Wikipedia:Reference desk/Archives/Computing/2012 August 12

= August 12 =

Brother driver installation error message
Dear Wikipedians:

I am trying to install my brother DCP-7065DN drivers on my Windows 7 64 bit computer. But keeps on getting the following error message during the installation process:



What is going on?

Thanks,

L33th4x0r (talk) 02:14, 12 August 2012 (UTC)


 * Are you sure you are installing the correct version of the driver ? That 32 in the error message makes me think it might be a 32-bit versus 64-bit problem.  Whichever version you are trying to install, I suggest you try the other. StuRat (talk) 03:01, 12 August 2012 (UTC)


 * If you have to ask, you should change your user name :-). Okay, sorry.  That error message is generated by InstallShield, and all the information in it is specific to the Install script that Brother set up.  Unless you can simply guess the problem, there is probably no way to figure it out except by contacting Brother's technical support. Looie496 (talk) 03:16, 12 August 2012 (UTC)


 * To follow up on that, IS026 indicates that this is version 26 of the InstallShield script, and MoveFileData indicates that the problem occurs when the installer attempts to move files to the place where they need to go. But without access to the script it is impossible to say what problem produces error code 32. Looie496 (talk) 15:59, 12 August 2012 (UTC)

Print screen and scroll lock key
What is the use of 'Print screen and scroll lock key' in computing? Sunny Singh (DAV) (talk) 02:27, 12 August 2012 (UTC)


 * Print Screen is quite useful on Windows PCs. It places a snapshot of the current screen in the graphics buffer, where it can be pasted with Edit + Paste into MS Paint and other  applications.


 * Scroll Lock is less useful. It was originally used to pause a long scrolling list so you could read it, but few applications support this feature anymore (mainly because few applications produce a long scrolling list as output, since that's not very user friendly).  More modern applications tend to divide up the output into pages for you, and give you controls to flip through the pages. StuRat (talk) 02:55, 12 August 2012 (UTC)


 * Your description of Scroll Lock is actually a description of Pause. As the scroll lock article says, its purpose was to toggle the arrow keys between their usual function (command editing, etc.) and scrolling the whole buffer. Most software doesn't support it, which is unfortunate since it's actually kind of useful. The Win32 terminal called "Console" does support it for viewing the scrollback buffer. -- BenRG (talk) 05:17, 12 August 2012 (UTC)


 * OK, thanks for the clarification. StuRat (talk) 08:49, 12 August 2012 (UTC)

Follow up question: If I press Print screen key, where should I go to get that snapshot. I use Windows XP. Provide me the location of that snapshot. Sunny Singh (DAV) (talk) 06:52, 12 August 2012 (UTC)


 * As StuRat said above, it's in the graphics buffer, so just open any graphics program (such as "Paint" or any photo editing or graphics software), and paste into that program. You can then crop the image to remove any borders from the part of the snapshot you wanted.    D b f i r s   07:44, 12 August 2012 (UTC)


 * If you have a print screen utility, such as Gadwin's aptly named "PrintScreen", you can use the print screen key to call up the program. (Not trying to advertise Gadwin's product, I just happen to use that utility instead of some other print screen application).  Dismas |(talk) 09:49, 12 August 2012 (UTC)


 * Scroll lock is also often used as the dead key to mimic the Fn key of a laptop. This is particularly useful if you use your laptop on a docking station with the lid closed.  Output is through an external screen attached to the docking station, and input is via external keyboard and mouse connected to the docking station.  So, when my laptop is at work, I put it on the docking station kmeeping the lid closed, and press Scroll-Lock and F8 to get the display to appear on my external screen (I'm sure it used to switch automatically until our IT dept fiddled with the settings!).  Astronaut (talk) 13:05, 12 August 2012 (UTC)


 * On the subject of print screen, pressing Alt-PrntScrn copies only the currently active window into the graphics buffer. Usually saves you some image cropping.  Astronaut (talk) 13:07, 12 August 2012 (UTC)


 * What people are calling the "graphics buffer" is really called the clipboard. -- BenRG (talk) 19:03, 12 August 2012 (UTC)


 * But that term is confusing, since there's also a text clipboard. StuRat (talk) 02:37, 13 August 2012 (UTC)


 * Don't they work the same way? If I highlight text and press CTRL-C, and immediately following that I press Print Screen, I find that CTRL-V in Paint produces an image of the screen (just like I'd expect), but CTRL-V in Notepad does nothing and CTRL-V in Word puts in a miniature screenshot.  It's the same as if I copy a file from one folder to another: the clipboard loses everything that was on it before, retaining only the most recently copied thing.  Nyttend (talk) 04:06, 13 August 2012 (UTC)


 * Perhaps they are stored in the same location, but that doesn't make them the same thing. One is text and the other is a bitmap. StuRat (talk) 04:12, 13 August 2012 (UTC)
 * That I understand, but how many clipboards are there? Nyttend (talk) 04:29, 13 August 2012 (UTC)


 * There's one system clipboard. When you cut/copy an image to it, it holds the image. When you cut/copy text to it, it holds text. It's never called "the graphics buffer" or "the text buffer" depending on what it currently contains. That would be confusing. -- BenRG (talk) 07:04, 13 August 2012 (UTC)


 * Seems less confusing to me, since it specifies the current contents, while "the clipboard" does not. StuRat (talk) 07:08, 13 August 2012 (UTC)


 * The clipboard holds whatever you cut/copy. It's not limited to text or graphics - it can include formatting information (eg bold, italic, indentation etc, if you copy text from a word-processor) or even (conceptually) a file. When you copy cut/copy/paste a file the location of the file (but not the actual file contents) is stored in the clipboard. Mitch Ames (talk) 12:35, 13 August 2012 (UTC)


 * It comes down to referring to the container or the contents. In real life, would you say "bring me the milk"/"bring me the ketchup" or "bring me the container" ? StuRat (talk) 21:29, 13 August 2012 (UTC)


 * Since you're placing your screenshot "in the graphics buffer", your grammar makes it sound as if you're referring to the container. In real life, if you're weird enough to put ketchup and milk in the same container at different times, "put your liquid in the container" would be equivalent.  Nyttend (talk) 01:44, 14 August 2012 (UTC)


 * To refine my analogy a bit, let's say you have a pitcher which you sometimes use to hold milk and sometimes orange juice. If sending somebody to get it out of the refrigerator, I would say "hand me the milk"/"hand me the orange juice", or perhaps "hand me the milk pitcher"/"hand me the orange juice pitcher".  Yes, it's the same container no matter what is inside, but just saying "hand me the pitcher" might result in getting the wrong thing, on occasion, if it doesn't contain what I thought it did.  So, might as well be as specific as possible. StuRat (talk) 20:56, 14 August 2012 (UTC)


 * In Microsoft Excel the Scroll lock key toggles your cursor keys from moving between cells to moving the whole sheet without changing the selected cell. Zunaid 15:23, 13 August 2012 (UTC)

Relay server?
I'm seeking an appropriate wikilink for Relay server, in the sense of a network-connected communication server which acts as an intermediary, simultaneously for two remote client/servers. It's not about IRC. I was thinking there would already be something for Relay (networking). --Lexein (talk) 04:21, 12 August 2012 (UTC)


 * Packet forwarding, maybe? RudolfRed (talk) 05:02, 12 August 2012 (UTC)


 * Packet forwarding would be a transparent version... also any sort of tunneling or VPN would act as a "relay" in this sense. What specific application are you looking for? In other words, what are you trying to accomplish by "relaying" it? Shadowjams (talk) 05:39, 12 August 2012 (UTC)


 * Sorry, I was working on Bitblinder. Source's description used the words relay server. --Lexein (talk) 06:08, 12 August 2012 (UTC)

You mean a proxy server? 67.122.211.84 (talk) 23:43, 12 August 2012 (UTC)
 * Very possibly so, but the developers didn't describe it as such, nor have the other sources. I went with Packet forwarding anyways; if you feel strongly about proxy server, I won't revert it. --Lexein (talk) 07:07, 13 August 2012 (UTC)

learning python: for in loops
The Python for...in loop does not use a loop counter, but is there a pythonic way to get the index number of an item of the iterable (for example, position of a name in a sorted list of names)? I understand range(len(iterable)) is unpythonic and sometimes I may only need to get the index number for a small percentage of items in a large iterable. — Preceding unsigned comment added by 220.255.2.49 (talk) 09:56, 12 August 2012 (UTC)


 * Use the enumerate function:


 * This is better than range(len(iterable)) for more than just style reasons - some iterables don't have a length - you can iterate on them until they're exhausted, but they don't know at the beginning how long that will be. Take this rather contrived iterable:


 * It generates random integers for a while, and then stops. When you create it, it doesn't know how many integers it will generate, so asking it its "length" wouldn't be meaningful. -- Finlay McWalterჷTalk 10:38, 12 August 2012 (UTC)

THANKS! — Preceding unsigned comment added by 220.255.2.94 (talk) 12:19, 12 August 2012 (UTC)

Inequality Involving Kolmogorov Complexity.
Show that $$K(x) := \min_p \{l(p) : U(p) = x\} > K(x|y) := \min_p \{l(p) : U(y'p) = x\}$$ --150.203.114.14 (talk) 10:25, 12 August 2012 (UTC)

This looks like a homework problem, so please say what you have tried so far and where you are stuck. It would also help if you explained the notation. Obviously K(x) is the Kolmogorov complexity, but the other letters' meanings aren't so clear. The article Kolmogorov complexity may of course be helpful to you as well. 67.122.211.84 (talk) 23:45, 12 August 2012 (UTC)

Is it possible to handle errors of file_get_contents in PHP?
I'm trying to handle all types of errors, like convention timed out, SSL errors, DNS error, or served refused connection, but I can't seem to find a way to do it... Maybe there is a better function to do this, I'm using php5 in windows7, thanks. 190.158.212.204 (talk) 16:18, 12 August 2012 (UTC)


 * You should be able to install a custom error handler with set_error_handler and then make decisions based on the errno that your handler gets. I don't know how distinguishable all those different failure families you're worried about are just by errno, but hopefully that gets you more useful information that just "False". -- Finlay McWalterჷTalk 16:37, 12 August 2012 (UTC)


 * On experimenting with this, I see I've misled you a bit above. The $errno reported to the custom handler is a PHP error level constant, not the libc errno - so most of those errors you care about will all be E_WARNING. $errstr is properly informative, so I guess you can parse that (yuk). I don't know a way to access the real OS errno. -- Finlay McWalterჷTalk 17:59, 12 August 2012 (UTC)

proxie
how do i set up proxies on my home pc. — Preceding unsigned comment added by 205.142.178.36 (talk) 17:45, 12 August 2012 (UTC)
 * It depends what you mean by "set up". Are you sure you wish to turn your PC into a proxy server? (That's not the same thing as using a proxy: the former is tricky, the latter easy.) Either way, I suggest you use Google, it's a much written about topic. - Jarry1250 [Deliberation needed] 19:26, 12 August 2012 (UTC)
 * you should read the wikipedia article — Preceding unsigned comment added by 190.158.212.204 (talk) 00:23, 13 August 2012 (UTC)

Need help with infobox
I'm trying to create the infobox for roads on another wiki, but it shows "}}" at the top when there should be nothing. It works fine here. Velo ciraptor  888  19:58, 12 August 2012 (UTC)


 * So either the infobox code differs, or the wiki backends. ¦ Reisio (talk) 20:11, 12 August 2012 (UTC)

kubuntu screen refresh problem
Hi. kubuntu 12.04, HP EliteBook 8560, with 2GB ram. I am having problems with windows not redrawing themselves. If I move a window around I can see parts of the windows behind it, and the fragmented bits of image stay there for ages. It's really annoying. I thought at first it was the applications not behaving themselves, but all the apps do it (Firefox, emacs, okular etc etc). I am not 100% sure, but I don't recall this happening with kubuntu 11. The machine is not sluggish at all in any other respect. So, what's going on, and secondly, can anyone suggest how to minimize this problem? Robinh (talk) 23:20, 12 August 2012 (UTC)
 * This happened after upgrading an existing Kubuntu installation? Looie496 (talk) 00:39, 13 August 2012 (UTC)
 * yes, I think so (at least it wasn't a serious problem on the same machine in kubuntu 11 IIRC).  Robinh (talk) 02:28, 13 August 2012 (UTC)
 * Then it's probably to do with a less than optimal (for your hardware, for whatever reason): graphics driver, kernel, window manager, or X versions (in order of likelihood). You'll resolve this much faster by going to http://webchat.freenode.net/?nick=redrawingBug&channels=#ubuntu ¦ Reisio (talk) 21:05, 13 August 2012 (UTC)
 * (OP) thanks for this Resio. I've got zero experience of this kind of webchat.  After the cachpa, it seemed to know what hardware I was on.   Can I just type my question in and not get flamed?  Robinh (talk) 22:44, 13 August 2012 (UTC)
 * It knows what your browser knows, which is normal. If it says '#ubuntu' at the top in black text on white (or off white), then yes, just type your question.  The ops are pretty picky in there about flaming, but you should ignore such things regardless. :) ¦ Reisio (talk) 23:03, 13 August 2012 (UTC)