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

April 16

"Blue screen of death"

I recently had a computer that blue screen of death-ed. It froze and then completely erased Windows from the system. It is currently on the way to the manufacturer to have the hard drive replaced. With that in mind; I was wondering if there is something, specifically, that I should do to prevent this from happening to any more computers? I intend to install some virus software, but that does not always work. Are there any clues as to whether or not a website is infected or not? Sumsum2010·T·C 04:53, 16 April 2011 (UTC)

Only go to websites you know and trust ? StuRat (talk) 05:05, 16 April 2011 (UTC)

For a safer browsing experience, I recommend starting by using firefox with the 'no script' plug-in [1]. SemanticMantis (talk) 05:58, 16 April 2011 (UTC)

Well, Linux is famous for being safe from many types of attacks and Ubuntu isn't hard to use even for a newcomer. The feasibility of switching to Linux depends a lot on what you're going to use the computer for - office work, Wikipedia/web browsing and software development are easy with Linux, but if you play games that have problems with Wine or really need to use MS Office or Visual Studio or anything, or just are reluctant to switch OS, it's better to not switch, in which case I recommend the advice given earlier. Zakhalesh (talk) 06:12, 16 April 2011 (UTC)

You could try use Norton Safe Web, which lets you enter a website and show whether there seems to be anything bad in it. However, common instinct is obviously very important in stopping maculious malware. General Rommel (talk) 07:01, 16 April 2011 (UTC)

Far from being a malware problem, the obvious explanation is a simple hard drive failure. To protect yourself from that kind of catastrophe, a good backup policy is recommended. Astronaut (talk) 10:42, 16 April 2011 (UTC)

1. As Astronaut wrote, back up your data frequently. If possible, back it up automatically to a 2nd hard disk or even a 2nd computer system, or via a service like Mozy that backs up your data offsite. This will give you a way to save your data from either a hard disk failure or from a malware attack. It is useful to adopt the mindset that when it comes to hard disks, it's not a question of "whether" the hard disk will fail, but "when". 2. To reduce the damage malware can do, set up a user account with no administrator rights on your computer, and use that account habitually. Do not use the administrator account unless you have to (to install software, for example). This makes it harder for the bad guys to get to your system files. 3. This should be obvious, but don't download software unless it is from websites you know and trust. Comet Tuttle (talk) 20:31, 16 April 2011 (UTC)

Picasa web video download problem solution failure help request

Hi everyone. If you upload a video to picasa web, It doesn't seem possible to download it again directly and I'm looking for a workaround. I am using firefox, macosx 10.5.8 and someone advised me to type "about:cache" in the address bar and find local cache files. Well, there's a file in there that has the right datestamp, and is about the right size. I've tried renaming it .flv and .mvi, but quicktime won't play the video. Any advice? Robinh (talk) 05:09, 16 April 2011 (UTC)

I'm a little rusty on OS X, but I think this may give us a clue. Open up the Terminal application (it's in Utilities by default, I think). Type "file" and hit the space bar, and then drag the file into Terminal. Its path should appear. Then hit enter. What does it say? Paul (Stansifer) 13:45, 16 April 2011 (UTC)

Hi Paul. Thanks for this:

slug:~/Desktop% file flowers.flv 
flowers.flv: XML 1.0 document text
slug:~/Desktop% 

But I'm n wiser. Any ideas? Robinh (talk) 20:20, 16 April 2011 (UTC)

Weird. I don't think there are any XML-based encodings of video (although you say it's the right size, which suggests that it's a terrible encoding of something large into XML). Well, maybe try the same thing, but use "head" instead of "file" (to view the first few lines of text). Paul (Stansifer) 22:51, 16 April 2011 (UTC)

OK here goes:

slug:~/Desktop% head -20 flowers.flv 
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
   "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Cache entry information</title>
<style type="text/css">
pre {
  margin: 0;
}
td:first-child {
  text-align: right;
  vertical-align: top;
  line-height: 0.8em;
}
</style>
</head>
<body>
<table><tr><td><tt><b>key:</b></tt></td><td><a href="http://v9.nonxt4.googlevideo.com/videoplayback?id=2a4fbdbfdf362628&itag=35&begin=0&len=2147483647&app=picasa&et=INVALID&el=INVALID&ip=0.0.0.0&ipbits=0&expire=2879698237&sparams=id%2Citag%2Cip%2Cipbits%2Cexpire&signature=70140B912E84A0D591150CCC617870859341BF37.5EA1AF515C9CA9B25C5C81459693638705DDD039&key=ck1">http://v9.nonxt4.googlevideo.com/videoplayback?id=2a4fbdbfdf362628&itag=35&begin=0&len=2147483647&app=picasa&et=INVALID&el=INVALID&ip=0.0.0.0& amp;ipbits=0&expire=2879698237&sparams=id%2Citag%2Cip%2Cipbits%2Cexpire&signature=70140B912E84A0D591150CCC617870859341BF37.5EA1AF515C9CA9B25C5C81459693638705DDD039& amp;key=ck1</a></td></tr>
<tr><td><tt><b>fetch count:</b></tt></td>

Robinh (talk) 01:31, 17 April 2011 (UTC)

Perhaps this is obvious at this point, but the file in question was some kind of HTML/XML file linking to the actual file. If you click on the link created above (the googlevideo.com one), it'll download the FLV to your hard drive. (I like flowers in my garden, too.) --Mr.98 (talk) 18:27, 17 April 2011 (UTC)

Thank you! But I'm still missing something here. The file I gave the head for above, was about 43MB, which matches the origincal AFAIR, and the file that I've just downloaded was about 7MB (and won't open with quicktime anyway). Just to check, you meant clicking on "http://v9.nonxt4.googlevideo.co..."? Robinh (talk) 19:16, 17 April 2011 (UTC)

The link goes to a FLV (Flash Video) file, which is what Google Videos and YouTube and etc. convert videos to. It's a smaller file size (and less quality) than the original. It's all you can download from the web, usually. If you want to view FLV files on a Mac, download the Perian plug-in for Quicktime. --Mr.98 (talk) 04:35, 18 April 2011 (UTC)

(OP) OK, thanks for this. I have downlowaded Perian, and can see it in my preferences pane (a red penknife), but Quicktime stills says that flowers.flv is not a movie. What do I do to get it to work? Probably something obvious, but I read the redame.rtf and it didn't say how to make use of perian. Best wishes, Robinh (talk) 07:27, 18 April 2011 (UTC)

Are you using Quicktime X or Quicktime 7? Perian only works with Quicktime 7 (which is the fault of Apple, not Perian — Quicktime X, for no reason that I know of, does not support any third party plugins). You may have to re-download Quicktime 7 (link). Perian more or less works after you install it (if it is on the preference pane, it should be installed), so my guess is that it has to do with Quicktime. (It works fine on my machine, with Perian.) --Mr.98 (talk) 19:04, 19 April 2011 (UTC)

Art of Computer Programming

Go Go Gadget Donald Knuth's assembly language simulation software (ability to simulate other assembly languages appreciated). Thank you! Zakhalesh (talk) 11:39, 16 April 2011 (UTC)

MIX and particularly MMIX list implementations, including simulators. -- Finlay McWalter ☻ Talk 12:02, 16 April 2011 (UTC)

Thank you. Zakhalesh (talk) 12:03, 16 April 2011 (UTC)

How does AT&T ban third party apps on the Android?

Dear Wikipedians:

I was just flabbergasted when I read that AT&T bans third party apps on the Android. I mean, how are they able to do it? I always thought of Android as an open platform where I can browse the web, find the app I like, and just download and install it. None of AT&T's business. So how does AT&T do it?

And also, to raise what maybe an unpopular question here: wouldn't the US be somewhat of a hypocrite applying double-standards, when it accuses China of censoring online stuff, when major companies like AT&T and Apple are doing just the same things to their customers right in the U.S.?

70.31.154.4 (talk) 17:42, 16 April 2011 (UTC)

From what I understand AT&T only allow you to install applications via the Android Market. On Android under Settings menu -> Applications there's a checkbox for "Allow unknown sources" and unless that is ticked you can only install from the market. As such I suspect that AT&T have simply customised the software for their handsets and removed that option. This doesn't really stop anyone from rooting their phone and installing apps that way or in turn installing a custom ROM which has normal functionality though.  ZX81  ^talk 17:51, 16 April 2011 (UTC)

The second question doesn't have anything to do with computing, but it's a very common category error. Freedom of speech means that the government doesn't make certain speech acts illegal. It doesn't say anything about the kinds of platforms-for-speech people may create. AT&T is legally free to make a phone network where it's against the terms of service to, say, criticize AT&T, or speak in non-limerick form, etc. In practice, a government may see fit to pass laws that prevent abuse of this kind of thing (which can be a danger with monopolies), such as network neutrality. But it's a matter of legislation to figure that stuff out (what counts as a common carrier-like arrangement, and what doesn't), because most people really, really don't want a principled rule that, if you relay something that someone says, you have to relay everything that anyone says. This would, for example, make things like removing vandalism on Wikipedia and comment moderation on blogs illegal, and perhaps the act of gathering together any community of like-minded people. Paul (Stansifer) 22:48, 16 April 2011 (UTC)

Thanks. I am a lot more clear on this subject now. L33th4x0r (talk) 15:24, 17 April 2011 (UTC)

Resolved

1 connection per second

I am looking for a way, on Windows 7, to limit internet traffic from all programs running on the computer collectively (firefox, wget, IE, etc) to just one connection per second. For example, say example.com only allowed 1 connection per second, and returned an error if it detected more than 1 connection per second. Five requests to example.com are made at the same time (2 from Firefox, 1 from Internet explorer, and 2 from wget) and thus they all get an error. Instead, I would like some way to take those 5 or more connections and make them wait and do each request one by one. Is there a setting in Windows which can achieve this, or does anyone know of a program (like a proxy server or something) that can do this? Setting each program individually to only use one connection per second is not sufficient as collectively they still use more than one connection per second. It is very important that each connection is dealt with and not closed or given an error from the remote server. 82.43.89.77 (talk) 18:01, 16 April 2011 (UTC)

You could do it with a proxy server but you probably want to throttle bandwidth rather than connections. Browsers will usually open several parallel connections to get the images on a page. 69.111.194.167 (talk) 07:01, 17 April 2011 (UTC)

Any good suggestions for easy to use proxy server programs on Windows 7? 82.43.89.77 (talk) 16:18, 17 April 2011 (UTC)

Whizz with vector files?

There's a request for help at Wikipedia:Graphic Lab/Illustration workshop#Dindigul town crest which some readers of this desk may be able to assist with. Ta! ╟─TreasuryTag►high seas─╢ 18:51, 16 April 2011 (UTC)

I'm uncertain whether I'm looking at the right thing, because I can't read the text. Is this [2] the image you're talking about? (Faithfully copying the text will be difficult, too, for those who don't know what the characters should really look like. Is it Tamil?)  Card Zero  (talk) 23:11, 16 April 2011 (UTC)

Yes, that's the image. The Tamil actually comes out fairly clearly if vectorised in Inkscape, it's more the actual crest which I'm having trouble with... ╟─TreasuryTag►pikuach nefesh─╢ 07:57, 17 April 2011 (UTC)

I had some success using a pixel art scaling algorithm before tracing the bitmap in Inkscape. Now I just have to do the ovals and lettering. Guess I'd better put a note on the Graphic Lab page too.  Card Zero  (talk) 11:04, 17 April 2011 (UTC)

C# compiling

Hello. I am very new to programming. I have been playing around in C# and would like to test out my programs. I wrote one in Notepad++ and saved it to my Desktop. In command prompt, I tried to use Microsoft Visual C# 2010 Compiler to compile my .cs file. I entered csc.exe Welcome.cs and it returned error CS2001: Source file 'Welcome.cs' could not be found fatal error CS2008: No inputs specified I tried again with the complete path of my file and got the same results. What I am doing wrong here? Any help would be greatly appreciated. BurtAlert (talk) 19:01, 16 April 2011 (UTC)

Maybe you haven't enabled file extensions yet, and the file is actually named Welcome.cs.txt? If that is the case, http://www.fileinfo.com/help/windows-show-extensions.html might help. Unilynx (talk) 20:09, 16 April 2011 (UTC)

Nope, just checked, it's definitely Welcome.cs BurtAlert (talk) 23:03, 16 April 2011 (UTC)

Make sure your command prompt is in the folder where this file is (if you type 'dir' in the command prompt, you should see your file). Or, type in the full (absolute) path to the file. I don't know what the default folder the command prompt opens to (in whatever version of Windows you're using), but it's probably not to the desktop. Invrnc (talk) 01:06, 17 April 2011 (UTC)

Try doing a "dir" followed by the full-path file name, exactly as you entered it before. This will tell you if you have the wrong slash or some such problem. StuRat (talk) 01:23, 17 April 2011 (UTC)

Ah, thank you very much guys. I put it in the same directory as the command prompt and it worked! BurtAlert (talk) 01:40, 17 April 2011 (UTC)

Resolved

StuRat (talk) 22:56, 17 April 2011 (UTC)

Firefox Sync

I cannot access my account in spite of having reset my password about three times, in one instance with the same password. And my Sync secret phrase is correct. What the hell is going on? —Preceding unsigned comment added by 24.189.87.160 (talk) 21:14, 16 April 2011 (UTC)

Have you looked at their troubleshooting page? If that doesn't help, there is a link to a support forum at the bottom - you are probably far more likely to get help there than here. 81.98.38.48 (talk) 14:28, 17 April 2011 (UTC)

April 17

AOC Slot

  In the context of this chassis, what is an ‘’AOC’’ slot? I tried looking it up, but all I got is this disambiguation page, and none of the options seem to apply. Thanks. Rocketshiporion♫ 10:46, 17 April 2011 (UTC)

I think this means add-on card. ---— Gadget850 (Ed) ^talk 13:45, 17 April 2011 (UTC)

hi-speed internet service that does NOT involve a fixed IP address (but not using a proxy)

Dial-up internet access involves a non-fixed IP address. Some high-speed internet access necessitates a fixed IP address. I've heard that at least one type of high-speed access (for an ordinary home computer) does NOT necessitate a fixed IP address (I am not referring to the use of proxies). What is it / are they? TIA63.17.51.171 (talk) 08:47, 17 April 2011 (UTC)

As a general rule, home broadband connections do not have a fixed IP address.--Phil Holmes (talk) 12:00, 17 April 2011 (UTC)

More specifically, the internet connection does not require a fixed IP. If your internet provider chooses to give you a fixed IP, there's little that you can do about it. This problem falls into the category of "contact your network administrator," who is in this case your internet provider; realistically, it's unlikely they will change their network management practices to suit your preferences one way or the other, but it ultimately boils down to a decision made by the NOC engineer. Nimur (talk) 16:03, 17 April 2011 (UTC)

video resolution; crt vs lcd?

ok, this is a question about: can the resolution of a display adapter possibly be affected by the monitor type? here's the story: an HP media center with a PCIexpress video board. (nvidia 9400). not very high end because power supply is only 300 watts, but good enough for nonhd tv. windows 7. anyway. that doesn't matter so much, since this starts with the board getting sick, and removed from the machine when i realize the motherboard has a built in vga port that shuts down when the pciE slot is occupied. so, i run the (dell 15 inch) crt monitor off the builtin port on the motherboard, and it runs in straight vga resolution, only. that seems reasonable, if the builtin port had better resolution, they wouldn't put the pcie video board in, would they? next, i put the flaky video board back, figuring intermittent 1200 pix resolution is better than fulltime VGA. meanwhile, i find a NEC 17 inch LCD monitor at goodwill for $15. Woohoo! then i decide to remove the video board again and run the lcd monitor off the builtin video port, the one that was vga only with the crt. but this combo runs nicely at 1200 pix, true color; and i can even choose 1600 pix if i want. seems just as fast as the pcie board, too. so; where/how/why is this possibly working? and, as a practical matter, why not just abandon the PCIE board entirely, right? Gzuckier (talk) 17:00, 17 April 2011 (UTC)

Have you installed the driver for the onboard video card? It sounds a lot like it doesn't have a driver installed and thus it falls back on the default mode for safety. Also the reason that you can't get both working at once is because the onboard one is actually PCIe and your motherboard will only let you use either the onboard PCIe or an expansion PCIe video card. The onboard one should be more than capable of running at a decent resolution, but you still need to install the driver (try the support website of whoever makes the computer). If however the onboard one isn't powerful enough (gaming for example) that's when you'd want to use a separate card.  ZX81  ^talk 17:13, 17 April 2011 (UTC)

Yes, just use the built-in board. The only disadvantage I can think of is that some use part of the computer's RAM for graphics, but probably not much. As for why it refused to give a higher res on the smaller monitor, I suspect they have that logic there to avoid high res on a small CRT screen, since, with some monitors, that just makes it fuzzy (due to overlapping pixels). The separate graphics card is probably newer, so doesn't use that same logic, since they assume newer monitors can handle it. StuRat (talk) 22:54, 17 April 2011 (UTC)

DHL Indian premier league

Hi, Can I get detailed scoreboard of DHL IPL KKR vs Rajasthan royals?Gio2050 (talk) 17:43, 17 April 2011 (UTC)

Either this or this. I don't understand any of the numbers and terms in the linked pages, though. 118.96.166.45 (talk) 02:21, 18 April 2011 (UTC)

Connecting computer to TV via HDMI - screen resolution problem

Hi, I have a computer that is connected to the living room TV (a Panasonic) via HDMI. There is no other monitor connected. My problem is that the computer, which is running Windows XP, does not allow me to set the proper resolution for the TV. Both the graphics adapter and the TV should support the 1280x720 resolution, but it cannot be selected - the only available options are 1280x600 and 800x600, both in the "native" Windows dialog box and the custom Intel graphics options dialog box. Do anyone have a suggestion for a solution for this? Things I've thought of:

• Setting the resolution directly in the registry (where?)
• Installing some "custom" monitor driver (the TV manufacturer does not appear to provide any, currently the "generic" one is used)

Details on the setup is in the collapsed box.

Details

Connection: DVI output on the computer via a passive DVI->HDMI adapter to the HDMI input on the TV, audio is run on a separate link, the TV is able to combine video and audio without any problem, the problem is there regardless of whether or not the audio is connected. The connection is several meters long through some walls, for this reason using a VGA cable instead is not an option. TV: Panasonic TX-L32X10Y, European version; a 720p 32" quite "regular" LCD TV. Allowed resolutions according to manual: Signal name: 640x480 @60HZ Horizontal frequency: 31.47 kHz Vertical frequency: 60Hz Signal name: 750/720) /60p Horizontal frequency: 45.00 kHz Vertical frequency: 60Hz Signal name: 1,125 (1,080) / 60p Horizontal frequency: 67.50 kHz Vertical frequency: 60Hz (this is exactly how the manual presents it. PC via D-SUB (VGA cable) and "regular" HDMI have more alternatives.) Messing with the "zoom" settings on the TV does not affect the available resolution options on the computer. Computer: The following is a printout from one of the graphics adapter option pages. I think it covers most of it. The computer is a Dell. INTEL(R) EXTREME GRAPHICS 2 REPORT Report Date: 04/17/2011 Report Time[hr:mm:ss]: 20:18:02 Driver Version: 6.14.10.4396 Operating System: Windows XP* Professional, Service Pack 3 (5.1.2600) Default Language: English DirectX* Version: 9.0 Physical Memory: 1021 MB Minimum Graphics Memory: 1 MB Maximum Graphics Memory: 96 MB Graphics Memory in Use: 6 MB Processor: x86 Processor Speed: 2593 MHZ Vendor ID: 8086 Device ID: 2572 Device Revision: 02 * Accelerator Information * Accelerator in Use: Intel(R) 82865G Graphics Controller Video BIOS: 2972 Current Graphics Mode: 1280 by 600 True Color (60 Hz) * Devices Connected to the Graphics Accelerator * Active Digital Displays: 1 * Digital Display * Monitor Name: Plug and Play Monitor Display Type: Digital Gamma Value: 2.20 DDC2 Protocol: Supported Maximum Image Size: Horizontal: Not Available Vertical: Not Available Monitor Supported Modes: 1280 by 720 (50 Hz) 1280 by 720 (60 Hz) Display Power Management Support: Standby Mode: Not Supported Suspend Mode: Not Supported Active Off Mode: Not Supported * Other names and brands are the property of their respective owners. Note that the report explicitly says that the TV supports 1280x720. Still, I am not allowed to select it in Graphics Options, only 1280x600 and 800x600 is available. For 800x600, there's a lot of black around the edges; for 1280x600, the screen is "zoomed" so the edges of the monitor image (like the taskbar) is not visible. Other: The computer is running Windows XP. More recent versions of Windows are not an option (I have no licence). Linux is probably not an option (some of the video streaming sites I plan to use do not support it, I think)

Thanks for any help! Jørgen (talk) 18:47, 17 April 2011 (UTC)

Note that just because a certain resolution is supported, that doesn't always mean it's supported via all connectors. It's possible that the 1280×720 res is only supported via VGA. You might want to temporarily move the computer close to the TV, so you can test with a VGA cable to see it that works. StuRat (talk) 22:39, 17 April 2011 (UTC)

Another option is to go with the 1280×600 res, and adjust the vertical height on the TV (if it is adjustable) to stretch it a bit. Yes, that's not ideal, but you might prefer it over the black bars. StuRat (talk) 22:43, 17 April 2011 (UTC)

Thank you, but that is sadly not feasible. As said above, the TV explicitly says it supports the resolution via HDMI. And I do not see whether it works via VGA or not would teach me anything new. Yes, I can stretch the TV picture somewhat, but I think it will make for inferior film-viewing quality... Do anyone know how to force the screen resolution on the computer? Jørgen (talk) 14:04, 18 April 2011 (UTC)

There appears to be something weird about that particular model of TV. According to your TV's manual it would appear to be capable of supporting 720p and 1080p signals received through a HDMI cable (see p.59), yet it only has 1366x768 pixels on the LCD panel (see p.63). I am somewhat unsure how it would display a 1080p image (with 1920x1080 pixels) on the lower resolution screen.

I do know I have no such problems connecting my PC to my Panasonic TV using a HDMI cable, but my TV has the full 1920x1080 pixels and my PC has a HDMI output port. Even so, I think your problem is more likely to do with the PC's display driver - I do wonder why it opts for "plug and play monitor" and restricts you to just 2 resolutions? - or it could be something to do with you converting DVI to HDMI.

One hint: if you do get it working you will need to turn off the "picture overscan" feature (mentioned on p.29 of the manual) or it will crop an annoying few pixels from around the edge. Astronaut (talk) 17:14, 18 April 2011 (UTC)

Thanks! I think the TV, if fed a 1080p signal, just downscales it - if I set my TV set-top box or DVD player to 1080p output the TV still works fine. I think you are right in suspecting the display driver. Another annoying quirk is that it has to recognize the TV at start-up time - if the TV is not on and connected when I turn on the computer it won't send any signal when I turn the TV on later. Jørgen (talk) 20:29, 18 April 2011 (UTC)

"Address of property" in C#?

At work, I have to deal with "data container" classes in C# that have many properties to contain values, and the code that handles these properties makes pretty much similar checks for every property, with the only variations being the name and type of the property. So I got an idea to write a reusable method for the checks, but I don't know how to do that in C#. The idea is, I think, best expressed in C code:

#include <stdio.h>
struct foo {
  int a;
  int b;
};
 void setvalue(int *address, int value) {
  *address=value;
}
int main(void) {
  struct foo testfoo;
  setvalue(&testfoo.a, 1);
  setvalue(&testfoo.b, 2);
  printf("%d %d\n", testfoo.a, testfoo.b);
}

This code prints out "1 2". You'll notice there is not a single direct assignment to testfoo.a or testfoo.b in the code, all assigning is done in the setvalue() function. In analogue with the real-world code, setvalue() is more complex. Is there a way to do such a thing in C#? In C#, the "data container" classes are more like this:

class Foo {
  public int A { get; set; }
  public int B { get; set; }
}

Is there a way to store the "properties themselves" A and B in some variable, rather than accessing their values? JIP | Talk 19:03, 17 April 2011 (UTC)

I'm not sure I understand what you're trying to do. If you use fields, ref does what you want. If you use properties, ideally this kind of checking should happen in the set method; that's what it's for. The notion of a property reference does make sense; it would simply be the get and set methods (as delegates) packaged together. But there's no syntax for that. I don't think C# even lets you refer to these methods (without calling them), even though they're just ordinary methods at the .NET level. You could do something like setvalue((x) => { testfoo.a = x; }, 1);, but it's ugly. You could also consider testfoo.a = checkvalue(1);, where checkvalue either returns its argument or throws an exception. -- BenRG (talk) 10:59, 18 April 2011 (UTC)

The setting of the property values is a bit complex. The values are read from a different object, where they reside in a name-based dictionary, not as separate fields. There is separate validity checking for each field. What this means in practice is that each assignment goes something like this:

if (source.IsValid("A")) {
  destination.A = source.GetValue<int>("A");
}
if (source.IsValid("B")) {
  destination.B = source.GetValue<int>("B");
}

I would like to make a reusable method so I could do something like this (not valid C#):

void SetValueToFoo<T>(Foo foo, Source source, Property prop, string name) {
  if (source.IsValid(name)) {
    foo.prop = source.GetValue<T>(name);
  }
}
SetValueToFoo<int>(destination, source, A, "A");
SetValueToFoo<int>(destination, source, B, "B");

But I don't know how that is possible in C#. JIP | Talk 19:15, 19 April 2011 (UTC)

I think that should be possible if you utilize reflection. That should allow you to set a property of source based on the property's name as a string. --Cybercobra (talk) 13:22, 22 April 2011 (UTC)

Hardware random number generators

I am interested in the range of prices at which USB hardware random number generators are available. What are the cheapest and most expensive ones that people know of? Thanks! ╟─TreasuryTag►consulate─╢ 22:18, 17 April 2011 (UTC)

Side-discussion about the true nature of random numbers. The question was about the price of USB RNGs. ╟─TreasuryTag►consulate─╢ 17:10, 19 April 2011 (UTC)
The following discussion has been closed. Please do not modify it.
If you have a modern Linux, you can use /dev/random to create hardware (non-pseudo) random numbers. If you need random numbers for security or cryptographic purposes, read the detailed descriptions for your particular Linux and hardware configurations. Some esoteric Linux distributions replace or alias /dev/random with /dev/urandom, which is a software, pseudo random number (which may or may not be hardware-seeded, depending on your system). Again, if you aren't sure of the difference, feel free to ask followups or clarify your question. Ultimately, you need to decide whether a thermal noise meter or a radio-receiver is actually more random than any other set of hardware-seeded random numbers. There's a critical and subtle distinction between "uniformly distributed" and "unpredictable." Similarly, there is a difference between a hardware-based random number and a hardware-seeded pseudorandom generator. Nimur (talk) 02:19, 18 April 2011 (UTC) That didn't answer the question, though which was about USB hardware random number generators and the prices at which they retail. ╟─TreasuryTag►pikuach nefesh─╢ 08:09, 18 April 2011 (UTC) The point is that a modern computer has a hardware random number generator in it already, so you can get one for zero dollars. Nimur (talk) 13:31, 18 April 2011 (UTC) Is it a USB hardware random number generator? No. What's the matter with you? ╟─TreasuryTag►Speaker─╢ 07:17, 19 April 2011 (UTC) I'm not sure /dev/random counts as a "hardware generator". It's essentially a software generator whose entropy pool can be configured to use various hardware sources as inputs (Typically mice and keyboards and whatnot, but also the more dedicated hardware devices the poster is probably asking about.) APL (talk) 15:20, 18 April 2011 (UTC) Why is diode shot noise any more random than mouse input? Both are based on non-software interaction between the computer and the physical world. Nimur (talk) 15:57, 18 April 2011 (UTC) I didn't say it was. My point was only that /dev/random itself is a software RNG, that can (optionally, but by default) use some hardware elements. (Potentially even including purpose-built equipment of the sort I assumed the question was about.) You might claim that the mouse,keyboard, and IDE harddrives themselves form a hardware random number generator to which /dev/random is only the interface. But that's clearly not true. None of those hardware items generate acceptable random numbers. Their only value is as entropy for an actual software-based RNG. The question is about hardware-based RNGs. So I stand by my comment that, despite it's usefulness, /dev/random does not count as a "hardware random number generator" However, if you want me to play devil's advocate, I'd say that mice and keyboards generate little to no entropy when there is no user present. Most of /dev/random's commonly used entropy sources fall victim to potential problems along those lines. A default Linux install will typically depend on mouse,keyboard, and IDE. On a server that doesn't access the disk very often the entropy pool can often run dry. Also the level of entropy from such devices may be significantly less than they appear. (For example, An unattended mouse may continue to report movement, but in a highly repetitive manner.) APL (talk) 18:16, 18 April 2011 (UTC) Yes, but as I mentioned before, a modern CPU has a hardware random number generator in it. Here's the Intel vPro implementation: Advanced Security Features of Intel® vPro™ Technology. Nimur (talk) 17:02, 19 April 2011 (UTC)

There are some prices at comparison of hardware random number generators. Prices in that table seem to be more-or-less correlated with throughput. Gandalf61 (talk) 14:29, 18 April 2011 (UTC)

The most straightforward thing to do is use an RNG-equipped smart card (US$5-10) and a USB card reader (start around $10), or a security token containing basically the equivalent. Depending on your application, you may actually want a host security module, which costs a lot more. Some Intel chipsets used to have built-in RNG's but I don't know if they are still made. It's not clear to me who (if anyone) uses those high speed RNG's in the "comparison" article. Usually you just need enough physically random bits to seed a CSPRNG and freshen it up once in a while. 69.111.194.167 (talk) 17:38, 19 April 2011 (UTC)

The Comparison of hardware random number generators article neglects to mention a much cheaper (albeit) slower device. And since all numbers are binary anyway, this is probably cheaper still! Mitch Ames (talk) 11:41, 22 April 2011 (UTC)

April 18

Email Client

Where is the descendant of Outlook Express in Windows 7 ?  Jon Ascton  (talk) 00:15, 18 April 2011 (UTC)

There isn't one, you need to download it as part of Windows Live Essentials  ZX81  ^talk 00:46, 18 April 2011 (UTC)

Cookies and Google Chrome

Hi,

I'm trying to create a webpage which uses cookies. It works fine on all browsers other than Google Chrome. I'm creating cookies in a php script and attempting to read them in with javascript, using code very similar to this. My page does manage to save the cookie, but can't retrieve it.

After of bit of googling, I can see that chrome handles cookies differently from other browsers. Specifically, it apparently doesn't allow "local cookies." My page is on a server, not running on my own computer. Is that still probably my issue?

In general, could someone please give me an example of a setcookie call in php which should be chrome compatible? Thanks!

137.165.171.130 (talk) 04:30, 18 April 2011 (UTC)

Apologies. I've resolved the problem. I spent two hours trying to figure it out, ask it here, and immediately spot my problem (not at all what I thought). Magic.

Thanks anyways, 137.165.171.130 (talk) 04:35, 18 April 2011 (UTC)

Glad we could help, if only via Murphy's Law (in this case, that you couldn't fix the problem until you wasted your time posting it here). :-) StuRat (talk) 10:29, 18 April 2011 (UTC)

Resolved

Visual Studio 2010 not installing

Hi everyone, I've downloaded Visual Studio 2010 Professional from DreamSpark (a Microsoft academic thing) and it won't install. I've uploaded the log file to my SkyDrive:

http://cid-cf9b0aa66e9b2bfc.office.live.com/browse.aspx/.Public

The installer gets to installing Visual Studio 2010 (the stuff before that works fine), I have downloaded 2 ISOs (at 2.2GB a pop!), burned the ISOs to a DVD, tried to install it from a mounted ISO, I've extracted the ISO contents and tried it locally as well. I have tried it with no anti-virus/other programs running, I have installed an Express version of Visual Studio 2010 without any problems, and I have Googled the HRESULT error in the log file, and tried everything there. I'm absolutely stumped, and was wondering if anyone has done this before/has any ideas?

Thanks in advance!

110.175.208.144 (talk) 08:00, 18 April 2011 (UTC)

Hello Aussie! (from IP address)

Perhaps contact your school administrator? He/she may be able to shed some light. Or have you uninstalled the Express version? Perhaps that will clear some issues. General Rommel (talk) 08:50, 18 April 2011 (UTC)

Compute the SHA-1 hash of your ISO image and compare it against the one published by Microsoft. You can probably find it on the page where you originally went to download the file. If the hash doesn't match then you'll have to download the ISO again. If it does match then I don't know what to suggest... -- BenRG (talk) 09:23, 18 April 2011 (UTC)

The original page does not have the MD5/SHA-1 hash of the original file, so maybe there is something wrong there, I will find an alternate source overnight... Also, the whole DreamSpark thing is done pretty much entirely separately from the school - it is self-registered, etc., all you need is a school e-mail address. And before I installed the express version, I was getting the exact same errors as afterwards. 110.175.208.144 (talk) 09:58, 18 April 2011 (UTC)

If you can't find the official SHA-1 hash, you could also try searching the web for your file's hash (as a 40-letter word). If neither Google nor Bing finds any occurrences of that word, the file is probably corrupt. -- BenRG (talk) 22:52, 18 April 2011 (UTC)

Googled the SHA-1 checksum, and precisely zero results... I shall download a copy from a different source overnight :) 110.175.208.144 (talk) 08:17, 19 April 2011 (UTC)

Blue line suggestion in MS Office 2010

Hi,

Does anyone know how to get rid of the silly new blue line suggestion in MS Office 2010? It keeps trying to get me to hyphenate words (such as take over) which I find incredibly distracting as I'm trying to take notes during a lecture! I mean technically perhaps there should be a hyphen there but I don't really want one and would much prefer not seeing blue lines everywhere

The worst thing is, it doesn't allow an 'ignore all' or auto correct feature so you have can't have it automatically do its thing (which may actually be useful)

Thanks, --58.175.32.140 (talk) 12:11, 18 April 2011 (UTC)

Untick "Use contextual spelling" in the Spelling & Grammar options. AndrewWTaylor (talk) 12:20, 18 April 2011 (UTC)

Thanks! --58.175.32.140 (talk) 11:56, 19 April 2011 (UTC)

Resolved

Extra Rams For Computers

Dear All i have one question abot adding new rams for my pc but i dont want to remove the old one just iwant to increase the ram ( add new rams only ) my question is what i need to check before install the new rams ?

to make sync between tow rams check the Memory clock , Cycle time .......... , CAS latency its should be same or not or what i can check it before installing the new rams with my rams . — Preceding unsigned comment added by Net-order (talk • contribs) 12:23, 18 April 2011 (UTC)

As a general rule, on a modern motherboard, all RAM is clocked at the speed of the slowest RAM module you have loaded on the machine; so you want to make sure your new RAM is at least as fast as your existing RAM. Depending on your motherboard, your performance optimizations will work best if each RAM cartridge is the same size (to be technical, this only makes a difference if your hardware uses naive implementations of virtual memory management and memory access load balancing). So, in order, make sure:

1. The new memory is compatible with the motherboard (make sure it is the correct type of memory and the correct module connector), e.g. "DDR3 in a 240-pin DIMM"
2. The new memory should be ideally clocked at the same speed as your existing RAM module, e.g. "800 MHz", or "800/1066/1333" if it supports multiple frequencies; at least one of those available speeds should match your existing RAM
3. The new module may be any size (in MB/GB), but for peak performance on most motherboards, select the same size as previous modules, e.g. "1 GB"

A lot of the other specs on your RAM will only matter if you are really fine-tuning your system, or doing something very unusual with your hardware. Here's a relatively recent article, Memory Upgrade, from Tom's Hardware, a reputable computer hardware review website. Nimur (talk) 14:19, 18 April 2011 (UTC)

You may have no choice but to replace some of the RAM. PCs only have a limited number of slots into which the RAM can be fitted. For example, my laptop has 2 slots; both slots are occupied by the current memory so if I wanted to add more RAM I would have to replace the memory I already have. Also, some motherboards restrict you to certain memory configurations - check your PC's hardware manual (it either came in the box when you bought it, or you can download it). Astronaut (talk) 17:22, 18 April 2011 (UTC)

Note that there are different form factors for RAM, so you have to get the right shape, such as DDR, DDR2, or DDR3. I suggest you download and run the tool at Crucial.com, which will examine your current configuration and recommend possible upgrades to your RAM. StuRat (talk) 17:33, 18 April 2011 (UTC)

Adobe Acrobat and Data Execution Prevention

An irritating feature has recently cropped up on my laptop. I have been opening (and creating) PDF files using Adobe Acrobat v8 for ages with no problems. In recent weeks though, whenever I try to open a PDF file, I get an error message saying that Acrobat has to close down. When I click 'search online for a solution' I am referred to some security software called Data Execution Prevention (DEP). The notes about DEP instruct me on how to disable it for a specified program, but when I attempt to do this I am told that I am not allowed to do it in the case of this particular program. So I'm in the ridiculous position - alone in the whole world I should think - of not being able to open a PDF file. Can anyone help? —Preceding unsigned comment added by 86.186.85.177 (talk) 13:12, 18 April 2011 (UTC)

I've heard that Foxit reader is a good lightweight PDF reader for Windows. Unfortunately, given the error that you're getting, it sounds like you may have a PDF that uses fancy (and possibly insecure! Do you trust the source of the PDF?) features that Foxit won't be able to handle. It's worth a shot, though, especially since disabling protection against potential Adobe Acrobat security holes sounds like a bad idea. Paul (Stansifer) 14:05, 18 April 2011 (UTC)

(ec) DEP is a legitimate safeguard, and it "exists for your protection," but it sounds like it's incorrectly identifying either Adobe Reader, or the PDF, as a forbidden file. The PDF may have active script-content, and instead of falling back to a read-only mode, DEP is forbidding all access to the file. Unfortunately, only a computer administrator has permission to enable and disable data execution prevention; if your user-account on the machine is not an administrator, try logging in as one to make the change (or ask your system administrator for help). If you prefer, you can try an alternative PDF viewer; we have a list of PDF software. Foxit Reader and Evince are both well-liked alternatives to Adobe, and may circumvent whatever DEP error you're having by loading the document as a read-only file. (Though, if you're having DEP permission problems, you may be unable to install new software). Nimur (talk) 14:08, 18 April 2011 (UTC)

Thanks for your efforts, much appreciated, but I think possibly not getting to the root of the problem. One thing that puzzles me is that this has only started to happen recently. Another surprising feature is that it applies not just to a single file, but to all of the many files I have tried to open in recent weeks, including those I have created myself (which I hope answers the question about whether I trust the source of the PDFs!) My account is that of an administrator, but that does not seem to be the problem - I'm not told 'you can't do this because you're not an administrator', I'm told 'DEP cannot be disabled for this program'. Any further thoughts would be welcome. I'm reluctant to use an alternative PDF reader because I swap files with other organisations, all of whom use Acrobat, so any files I create need to be in the same format - and I don't want to be in a situation where I create files that I myself cannot read, which is where I am at the moment. —Preceding unsigned comment added by 86.186.85.177 (talk) 14:17, 18 April 2011 (UTC)

Have you had recent update to Adobe Acrobat ? Perhaps that messed it up. If so, a rollback to before that update may be in order. StuRat (talk) 17:40, 18 April 2011 (UTC)

Foxit reads ordinary PDF files; if it can read something, Acrobat can read it (and vice versa most of the time). But it can't create PDFs; if you need that, I don't have any suggestions. Paul (Stansifer) 18:57, 18 April 2011 (UTC)

Hotmail emails all deleted - why?

Recently I looked at my Hotmail emails and I found that they had all been deleted, apart from one or two hundred recent ones. Luckily I was able to un-delete them. It appears to be the "Windows Live" variant of Hotmail - I don't understand the difference.

Does anyone know why they were deleted? Is this a MS "surprise!" policy? Is it going to happen again? 92.28.241.233 (talk) 18:30, 18 April 2011 (UTC)

This sounds like the sort of thing a hooligan might do if they got control of someone's email account. Change the password immediately (and of any other accounts that share that password). Paul (Stansifer) 18:48, 18 April 2011 (UTC)

Are you using Hotmail's web interface or a mail program? If the latter, check whether your POP3 settings say to leave messages on the server or not. --Mr.98 (talk) 19:06, 18 April 2011 (UTC)

Hotmail recently had some problems with mails being deleted. See here. Astronaut (talk) 10:43, 19 April 2011 (UTC)

Mr. 98, I installed Thunderbird with a view to backing up my emails, but have not figured out how to do that yet. I've used Thunderbird a few times to send emails. Thanks 92.15.24.113 (talk) 21:28, 20 April 2011 (UTC)

harddisk size, is it real

somebody please this question for me. assuming my hard disk is 20G and it is filled with a data of 20G. now, i delete this 20G data and store another 20G data. if there is a software that can retrieve the first 20G deleted then where was it hidden? or my hard disk is not 20G as labeled ? — Preceding unsigned comment added by Rhaskhan (talk • contribs) 22:18, 18 April 2011 (UTC)

The process you describe is, in general, not possible. Data that is deleted, and then overwritten, can not be recovered. There can be slight variations in the reported size of a disk, related to details of how data is actually stored on the file system, (and whether convention dictates the use of "1000" or "1024" for "kilo"); but a factor of 2x is unheard of. Nimur (talk) 22:28, 18 April 2011 (UTC)

Think of your hard disk like a book with a table of contents at the front which lists where each file is located on your hard disk. When you write 20GB of data to the hard disk, the table of contents is updated for you automatically, to tell you where to look for each file. When you delete the 20GB of data, most operating systems just erase the table of contents, because it's fast to do so. All your old files are left there, untouched, but the table of contents tells you that the book is empty. Now when you start writing new files, the new files will overwrite whatever used to be on all those pages, and the table of contents will be updated to tell you where to look for the new files only. If you write, say, 8GB of new files, then you know that about 12GB of your old files are still there on the hard disk, if you have software that can go and identify them. (The old files may be scattered all over the place, and parts of the files may have been overwritten by the new files; but that's another matter.) This is what undelete software does — it finds the old files and changes the table of contents to point to them. Comet Tuttle (talk) 00:15, 19 April 2011 (UTC)

In some cases it may be possible for a forensic lab to recover data which has been overwritten. In this case, don't think of the bits as ones and zeros, but maybe having any range of values between one and zero. The software then normally considers everything above, say, 0.5, to be a 1, and below to be a 0 (or they could have some range in the middle which is considered an error). So, if you had a zero and overwrote it with another zero, maybe if would be very close to 0.0, while a one overwritten by a zero might be more like 0.1. Now that 0.1 contains some hidden data that it was a one previously. The same also can happen with a zero overwritten by a one, you might get a value close to 0.9. This is a lot like erasing pencil writings then writing over them, they still leave a faint trace behind. However, if you continue to erase and rewrite things, the earlier messages are eventually completely obliterated. Some software will actually overwrite each bit several times to ensure that no record remains of the original. StuRat (talk) 01:06, 19 April 2011 (UTC)

It's often said that someone with good enough technology might be able to read overwritten data. However, there are currently No credible cases of anyone reading any significant amount of overwritten data on a hard drive with any reasonable accuracy. Maybe the CIA and their electron microscopes are doing this without anyone knowing, but even the U.S. government considers one overwrite sufficient to protect against even laboratory attack in modern hard drives [3]. In practice, the armed forces typically use three to four overwrites [4]. Any more than this, and you're into "voodoo incantation" territory. See also Data erasure. Buddy431 (talk) 01:56, 19 April 2011 (UTC)

April 19

Gmail for BlackBerry

So a Google search produces results far too complicated for the likes of me to understand. My question is this: on a BlackBerry, is there a way to set up a Gmail account in the normal email application in such a way that messages deleted or marked 'read' from a normal web-browser are so marked on the BlackBerry and messages deleted or marked 'read' on the BlackBerry are so processed on the normal webmail page? Thanks. ╟─TreasuryTag►voice vote─╢ 08:32, 19 April 2011 (UTC)

I believe this is what you are looking for. Please note that Gmail imap is not currently supported on the blackberry. Make sure you enable IMAP in gmail settings before starting. Please come back if you have any questions. Kushal (talk) 13:06, 19 April 2011 (UTC)

Perhaps you could copy-and-paste a quote from that page which answers the question I asked? "My question is this: on a BlackBerry, is there a way to set up a Gmail account in the normal email application in such a way that messages deleted or marked 'read' from a normal web-browser are so marked on the BlackBerry and messages deleted or marked 'read' on the BlackBerry are so processed on the normal webmail page?" – ╟─TreasuryTag►belonger─╢ 13:11, 19 April 2011 (UTC)

This is how IMAP works, as long as you set it up properly. If I may ask, what version of Bb are you on? What problems are you facing with Google's native app for Bb? Is it just a preference? Kushal (talk) 13:17, 19 April 2011 (UTC)

There are a lot of very confusing suggestions that there is just one-way BB>Gmail sync, which is what I am concerned about.
I'm on BB6, using a Bold 9780, and would prefer to use the 'official' email app because it's integrated into the system, click on online email address links and they open in it etc. It's just better! ╟─TreasuryTag►most serene─╢ 13:22, 19 April 2011 (UTC)

Give imap a shot. From what I've read so far, the issue is inconvenience more than anything else. I like the zero inbox idea but your Bb is built to handle lots of emails. I'd love to learn if imap eventually deletes email on your device. Kushal (talk) 14:19, 19 April 2011 (UTC)

Windows 7

Does Windows 7 Ultimate have a TCP connection limit like Windows XP does? 82.43.89.77 (talk) 10:43, 19 April 2011 (UTC)

As far as I know, there is no limit by default. Kushal (talk) 13:14, 19 April 2011 (UTC)

This might answer your question. It says This limitation has been removed in Vista SP2 and later releases (Server 2008 SP2 and Windows 7) Mo ainm~Talk 13:15, 19 April 2011 (UTC)

Note the limit above is not a limit on the number of TCP connections but on the number of half open connections Nil Einne (talk) 13:19, 19 April 2011 (UTC)

This isn't really what you asked, but I feel it's worth mentioning as it may be of use to you: If you're using a Windows 7 machine as a file or print server, it is limited to a total of 20 connections (one machine might use two connections and you can confirm this limit by running a command prompt as admin and typing: net config server). This is an increase on previous versions of Windows though where it was 10 connections. If this is not relevant to you though then I apologise and please ignore!  ZX81  ^talk 13:56, 19 April 2011 (UTC)

MediaWiki

I've recently installed mediawiki & updated it with the wikipedia dump, &installed some extensions, but I can't seem to activate the interwiki links. How do I do that? Thanks. —Preceding unsigned comment added by 79.176.48.210 (talk) 16:30, 19 April 2011 (UTC)

The last time I checked, various language Wikipedias are actually independently-installed instances of MediaWiki. I'm not sure which data dump you got, but it's probable you only got an English language database. If you're trying to replicate the entire Wikipedia, you should anticipate several other problems: it is a known fact that the size of Wikipedia is too large for MySQL, unless you make custom modifications. You may also find these InterWiki instructions helpful. Nimur (talk) 16:46, 19 April 2011 (UTC)

The second link's instructions didn't seem to work. I created a "mirror" of one of the different Wikipedia, for my personal use, and I want the interwiki links to point to the original wikipedias. Thanks. --79.176.48.210 (talk) 17:15, 19 April 2011 (UTC)

Save yourself, choose a different engine. ¦ Reisio (talk) 00:01, 20 April 2011 (UTC)

Automatic mounting (udev?) and filename case in Linux

Now, apparently, my Fedora 12 Linux system has started automatically recognising my Olympus E-520 camera when plugged in, probably thanks to udev. This is fine, but has led to another problem: the old "filename case" problem has come back. Apparently the files on the memory card are all in upper case, whereas I have been storing the pictures on my hard disk with filenames in all lower case. Because Linux filesystems are case-sensitive, this means that if I mix filename letter cases I end up with duplicated pictures, which would needlessly consume disk space. But how can I make the system see the filenames in all lowercase even if they are in all uppercase?

Typing "mount" after the camera has been automatically recognised displays this at the end of the listing:

/dev/sdg1 on /media/NO NAME type vfat (rw,nosuid,nodev,uhelper=devkit,uid=500,gid=500,shortname=mixed,dmask=0077,utf8=1,flush)

It appears that it should say "shortname=lower". But how can I make it say that? None of this appears in /etc/fstab. Is there a configuration file somewhere where I can set this? And if there is, is it possible to make it apply only to the camera, not to any other media mounted with udev?

I could, of course, go around this by running:

for $i in *; do mv $i `echo $i | tr [:upper:] [:lower:]`; done

but it would get tiresome having to remember to do that every time, even if I make a script file for it. JIP | Talk 18:02, 19 April 2011 (UTC)

I recommend you use rename to transform all the file names into lowercase. It's a pretty complex command and I don't remember it by memory, but a quick search online gives this: "rename y/A-Z/a-z/ *", without the quote markers. If you know Perl expressions you can probably figure it out way better than me. Happy hacking! Zakhalesh (talk) 18:08, 19 April 2011 (UTC)

Tested it myself, appears to work just the way I said in my last post. Zakhalesh (talk) 18:09, 19 April 2011 (UTC)

Oh yes, forgot to mention: run it in the folder where the files whose names you want to change are. Zakhalesh (talk) 18:11, 19 April 2011 (UTC)

The renaming script I wrote above works just fine. I would prefer not having to rename the files at all, but instead make the system see them already all in lower case. JIP | Talk 18:16, 19 April 2011 (UTC)

I think it is all tied up with the mysteries of udev rules. I tried to do something similar to you but I gave up as I didn't understand the udev documentation. Somewhere out there is a tutorial on how to create device matching udev rules, which I remember reading when I was trying to do it. After getting a severe headache trying to fathom it, I decided it was all too hard and wrote a script to check for duplicate names. --TrogWoolley (talk) 13:15, 20 April 2011 (UTC)

I have asked the same question on www.fedoraforum.org, let's see if I get a reply. I've also noticed that this is happening with my external hard drives too. Previously it only happened with CDs, DVDs and memory sticks. Now it seems to happen with any file system that isn't already present at boot-up. The only problem I have with this is that I no longer get to edit the mount options myself, at least not if I can't find the right place to configure it. My external hard drives get mounted under /media/8 hex digits-4 hex digits-4 hex digits-4 hex digits-12 hex digits, which I suspect is some unique identifier for the drives. I've modified my automatic rsync script to find any mount point confirming to the pattern and rsync to that instead of a pre-defined mount point. JIP | Talk 18:56, 20 April 2011 (UTC)

I think you probably want to be looking at HAL, which afaik does most of the auto-drive mounting. Unfortunately, HAL doesn't actually handle setting the default mount options anymore - it passes that off to your desktop environment (KDE or Gnome). See the "changing default mount options" section here for more. There's a couple ways to do it in Gnome, as they mention on that page, but the situation with KDE is more confusing. It's handled by KDE Mediamanager, and this post pretty well sums up the problem. I couldn't find an answer after a few minutes of searching, so... I hope you're using gnome. :) If you're really desperate, you might have to write a udev rule that cuts HAL out of the picture and does all the automounting itself. Indeterminate (talk) 20:58, 20 April 2011 (UTC)

Yes, I am using Gnome, not KDE. I had a look at the link you provided, and it appears to be possible to change the default mount options for each filesystem type. So I could make HAL mount VFAT filesystems as shortname=lower instead of shortname=mixed. But that would mean that all VFAT filesystems would be mounted like this, when I would like it to happen only to the camera. The article in the link doesn't mention any way to configure default mount options with deeper specification than filesystem type. There is, of course, the question of how would Linux know what kind of thing the mounted filesystem actually is on. I've noticed that the camera always mounts at /media/NO NAME, while CDs, DVDs and memory sticks usually have some kind of name instead of "NO NAME". My external hard drives wouldn't be affected by this anyway, as they are formatted as ext3, not as VFAT. JIP | Talk 19:31, 21 April 2011 (UTC)

microsoft error

Resolved

I'm using Polipo on Windows 7 and every now and then it crashes. There seems to be no pattern to it, nor do I know why it crashes. This is not too much of a problem though because I've devised a simple .bat script that will restart the program when the previous instance terminates. However, when Polipo crashes a Windows dialogue box is displayed which asks if I want to send the crash data to microsoft. This dialogue makes the Polipo instance hang until I click "don't send". How can I disable these crash report dialogue boxes? 82.43.89.77 (talk) 18:30, 19 April 2011 (UTC)

Click the Start menu, then type problem reporting, and click "Choose how to report problems". From the next screen, you can choose whether to do this automatically, or whether to never check for solutions. You can also click "Select programs to exclude from reporting" and exclude Polipo or any other app. Comet Tuttle (talk) 18:58, 19 April 2011 (UTC)

Thank you! Is there a way to do this on Windows XP too? 82.43.89.77 (talk) 19:16, 19 April 2011 (UTC)

I googled disable error reporting "windows xp" and the first entry was this page, and I verified on a Windows XP box that the sequence of steps appears correct. The option is at Control Panel -> System -> "Advanced" tab -> Error Reporting. Comet Tuttle (talk) 19:32, 19 April 2011 (UTC)

Thanks! 82.43.89.77 (talk) 19:41, 19 April 2011 (UTC)

You're welcome! I salute you for working around a crash, which normally isn't something one works around. Comet Tuttle (talk) 19:56, 19 April 2011 (UTC)

April 20

do people get their emails

I sent an email to someone at their work address, having no other contact details for the person, and they haven't replied. Do people at companies get their email, if sent from an address that is not listed in their address book, or is it always fairly sure they have received it? If they always get it (ie. with only the usual spam filtering), how do they deal with the spam that must come from having an email address listed publicly? Thanks in advance, It's been emotional (talk) 03:24, 20 April 2011 (UTC)

We can't possibly know. Maybe they got it. Maybe their company spam filter ate it. There's no generalized rule. Different companies use different spam filters. Different individual have different patterns of e-mail use. Wait a week, send the e-mail again with a "Hi, I'm not sure this got through..." and see if that helps. --Mr.98 (talk) 04:03, 20 April 2011 (UTC)

It would be pretty unusual for a company to dis-allow mail from unknown senders. (It would make it difficult to conduct business.)

It wouldn't surprise me if some company, somewhere has tried it, in the name of security.

It's very likely that the mail will be monitored by someone and an unusual email address might get their attention. Depending on how oppressive the workplace is about those sorts of things, the person you emailed might not want to even acknowledge the email until they could use a personal account, for fear of being accused of misusing company time and resources. APL (talk) 19:58, 20 April 2011 (UTC)

There's also nothing in email that guarantees delivery in any specific amount of time, it could take a week, it may have not even reached their servers at all. If you want to really talk to someone, email is not the way. ¦ Reisio (talk) 09:13, 20 April 2011 (UTC)

An email delivery that took a week would not break any rules. It would still be standards-compliant. ... But I think it's safe to say that if it took more than a couple of hours, most people would consider that a problem. APL (talk) 19:58, 20 April 2011 (UTC)

One of the best comments I've heard about email is that its reliability and security is worse than what you would expect with a postcard sent from another continent while on vacation. HiLo48 (talk) 23:57, 20 April 2011 (UTC)

Firefox 4 Navigation Bar

So I recently got Firefox 4, and it's all good, except for one thing. When you type something without a .com or .co.uk or whatever into the bar it used to try to find you that website, and if it failed would search it. So typing 'google' would get me google and typing 'BBC' would get me the news. But now it just does what the others do, searches for it in Google. So typing Google doesn't get me Google it gets me the Google of Google, and so on (I should have used a better example). Is there any way to change this back to what it used to do, since this is really bugging me now? Prokhorovka (talk) 13:37, 20 April 2011 (UTC)

Read this official guide from Mozilla to configure your Location Bar. This feature (treating the location-bar as a "smart toolbar" instead of a strict URL parser) is a very dangerous security vulnerability, because it is incredibly prone to phishing attacks; for this reason, Mozilla and other major web browser vendors are trying to "un-train" users who have grown dependent on it. Read more about Mozilla Phishing Protection design if you are interested in this topic. Nimur (talk) 18:07, 20 April 2011 (UTC)

The keyword.URL value you'd want would be something like this: http://www.google.com/search?ie=UTF-8&oe=UTF-8&btnI=&q= ¦ Reisio (talk) 22:12, 21 April 2011 (UTC)

Cheers, that's exactly what I was looking for. So it's dangerous to have the auto-complete, but not the auto-search you say? Good to know. Prokhorovka (talk) 18:14, 20 April 2011 (UTC)

Well, if you understand how to read a URL, there's very little that a phisher can do to "fool" you; so it doesn't matter what the browser delivers to you (you will be able to determine whether the delivered content is malicious or trustworthy). The problem is, most internet users have no idea how to read a URL, and tend to be very trusting of "whatever the browser returns," which could be a Google "I'm Feeling Lucky" search result, or could be anything else. Safe browsing will always require a little human-side intervention. The "danger" is breaking the one-to-one mapping between what you typed, and what you got; the "smart URL bar" does this for convenience. Nimur (talk) 18:17, 20 April 2011 (UTC)

As to how to teaching someone how to read a URL, some Carnegie Mellon researchers wrote a game that teaches you to discriminate phishing links from genuine. Their (regrettably rather minimal) demo is here now. -- Finlay McWalter ☻ Talk 18:27, 20 April 2011 (UTC)

That looks a little dangerous itself. Yes, a funny URI can tip you off, but a perfectly ordinary looking domain can have malicious intent, too, and what makes it phishing is when they go after your personal data, not just visiting the site. ¦ Reisio (talk) 22:12, 21 April 2011 (UTC)

I should be OK so long as I always type it in myself if I'm logging into my banking, look for https if possible and generally read properly any sensitive sites addresses right? Prokhorovka (talk) 18:31, 20 April 2011 (UTC)

Sure. I mean, phishing isn't going to break your computer - it just lulls you into a false sense of security. If you are careful about which sites you use when you enter your financial and personal details, you will generally be okay. Nimur (talk) 18:34, 20 April 2011 (UTC)

You should consider using keyword bookmarks instead. Bookmark every page that you want to access by keyword, and in the "keyword" field of the bookmark properties, enter something like "bbc" or "google", or even "b" or "g". Then typing the keyword into the address bar will immediately take you to the bookmarked page. Keywords can also take arguments. For example, if you bookmark https://encrypted.google.com/search?q=%s and give it the keyword "g", then typing "g keyword" in the URL bar will immediately take you to the search results for that keyword. You can attach a keyword to http://www.bbc.co.uk/search/news/?q=%s to search for BBC articles, https://encrypted.google.com/search?q=site:en.wikipedia.org+%s to search Wikipedia using Google, etc. -- BenRG (talk) 20:48, 20 April 2011 (UTC)

Then you're trusting your bookmarks database instead of your eyes. I'll take my eyes. ¦ Reisio (talk) 22:12, 21 April 2011 (UTC)

Huh? If you don't trust the keywords you created (why?), you can still look at the URL, which replaces the keyword in the address bar as soon as you press Enter. -- BenRG (talk) 22:26, 21 April 2011 (UTC)

Because anyone who has access to your computer for just a few minutes can change a bookmark keyword. Yes, you can still look at the address bar, if you haven't developed a habit of relying on your bookmarks being invulnerable. ¦ Reisio (talk) 22:50, 21 April 2011 (UTC)

Blender 3D Rendering Problems

I am able to render a movie in whatever format I would like to in Blender 3D 2.56, but only the "AVI RAW" format works in Windows Media Player. By that I mean the other formats do play, but the screen is black like if it weren´t a movie I tried to play? 83.183.172.203 (talk) 17:02, 20 April 2011 (UTC)

It sounds like you have a problem with Windows Media Player and installed codecs on your system that is unrelated to Blender. You may find the tool ffdshow helpful; it installs ffmpeg on Windows as a DirectShow filter, (and usually solves most common codec problems). Instructions and a tutorial are available here: FFDShow on VideoHelp.com. Nimur (talk) 17:36, 20 April 2011 (UTC)

Simpler and more useful to you in the long run to switch to VLC media player for all your media playback needs. ¦ Reisio (talk) 22:44, 21 April 2011 (UTC)

The mysteries of .NET appdomains

Today at work, I had the following problem:

The application I was working on creates several appdomains running concurrently. I was developing a piece of code that is used by each appdomain, but is the same regardless of which appdomain it's used by. It has an initialisation method that only has to be run once in the entire application, so I tried to make initialisation checking code to prevent it from being run multiple times. This turned out to be more difficult than I thought.

I first tried a simple class-level static flag and a monitor statement to check and set that flag. That failed miserably, because it appears each appdomain has its own private copy of the flag, which makes it useless. Then I discovered we already had a class that was intended to be shared across several appdomains, which inherited from MarshalByRefObject. I added the following code to it:

private Dictionary<string, object> attributes = new Dictionary<string, object>();
public Dictionary<string, object> Attributes { get { return attributes; } }

However, when I then tried to check and set flags via the Attributes property, this didn't work any better. I changed the implementation to:

private Dictionary<string, object> attributes = new Dictionary<string, object>();
public void SetAttribute(string name, object value) { attributes.Add(name, value); }
public object GetAttribute(name) { return attributes.ContainsKey(name) ? attributes[name] : null; }

And then it worked. But why did the first version not work when the second one did? JIP | Talk 19:07, 20 April 2011 (UTC)

I have no experience with this, but I imagine the dictionary is returned by value to the caller (since it doesn't inherit from MarshalByRefObject) and any subsequent changes by the caller affect only the copy. In the second case the dictionary stays on the callee's side and name, value and the return of GetAttribute are the only things that go over the wire (and they will be silently copied unless they inherit from MarshalByRefObject). -- BenRG (talk) 20:30, 20 April 2011 (UTC)

I showed this code, which I had written, to my boss:

SharedObject o = GetSharedObject();
lock (o) {
  if (o.GetAttribute("flag") != null) {
    return;
  }
  o.SetAttribute("flag", true);
}

and he said the code is not thread-safe. Why not? Is it because the statement lock (o) is in fact locking the appdomain's own reference to the object, not the object itself? Would it be better if I wrote it like this?

/* inside the shared object */
public bool CanEnter() {
  lock (this) {
    if (GetAttribute("foo") != null) {
      return false;
    }
    SetAttribute("foo", true);
    return true;
  }
}
/* in the calling method */
SharedObject o = GetSharedObject();
if (!o.CanEnter()) {
  return;
}

JIP | Talk 18:11, 21 April 2011 (UTC)

49 7/8' cable

I was doing a search for Ethernet cable on Best Buy's web site when I ran across this. It's 49-7/8' long. Why such an odd measurement? It's not even in meters either. Dismas|^(talk) 23:08, 20 April 2011 (UTC)

A look at the specification tab doesn't help much. I got this...

Product Height 1"

Product Width 1"

Product Weight 2 lbs.

Product Depth 49-7/8'

I see it as just further evidence that the USA MUST metricate. HiLo48 (talk) 00:03, 21 April 2011 (UTC)

My guess is that they cut off 50-foot lengths of cable, and the process of putting the ends on it uses up 3/4 inch on each end. Why don't they just cut off 50-1/8–foot lengths of cable, you ask? Probably because the spools of cable they get from the cable manufacturer come in even multiples of 50 feet, so if they used slightly more than 50 feet for each cable they'd have an odd length of cable left over at the end. —Bkell (talk) 00:08, 21 April 2011 (UTC)

By the way, metrication wouldn't make a difference—you'd just have, say, 14.96-meter-long cables instead. —Bkell (talk) 00:13, 21 April 2011 (UTC)

True HiLo48 (talk) 00:46, 21 April 2011 (UTC)

What exactly would be the advantage of having the cable length be a round multiple of either feet or meters? It is how long it is. If you want longer, buy longer. If you want shorter, buy shorter. It's not as though it's going to be pulled taut anyway. --Trovatore (talk) 00:31, 21 April 2011 (UTC)

I see the question more as one about human behaviour. How did such a length come about? Why mention it with such precision? Why not, as many salesmen over many centuries would have done, describe it as 50'?

Though maybe it's worth noting that the other three dimensions above are not so odd. Maybe the 2 lb weight is very precise and is the real defining measurement, with the length being a consequence of the weight. I'd have no idea why that would be the case though. HiLo48 (talk) 00:46, 21 April 2011 (UTC)

I assume they manufactured whatever is most convenient that is of approximately the correct length, then reported that length to available precision. What is strange about that? --Trovatore (talk) 00:50, 21 April 2011 (UTC)

Why not describe it as a 50-foot cable? Likely because knowingly selling a cable as a 50-foot cable when it is measurably shorter than 50 feet runs afoul of some product labeling laws. —Bkell (talk) 01:08, 21 April 2011 (UTC)

That sort of thing seems to happen in the auto industry all the time. Everyone knows that engine capacities are rounded up, when we all know that the manufacturers definitely know a more precise measure. HiLo48 (talk)

They're rounded up for model names. It's not like the manufacturers keep the real capacity a secret; you can easily find it in the owner's manual. --Trovatore (talk) 01:22, 21 April 2011 (UTC)

Also, as far as I'm aware, automobile engines aren't sold by capacity in the same way that Ethernet cables are sold by length, gasoline is sold by volume, food is sold by weight, and so on. If a cannery produced cans of corn labeled "15 oz" that contained only 14.75 ounces, or a filling station charged you for 10 gallons when you only pumped 9.9, you can bet they'd find themselves in trouble pretty quick. —Bkell (talk) 02:51, 21 April 2011 (UTC)

The reason for the precision is that, in the US as well as most other countries, consumer protection laws require that products be labeled accurately, or else it's considered false advertising, and fines can ensue. It certainly seems to me that a 1/8th-inch error across a span of 50 feet wouldn't count as false advertising, but maybe somebody in the legal department thought that since the "shortage" compared to 50 feet is consistent, they'd better be as truthful as possible on the packaging. Comet Tuttle (talk) 18:24, 21 April 2011 (UTC)

The difference is 1/8 foot, or 1½ inches, not just 1/8 inch. —Bkell (talk) 22:25, 21 April 2011 (UTC)

Aside: I found 49-7/8' very hard to interpret. Is this a standard method? I presume that this is parsed as 49 (- separator meaning "and" or "plus") 7/8 (' feet) more conventionally known as 49.875'. It was the - sign that threw me at first. -- SGBailey (talk)

That's a common convention in the United States when measurements include a whole number and a fraction, though it's more often seen with inches (e.g., 4-3/8″) because non-integer inch measurements are commonly expressed with fractions rather than decimals. (Most rulers and tape measures mark off eighths or sixteenths of an inch rather than tenths.) It's unusual to see a measurement that uses eighths of a foot. —Bkell (talk) 15:27, 21 April 2011 (UTC)

Just a thought. It could be a typo, intended to read 4' 9-7/8" i.e. 57.875" or 1470 mm. This might be 1.5 m of cable, less whatever is lost in making the connections. AndyTheGrump (talk) 19:42, 21 April 2011 (UTC)

Thanks for all the responses. There are a few things that could be in play here. Labeling laws, cord length with connectors vs. without, etc. As I said, I was doing a search for Ethernet cable and these are the results. You'll find the 49-7/8' cable near the bottom right above another cable that is labeled as 25-3/8'. Anyone care to explain away the 5/8'? That's more than enough to put connectors on the end. What drew my attention to it so dramatically is the fact that these two "odd" (for lack of a better word) cable lengths are after several other cables whose lengths are even (not partial) number of feet, 6, 14, 50, etc. Dismas|^(talk) 19:58, 21 April 2011 (UTC)

One further thought. Most metals and I assume plastics expand and contract slightly with temperature. How much is 50 feet of cable likely to vary in length over the usual range of temperatures it's likely to be exposed to? Maybe the length is actually measured at, say, NTP - "Normal Temperature and Pressure" - which stipulates 20C, but for legal reasons has to be quoted at, say, STP - "Standard Temperature and Pressure" stipulating 0C, at which temperature it would be slightly shorter: I remember the difference being mentioned as important in Physics and Chemistry classes, with the added joke that the US favoured higher-temperature standards because many of its labs are in sunny California, while impoverished UK scientists found zero Celsius closer to their everyday reality. It would be reasonable for there to be a minimum standard of accuracy, which length variations for cables shorter than 50 feet might not exceed. {The poster formerly known as 87.81.230.195} 90.197.66.111 (talk) 00:12, 22 April 2011 (UTC)

Facebook info page

Hello. The "help" page at Facebook is virtually useless, so I decided to come here and talk to real people. When I set up my Info page, I entered the name of my employer. At the time, the company did not have a Facebook page, so it linked to a blank generic site with the employer name at top. The company has since started a Facebook page, but I can't seem to get the old link to go away. I deleted the employer from my info page, and tried entering it back in as a new employer, but it still takes me to the generic page. How do I make the proper link? Thank you kindly. — Michael J 23:48, 20 April 2011 (UTC)

I can only think the employer is not deleting properly. I don't mean to tell you how to suck eggs, but I'll go through step by step.

1. Go to your Profile.
2. Go to 'Edit profile' (at top).
3. Go to 'Education and work' (at left).
4. At the right of your 'Employer' click the cross next to where it says 'Edit' (don't click Edit, click the cross beside it which will delete the employer)
5. A dialogue box will come up and you must then click 'Confirm'. Your employer field should then be blank.
6. At this point I would return to your profile; there is a 'View my profile' button just above the employer field to do this, or click the usual 'Profile' link at the top of the page - note that this step should not be necessary, but it's worthwhile to do to confirm that the employer is definitely deleted.
7. At the top of your profile it should now have an 'Add your current work information' link, where it used to list your generic employer. If so, this is good - click the link and continue below; if not, it hasn't deleted properly and you need to go back and delete it again.
8. Now back in the 'edit profile' screen, start typing your employer's name again. A list of possibilities should show up. Keep typing the exact name of your employer's page and it should eventually show up in the list. If it doesn't show up, chances are you're making a typo somewhere. You need to go and find your employer's page and check the exact name they're using. They do have to match.
9. Once you see your actual employer click on the name and it will add to the Employer field. A blue button should then show up that says 'Add job'. You must then click on this to actually add the new job.
10. If you now return to your profile the proper employer should be listed.

This should work, but it seems with FB there's no guarantees. --jjron (talk) 15:07, 21 April 2011 (UTC)

April 21

Font fallback

I know that in html and css I can specify a font fallback list, but where does Windows 7 get its fallback list from please? When I do some maths characters and set default serif and nothing else then I notice that Internet Explorer and Word on my machine seem to choose in order from Times New Roman, MS Mincho, Arial Unicode MS. Dmcq (talk) 08:04, 21 April 2011 (UTC)

Provide a web font with the characters you require and you won't have to worry about it. ¦ Reisio (talk) 22:15, 21 April 2011 (UTC)

Making a function that returns a dynamic array in C++

After having spent many years programming in higher-level languages, I've finally decided to buckle down and learn a lower-level one, specifically C++. I've just started and I've run in to some trouble already. I was making something where I needed a function that returned a dynamically generated array, where I wouldn't know going into it how big it would be, so that I would also have to return the final size of it. Since a C++-function only returns one value, I figured that I would have it return the size of the array, and one of the arguments would be a pointer to the array that I passed by reference, so that that pointer would point to the start of the array when the function would finish.

However, no matter how much I tried, I couldn't make it work. I couldn't figure out the right configuration of asterisks and ampersands in the pointer to have it do anything other than segfault. What I finally did is that I reversed the size-variable and the array; the function now returned the array pointer and the size-variable was passed by reference as an argument. I pasted some code showing how I did it below.

It works, but it doesn't seem to me to be the best solution. Or maybe it is, and I'm just kidding myself. I figure since this is something that proper grown-up C++ coders presumably must handle all the time, there's probably a "standard" way to do it. If anyone can enlighten me as to the best way to solve the problem, I'd much appriciate it!

Some code

#include <iostream> #include <stdlib.h> #include <time.h> #define ENDL "\n" using namespace std; int* make_array(int*); int main() { int* a; //The array int s; //The size of the array a = make_array(&s); //Printing the results for(int i = 0; i<s; i++) cout << a[i] << ENDL; } int* make_array(int* s) { srand(time(NULL)); int size = rand() % 10 + 5; //Making the size of the array random int* v = new int[size]; //Filling it with something for(int i = 0; i<size; i++) v[i] = 2*i; *s = size; return v; }

By the way, feel free to comment on anything else you might think of with this code. I'm just learning, maybe I'm doing something else really stupid or something, and I'd appreciate the feedback. Thanks! 83.250.233.57 (talk) 11:42, 21 April 2011 (UTC)

That's fair enough (I'm sure "real" C++ programmers, which I am not, will feel you should use a datastructure like a Vector rather than a native array). If you want to have make_array return the count and change the data called, you'd say

int make_array2(int** data)
{
    srand(time(NULL));
    int size = rand() % 10 + 5; //Making the size of the array random
    int* v = new int[size];
 
    //Filling it with something
    for(int i = 0; i<size; i++) 
        v[i] = 2*i;
 
    *data = v;
    return size;
}

which you'd call with s = make_array2(&a); -- Finlay McWalter ☻ Talk 11:57, 21 April 2011 (UTC)

Your code is fine, really. You don't need to #define ENDL because there's already an endl manipulator in std. And if you put main() at the end, you don't need to forward-declare make_array() -- Finlay McWalter ☻ Talk 12:03, 21 April 2011 (UTC)

You know, that solution seems so damn obvious now, I don't know how I couldn't figure it out! Thanks! 83.250.233.57 (talk) 12:08, 21 April 2011 (UTC)

Actually you can simplify the above further, by simply saying *data = new int[size]; and dispense with v altogether. -- Finlay McWalter ☻ Talk 12:12, 21 April 2011 (UTC)

I always forward-declare everything, because I figure I might at some point change the code so that it calls a function before it's defined, and it's less work to write the declarations than to recognize the error messages and rearrange the function order. Don't know if this is "proper" style or not. I too get paranoid about doing things properly.  Card Zero  (talk) 13:58, 21 April 2011 (UTC)

There is no right way to write in C, only an endless variety of wrong ways. :) -- Finlay McWalter ☻ Talk 15:27, 21 April 2011 (UTC)

If you meant C++, then I disagree. Even if you meant C, I disagree. -- BenRG (talk) 22:16, 21 April 2011 (UTC)

Don't use new. Use a vector, like this:

      vector<int> make_array()
      {
          srand(time(NULL));
          int size = rand() % 10 + 5;
          vector<int> v(size);

          for (int i = 0; i < size; i++) 
              v[i] = 2*i;

          return v;
      }

If you're learning C++ from a tutorial or book that tells you to use new, find a better tutorial or book. Fortunately, it's easy to tell the good ones from the bad ones: the bad ones mention new early on. (And the really bad ones mention malloc.) -- BenRG (talk) 22:16, 21 April 2011 (UTC)

Do the high level chess AI programs use Bayesian networks?

Subject says it all. 20.137.18.50 (talk) 14:18, 21 April 2011 (UTC)

Not that I know of. Chess is a perfect information game. Bayesian networks are good at dealing with uncertainty. One can imagine some use of them, but it would be fairly contrived. --Stephan Schulz (talk) 14:23, 21 April 2011 (UTC)

I see, thanks for pointing out perfect information. Maybe with the AI card game programs like poker (assuming the computer opponent thread doesn't have access to the player's cards). 20.137.18.50 (talk) 14:40, 21 April 2011 (UTC)

Thinking about it again, though, Stephan Schulz, if the computer were playing against someone with a reviewable history, like Garry Kasparov, the computer could identify a style and calculate probabilities of how often a player does so and so in such and such situation. The other player's mind is an unknown, and maybe their proclivities will lead them in other directions than that of a completely logical move. I think I read somewhere that Kasparov did anticipate that the computer would think he would take a certain move (that he could see a computer would calculate as better at the moment) and used that knowledge to his advantage. 20.137.18.50 (talk) 14:57, 21 April 2011 (UTC)

I don't think there's enough information to train it. What you're interested in is not a general summary of how Garry Kasparov plays chess in general, but how he'll play in this specific move. So you'd need lots of examples of this specific position, or one very very like it. He's played a lot of chess, but it's quite varied (problem space is very divergent), and not yielding the huge amounts of info that say a spam filter sees. You might end up with some rule that "knows" that Garry Kasparov likes using knights in the 6th file, but that just gives you a (probably) slight statistical weight, and isn't much use for formulating a strategy. Bayesian inference really isn't that powerful, anyway - the most obvious case is in filtering spam: it does a pretty good job, but it's still a poor substitute for you or I (that is, it only rejects spam we humans would trivially identify as such). Figuring out what move to play isn't a trivial task for anyone, so I doubt Bayesian analysis would really help. I suppose if your expensive tree-traversal algorithm was running out of time (and couldn't afford to do another layer of traversal) then a Bayesian guess to pick between candidate moves might be worthwhile - but it'd be statistical icing on a very brute-force cake. -- Finlay McWalter ☻ Talk 15:53, 21 April 2011 (UTC)

Where does Firefox 4 store its bookmarks?

My PC at work has been re-imagined from Win XP to Win 7. I neglected to export my bookmarks from Firefox before the re-image but I have a back up of my whole hard drive that I can access. I thought that all I would need to do is copy my bookmarks.html file from my backup to my computer but apparently Firefox doesn't store my bookmarks in this file. Anyone know where they're stored? I know its my fault for not doing an export before the re-image but the data has to be stored somewhere where its recoverable. A Quest For Knowledge (talk) 14:28, 21 April 2011 (UTC)

places.sqlite (in the same profile dir as the old bookmarks.html). You can browse it with the sqlite-manager plugin. I think Firefox 3 used sqlite too. -- Finlay McWalter ☻ Talk 15:39, 21 April 2011 (UTC)

Yep, it did. More information on Profiles and how to recover them here. --jjron (talk) 15:47, 21 April 2011 (UTC)

You can just copy the contents of your old profile directory into and over a new profile directory. ¦ Reisio (talk) 22:16, 21 April 2011 (UTC)

Backing Up A Computer

Right, I have not addressed this before, simply because I think that backing up a computer (i.e. copying the entire hard disk) is going to take up double the amount of space that your hard disk has, because by definiton, copying something means reduplicating it, and if you only have one hard drive, then where do you copy it to? Thing is, I'm very interested in why there are so many softwares out there (yes, I use plural for this) blerting out that they will help you backup. How? I mean, I have 20GB left from a 250GB HDD. I would like to ask once and for all, are these 'backup' thingies only for instances when you have an external drive (of the same size or bigger than your partition)? An example of what I am being told is here.

We have a whole article on this: backup. Your intuition about disk space is not quite correct. If you simply copied all the files, then the backup would take up as much space as the original files (not as much space as the whole hard disk). But every decent backup program also compresses your files while copying them, so the backup will take a bit less space than the original files. Another reason there are many backup programs — we've got a list at list of backup software — is whether they support convenient features like incremental backup, or a mirror backup, sector by sector, of the hard disk. Also, lots of backup software lets you back up your hard disk (or your "My Documents" folder only, or whatever) to optical discs like DVD+R discs. Having a second hard disk is much more convenient for backups, of course, than inserting 50 DVD discs in a row. There are also services like Mozy that cost like US$5 per month which back up your computer's data to servers located God-Knows-Where on the Internet; this is even more convenient. You should definitely back up your important files, though. The correct attitude to adopt is: It's not a question of whether your hard disk will fail and lose data. It is a question of when. Comet Tuttle (talk) 18:15, 21 April 2011 (UTC)

how to monitor cumulative bandwidth - windows vista

I use T-Mobile stick (MF100 web stick) which comes with connection software that just so "happens" to not work when it comes to tracking usage (the data record window is blank). Obviously this is T-Mobile wanting to keep its customers from seeing their data usage and changing their habits accordingly.

But anyhoo, is there some free Windows Vista software I can install that just lets me see all cumulative uploads and downloads? Or do I have to keep waiting to get the next SMS through the software, saying I've again used up my top-up allowance.

Thanks. 79.122.79.3 (talk) 18:44, 21 April 2011 (UTC)

Windows Task Manager can show your cumulative data transmitted up and down on each network interface. You may need to enable "cumulative statistics", explained in our article subsection. Windows can report total bytes uploaded, downloaded, and other more technical network diagnostics.

If you need more detail, or want cumulative data across multiple system reboots, you can use Network Diagnostics in the Windows Event Log, explained here. Nimur (talk) 19:41, 21 April 2011 (UTC)

Custom Cursors in HTML5

If you do

<html>
<head>
</head>

<body>

<div style="background-color:red; cursor:url(pen.cur)">Test</div>

</body>
</html>

where "pen.cur" is a standard Windows cursor file, this cursor will be used when the mouse is hovering the DIV.

But if you insist on the document's being a HTML 5 document, that is, if you write

<!DOCTYPE HTML>

<html>
<head>
</head>

<body>

<div style="background-color:red; cursor:url(pen.cur)">Test</div>

</body>
</html>

it doesn't work anymore. I have tried this in Internet Explorer 9 and Google Chrome 10. What's going on here? --83.183.172.203 (talk) 19:54, 21 April 2011 (UTC)

It's not uncommon for browser engines rendering in a legacy quirks mode (because of a lack of a doctype declaration, for example), to be more forgiving to malformed CSS. This includes things like omitting required units in code like height: 200; which should be height: 200px;, and also things like this, omitting a comma separator and value name. The W3C CSS validator would have pointed this out to you. What you probably want is something like cursor: url(pen.cur), default;, and to always, always use a doctype declaration that validates properly, which has no characters whatsoever before it. ¦ Reisio (talk) 22:33, 21 April 2011 (UTC)

research question related to Apple product history?

Are the leather Smart Covers the first leather product Apple has directly sold (as opposed to third-party leather products) in its history? I'm having difficulty finding an answer to this question. It seems that there are maybe a couple of niche cases, but I can't decide if Apple made them. Anyway, my question relates mainly to mainstream products that Apple is targeting at a lot of people: is the smart-cover in leather the first such leather product? Thanks. 188.156.7.193 (talk) 20:14, 21 April 2011 (UTC)

The Twentieth Anniversary Macintosh had leather wrist pads. -- Finlay McWalter ☻ Talk 21:36, 21 April 2011 (UTC)

Thank you, nice response. The article states that it was a "limited-edition" personal computer, and further, that it was delivered by a door-to-door concierge service. It's still a good example though! Anything else like that, anyone? Maybe something a little more "mass-market"? 188.157.186.22 (talk) 23:43, 21 April 2011 (UTC)

StartManSvc.exe

How can I get StartManSvc.exe off my computer? Corvus cornix_talk 21:49, 21 April 2011 (UTC)

Searching Google suggests it's part of the install of several PC Tools products, including their Spyware Doctor system. -- Finlay McWalter ☻ Talk 22:05, 21 April 2011 (UTC)

If it is a service, as the file name suggests, then you can stop it and set it to "Disabled" to prevent it from starting in the future. The article Windows service explains how. Uninstalling PC Tools would also work, and might be a good idea, since there are probably free programs that will do a better job of whatever PC Tools is doing. -- BenRG (talk) 22:44, 21 April 2011 (UTC)

I don't have Spyware Doctor or PC Tools in my list of programs, and I don't have Windows service in my Control Panel. Corvus cornix_talk 01:11, 22 April 2011 (UTC)