Welcome to the computing section
of the Wikipedia reference desk.

Select a section:

WP:RD/C

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.

December 28

Why isn't "United States" is not on the list for Countries on YouTube on account settings?

Venustar84 (talk) 04:20, 28 December 2013 (UTC)[reply]

This is NOT a computational question. No concepts of Computer Science can explain this observation. Perhaps you should post this question in the Humanities section. 220.239.51.150 (talk) 06:41, 28 December 2013 (UTC)[reply]

I think it's fine to post Q's related to computers here. As for the answer, I would guess that US is the default, so you don't have to select it. I've seen this in other US-based sites, where the largest group of users is in the US, so they assume that each user is in the US, unless told otherwise. StuRat (talk) 14:18, 28 December 2013 (UTC)[reply]

Type punning and CPU microarchitecture

Do modern Intel and AMD CPUs have microarchitectural limitations that would affect the performance of a program that accessed both members of a C/C++ union {int; float} or union {long; double} in the same inner loop? Is this an exception to the general rule that a mix of integer and floating-point arithmetic improves instruction-level parallelism compared to using one or other exclusively? For example, does the FPU have a separate register file, and if so, do transfers between an integer register and a floating-point register have to go through the cache? Neon Merlin 06:40, 28 December 2013 (UTC)[reply]

I don't know enough to answer the general question but processors using AMD's Bulldozer (microarchitecture)'s have modules which (again this is probably over simplified) have the performance of two independent cores (albeit with shared L2 cache and some other portions) for integer calculations but only really have sufficient resources to perform as one for floating point. I imagine this is likely to have an effect if you're combining floating point and integer compared to just integer although probably in complicated ways (e.g. [1] suggests if one of the cores is dedicated to floating point and one to integer you should get roughly the performance you would expect from two cores). I would imagine though if you're running two such loops, one per core you would generally expect it to be slower if it mixes the two on a Bulldozer microarchitecture process than if you were running two such loops that only use integer although it would likely depend on your specific code as my understanding is considering all the optimisations and other features, it's frequently impossible to predict predict precisely how fast any specific code will run without benchmarking when you make such substanially changes. Nil Einne (talk) 07:24, 28 December 2013 (UTC)[reply]

SSE floating point uses registers that also support integer operations and can be transferred directly to and from general purpose registers, but the x87 FPU has its own register file and the only way to transfer those bits to/from a general purpose register is via memory. Aside from that, I'm pretty sure there are no performance problems with type punning. If there are they'll be documented somewhere in the official manuals. For Intel you probably want this one and AMD's should be here somewhere.

On a related note, using a union for type punning is not safe. The C and C++ standards permit the compiler to assume that variables of different non-char types don't alias, even if they're members of the same union. This means, for example, that the load from one union member might be reordered before the store to the other. The only safe way to do what you want is with memcpy or some equivalent. A modern compiler with optimizations on and an intrinsic memcpy will probably produce optimal code from this. That said, the Win32 API uses unions for punning, so any C or C++ compiler that works on Windows must be stricter about aliasing than the standard requires. But I don't know whether they're stricter always or if there's some magic in the Windows header files. -- BenRG (talk) 08:22, 28 December 2013 (UTC)[reply]

NeonMerlin, the behavior also depends on whether your instructions - punned or non-punned - imply a data hazard due to writeback. If so, then any correctly-functioning CPU will stall until the hazard clears, forcing serialization and creating a pipeline bubble in your intended instruction-level parallelism.

If floating-point hardware acceleration has a separate register bank, you can bet that any correctly-functioning CPU must use a snooping algorithm to check for data-hazards: data shared across two banks must either be guaranteed coherent or guaranteed to have serial-only access.

Here's a good read, right at the edge of the state of the art: Architecture-Independent Data Flow Tracking, from the fine folks who brought you the LLVM compiler technology. In this case, "architecture independence" means the same high-level llvm compiler logic works on the CPU, the FPU, the whatever-Intel's-latest-AVX accelerator, the ARM core, the ARM Neon core, ... this is quite different from, say, gcc, in which the gnu intermediate representation language was compiled by a specific piece of back-end logic based on its pre-determined target, excluding an entire category of possible optimizations. Nimur (talk) 15:39, 28 December 2013 (UTC)[reply]

As far as I know the Intel core processors apply register renaming to memory locations as well as to registers so the value stored to memory may be passed back to a following instruction without reading the cache. Besides compilers can often avoid actual memory reads and writes for type conversion using unions. Dmcq (talk) 17:40, 28 December 2013 (UTC)[reply]

The paper you linked seems irrelevant. The question is about x86 CPUs specifically, and it's about speed, not instruction semantics. -- BenRG (talk) 21:39, 29 December 2013 (UTC)[reply]

You should be okay directly changing a union in C, see [2]. I really don't see C++ violating that. The strict standards way if you're desperate is to use memcpy but I think that will lead to more bugs than it solves! Dmcq (talk) 15:57, 28 December 2013 (UTC)[reply]

According to that document, C99 added a paragraph allowing type punning through unions, which I didn't know. The original C++ standard doesn't include that paragraph, or anything else from C99. The document is careful to say that the union solution doesn't work in C++, presumably meaning the original standard. I don't know whether C++11 added the paragraph (though it seems likely). Compilers can still use the old rules if you don't compile in C99 mode (or C++11 mode, maybe). The document that I linked recommends using memcpy for maximum portability, and says that it's just as efficient as the union solution in gcc 4.4.1. -- BenRG (talk) 21:39, 29 December 2013 (UTC)[reply]

As to the original question yes some processor implementations have a problem moving between ints and floats and it takes longer than one might expect. This can affect some code that for instance looks at the exponent of a floating point number and chooses different cases dependent on that. Dmcq (talk) 16:03, 28 December 2013 (UTC)[reply]

Are photos from here copyrighted?

I want to use photos of peoples in my android app.
I understood that certain people wouldn't want me to use their photos... Can I use photos from wiki-commons without a problem? br /> If its a problem - can I upload a new version for the app anytime someone asks me to remove him, or would I be sued? br /> The app should be free, with commercials (if that matters). רן כהן (talk) 17:01, 28 December 2013 (UTC)[reply]

Just because an image is hosted on Wikimedia Commons does not mean you may freely use it for all purposes. Many image licenses specifically forbid commercial re-use.

Each image has a license tag stating how it may be used. Even still, you should use caution, as some images may be incorrectly labeled. Nimur (talk) 17:16, 28 December 2013 (UTC)[reply]

I would suggest Commons:Commons:Reusing content outside Wikimedia before anything.

Anyway, for clarification, Wikimedia Commons does not allow any form of nonfree media. The definition of free used by wikimedia commons, as with wikipedia and all wikimedia licences, requires that the content including derivatives be reusable for any purpose provide they obey the other terms. The terms may require you give attribution, include the licence and share the content under a compatible licence and some other things, but cannot restriction you from using it for certain purposes like commercial ones (beyond the burdens obeying the licence may place on any commercial aims).

In other words, while you do have to obey the terms of the licence, the licence cannot forbid commercial re-use. (While some other free content projects may include allow such restrictions, many definitions of free content don't allow such restrictions.) Edit: Actually more correctly, while the content could include a licence preventing commercial use, it will also need another free licence which does allow such use.

You are right that either way, beyond obeying the terms of the licence, reusers should bear in mind we try to but have no way to stop content being mislabelled.

In addition, for cases where the content is in the public domain or where otherwise the content is claimed free based on some element being uncopyrightable, wikimedia commons only requires this for the country of origin and the US. The former because this hopefully means it will be likewise in other countries. But the later because it's not always the case. (And if the material has been taken from somewhere else like a website, we require it be free in the country of that as well.)

Note that the policy Commons:Commons:Licensing is sometimes said to be free in the country of origin and US but if someone tried to release content under a free licence but only for the US and where they live, their content will almost definitely be rejected. (Or will be if anyone who knows enough sees it.)

But anyway, the main point is that, if you live outside the US, you have to consider the possibility the content could actually be covered by copyright and non-free in your jurisdiction even if it is in the US and in the country of origin. And even if you live in the US, there's plenty of cases like Commons:Commons:Requests for comment/Non-US Freedom of Panorama under US copyright law and possibly Commons:Commons:Copyright rules by subject matter#Graffiti (although it looks like we may have gotten better here since I raised the issue) where we are uncertain (or not uncertain but wrong) of how US courts would treat the copyright claims but allow them anyway.

Oh and if you so happen to be in the country of origin, bear in mind there are a few cases there the wikimedia commons doesn't require the content be free in the country of origin (like faithful reproductions of public domain 2D artwork).

Also we only care about copyright restrictions. There may be some non copyright restrictions which will apply to reusers but not to wikimedia commons, particularly in the case of commercial reusers and images of living people.

And remember, even if your use is perfectly fine under US or whatever country law, this doesn't stop someone taking you through a long court battle.

P.S. As a final example of how careful you have to be, some of the licences we allow such as the Creative Commons ones, allow licensors to specify the manner of attribution. It's generally suggest our ToU [3] limit how wikimedia contributors may request attribution although IANAL it doesn't seem so clear cut to me for non text. But either way we will accept content from elsewhere which does specify a different manner of attribution. From some experience I would have to say I'm not sure how well people actually pay attention to such things even on wikimedia projects.

For example images which require visible in image attribution may be allowed even though we don't like such things and people may even remove the attribution. Or images which require attribution in the caption of wherever the image appears even though we don't actually follow that most of the time. So far, this hasn't cause any major problems to use, but a reuser may not be so lucky. Hence as said before, you will need to check the terms yourself, even if you discount all the other potential pitfalls.

Nil Einne (talk) 17:35, 29 December 2013 (UTC)[reply]

How to edit a BCD file?

Hello there,

I just tried to open my BCD file (Windows 7) and realized that it is all encrypted. I have two OS's and I have to remove mentioning of one of them to clear the way for Linux. I remember years ago BCD files were plain text, easily editable. Not anymore. Any suggestions? Thanks --AboutFace 22 (talk) 18:01, 28 December 2013 (UTC)[reply]

There are binary editors that will display the source as some combo of octal, hex, decimal, and ASCII. One I used a long time ago was called beav (for Binary Editor And Viewer). As I recall, you couldn't shorten or lengthen the file, as they use direct memory addressing and that would cause the index to point to the wrong place, but you could change text strings to new ones of the same length (possibly including spaces). So, rather painful to use, but it is possible to edit a binary directly using such tools. I found it most useful to fix annoying typos in executables, where I didn't have the source code. StuRat (talk) 18:15, 28 December 2013 (UTC)[reply]

OK, I just found out that bcdedit.exe located in Windows\system32 is the answer but this is what happens. When I try to run it it flashes cmd prompt which then disappears. So, I went to cmd prompt, ran it as administrator and was able to print the content. Now I have to find out how to edit it. OMG, I forgot so many things! StuRat, thank you. It is interesting. --AboutFace 22 (talk) 18:19, 28 December 2013 (UTC)[reply]

OK, there is a bcdedit command in cmd prompt DOS emulation and most likely I will be able to edit the bcd file with no problems. --AboutFace 22 (talk) 18:42, 28 December 2013 (UTC)[reply]

Cool. This is a good opportunity for you to refresh your old knowledge, before it's lost for good. StuRat (talk) 21:07, 28 December 2013 (UTC)[reply]

Refresh rate on power consumption.

I just got a second monitor, which I'm not going to use for games or anything more than multitasking stuff. Would it save any amount of power to change the refresh rate to 50 from 60Hz? Is there any point to turn the refresh rate down? This was question that popped into my head when I was setting it up. Thanks. Bluefist ^talk 21:17, 28 December 2013 (UTC)[reply]

I wouldn't expect a significant power savings. AFAIK, the only reason to lower the refresh rate is if it doesn't display properly at the higher rate. StuRat (talk) 07:57, 29 December 2013 (UTC)[reply]

Unicode characters in Firefox

I'm somewhat ashamed to ask as I'm usually the IT guy myself, and I did enjoy this cool video about how Unicode is supposed to work. In theory. Yet I can't get it to work on my own PC. All I see is FireFox (or Windows XP itself, maybe) giving up, showing a little box with numbers in it. Even Google lets me down on this. TIA! Joepnl (talk) 23:56, 28 December 2013 (UTC)[reply]

If you see a little box with numbers, it means that the font Firefox is using does not support the characters you are asking it to display. Looie496 (talk) 01:03, 29 December 2013 (UTC)[reply]

Yes, maybe Help:Multilingual support can help. At http://rishida.net/tools/conversion/ you can copy-paste the characters into the "Characters" field and click "View names" to see the names of the charaters and see them as graphics. PrimeHunter (talk) 00:44, 30 December 2013 (UTC)[reply]

Mmm, Tahoma doesn't work either. Even a font called Unicode doesn't. Joepnl (talk) 21:54, 2 January 2014 (UTC)[reply]

December 29

How can a compromised BIOS compromise the security of a computer?

As I understand it, a BIOS will just boot (or not) and pass control to a OS, but the OS doesn't need to call it after it's running, nor will it need parameters from the BIOS as to how to run. So, how would an attacker exploit it? (if at all) Isn't the OS isolated from the BIOS? OsmanRF34 (talk) 13:29, 29 December 2013 (UTC)[reply]

It's still possible to read from it in some way, and the fact that certain laptops come with firmware-based rootkits for security purposes make it viable for a BIOS or an EFI firmware to be tainted and/or used for malicious purposes. Writing to the ROM in a platform-independent manner is another story - a surefire way to rig the BIOS would be manipulating the PC yourself and flashing it with a hacked one. Blake Gripling (talk) 14:13, 29 December 2013 (UTC)[reply]

The BIOS has a lot of power. It could, for example, arrange for malicious code to run in System Management Mode after the OS has started. Or it could force the OS to boot in a VM. Or it could reprogram other motherboard components. Many motherboards have an embedded controller that runs code even in sleep/standby mode. -- BenRG (talk) 21:51, 29 December 2013 (UTC)[reply]

It is possible to install a key logger into the bios. Vespine (talk) 00:19, 30 December 2013 (UTC)[reply]

What Is New in Windows Server 2012

Well, I have this question. I do have an installation disk for Win Server 2008 (x64) and one option is to install it on my newly cleared second disk drive. The second option is either to subscribe to MSDN and get WinServ 2012 from there or purchase Win Server 2012 new disk alone which will be less than half the price. The description of Win Server 2012 new features is available here and here (R2). My question is: Is there anybody here with a good knowledge of both versions who could confirm that owing WinServer 2012 offers a major advantage? Thanks. --AboutFace 22 (talk) 18:04, 29 December 2013 (UTC)[reply]

What is your purpose for this server? We use 2008r2 where I work and no one is in a terrible rush to upgrade. But knowing what you are actually doing with the server might help make a more informed decision. Vespine (talk) 06:00, 30 December 2013 (UTC)[reply]

Thanks, Vespine. In the meantime this is what I ended up doing last night. I installed Windows Server 2008 on my freed and newly formatted second hard disk and was surprised to get more than a hundred upgrades. So, I assume it is now more close to Server 2012 with all the upgrades factored in. Hyper V is a part of the server and this will allow me to install any VM. And Vespine confirmed that with his first hand experience. Thanks --AboutFace 22 (talk) 17:59, 30 December 2013 (UTC)[reply]

Flickr fees vs free Flickr

I have subscribed to Flickr for years - paying $29.99 per year (I believe). I still get charged this amount on my credit card, however I have heard there is a free Flickr account possible with uploading large amounts of pictures. So, what is the advantage of me continueing to pay their annual fee? Does it get rid of advertising banners, that might come with a free Flickr account? They are a nousance, that I would rather not see. I'll even pay the fee NOT to see the advertising banners! Thanks for answering my dumb blonde question.--Christie the puppy lover (talk) 19:38, 29 December 2013 (UTC)[reply]

Surely you can easily find this info on Flickr it self. Google Flickr membership levels, I guarantee they have a page that compares the different accounts you can get. I'd do it for you but flickr is blocked where I work. Vespine (talk) 23:31, 29 December 2013 (UTC)[reply]

See Flickr#Accounts.--Shantavira|^{feed me} 11:11, 30 December 2013 (UTC)[reply]

Thank you gentlemen.Christie the puppy lover (talk) 16:43, 30 December 2013 (UTC)[reply]

How to print the escape character in UNIX?

Way back in the 1990s, I made a simple AmigaDOS shell script to toggle between the original and New Worlds versions of Utopia: The Creation of a Nation. I'd like to convert this script to a UNIX shell script so I could use it directly from Linux, without having to start up an Amiga emulator. I know enough about UNIX shell scripting for the most part, except for one thing: the AmigaDOS shell script uses ANSI colour graphics to print its messages in a pretty format. I think that ANSI colour graphics should work equally well under UNIX, but how do I make the script print the escape character, rather than having to write a physical escape character into the file? On AmigaDOS, the echo command understands *e to mean the escape character, but is there a similar thing in UNIX? JIP | Talk 20:18, 29 December 2013 (UTC)[reply]

At least in bash, you can say echo $'\e[36mCyan text'. In principle Unices support many different terminal types with unrelated control codes, but in practice, the codes listed in ANSI escape code will probably work. -- BenRG (talk) 21:10, 29 December 2013 (UTC)[reply]

I've been writing shell scripts (and emitting ANSI terminal escape sequences) for 30+ years, and I've never come across a way of doing this other than embedding the ESC character in my shell script, which is what I do all the time. —Steve Summit (talk) 23:34, 3 January 2014 (UTC)[reply]

If you don't like embedding the escape character all over the place, you could do it once:

e='␛'

(where that thing between the single quotes is a single ESC character), and then use it all over the place (remembering to use double quotes, so that the shell variable is expanded):

echo "$e[H$e[2J"

echo "$e[1mbold$e[m"

echo "$e[4munderlined$e[m"

—Steve Summit (talk) 01:09, 4 January 2014 (UTC)[reply]

December 30

Gfortran download (2nd attempt)

This is what I did. Google found me this website. From the list I chose "GFortranBinaries - GCC Wiki" link which led me to this page. There was a highlighted link: "MingW-w64" I clicked on that. That opened me this page. There was a button: "Download MinGW-W64" I clicked that and ended up on this page. There was a link highlighted there: "Download mingw-w64-v3.0.0.tar.bz2 (7.0 MB) " I clicked that. Then at the bottom of the page there was this security question: "Do you want to open or save mingW-W64-v3.0.0.tar.bz2 from hivelocity.d.sourceforge.net?" So, I saved it in downloads. So far nothing bad happened. I am doing it second time but the first time it wanted to open this file and I had no program to open it. I know there is a program on the web that can open bz2's. Before I go for it, I want to ask StuRat perhaps or someone else, familiar with this download if I am on the right track. Any help will be much appreciated. Thanks --AboutFace 22 (talk) 00:02, 30 December 2013 (UTC)[reply]

Right track? By my count you've made at least half a dozen decisions in this project, and every single one has been wrong. Everything you do just gets you farther off track, and it's just wasting everybody's time to ask for advice about it. Looie496 (talk) 02:36, 30 December 2013 (UTC)[reply]

Looie, could you be specific? You are big on generalities and you speak for other people for no reason. You were the one who insisted that I should use optimization on a task that do not allow it, which has no room for it. If you cannot say anything specific, just keep your mouth shut. Have you ever downloaded GFortran? What decisions did I make that are wrong? Be specific. --AboutFace 22 (talk) 03:31, 30 December 2013 (UTC)[reply]

Put even more bluntly, the OP is repeatedly failing to demonstrate the basic competence that is prerequisite for the task he is (claiming to be) undertaking. The style of questions, the types of trouble, the total lack of self-directed troubleshooting, all indicate a profoundly novice level of knowledge - despite the OP's claims of expertise. More than a few of us following along can clearly see that this task is beyond the OP's current capability. Either the OP is intentionally wasting our time, or he needs to seriously rethink his endeavor.

Many others have volunteered specific help and instructional websites, but you seem to be struggling with first-steps - and even struggling to follow step-by-step tutorials. Do you need help finding introductory book on computing, or help locating an introductory programming class in your region? Numerical programming in FORTRAN is not a simple task, and you are still struggling with simple tasks. We can direct you to .bz2, and we can even provide instructions on how to install and use software to decompress this archive file format; but we will not hand-hold you through every keystroke. You'll probably have to pay good money for that!

In closing, I have downloaded and installed gfortran, and even compiled from source, on many many many operating systems in many troublesome environments. Nonetheless, downloading and installing it on Windows should take a user just a few moments. When we - anonymous volunteers on the internet, with nothing to gain or lose from your efforts - when we see that the OP needs a few days or weeks for this task, we quickly recognize something is awry, and it's more likely PEBKAC than FORTRAN. Nimur (talk) 03:46, 30 December 2013 (UTC)[reply]

I think everyone is being too hard on About Face here. It's entirely possible to be an expert in Fortran yet never have downloaded anything before. This is because Fortran was often available at work, in a mainframe environment. Therefore, familiarity with downloading, decompression, web searches, etc., was not needed there, so we should help him out wherever we can.

As for his project, it may or may not work, but we should not discourage him from trying. Now, for the specific advice on how to decompress a tar/bz2 file, I use WinZip. It costs $30, but if you don't want to pay that, there's a free trial (30 days ?). They try to give you extra junk too, like AVG, but pick "customized download" and deselect all of that. I'm downloading Gfortran and WinZip on my new (Windows 7) PC now, to see if it all works smoothly here. I'll let you know how it goes.

So, keep at it, About Face, and you will become an expert in no time ! StuRat (talk) 14:42, 30 December 2013 (UTC)[reply]

UPDATE: I tried out what you were trying, About Face, and I was able to uncompress it with WinZip, but after that it seems to get rather complicated to install it. So, instead I found this YouTube video that walks us through a different download and install process: [4]. They download a version of MinGW which has options to include Gfortran with it. I just used that method successfully. I do have a few comments and suggestions that differ a bit from the video, though:

1) You need to pick on the "Installation + Apply changes" pull-down menu once you select the packages to download. (If you pick all the other languages it takes quite some time.)

2) If you don't want to change the $PATH in the dangerous way he does it, I believe you can change it just for the current Command Prompt window (but I forget how, does anybody here know ?). Or you can compile right in C:\MinGW\bin, then move the executable elsewhere.

3) If you don't specify the output file name when you compile, it creates "a.exe", and you can then rename it.

4) Rather than pick a.exe from a window, if you type in "a" (or the new name) at the Command Prompt window, it will run there without that annoying problem of it closing the window once the program completes. I usually leave the name a.exe until I test it and decide to keep that version, then I give it a better name and maybe move it to another folder.

5) Here's a simple "Hello world !" test program for it (I named mine hello.f):

         program hello
         print *,"Hello world !"
         end

I stored that in the in C:\MinGW\bin directory, then typed "gfortran hello.f" , then typed "a", and I got the expected output. Once you are able to do that, then we are ready to try your code. There might be problems if it's written for an older Fortran version or another operating system, so let me know if you get errors.StuRat (talk) 16:44, 30 December 2013 (UTC)[reply]

StuRat, why did you learn to store your source-code and your compiled program in the compiler's bin directory? More to the point, why do you feel the need to spread that antipattern to others?

This is exactly why Looie496 expressed such frustration. The OP is so lost, he's following advice from somebody who doesn't know what they're doing, which leads to more confusion. The best solution here is for the OP to find a programming class taught by a reputable, experienced teacher, and learn the correct way to do things. At this stage of the game, you don't have the experience to distinguish between good advice and bad advice. Nimur (talk) 17:11, 30 December 2013 (UTC)[reply]

I'm not suggesting that he does that permanently, just as an initial test. Once he establishes that it can compile, he can set up proper directories, environment variables, etc. (It's important to test things with one change at a time, so, if there's an error, you know exactly where it occurred.) Also note that if he does accidentally delete anything from the compiler's bin directory, he just has to download it again to fix that, so it's not a serious risk. Globally changing the $PATH variable, on the other hand, is risky. StuRat (talk) 17:13, 30 December 2013 (UTC)[reply]

If you're the sort of person who is paranoid about putting extra items on your path, then you should use a fully qualified path name to specify the compiler; you should not be moving your working-directory into the compiler's bin directory. If you're the sort of person who is paranoid about putting extra items on your path, why are you permitting write-access to the compiler's bin directory in the first place? Probably because you don't know why you're following these rules. They're just arbitrary arcana, and you aren't using logic and critical thinking to understand them. That's called cargo cult programming, and it leads to very bad accidents. Nimur (talk) 17:39, 30 December 2013 (UTC)[reply]

I don't think fully qualified path names always work, because, while they will find the initial compiler, they won't find other things in that bin directory which that compiler needs to do it's job. StuRat (talk) 17:44, 30 December 2013 (UTC)[reply]

StuRat, you aren't sure which executable programs you want to run, but you don't want to add anything to your path to prevent yourself from running an unknown program. But, you will allow an ordinary user to have write privileges to a directory that allows the user to execute code. In other words, you have no idea why you're following these rules, but you repeat them - half-correctly - to other people. Nimur (talk) 17:52, 30 December 2013 (UTC)[reply]

A common solution is to have a script set up your build environment. The PATH is only modified for terminals that have run the script. You can also use the makefile - a set of declarations can add a prefix (possibly from an environment variable) to each of your build tools. This is useful when working on projects with multiple toolchains, such as something that requires a cross-complile. Katie R (talk) 18:00, 30 December 2013 (UTC)[reply]

Yep, I've used those on larger projects, especially where there's a compile command followed by a link command. But gfortran does both with the single command, so when I just need to compile/link one program, it seems like overkill to use a makefile. StuRat (talk) 18:26, 30 December 2013 (UTC)[reply]

Unfortunately I don't have time now to read all new contributions but I only want to mention that I am really paranoid about software as one of the contributors guessed. I already ran into a trouble once with this download. I ended up with some Trojan or whatnot which eventually killed my OS to the point it could not start. I restored the OS from a system image. I will get back to this stuff on Jan 1. Happy New Year everyone. --AboutFace 22 (talk) 02:20, 31 December 2013 (UTC)[reply]

I can appreciate you being paranoid (I get like that when the Mother-in-law comes over to stay). Yet, if you could only beg-borrow-or-steel another machine and it solely load it with Linux, that would be cheaper in the long run that filling out a year's prescription of Xanax. Me thinks: you're torturing yourself (and us) for no good cause.--Aspro (talk) 14:59, 31 December 2013 (UTC)[reply]

Android -- setting status bar notification priority or grouping them

As in the title, is it possible? Ever since I updated to 4.3, the GOSMS status bar icon (for new SMS) often gets overwhelmed by the Twitter ones. I am rooted, so I don't mind flashing ROMs. I wouldn't even mind a paid app. What I'd like to do is either make some apps get priority for status bar space, or have the notifications grouped within a single icon, with possibly a small number indicating how many there are.

The abomination in question: http://i.imgur.com/SsOFDxQ.jpg — Preceding unsigned comment added by 24.201.128.254 (talk) 19:00, 30 December 2013 (UTC)[reply]

December 31

Linux sound routing

Basically I want for my sounds from Rhythmbox/VLC to be routed towards Dota 2, and I also need to route my mic to Dota 2 voice chat too. Usually I use PulseAudio Volume Control and set Dota 2 sound input toward monitor of the speaker (?) but using that I couldn't use my mic for voice chat and it also routes my Dota 2 sounds to voice chat, which is a bad thing. I have even tried using JACK and qjackctl, but I simply doesn't understand it 119.2.49.170 (talk) 23:33, 31 December 2013 (UTC)[reply]

January 1

Noob looking for help with Javascript

First of all, Happy New Year everyone. I want to add the TimeAgo JavaScript to my website. But I'm a total noob. I see the website has a "Download" link. Okay, so I download the JavaScript code. What am I supposed to do with it now? Upload it somewhere on my own site? Thanks.--94.215.21.230 (talk) 10:59, 1 January 2014 (UTC)[reply]

Htaccess rewrite rule in apache

I want to redirect: (1) http://mydomain.com/xyz to http://mydomain.com/mypage.php?url=xyz (2) http://mydomain.com/xyz/pqr to http://mydomain.com/mypage.php?url=xyz/pq (3) http://mydomain.com/xyz.jpg to http://mydomain.com/mypage.php?url=xyz.jpg

Only if the specified url doesn't exists. What can be htaccess rule or is there any other way? AmRit GhiMire 'Ranjit' (talk) 13:28, 1 January 2014 (UTC)[reply]

Email = postcard?

According to electronic envelope: ". Just like the postcard, where any postal worker handling the mail can read its contents, any server operator and programs from governments can read your E-mail (also "email")."

I thought that the email servers would communicate through secure means with each other. OsmanRF34 (talk) 16:53, 1 January 2014 (UTC)[reply]

Nope. That would require transport layer security, and the technology that we call email does not use it.

In principle, some email servers may choose to use secure transport sockets for some or all of the communication. But that type of security is not a technical requirement. In general, if you use email, you should assume that the message can be sent in plaintext across network links that you do not control.

This is why the technology Pretty Good Privacy, and its free software alternative GNU Privacy Guard, were created. These technologies allow you to provide encryption at the application layer. When you use such tools, you first encrypt your message securely, and then it is usually encoded in base 64 text and sent via email. That code text is still transmitted and received in "plain text," but because it was already encrypted, its plaintext form is meaningless unless the recipient has the key to decode and decrypt it back into the real plaintext message.

For comparison, technologies like Jabber do permit end-to-end transport layer security (provided that you correctly manage security settings and share the necessary keys securely). Conceivably, you could create a software application that looks and feels exactly like email, but is implemented under the hood by Jabber technology. The hard part would be getting an organization to adopt this technology. Email continues to exist - and will persist for many many years after better technologies can replace it - because unsecure communication is very convenient, and most organizations do not have the wherewithal to force a transition. Nimur (talk) 18:39, 1 January 2014 (UTC)[reply]

I work in IT for a international financial institution and we user TLS between servers, so the messages are encrypted over the network. HOWEVER I would like to add that it is actually a legal requirement that we be able to retrieve, recover and inspect company email in case of legal dispute or regulatory requirements. So we have to be able to read the email sent to and from our email servers. There are of course restrictions and approvals that need to take place before that happens, not anyone can just log on and do it, but we don't encrypt emails end to end not because we haven't bothered to 'adopt this technology', but because it is a legal requirement for us not to do so. Vespine (talk) 22:33, 1 January 2014 (UTC)[reply]

January 2

Wikipedia's SSL certificate wierdness

Dear Wikipedians:

How come https://en.mobile.wikipedia.org would trigger a certificate warning. Whereas https://mobile.wikipedia.org and https://en.m.wikipedia.org would not.

I know that a wildcard certificate is used: *.wikipedia.org. My logic goes as follows:

If the wildcard is used in the same sense as the UNIX wildcard, then https://en.mobile.wikipedia.org should be allowed.
If the wildcard does not permit further dots inside its representation, then https://en.m.wikipedia.org should be disallowed, yet it is allowed.
If mobile is somehow excepted, then https://mobile.wikipedia.org should be disallowed, yet it is allowed.

Much appreciated if someone can elucidate this situation.

Thanks,

184.148.180.144 (talk) 20:23, 2 January 2014 (UTC)[reply]

Need low-level tool for sending HTTP requests

I'm looking for a tool for sending HTTP requests. Something that runs on Windows. Specifically, I'm looking for something that will let me send an HTTP 1.0 request without a host header. Every tool I've tried forces me to include a host header. I've tried Fiddler and several others. I even tried writing my own tool using .NET but the .NET Framework adds host header even if you remove it. Can anyone recommend anything? AnonComputerGuy (talk) 20:40, 2 January 2014 (UTC)[reply]