Wikipedia:Reference desk/Archives/Computing/2012 April 30

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April 30

Screen anti-burn-in app ?

I had an idea for an app that could be used to counter screen burn-in on a computer monitor:

1) Establish a link between a cell phone with a video camera and the PC or TV in question.

2) Have the monitor fire each pixel in turn and record it's brightness on the cell phone. This would require a very good camera.

3) Once it has the map of the relative brightness of each pixel (or relative brightness of the RGB components of that pixel), it could then compensate by variably changing the brightness of each pixel in each displayed image. I'm not sure if any graphics card or TV could currently support tweaking each pixel like this, though.

So, is this an idea for the future, perhaps ? It sure would be nice to be able to fix expensive monitors and TVs up, so they are as good as new. StuRat (talk) 00:08, 30 April 2012 (UTC)

It strikes me, as a non-engineer, that it would require not only a good camera, but really quite controlled conditions for step 2 to work correctly. It doesn't sound like the kind of thing that would be doable by your average television owner unless it was something that was literally strapped to the television and came with its own light source. In the long term I would bet on pixels that don't burn out or are cheap to replace, not repair, but that's just my sense of the trends. --Mr.98 (talk) 00:41, 30 April 2012 (UTC)

I'm not talking about burnt-out pixels, as there's nothing to be done for them. I'm talking about dimmer pixels. This happened on old CRTs, but also can happen with other technologies. For example, I have various vertical stripes visible on my LCD monitor, which probably has to do with an uneven back-light. StuRat (talk) 00:52, 30 April 2012 (UTC)

The problem that I can see is that even at full brightness, the burned in pixels will still be dimmer then non burned in pixels. So at best you'll have half a temporary solution if the scene is dark by "overdriving" the burned in pixels, which will also most likely contribute to their even quicker and more substantial demise. Vespine (talk) 01:36, 30 April 2012 (UTC)

The current thinking seems to lean towards avoiding the problem in the first place. I can see no theoretical reason why your idea would not work (though there would have to be some interactive calibration to ensure that the correct pixels were identified). The problem as I see it is that the control software would have to be built in to the display driver, and this would be very expensive unless it became an international standard. Dbfirs 07:29, 30 April 2012 (UTC)

Professional imaging monitors, like these Eizo ColorEdge, are factory calibrated and come with equipment for field recalibration. They are expensive compared to consumer-grade monitors or televisions. On their website,myou can see camera-based calibration, and this brochure illustrates the field calibration process. Nimur (talk) 15:59, 30 April 2012 (UTC)

Thanks, so my idea does work. At some point in the future, when graphics cards allow individual pixel tweaking, and cell phone cameras are better, such an app may make sense, assuming we still have TVs/monitors subject to uneven pixel fading. StuRat (talk) 23:27, 30 April 2012 (UTC)

Thanks all, I will mark this resolved. StuRat (talk) 23:27, 30 April 2012 (UTC)

Resolved

Windows Movie Maker and MP3s

I am making a video with WMM and importing music to use. I want to use some MP3 files I bought on Amazon.com, but when I try to import them into the project it claims they are corrupted or not supported. WMM supports MP3s, and the files are not corrupted. All my tunes from CDs that I use do not do this. What is the cause and solution? 75.73.226.36 (talk) 02:23, 30 April 2012 (UTC)

I found a couple of forum posts that suggest converting to WMA before importing into WMM: [1] and [2] RudolfRed (talk) 03:14, 30 April 2012 (UTC)

It could be that your mp3's are variable bit-rate (VBR) and this is not supported by Moviemaker. You could export them as wav files from your player to use them. Zzubnik (talk) 12:34, 30 April 2012 (UTC)

I think that's it. According to Amazon, the MP3s are variable bit rate ("when possible"). I found that here: [3]. RudolfRed (talk) 17:17, 30 April 2012 (UTC)

Why does the IT department need BRMs - are they "worse" than other departments?

Someone pointed out to me that the IT department is the only department in most companies that needs Business Relationship Managers to align its work to the business. On thinking about this, other departments such as Legal, Accounts, etc. are just as capable of talking Jargon among themselves but have no difficulty communicating with the business, ensuring that they are working with the business, guiding the business, and even telling them "no that can't be done". Why is the IT department an exception? Is it to do with the perceptions of the business, some unique relationship between IT and business, or some inability to communicate in IT departments and staff? -- Q Chris (talk) 11:02, 30 April 2012 (UTC)

The IT department operates differently than many other departments. While Legal, Accounts, Sales, etc will operate on a normal schedule facilitating communication, IT and maintenance need to be running 24/7. Additionally, other departments are designed to work together with information flowing from one department to another in a scheduled manner. IT on the other hand is a department serving the rest of the company. They are on call for any needs that need to be addressed. This leads to IT operating much like a small company inside the larger one. 206.131.39.6 (talk) 15:28, 30 April 2012 (UTC)

Thanks, that makes sense. I suppose it is like a supplier representative for an external supplier. -- Q Chris (talk) 18:18, 30 April 2012 (UTC)

I'm reminded of the sitcom The IT Crowd where the computer nerds are incapable of communicating with anyone without insulting them. StuRat (talk) 19:27, 30 April 2012 (UTC)

Boot Linux from RAM

Is it true that with the following procedure, is is possible to have any distro run entirely in RAM?

1. create a tmpfs
2. copy everything under / into the tmpfs
3. and then execute chroot, or umounts the old filesystem + mounts the tmpfs as /.

Can you confirm this, or I'm missing something? --151.75.46.87 (talk) 12:44, 30 April 2012 (UTC)

In addition to chroot (which affects the file system), you'd also need the kernel to jump out to the newly updated kernel. This is not a feature of Linux. However, some enthusiasts have created Ksplice, which can be configured to perform something similar to this task (with significant limitations). This can fail for many reasons, and is only designed to splice certain parts of the kernel, but it has been successfully integrated into many versions of free and commercial Linux, including Ubuntu. Nimur (talk) 14:03, 30 April 2012 (UTC)

Ok, and what about booting from RAM? I know that there are some distros which are configured to boot from RAM automatically, like these ones, but can this be done with any distro, for example by providing an additional login script or such? --151.75.101.147 (talk) 14:10, 30 April 2012 (UTC)

As I mentioned, Linux does not include any ability for Linux kernel to arbitrarily jump to a different kernel (and, presumably, never to return). Nothing stops you from hacking up some type of kernel module that could do so - after all, Linux is open-source and free software; and a kmod can be dynamically loaded, and still execute in kernel space.. However, kernel modules that execute arbitrary code and steal control from the kernel are categorically defined as either "malware," "security flaws," or just "buggy." As far as "booting from RAM," we're essentially getting into semantics. What does "boot" mean to you? It means something very specific to Linux; and to most peripheral device drivers; so it's moot to talk of "booting" if those peripherals are already initialized. Nimur (talk) 14:18, 30 April 2012 (UTC)

I'd recommend you read up on, for example, Project Athena, a free and open source software methodology for running Linux and other *nixes, generally in large institutions like universities. The techniques used there - like networking your home and application directories - probably get you 99% of the things you actually care about, (like sandboxing, and being agnostic of what's actually on the machine's hard disk drive) without the hard technical details of actually jumping out of the kernel. Or, consider running a virtual machine, which abstracts the problem. Nimur (talk) 14:23, 30 April 2012 (UTC)

Maybe I should clarify that my question is related to this article. With Puppy Linux I can umount the medium after boot. However, I'm not able to figure out what kind of technique it uses. But I guess that, whatever it is, it could be applied to any other distro, in principle. So I can't understand why the sentence "Technically, other distributions can be made to boot from RAM as well" is marked as "citation needed". Hence my question. --151.75.101.147 (talk) 14:46, 30 April 2012 (UTC)

Aha! This clarification helps me understand your question. "Technically," "any" distribution could do anything, so this all-encompassing statement is false. I could build a variant of Linux that queries its boot medium every few microseconds - so it'd require the boot volume to remain present. Puppy Linux, Knoppix, and many similar distributions, have been carefully designed so that they don't require the boot volume - which is the exception, not the norm. Strictly, the Linux kernel itself tends to be pretty small; the kernel can live in RAM on many very-resource-constrained platforms. The peripherals: device drivers, user programs, resources like sound-effects and animations - all of these tend to balloon the system to a larger image, which must either be resident in memory, or accessible from a file system. Many distributions contain so much stuff - not just silly bloated resources, but even system stuff - things like redundant and failsafe copies of graphics drivers for different types of hardware. Many distributions contain X, and also package full-blown desktop managers like Gnome and KDE - that can be huge depending on what's included. So, to be very clear: technically, some distributions can not unmount their boot volume; they rely on system images larger than the available physical memory of their host machine. Knoppix and Puppy and some others are carefully designed around this constraint; and by ensuring that no program attempts to access data outside of the in-memory image, it is safe to unmount or eject the boot volume. There's no "special technique" for that: it's just a regular unmount of a regular volume once the system has guaranteed that it's finished copying needed data to main memory. Nimur (talk) 15:09, 30 April 2012 (UTC)

Thank you very much! --151.75.101.147 (talk) 15:22, 30 April 2012 (UTC)

You wouldn't need to jump into a new kernel, as the Linux kernel isn't paging itself - it runs entirely from RAM. Most distributions actually do the reverse of what you describe during the boot: they run from a completely-RAM filesystem (which is decompressed and mounting during boot: initrd). You could change the root back to a tmpfs after logging in using pivot_root. However, you cannot unmount the original filesystem as long as it still has processes running, as the usermode processes usually _are_ pageable and might want to access their data. I'd figure if you boot into bash instead of init (eg. init=/bin/sh on the kernel's command line), you could set up a tmpfs, pivot_root into it, and exec into a shell or init process on the new filesystem, and then unmount the original FS. The pivot_root manpage goes into a bit more detail on switching root filesystems. Unilynx (talk) 17:07, 30 April 2012 (UTC)

Thank very much to you also, I will try it. --151.75.51.8 (talk) 06:34, 2 May 2012 (UTC)

Nested Scrollbars

My problem is a website where there are pages with scrollable areas within scrollable areas within a scrollable window. It looks the same in IE and Chrome so it is not just a quirk of one browser. Of course I don't know that it will behave the same way for everyone.

Here's an example: http://www.durhamregiontransit.com/durham/index.aspx?CategoryID=92&lang=en-CA

A couple of steps are needed to reach the problem page. On the initial page, set "route #" to "401" (as one example) and click "get your route". On the new page that appears, set "time of day" to "all day" and click "get your schedule". Then you see the actual bus schedule and the multiple scrollbars.

I'm sure that this could be coded differently to avoid all these scrollbars. But for a user of the page, is there a way to drill down and get rid of the outer scrollbars?

Also, I wonder if there are worse examples, ie, more than three sets of scrollbars. Thanks, Wanderer57 (talk) 13:20, 30 April 2012 (UTC)

In Firefox (and surely others) one can right click on the right "content" frame and pick this_frame->show_only_this_frame, and we get only the content (not the navigation to the top and left). No, it's not a very friendly piece of design. -- Finlay McWalterჷTalk 13:48, 30 April 2012 (UTC)

Ubuntu + Windows

I have a double boot system, Windows + Ubuntu. When I try to take a look, under Windows, on the Ubuntu partition, I cannot see anything. Where is the installation? (Ubuntu is working). — Preceding unsigned comment added by OsmanRF34 (talk • contribs) 13:53, 30 April 2012 (UTC)

Windows supports a far smaller set of file systems than Linux. So you probably have your Ubuntu partition under a f.s. that Windows cannot read. See File_system#File_systems_and_operating_systems and Comparison_of_file_systems#Supporting_operating_systems. A solution (IMO it's not worth unless you *really* need it) would be to reformat the Ubuntu partition as FAT32 and then reinstall Ubuntu, but you would lose the advantages of a modern f.s., for example you would have the fragmentation issue, no journaling, etc. --151.75.101.147 (talk) 14:00, 30 April 2012 (UTC)

I don't know if you can install Ubuntu on a FAT32 partition, even if it's sure that you can mount FAT32 partitions running it. It's also sure that you can install Ubuntu on a NTFS, however, I don't know if that's a good idea either. XPPaul (talk) 20:01, 30 April 2012 (UTC)

The absolutely easiest solution is to keep all files you need to access from both windows and ubuntu on the filesystem windows is installed on. --145.94.77.43 (talk) 14:35, 30 April 2012 (UTC)

Sounds as a good advice. OsmanRF34 (talk • contribs) 14:42, 30 April 2012 (UTC)

Or create a third partition for your personal data. XPPaul (talk) 20:01, 30 April 2012 (UTC)

Ubuntu is installed on a NTFS partition, which should be accessible for Windows... — Preceding unsigned comment added by OsmanRF34 (talk • contribs) 14:42, 30 April 2012 (UTC)

I've had problems like this before caused by disk errors (due to not shutting down correctly, etc.). Try booting up Ubuntu, shutting down, then trying Windows again. Also, if you do need to access ext partitions from Windows, there are programs that will do this - I don't know if any of them are compatible with ext4 yet, though. 130.88.73.65 (talk) 16:15, 2 May 2012 (UTC)

Adblock

I got a new google extension called "Adblock", but is it a scam and is it free?--Deathlaser :  Chat  20:05, 30 April 2012 (UTC)

There are a couple extensions using the Adblock name for Chrome. Adblock Plus is the official port of the extension of the same name that has been used on Firefox for many years, and it definitely reputable, and free. --LarryMac | Talk 20:39, 30 April 2012 (UTC)

Note that it's not from Google, but for Google (and many others). XPPaul (talk) 21:03, 30 April 2012 (UTC)

It's not for Google, the search engine, but for browsers: Mozilla Firefox, and Google Chrome. Paul (Stansifer) 03:02, 1 May 2012 (UTC)

But is it legal.--Deathlaser :  Chat  21:05, 30 April 2012 (UTC)

We can't answer that question, since the Reference Desk does not give legal advice. In fact, the question seems to be a tricky one for even legal minds to answer - I found articles arguing both sides: Web ad blocking may not be (entirely) legal and Why ad-blockers, ad-skippers and other user-control technologies are legal. - Cucumber Mike (talk) 21:23, 30 April 2012 (UTC)

Note that they go after developers of adblocks, not against users. XPPaul (talk) 22:04, 30 April 2012 (UTC)

It's impossible for us to know whether the file you got is a scam or not. Although Adblock Plus is a well recognised plugin that isn't a scam, we can't guarantee the file you got is what was released by the Adblock Plus developers, it's quite likely there are a lot of scam plugins out there given the name. You should make sure you either download from the official site, or from Google and the developer/releaser is the official one to reduce the chance of this happening. Nil Einne (talk) 03:12, 1 May 2012 (UTC)

Note that what I said applies to AdBlock (or pretty much any famous plugin e.g. Flash) too. Nil Einne (talk) 12:46, 1 May 2012 (UTC)

I use this extension. AdBlock is not from the developer of the better-known Firefox extension, AdBlock Plus, but it is a virtually identical product in most other respects. It was around prior to the AdBlock Plus developers creating a Chrome port of their software and this was a big deal for me because I wanted to make the switch to Chrome from Firefox (it has a lighter footprint and loads faster) but I was not going to do that without some sort of ad filter. AdBlock uses the same filter lists that AdBlock Plus does and to me, an end-user, there is no difference being as I see no ads either way.

So, in short, no it is not a scam and yes it is free--although if you like the product you can make a donation, but it is not required. -Amordea (talk) 12:11, 1 May 2012 (UTC)

I get it is not a scam and its free, but I still don't get if it is legal or not. I am not asking for legal advice, I'm just asking if you can clarify the law. Until then, I do not want to risk it so am going to remove Adblock.--Deathlaser :  Chat  16:38, 1 May 2012 (UTC)

Could you elaborate as to why you think it might not be legal? Are you concerned the name of the program has breached copyright or trademark regulations? I'm honestly puzzled at your concern and I suppose that's why nobody has addressed it. Matt Deres (talk) 19:28, 1 May 2012 (UTC)

While this does not directly answer your question (because I am no lawyer)--the day the feds come knocking at my door to charge me with filtering internet content that I view on my own computer in any way I please is the same day I make plans to find citizenship with another country. I cannot imagine living in fear of what would amount to petulant, OCD-level of control by the law. -Amordea (talk) 12:24, 2 May 2012 (UTC)

Websites are paying millions to maintain their servers and for some, their only source of income are ads. So do you really think they are likely to "sit back" while a million users visit their site with Adblock!--Deathlaser :  Chat  16:46, 2 May 2012 (UTC)

Be aware that according to this, the web-masters cannot really know if you have it or not. XPPaul (talk) 22:32, 2 May 2012 (UTC)

Who's censoring this stuff?

I'm having a very hard time trying to download the video at http://upload.wikimedia.org/wikipedia/commons/9/9a/Devoirs_de_vacances.ogv (File:Devoirs de vacances.ogv), some kind of wild French silent film involving nuns, sex, and a pet dog. I keep having the downloads quit in the middle - out of 41 MB, I'm getting 688 kb, 7.5 MB, 3.3 MB, 7.7 MB, 7.7 MB. Because I think I've had trouble with some non-porno OGV files before, I'm not entirely sure someone is messing with my download, but certainly I should find out. To begin with - has anyone heard of some kind of censorship within the U.S. that affects something in the middle of a download, not at the beginning? Wnt (talk) 21:35, 30 April 2012 (UTC)

Its likely just a corrupt file. Youreallycan 21:54, 30 April 2012 (UTC)

Corrupt file that stops downloading at different places? Which other people on User talk:Jimbo Wales/Archive 104#Wikipedia's hardcore sex films say they're watching? Wnt (talk) 21:58, 30 April 2012 (UTC)

I just downloaded it - start it at commons and right click in the video - save video - no problemo - I just had a look - it is likely illegal to posses this in the UK and I have deleted it. Youreallycan 21:59, 30 April 2012 (UTC)

I'm in the U.S., so hopefully if it's legal for Commons... (and I know there are a bunch of folks stalking Jimbo's page who would have tried to make trouble for Commons if it weren't, but it's pretty clear the Miller Test passes it). Problem is, for me the download fails and I don't know why. Wnt (talk) 22:05, 30 April 2012 (UTC)

Just follow the steps - start the video and then place your mouse pointer over the video and right click save video - Don't use the download link on the page - that didn't work for me either - Youreallycan 22:07, 30 April 2012 (UTC)

note - I got it from wikipedia so it must be legal will not protect you in a court of law. - Youreallycan 22:10, 30 April 2012 (UTC)

I'm not looking for another one of our arguments, but a technical explanation. (Though note 70,000 people have viewed it on Reddit) I right-clicked and hit save on the video just like you did, but with those incomplete downloads as the result. I also gave the direct link above for direct comparison. Wnt (talk) 22:12, 30 April 2012 (UTC)

Viewing it and possing it are two different things in law. Yes, please lets not argue I am only here chatting and helping - http://commons.wikimedia.org/wiki/File:Devoirs_de_vacances.ogv - are you attempting to download iit from the commons location? - Youreallycan 22:15, 30 April 2012 (UTC)

Viewing it, and having it at a temp directory somewhere, are the same thing. XPPaul (talk) 22:18, 30 April 2012 (UTC)

Temp directory ... if its temp then its deleted from there - ... hm ... anyway - I take my Father's expensive lawyers legal advice only and err on the side of caution is a constant theme in his replies. - Youreallycan 22:24, 30 April 2012 (UTC)

Did you ask your Father's expensive lawyers if it was OK to download strange porn from the Internet? And did they really advise you to take care, to delete the temp files? XPPaul (talk) 22:44, 30 April 2012 (UTC)

The way I see it, the U.S. government could go after 1 out of 100,000 people downloading an old film, despite the Miller Test and all the other bull. Or radical Islamists could stalk down and kill 1 out of 200 people voting to keep images of Muhammad on Wikipedia. Either would be an act of terrorism. The only difference would be that the U.S. government would be claiming authority from a constitution that it would be ignoring, whereas the Islamists would be acting on the word of a prophet who merely happens to be wrong, making the latter action marginally more legitimate, as well as more likely. But both deserve the same response as one usually favors toward terrorists, whatever that might happen to be. Wnt (talk) 23:14, 30 April 2012 (UTC)

(ec)It all comes down to the link at upload.wikimedia.org, no matter where or how you download it. (Unless you get the Pirate Bay torrent at http://thepiratebay.se/torrent/6466352 , that is - no data yet, though) Wnt (talk) 22:19, 30 April 2012 (UTC) (not sure that's the same thing, though!)

No idea then - it was easy peasy for me - Youreallycan 22:25, 30 April 2012 (UTC)

The torrent works, and apparently it is a much longer full length film from 1915 including this scene. But, my principal interest is still - who is censoring this stuff, where and how? I wasn't aware that the ISPs had the equipment to watch a video as you download it and stop it when they see a frame they don't like. Or did someone pervert an "anti-virus" program like Avast or Windows Defender? (But no, they missed the torrent). Any ideas? Wnt (talk) 23:10, 30 April 2012 (UTC)

Not convinced anyone is censoring it on your end, but lots of countries, governments, organizations, ISPs, network admins, etc. do censor things, and it'd depend on where you are what the answer would be if someone were. As Youreallycan stated, he was able to download the video despite having the same sorts of problems as you've been talking about - the simplest explanation (which is easy for me to believe) is that the server it's on is just imperfect. ¦ Reisio (talk) 23:31, 30 April 2012 (UTC)

It could also be a generic problem on the part of Wnt's internet connection (how wide it will be will depend on where the problem is). I would note they've said they've successfully downloaded files from the WMF servers before, but they didn't comment on how recent this was, nor on how big the files were. From my own simple test, the WMF servers support resuming so using a decent download manager should help, personally I was able to successfully download the file in about 30 seconds although I'll note my download manager automatically segments files so it wasn't downloaded in one part. Nil Einne (talk) 02:43, 1 May 2012 (UTC)

As it turns out, I did have a similar problem with Firefox, it only downloaded 8,207,950 bytes. The way it failed, I think the server must have sent a 'complete' or whatever message, since Firefox thought it was finished (I've had this before with other servers) which I had somewhat expected since I believe FF does try to resume if the download just cuts off. And I'm not sure how well YRC checked their download so it's possible the file wasn't complete. However I also had no problems the second or third time I tried it with Firefox nor the time I tried it with my download manager Free Download Manager without segments. As my ISP has a transparent caching proxy (which I can ask them to turn off for my account but I didn't), it's possible it may be pointless trying too many times so I won't bother further. In any case, the problem must be on the WMF's side. Hopefully my findings aren't going to lead to any more wacky theories, the WMF servers are well known for doing odd things. Nil Einne (talk) 03:39, 1 May 2012 (UTC)

Thanks for lending me a clue! I tried this download manager ([4]) and set it to work on the http link at top. It reported 33 "Connection with the server was lost" errors, but eventually got the file intact. (It is indeed a portion of the torrent I linked above - one in which the actor deserves to receive a medal for bravery above and beyond the call of duty, then be whacked with a bluefin tuna) Whatever the reason, this solves the download problem. Now, I just wonder what is the reason... Wnt (talk) 04:42, 1 May 2012 (UTC)

Be careful, or pretty soon you'll be wondering about all sorts of inconsistencies. :p ¦ Reisio (talk) 05:14, 1 May 2012 (UTC)