozzle to tell it to shoot a splotch of ink - or is there some complicated sequence of operations needed?

SteveBaker (talk) 19:18, 20 September 2013 (UTC)

I have no direct experience, but Thingiverse and Make have articles on DIY inkjet printers that may have some useful information. There is a kickstarter project for interfacing an Arduino with a print head. --Mark viking (talk) 19:37, 20 September 2013 (UTC)

Wow! That's stunningly useful! Thanks. SteveBaker (talk) 16:42, 21 September 2013 (UTC)

You may need to look into the various 'squirting' technologies used. I worked on Siemens PT80i2 inkjets that used piezo-electric principles. This required rather high voltages from a driver board, so I think that type of print-head would be to be avoided. I would think that your "level for each color and each nozzle to tell it to shoot a splotch of ink" would be about right. I would be surprised if the print-head was any smarter than that, but it it possible. The ones I worked on also included a heater in the head to keep them at a constant temperature. This seemed unnecessary as we still used ones where the heater had gone open circuit, though I had to bypass the temperature level alarm. The printing result seemed much the same, but these were just B&W text logging printers, not high-res colour.÷ 220 of ^Borg 04:15, 21 September 2013 (UTC)

Well, after perusing Inkjet printing I withdraw my comment about avoiding piezo type heads as they are fairly common: "Most commercial and industrial inkjet printers and some consumer printers (those produced by Epson and Brother Industries ... )", use piezo printheads.
Steve, I presume you have a more interesting application planned than printing text? :-) œ 220 of ^Borg 05:41, 21 September 2013 (UTC)

I'm considering adding one to the head of my lasersaur laser cutter so I can print perfectly registered color on top of laser cut parts. But I will need considerable control over the printing - and also will need to modify the thing so I can feed it with bulk ink bottles rather than the $50 a pop thimble-sized cartridges. I have found kits for that modification - but I'll need to control the ink feed and the speed that my laser head moves. SteveBaker (talk) 16:42, 21 September 2013 (UTC)

Steve, wouldn't it be easier to use your laser to etch a metal-foil stencil, or burn out the emulsion on a silkscreen master stencil, and then manually apply inking over the stencil in a second step? You'd have to be careful about alignment, but that is a tractable and solvable problem. Silkscreen printing is the standard procedure in industrial electronics manufacturing, and it sounds like your lasersaur is practically industrial-strength. Nimur (talk) 14:17, 22 September 2013 (UTC)

Well, we make relatively small batches of model buildings (check out http://RenaissanceMiniatures.com) - and for us, there is great benefit to being able to toss a sheet of plywood into the machine, push the "GO!" button and let it run for several hours before we have to empty it and start over. Using an ink head inside the lasercutter to ink in some stuff like sign-boards that need lots of colors - but not much area - is pretty efficient compared to adding an entire new processing stage. The perfect registration of print and cut/etch would also be beneficial. Also, we have about 300 different parts that we make - and just storing 300 2'x4' silk-screens would pretty much kill us! We're always interested in processes that engineer the human out of the loop - and as a one or two person business - anything that eliminates extra steps for a human to do is worth having. SteveBaker (talk) 22:22, 22 September 2013 (UTC)

September 21

iOS 7

Has anyone had good or bad experience of ios 7 please?85.211.135.199 (talk) 08:08, 21 September 2013 (UTC)

Yes.

As it says at the top of the page, "We don't answer requests for opinions, predictions or debate". So, we shouldn't really debate the pros and cons or rant and rave about a particular OS or device, etc. If you have a specific question about the OS, we'll be happy to answer that. But as far as experiences go, you would get a better idea of experiences by simply searching for "iOS 7 review" or something like that with your favorite search engine.

That said, I would suggest waiting a week or two until the 7.1 update comes out. There is normally an incremental update that comes out shortly after the initial release. It usually addresses the bugs that people discover in the initial release and they complained about in all those reviews. Dismas|^(talk) 08:31, 21 September 2013 (UTC)

Technically the OP simply asked if anyone has had good experience with iOS 7 not what does experiences were or how common they were. This is a dumb question, if iOS 7 has been released and it's resonably popular it's guaranteed someone has had a good experience and someone has had a bad experience, but it is simple enough that it can arguably can be answered with references. Nil Einne (talk) 14:07, 23 September 2013 (UTC)

Ah Gosh, I am covered in shame and disgrace, shan't do it again - ever!85.211.135.199 (talk) 10:34, 21 September 2013 (UTC)

Chrome Apps

Until yesterday, opening a new tab in Chrome gave me links to all the apps I'd downloaded from the Google Apps Store. Now, I get the Google search box. Apparently, there's now a Google Apps Launcher external to Chrome, and/or an Apps bookmark in the bookmarks toolbar. I can find neither of those things. How can I get to my apps now? Rojomoke (talk) 09:11, 21 September 2013 (UTC)
BTW I'm using Chrome Version 29.0.1547.76 m (the latest) on Windows7 Pro. Rojomoke (talk) 10:47, 21 September 2013 (UTC)

There are small 'buttons' on the bottom of the page in the middle that allow you to select either a 'Most visited' page (left button) or 'Apps' (right button). There are also 'buttons' on the side of the screen, (For Win 8/touchscreen use I imagine). Perhaps the last update re-set these to default? I am certainly not getting the search box by default. Nb. Ver. 29.0.1547.66 ₴ 220 of ^Borg 11:16, 21 September 2013 (UTC)

Those used to be there in the old setup, but have now disappeared. Rojomoke (talk) 11:38, 21 September 2013 (UTC)

Sounds like an 'update' that reduces functionality, and now I'm being prompted to 'update'. If I recall right the buttons at the bottom have only been there for a 'short' time (months?)
• If you go to the Google store are your Apps still there?
• Are these Apps for use on Windows or a Tablet? (as I see that my tablet apps also appear there)
• I would check your Chrome Settings under "On startup", see if "Open the New Tab page", which is what gives me the 'buttons' page, is selected. -Δ- 220 of ^Borg 02:57, 22 September 2013 (UTC)

• This is for Windows.
• If I go to https://chrome.google.com/webstore, I don't see the apps I've chosen, but I don't think I ever did.
• My startup setting is "Continue where I left off", as I want to reload whatever pages I had open before. I'm talking about opening a new tab page after I've started Chrome.

If I add a new app, it takes me to chrome://apps, which is the page I want, so I can at least find my way there now. Rojomoke (talk) 05:11, 22 September 2013 (UTC)

IT videos for execution

HI to all. can anyone suggest a website which contains video demo's for installation of routers.ip serveillance cameras, wifi switches, etc etc all i mean is a comprehensive place where help can be found in the form of videos.thanks in anticipation — Preceding unsigned comment added by 117.199.71.187 (talk) 12:37, 21 September 2013 (UTC)

If you want a "comprehensive place" for such an all-encompassing subject that would be a video search engine such as Google videos or YouTube, where you will get millions of hits for a vague query such as "install router". If you are interested in a specific brand of device, first try the manufacturer's website.--Shantavira|^{feed me} 16:21, 21 September 2013 (UTC)

My laptop was in problem with Returnil Systemsafe 2011 software

Hi, i'm Anudeep. I was installed a software named Returnil Systemsafe 2011. And now, i don't want the software now itseems. So, I was tried to uninstall it, but it opens a pop-up window like Turn-off the Virtual Mode. If I was turning-off, again it was opened a pop-up window i.e., "The RPC server is Unavailable". I don't know the meaning of that. What shall i do now? How can i uninstall that software? I'm requesting the people to solve the problem those who are online. regards, Anudeep. — Preceding unsigned comment added by 202.65.155.54 (talk) 15:50, 21 September 2013 (UTC)

What operating system ? Also, you didn't say how you tried to uninstall it. Did you use the uninstall program that came with it, or are you using something like the "Add/Remove Programs" function in Windows ? One suggestion, if nothing else works, is to go back to your last backup/checkpoint before the install, although this might lose more than just that software. Also, it might be possible to simply disable the software, without uninstalling it. StuRat (talk) 00:39, 22 September 2013 (UTC)

Blank text messages on AT&T phone

I'm getting about 2 blank texts a day now, with no phone number attached, nor a "withheld". Could this be a symptom of being tapped by the NSA, analogous to the telltale beeps one heard on the line when an oldfashioned phone was wiretapped? (I'm wondering because I recently sent a "chain letter" text to friends, taunting NSAers with the statement that anyone eavesdropping on me wasn't half the man Manning and Snowden are.) Thanks. 76.218.104.120 (talk) 15:57, 21 September 2013 (UTC)

I seriously doubt the NSA are that incompetent. Rojomoke (talk) 21:09, 21 September 2013 (UTC)

Somewhat old thread, but I found here it may have something to do with the content on the sender's end which makes the message show up blank when you recieve it. However, the consistency of these blank texts leads me to believe they are automated; but beyond that I don't know. --.Yellow1996.^(ЬMИED¡) 00:05, 22 September 2013 (UTC)

September 22

array assignment with fewer characters

is there a way to do G[]={247570,280596,280600,249748,18578,18577,231184,16,16} in fewer characters (same effect)? in C/C++

( I mean like maybe it's possible to assign one big hexadecimal number somehow or some other trick. We're just optimizing for source code space here, not readability.)— Preceding unsigned comment added by 89.132.116.35 (talk) 15:46, 22 September 2013 (UTC)

Are you concerned with this specific array full of magic numbers, or are you interested in a general solution? In either case, some of your numeric constants can be represented in hexadecimal, using fewer characters than in decimal. If you help us understand your motive, we might be able to offer a better targeted solution. Generally, it is not helpful to reduce source-code length as measured by number of characters. Nimur (talk) 15:48, 22 September 2013 (UTC)

Note that the original poster is talking about this code -- Finlay McWalterჷTalk 15:56, 22 September 2013 (UTC)

Ah, that makes much more sense in context. If this is an exercise in recreational program obfuscation, certain silly tricks might be in order, like replacing usage of the array by a simple polynomial; and so on. Some code obfuscation algorithms can actually optimize for smallest source-code size, and produce equivalently-functional, but shorter, source-code as output. After briefly scanning that code and its explanation, I doubt I could make it much shorter - at least, not without a lot of effort, and at the expense of a good deal of portability.

As a goofy example, you can (without loss of generality) represent a nine-element array of integers as a nine-term polynomial (or fewer, if you choose your constants wisely). This process is explained in detail in the curve fitting article. Of course, you have to design for minimal floating point error and assume the target computer rounds and calculates in the standard way, lest your integer constants get nudged off by a few bits when you calculate and cast them! It is probable that the representation of a nine-term polynomial is longer than a nine-element array of integer constants, but it depends on the coefficients you need. And there are alternatives to polynomials: in fact, a whole branch under the science of wavelet transformation is specifically dedicated to the mathematical study of minimal representations of arbitrary arrays of constants (signals) through the clever construction of transform domains. If a little error is acceptable, you can get orders-of-magnitude reductions in code size, which is (not coincidentally) the means by which modern image compression works. Now, in the example above, the numeric constants form a very low resolution bitmap image (with one bit per pixel), representing the positions of spheres in a world geometric model. Lossy compression is not great for low-bit-depth, low-resolution images. But if the world representation needed a longer array, the tradeoffs would start to look pretty good. Nimur (talk) 16:19, 22 September 2013 (UTC)

Wow, Nimur, what a detailed response. But this isn't the mathematics desk and I really was just interested in some kind of syntax in C/C++ or simple cheap trick that would shorten the assignment. For example, maybe there is a way to take a string "lkjr3lkjfsdf" and get those numbers, or hexadeciaml, or some other trick. The point is if you want to keep the array, but reduce the number of bytes to assign like so "={247570,280596,280600,249748,18578,18577,231184,16,16}" are there any cheap tricks to do so in C/C++? Things like hexadecimal, or character arrays, or anything else you can think of.... 178.48.114.143 (talk) 18:13, 22 September 2013 (UTC)

I've been playing on this problem for fun... and so far, I can not contrive a legal C program that uses correctly represents {247570,280596,280600,249748,18578,18577,231184,16,16} in fewer characters. I have tried a polynomial fit, and a recursive function, and a few variations of boolean and bitwise logic; it is easy to generate the constants, but the code takes more space. My next step is to try a Karnaugh map, as the process of trial and error is not yielding results. Nimur (talk) 22:55, 22 September 2013 (UTC)

Okay. I had to dig up espresso (it's been a long time!), because I wasn't able to minimize this one by hand. And I had to use this variant of the source-code from the University of Manchester (the antiquary Berkeley copy gave me compiler trouble); even the variant from Manchester used restrict as a variable name, which my C99 compiler treats as a keyword. (So, if you're following along at home, either disable C99 mode on your compiler, or replace all instances of "restrict" with some other variable name in unate.c).

Then I used this as my input function - (the espresso-representation of the array constants, and their array indices, in binary):

.i 5
.o 19
0000 -0111100011100010010
0001 -1000100100000010100
0010 -1000100100000011000
0011 -0111100111110010100
0100 -0000100100010010010
0101 -0000100100010010001
0110 -0111000011100010000
0111 -0000000000000010000
1000 -0000000000000010000

In other words, five input bits (for array index 0 through 8); and 19 output bits, because there are 19 bits in the longest represented numeric constant, the rest being "-" or do not care bits. I ran espresso on my input file ...which gave me output:

.i 5
.o 19
.p 9
-000- 0000000000000010000
0101- 0000100100010000001
0010- 1000100100000001000
0001- 1000100100000000100
0110- 0111000011100000000
0---- 0000000000000010000
0100- 0000100100010000010
0000- 0111100011100000010
0011- 0111100111110000100
.e

... in other words, a nine-element boolean logic expression; or, almost no reducible complexity whatsoever. Translating that back into the C programming language, I got a string that is significantly longer than the array of nine constants; the first few elements being:

((k>0&&k<8)?0x40:0)+((k^0xA)|k^0xB)?0x4881:0 // ... and so on; already too long by the third term, and painstakingly difficult to do correctly.

Now, we can't say we've proven that the string is best representable as a magic number sequence; in fact, it's nearly impossible to prove anything about the minimally-complex representation of a string; but we can say that we've thrown a lot of manual effort and computational horsepower at the problem and not made any headway towards a shorter string.

A few things I noticed during my experimentation: the a character and the e character glyph could be rendered slightly differently, such that one is a rotation of the other. The k glyph could be truncated so that it is only eight pixels tall, instead of nine. These single-pixel changes would make the entire problem much more tractable without affecting the human readability of the output. As it stands, neither I nor my computer were able to losslessly compress that nine-element array at all. The obvious solution is to represent it as the ASCII characters aek - but again, if you've been following along at home, you'll readily see why that representation, though shortening the constants-array, actually requires increasing the total length of the program. Nimur (talk) 00:11, 23 September 2013 (UTC)

How to handle very large arrays

Assume that I am using an interpreted programming language where array indexes start at zero. Given an array of millions of items and a function that does integer arithmetic, the program has to get array[f(x)-1] for a million different values of x. Would it be more efficient to give the array an empty zeroth element and have the program get array[f(x)] instead of repeatedly subtracting 1 from x? Is the answer different for different programming languages or are there other factors to consider (besides the additional memory for storing the empty zeroth element)? — Preceding unsigned comment added by 116.14.196.239 (talk) 19:47, 22 September 2013 (UTC)

It should be slightly faster to do that. That eliminates a million subtractions and wastes just one array element out of a million+. But the million subtractions might only take a fraction of a second anyway. The cost of that subtraction could be a lot less than the cost of the function, depending on what the function is. Bubba73 ^{You talkin' to me?} 20:26, 22 September 2013 (UTC)

Your way of thinking about this problem is 21 years out of date. For all but the tightest computational kernels on tiny windows of data, details of how many instructions are needed are in practice of secondary importance at best. For almost any operation on data sets with "millions of items", the overwhelming performance criterion of note is likely to be cache locality. Incrementing an integer held in a register is something CPUs are already ludicrously fast at, and its presence or absence will not yield a measurable time differential. -- Finlay McWalterჷTalk 21:46, 22 September 2013 (UTC)

Indeed, memory access is by far the dominant factor in most programs. For large arrays where many of the elements are zero (for example) you might benefit from using sparse array techniques. These can dramatically reduce the amount of memory needed for the array - and improve cache occupancy. The additional CPU time required to access them will typically be less than the cache hit improvement. But this depends dramatically on how much of your array is zeroes (or some other known value). SteveBaker (talk) 22:13, 22 September 2013 (UTC)

(ec) In fact, there is a specific instruction in most computer architectures for many variations on the theme: pointer dereference with offset is such a common operation, it usually executes exactly as fast as a pointer dereference with zero offset; and for all practical purposes, consumes exactly the same amount of energy per instruction (because the granularity of logic clock-gating is too coarse to turn off the pointer-offset ALU execution unit). In the Intel 64 instruction set, the pointer-offset can be 64-bits long, meaning that RAM is really randomly addressable. Every single pointer-offset can be anywhere else in memory; nowadays, there is no such thing as a short- or long- (alternately, near- and far-) pointer. Immediate-operands can be 64-bits long for free. If you want faster code, investigate algorithm changes first; and then micro-optimize by investigating commonplace instruction-set enhancements like Intel's AVX vector instructions (or the equivalent vector set for your favorite non-Intel processor); but don't imagine the array offset calculation is even relevant to the execution performance. It isn't. Nimur (talk) 22:20, 22 September 2013 (UTC)

Like noted above, it shouldn't make a difference. However, you did mention that it is an interpreted language. In that case it really depends on the nature of the interpreter, but I doubt it changes much. The best way to answer the question is to write a program that times the operation done both ways so you have hard data on the subject. The biggest rule about making tweaks for optimization is don't do it on a hunch - wait until you're actually seeing performance bottlenecks caused by the code, then use measurements to back up your choice of changes.. Katie R (talk) 14:10, 23 September 2013 (UTC)

September 23

fatal error

in my PC when i am tring to open my skype account fatal error is appearing how can i remove fatal error? — Preceding unsigned comment added by 117.201.210.161 (talk) 02:47, 23 September 2013 (UTC)

What exactly does the error say? Then users familiar with these messages may be able to diagnose the problem for you. --.Yellow1996.^(ЬMИED¡) 02:52, 23 September 2013 (UTC)

Laptop Woes

Me again, in a shocking turn of events, my laptop is deceased (I would need to replace the motherboard and the screen, and it's simply not worth spending that much on an old computer when I could just buy a new one for the same price). This, along with my research on Mac and realizing how overpriced (substitute: out of my price range) they are, I starting looking for another system. I had always heard that Lenovo made a great, performance minded, rugged laptop. With my future in traveling, and using my computer on the go in who-knows-what situations (I foresee a lot of outdoors / toss it on huge counter type situations), this seems extremely appealing. I found this Lenovo G500s Touch... And I like what I see. Is this just me being easily impressed, or is this a good, sturdy laptop that can handle some video editing, business type software, and League of Legends when I get free time? I really like the processor speed, the 1TB of HD storage, and the easily upgrade-ready RAM (if I need to upgrade from 6GB). What makes me nervous is in reviews I keep running across something about the Ethernet being outdated, and I have no idea what that means. Also, I'm not sure whether the graphics are good or not, it's an Integrated Intel HD 4000. And the Bluetooth enabled is freakin awesome. It seems the webcam is also kinda low-end, but that is a non-issue for me. --Hubydane (talk) 14:09, 23 September 2013 (UTC)

Perhaps the main thing to think about is whether the battery life meets your needs. The description says "up to 5 hours", but in my experience that means "usually less than 3 hours". Looie496 (talk) 14:43, 23 September 2013 (UTC)

I would be okay with that, normally I back and forth between outdoors and inside, so I'd be able to charge if it became a problem. All of my LoL playing would be on charge, as well as a healthy chunk of the video editing. Off charge would be more the business programs and video showing, and that's if I don't have a tablet on me. After reading some reviews, DVD playback reached 3 hours 7 minutes, and I don't foresee my needs to go beyond the playbacks demands for any extended amount of time. And I could always buy an aftermarket battery if the need were to ever arise.--Hubydane (talk) 14:51, 23 September 2013 (UTC)