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October 24

Windows Explorer List Order

I'm using Windows 7. When I copy and paste files from one Windows Explorer folder to another, they get added at the bottom of the list, not alphabetically, even though the window is sorted on the Name column. I then have to refresh the window before they pop into place.

Is there a configuration option that will force Windows to drop new files in at the right place?

Thanks, Rojomoke (talk) 13:10, 24 October 2014 (UTC)[reply]

Advanced histogram plot

I am plotting a function, from reals to reals, that is a sum of a finite number of dirac delta functions. I need to plot it like a histogram, with the area of each bar proportional to the area under the corresponding delta function, and the width of the bar the maximum possible so as to avoid overlap with the neighboring delta function.

I'm using Octave on Linux. Can anyone suggest plotting software, or code that will do what I want? Thanks! --RM — Preceding unsigned comment added by 121.247.216.109 (talk) 15:47, 24 October 2014 (UTC)[reply]

Octave produces histographs. Example: hist (randn (10000, 1), 30); — Preceding unsigned comment added by 209.149.113.162 (talk) 18:32, 24 October 2014 (UTC)[reply]

Last I used Octave, it had to hook into gnuplot to do that sort of thing, and that could be a bit tricky on some installations. But if OP can get Octave to plot anything directly, then 'hist' will indeed plot a histogram [1]. SemanticMantis (talk) 20:58, 24 October 2014 (UTC)[reply]

Wait, the area under Dirac_delta_function is 1 for any interval that contains the center point, right? Are you thinking of something like a Dirac comb, but with some sort of weighting? I would suggest doing whatever manipulations you want to get the appropriate heights and widths, then just feed that vector to 'bar' or similar, rather than trying to get a plotting command to correctly interpret the deltas. SemanticMantis (talk) 21:04, 24 October 2014 (UTC)[reply]

The function is a sum of a finite number of weighted shifted dirac delta functions.

The "boxes" style in Gnuplot seems best as of now. Is there any plotting program that allows individual bar width to be adjusted for histogram plots? --RM — Preceding unsigned comment added by 121.247.216.109 (talk) 22:43, 24 October 2014 (UTC)[reply]

boxes does let you set each width—it even can compute it to touch like you want, but you still need them yourself to compute the correct heights. --Tardis (talk) 00:26, 25 October 2014 (UTC)[reply]

BeagleBoard: making it mobile

If you buy a BeagleBoard, can you make it mobile attaching a battery and a screen to it? And what battery and screen would be a choice? I'd like the less colorful screen (but still touch screen) and the bigger battery (think: less esthetically minded, prefer longer running time). — Preceding unsigned comment added by 217.12.24.130 (talk) 17:51, 24 October 2014 (UTC)[reply]

Yes, it is possible. Review the latest BeagleBoard System Reference Manual. There is a whole chapter on power supply systems.

If you provide 5 volt DC power, you can expect that the supply will need to source around a half an ampere. (The spec actually says 1.5 A minimum). Not all batteries can do that safely. Choose wisely!

In other words some batteries will fail gracefully, (i.e., your board will suffer a brownout). (This is a more likely scenario for most of the kinds of batteries that are within the price-range of the enthusiast/hobbyist). But if you decide to shell out big bucks for bigger batteries with longer lifetimes, you need to be aware: some batteries will leak chemical, catch fire, or explode, if you sink too much current out of them. Some (bigger) batteries will over-current the Beagle Board and blow out its overcurrent protection circuit.

The moral of this story : before you go connecting a yacht-sized marine battery to your computer, you should read up on DC-DC power supply design. Choose an appropriate energy source (battery); choose an appropriate DC voltage and current regulator; choose appropriate cables and protection circuitry. If you do it all correctly, you can hook up a yacht battery, and you can run the board for days, hours, weeks or months. I once worked on a project where we hooked up many dozen (about a metric ton) of marine batteries to a small embedded system... its computer system and radio uplinks survived for several years until "a shark ate it." Nimur (talk) 18:22, 24 October 2014 (UTC)[reply]

Are you really set on using a BeagleBoard? Those things are like 5 or 6 years old - a BeagleBone Black would be a more reasonable choice...and it's significantly smaller. If only needs 460 milliAmps at 5 volts - and then only when everything is running. Most of the time it's more like 250mA. Four rechargeable 2900mAh Nimh AA batteries would get you plenty of battery life. This display plugs directly into the BeagleBone and has an integrated touch screen...not sure how much power it'll consume though. SteveBaker (talk) 19:19, 24 October 2014 (UTC)[reply]

Thanks for the tips. Yes, I'd go with the BeagleBone and not the original BeagleBoard. And go with some kind of replaceable, small battery. I'll try to find one specific to the BeagleBone, since it looks they are developing components specific to it. — Preceding unsigned comment added by 87.222.207.165 (talk) 18:06, 25 October 2014 (UTC)[reply]

Yeah - I'm sure someone has already done exactly what you need. I've been using BeagleBones for quite a while now - they are a great platform for this kind of thing. I have one driving my $10,000 laser cutter! SteveBaker (talk) 22:45, 25 October 2014 (UTC)[reply]

October 25

Softcombing (Kuzhicombing), The Most Systematic Software Reverse Engineering Method

I wrote an article on "softcombing" and tried to put the article in Wikipedia. I could not find references. So the article is going to be discarded. How can I get references from the internet? There is a video clipping in YouTube on softcombing. But it is not acceptable to Wikipedia. Do I have to write a book on softcombing? Can someone else give references for me?

George Peter Kuzhikompil (talk) 09:33, 25 October 2014 (UTC)[reply]

If you invented this technique, then you should know if anything is published on the topic. For this kind of topic, a publication in a peer reviewed academic journal is where to write. But we would also expect that there is more than one writing on the topic to pass the notability criterion. Perhaps it has already been described by another name. By the way the draft is no where near deletion, Normally it would have to be abandoned for 6 months to be chopped. Graeme Bartlett (talk) 10:58, 25 October 2014 (UTC)[reply]

I sounds to me like what people have been doing since year dot in decompilers. You make a list of possible entry points and start disassembling from the first one till you get to a jump putting any new targets into the list as one goes. Rinse repeat. You need to do more though like spotting jump tables and method functions and function addresses passed as parameters for example to sort, and in old code there may even be overwritten code or there may be inline data after a call that the subroutine jumps over. Dmcq (talk) 15:42, 25 October 2014 (UTC)[reply]

External Memory

Why is it that some devices only support a limited amount of external memory? I have two 64GB SD cards, and neither of them works in my phone (Samsung Galaxy SIII mini) or my wearable action camera I use for cycling. They bot have to use a 32GB one. KägeTorä - (^影_虎) (Chin Wag) 15:34, 25 October 2014 (UTC)[reply]

Everything needs a software driver! Even the RAM on today's microscopic computer-on-a-chip needs a software driver, as mind-blowing as that is for most people who program computers! Storage devices like SD cards also need software support: the main computer cannot talk to it unless somebody programs in the specific language that the peripheral understands.

In this specific instance, the system doesn't speak the right language - but only for very large SD cards. The most likely culprits are either the file system or the device driver for the SD card interface. It is also possible that the storage configuration is malformed for this device, at a higher level of abstraction. Most probably, your devices do not support the SDXC protocol that is used for most cards with greater than 32 GB. Suffice to say, one or more software pieces are broken, but the exact nature of this problem is difficult to diagnose without deep inspection of the software and hardware on this device. This kind of software work isn't commonly accessible or fixable by nonprofessionals - even when the source-code is available!

As an example of the complexity, you can take a look at a free software implementation of an SD card driver, and try to decipher its inner workings. (I had an easier time finding good documentation and reference code for SD card drivers on Windows than for Linux or Android! And Apple makes a USB mass storage driver (with SD card support) available in source-code form, even though I'm not aware of any iOS devices that have an SD card slot!)

Instead of trying to fix it yourself, a better strategy would be to file a detailed bug report to your hardware vendor, so that they can actually track its occurrence and make a decision to prioritze a fix schedule.

Nimur (talk) 16:13, 25 October 2014 (UTC)[reply]

There's no SDXC protocol. The only difference between SDHC and SDXC is the file system (FAT32 vs exFAT). FAT32 supports volume sizes up to 2 TB at least, so there's no good reason for an SDHC-only device to reject a 64GB card if it's formatted with FAT32 (which is not to say they won't reject it anyway). If those cards are exFAT-formatted, you might even get them to work by reformatting them as FAT32. See this old thread for more.

RAM doesn't have drivers in a conventional sense. Main memory access is too much of a bottleneck to be implemented in software. Memory controllers are programmed by software, but that's nothing new. -- BenRG (talk) 21:37, 25 October 2014 (UTC)[reply]

The SD Association (the industry consortium that publishes standards for SD cards) publishes an SDXC standard. In addition to the file system, SDXC also has an entire set of new physical layer specifications, bus protocols, and software abstractions. These are summarized on the SD Association's website. Technical details for this standard are not available unless you join the consortium.

Regarding RAM: if you use any new hardware, it's probably standardized by the JEDEC. For example, the JEDEC standard for DDR3 is available at no cost to the general public: JESD 79-3D. That standard document explains the DDR3 specification for memory, including the mechanical and electrical design, and the standard software abstractions. Chapters 3, 4, and 5, standardize the software control for DDR3 RAM. Intel even published a white-paper showing a portion of their memory software architecture: Intel XMP white-paper, including a cartoon diagram of their software stack on both the MCH and the main CPU. This is but one of many software technology platforms that are common today. Depending on the type of computer and its operating system, those software pieces might appear totally opaque and invisible to the user - you might even choose to call them "hardware" if you don't know how they're programmed or where their software lives. But some of us do enjoy getting up to our elbows in system program software, recreationally and professionally!

Do you simply enjoy being contradictory, BenRG? I don't mind nitpicks - I'm a stickler for detail, and if I am wrong, I always appreciate that somebody corrects me... but when I am not wrong, I don't see why you choose to nitpick anyway. Nimur (talk) 23:43, 25 October 2014 (UTC)[reply]

Can you provide links (or at least info on how to get) to where the SD Association summarises the differences between SDXC and SDHC? I had a look at the link you provide and I couldn't find any mention of it. Actually all the info I saw supported what BenRG said which also concurs with my understanding of the situation. To be clear, I'm not saying you're definitely wrong, but if you're going to claim that there is a difference and the difference is mentioned somewhere other than only in details only available under certain conditions, it would be good if you could provide the evidence.

In any case, I won't comment on the rest, but it seems to me that BenRG had a very good point if they were correct and it's a point I myself have mentioned before, possibly somewhere on wikipedia but if not elsewhere. If the only real difference between SDXC and SDHC is the file system and capacity, then there's no particular reason why most SDHC devices can't support a SDXC card formatted with FAT32. Definitely it's known that many devices which only advertise SDHC support have no problem with FAT32 formatted SDXC cards. (To be clear, these devices don't necessarily support SDXC, as they may not be able to work with exFAT. Although some do, so you could say they are apparently compatible even if not officially compatible.)

This isn't to suggest devices can't have problems. Technically since the SDHC standard says the card size must be limited to 32GB, a device could either either not understand or simply refuse to work with such a card (although IIRC last time I checked, the standard also doesn't seem to say it has to). And there may be other reasons relating to the implementation why a device wouldn't work with such a card (e.g. the software was limited to working with 32GB partitions).

And while there have been numerous reports of devices working with SDXC cards despite only officially supporting SDHC, IIRC there have also been reports of some devices which wouldn't even when the card was FAT32 formatted.

It's perhaps also worth considering other factors. I believe some devices seem to have problems with newer high speed cards, e.g. UHS-II. While this is part of both the SDXC and SDHC standard, its introduction postdated the SDHC standard by a while so it's perhaps not so suprising some devices can't handle them (and I think history in many areas has show theoretical backwards compatibility doesn't always translate to practice). I think you're much more likely to get a SDXC card in such a speed, so you're unsurprisingly also likely to encounter problems (although it wouldn't be accurate to say the device doesn't support SDXC cards per se, since technically you can have a SDXC card that's speed class 2.

Incidentally, a significant counterpoint here is SD(SC) and SDHC. SDHC introduced a different way of reporting capacity etc rather than simply using more bits to allow a larger capacity. Therefore it's hardly surprising that a large percentage of SD(SC) devices don't work with SDHC cards. I believe there is some similarity with 4GB SDSC cards in that if you follow the 1.01 version of the standard, there's no reason why you can't have 4GB cards, except that the standard says they're limited to 2GB. (Note that there is an added complexity on that devices only supporting 1.00 may not work with 2GB or 4GB cards. As I understand it, this isn't simply the standard limiting the maximum, but a feature wasn't even implemented yet so there was no reason for devices to be expected to support it.)

Getting back to the OPs original question, even if it turns out BenRG and me are wrong about the standard, I stick by my other claim which was also mentioned by BenRG. Many devices which don't claim SDXC compatibility but only SDHC will have no problem with a FAT32 formatted card. Note an important point here, some devices, even though normally capable of formatting cards, may refuse or otherwise be unable to do so with a exFAT or SDXC card. So if the OP hasn't tried formatting the card in a computer or similar first, they may want to do so and confirm it doesn't work after formatting. (Since Windows refuses to format FAT32 partitions larger than 32GB, the OP will need to find ways how.) The fact that the device is nominally incompatible with SDXC or even the differences between SDXC may not be so important to the OP if their devices can actually work with the card, they just haven't worked out how.

I had a look around. It's difficult to find much since I'm getting a lot of stuff relating to the non mini (which I think official supports SDXC or at least 64GB cards). I did find [2] which may sound disappointing, but if you read the last post it sounds like they may have eventually gotten it working. Some more searching using quotes found [3] and h4wkst3p [4] find other reports of it working in a stock situation. (Unfortunately I still got a lot of junk posts such as people saying it doesn't officially support it so it won't work. Or the S2 which doesn't officially support it either has been tested to work with SDXC cards so it's better than the S III mini despite no evidence the the person has even looked for reports of the S III mini and SDXC cards.)

Nil Einne (talk) 14:52, 26 October 2014 (UTC)[reply]

Sure. Look at the Simplified SD specification. Chapter 3.6 includes the state machine for card identification. See how the state machine differs for various card types? That means a different set of commands are valid only for certain "types" of card. So, while "XC" refers loosely to capacity, its file system is not the only difference: the cards follow a different initialization sequence, and the controller must support extra capabilities in software and hardware.

Some enthusiasts have made SDXC cards "work" by formatting their file system differently. This is moot: some enthusiasts have powered a Corvette on vegetable oil. Almost anything is possible, but it isn't necessarily always going to work, so it's probably not the right choice for the user, nor is it necessarily good or sustainable long-term damage-free strategy for the machine!

As I mentioned earlier, the best thing that our OP can do is to send a bug-report to his hardware vendor with as many details as possible. Nimur (talk) 15:34, 26 October 2014 (UTC)[reply]

October 26

Carving XML/SVG files

I accidentally deleted data on a FAT32 filesystem on a 16GB memory card. It was half full. I need to recover some XML/SVG files from it. The delete was by a rmdir command on non-empty directories, while mounted via ADBFS onto Linux. I unmounted the filesystem immediately and tried Foremost. It recovered many of the files, but it does not recognize the XML/SVG format.

Is there some file carving software that handles XML/SVG files? Otherwise, is it possible to configure Foremost to recover them? Any help is greatly appreciated. --RM — Preceding unsigned comment added by 121.247.216.191 (talk) 04:46, October 26, 2014

PhotoRec has file carving for SVG files. It handles general XML files, too. But I don't have any personal experience with the program. --Mark viking (talk) 05:02, 26 October 2014 (UTC)[reply]

Can hear my mic from my speakers

I have a Gold Wireless Stereo Headset (PlayStation 3 & PlayStation 4) I use it on my PC which is ok it says you can on sony's website. When I use a program that uses a mic or could use a mic I can start to hear what is going into my mic. I have a fan behind me and the headset blocks out most of the noise but if I use skype or sony vegas I can hear my mic in my headset. I have tried to fix it in the sound and recording settings (windows 7) and it didnt do anything if I mute my mic on skype I can still hear it but if I mute my mic on the headset the mic noise stops. I really want to fix this it makes talking on skype impossible. — Preceding unsigned comment added by 204.42.31.250 (talk) 14:46, 26 October 2014 (UTC)[reply]

October 27

How to build GRUB2

I'm currently running Ubuntu 14.10 Minimal from inside a virtual machine. I ran apt-get source grub2 and unzipped the Debian tarball. Inside it, however, there are no makefiles or configuration scripts. How in the world would this build system work? — Melab±1 ☎ 01:55, 27 October 2014 (UTC)[reply]

I don't know what Canonical (or whomever maintains the APT repository) provided you when you ran the apt-get source command. But if you get GRUB2 from its official distribution channel - https://www.gnu.org/software/grub - it comes with a set of scripts that work with autotools. The official documentation also has a link to a tutorial and build instructions from the Linux From Scratch website.

Try:

 git clone git://git.savannah.gnu.org/grub.git

...and take a look at the conf scripts. If you aren't familiar with GNU autotools, our article is a good introduction.

Nimur (talk) 02:45, 27 October 2014 (UTC)[reply]

I'm not sure how easily the GNU version will build though. I might need to make changes to it and all and the APT version doesn't provide a diff file. — Melab±1 ☎ 03:41, 27 October 2014 (UTC)[reply]

You can diff -rq the GNU grub folder and the apt-get grub folder to see the differences. Chances are pretty high that grub itself is no different from mainline. Debian and Ubuntu (and other "distributions") probably provide a complicated variant of the menu.lst configuration (or whatever the equivalent is, now that we've got GRUB2); but there's little reason for them to significantly modify the GRUB source itself. Nimur (talk) 03:57, 27 October 2014 (UTC)[reply]

MS outlook & address book transfer with containing folder integrity

Is there a way to transfer MS outlook/outlook express and MS addressbook w/o loosing folder integrity? I used to transfer outlook and address book by transferring the containing folder to another computer but folders from the original PC are lost this way.TMCk (talk) 02:11, 27 October 2014 (UTC)[reply]

This might help: How to back up and to restore Outlook Express data. Mitch Ames (talk) 12:20, 27 October 2014 (UTC)[reply]

Thanks. Next time I'll try it with an .csv file instead of wab. Guess that should work :) TMCk (talk) 16:52, 27 October 2014 (UTC)[reply]

Why does Android not use X11

Why does Android not use X11 for graphics? Is Android's graphics system superior to X11 for mobile devices? --RM — Preceding unsigned comment added by 121.247.216.191 (talk) 11:33, 27 October 2014 (UTC)[reply]

I'm no expert on X or on modern GUI API's, so this is a pretty ill-informed response, but I think the answer is basically, yes, the new graphics systems are superior. X strikes me as being pretty old and obsolete; if it weren't for graphical Linux I don't think anybody would be seriously using it. More importantly, modern GUIs have lots of must-have bells and whistles -- transparency, whiz-bang animations, etc. -- that I suspect are only reasonably achievable with heavy ingrained support all through the infrastructure.

(I've probably been grossly unfair to X11 in this response, but perhaps my heresy will goad someone who knows into providing the counterargument.) —Steve Summit (talk) 18:36, 27 October 2014 (UTC)[reply]

Why does Android do anything? Because Google so decrees. To first order, Google has performed a technical evaluation and made decision that X11 is not part of their Android strategy. In this particular instance, some of their justifications are made public; and some of their reasoning must be surmised by observing industry trends at large.

Start by reading the official Android Graphics Design Overview. If you're a little bit more technical, Google hosts an "unofficial" deep-dive presentation on Android Graphics Architecture. Android has taken the approach of encouraging graphical applications to write data directly into a frame buffer. Frame-buffers are wrangled by a very minimalistic compositing architecture, suitable for hardware with severe constraints. This is conducive to hardware acceleration, but it is antithetical to a multi-tasking style "window manager" - and because X11 was structured to encourage multiple simultaneous clients all sharing a small part of a giant frame-buffer, the chief advantages are not useful for these kinds of platforms.

Read about X11. X11 is a protocol - and in order to correctly satisfy that protocol, the display client must necessarily perform some very inefficient bitmap-based operations. In exchange, the work of graphical composition is highly abstracted - it's great for inter-platform operability, because almost all the graphical work is very generalized. It's great for running multiple applications - even if the source-data for several of those operations is provided over a network layer. X11 is terrible for things like memory-efficiency or avoiding expensive deep-copies of redundant data. As a design-decision, think about how often you would want your Android telephone to render graphical application-data from an HP-UX server - and how much performance you'd trade off for that feature!

X11 can run on Android: but X11 doesn't take advantage of modern hardware capabilities.

Even on desktop platforms, many modern operating systems are moving away from X windowing. Most Linux distributions are moving towards Wayland or Mir. OS X has moved to a totally different graphics architecture, to the extent that Xquartz is no longer distributed with the operating system. Other Unix platforms - those few that are left! - are becoming more rare; and they probably continue to run X with Gnome or with some of the more insular window managers; but these platforms rarely get major overhauls - they'll probably stick with whatever worked in 1997, until it becomes cost-prohibitive to replace those dinosaur hardwares that run mission-critical systems. A while back, I toured an air traffic control facility, and those folks were running some kind of SGI workstations with the logos covered by sticker-labels from a major aerospace conglomerate! Full color graphics workstations that will keep ticking for fifty-odd years...

So, I won't say that X11 is dead - but it's widely acknowledged that new graphical systems are using newer software technology that takes advantage of a lot of lessons-learned with regard to platform-portability and hardware optimization.

Nimur (talk) 18:38, 27 October 2014 (UTC)[reply]

Readers of Steve's and Nimur's answers, with which I entirely agree, might be struck with a tad of cognitive dissonance - if X is so clunky, how come it's still used? As Steve says, it's chiefly Linux now, and as Nimur says, they're moving away too. But applications on Linux, which run on the X desktop, mostly don't explicitly use X itself any more - which will mean the transition to post-X display management (Wayland, Mir) won't be super hard. In the olden days of Unix(alike) GUI programming, one did write programs which used the X libraries directly, and if one used a (slightly) higher level toolkit library like Xaw/Xt and Xm (motif) one still made X calls too. But programs that work like that are pretty thin on the ground, at least on the Linux desktop. Most are written to more capable toolkits (of which GTK+ and Qt are have between them the lion's share); these toolkits are written to be platform agnostic, which forces them to be complete (that is, programs never have to explicitly call the underlying GUI system - X on Unix, GDI et al on Windows, etc.). They're more than a thin layer over X - they do most of the work themselves. X is lacking in many areas - e.g. its own drawing system is pretty rudimentary, lacking a modern rich drawing toolkit with Porter-Duff, anti-aliasing, and decent font rendering. A modern program like Firefox does the rendering client-side, with Pango/Freetype for text rendering and a library like Cairo for high-quality drawing. They then blit that completed image to the X window wholesale. Video games use another path - they typically write with OpenGL into a buffer given them by the video driver, again with no X calls being made. Right now X still owns the screen and all the input devices, so the bottom surface of toolkits running on X still have to make X calls to pump events, create windows, and blit chunks of display around. The migration to Mir or Wayland removes X from this central role (the Mir or Wayland server will do that instead). An X server will work, but it will be subordinate to the real display server (the way an X server on OS-X or Windows already is), and will survive (for a time, I guess) to support legacy applications and remoting. -- Finlay McWalterᚠTalk 13:05, 28 October 2014 (UTC)[reply]

Returning old dock appearance in Yosemite

I Just upgraded to Yosemite. Looks like they fixed the terrible Maverick menu problems! Question: Is there any way to return to the old dock appearance? The new light brown dock is quite a downgrade.--71.167.166.18 (talk) 13:37, 27 October 2014 (UTC)[reply]

There doesn't seem to be any way to revert to the 3D dock appearance (a la Leopard to Mavericks), however it if is the color you don't like, I believe that is based on a heavily blurred translucency effect on the desktop wallpaper, see samples in the Ars Technica review. --Canley (talk) 03:27, 29 October 2014 (UTC)[reply]

Is Windiff a better diff tool?

For example, to compare the text as follows


  old text   new text
  --------   --------
  aaa        ccc
  bbb        bbb
  ccc        aaa

it seems that Windiff can find out that "aaa" and "ccc" are swapped and give output similar to this (note that the lines are cross! See this too)

But I have never seen other diff tool can do that. Instead, they output like this

(I don't have Windiff installed on my "Linux" box)

So my questions are:

1. Does Windiff really have that kind of ability?

2. If so, what is the alternative tool for Linux?

Justin545 (talk) 13:58, 27 October 2014 (UTC)[reply]

I recently discovered Meld, http://meldmerge.org/, which has a Windows version which does a far better job than windiff. It is excellent for getting two versions of a file that have diverged slightly back in sync. It is a standard Linux tool. You may want to try it. It passes your test. --NorwegianBlue^talk 19:05, 28 October 2014 (UTC) EDIT: The image you linked to appears to have been created with Meld. --NorwegianBlue^talk 19:10, 28 October 2014 (UTC)[reply]

Yes, the image I linked was created by Meld installed on my own Linux machine. Meld may have better graphical presentation than Windiff, but my concern is the diff algorithm they use. In the case above when the positions of two text blocks are swapped, Windiff seems able to find out two swapped text blocks and correctly show their relation (that is, it could detect text move correctly even if two text blocks are swapped in position). On the other hand, Meld only shows me that the text block is first get deleted and then re-inserted at the other place, which means the diff algorithm Meld uses fail to detect text block move when text blocks are swapped! - Justin545 (talk) 02:09, 29 October 2014 (UTC)[reply]

Facebook group and search ?

what is suggested groups in facebook and how is the suggested groups list created , what is the algorithm behind it .I see that a person whose timeline i am frequently visitng and who was never my friend on fb and do not share any common friend with me that is a member of public but the groups to which that belong are appearing in my suggested groups list how and why is this happening.I have graph search enabled or turned on.Can that person sense somehow directly/indirectly that i am very frequently visiting that guys page whenever i type the first letter of his name in search box on top i am getting his name with profile and pic as suggested searck although he is a member of public in fb terms whats the reason for this and how is it so what is the significance.117.248.136.24 (talk) 14:56, 27 October 2014 (UTC)[reply]

matrix in latex conflict with packages

In preparing my presentation I have a problem in writing a matrix Array, tabular are not working gives an error message .I m using the following packages: \usepackage[screen,panelright,gray,paneltoc,sectionbreak]{pdfscreen}%È±Ê¡×´Ì¬ÎªBlue,Ñ§Êõ±¨¸æÍÆ¼ö²ÉÓÃ"gray"¡£ \usepackage{xspace,colortbl} \usepackage{fancyvrb} \usepackage{graphicx} \usepackage{CJK} \usepackage{color} \usepackage{times} \usepackage{type1cm} \usepackage{tabls} \usepackage{background} \usepackage{geometry} \usepackage{hyperref} \usepackage[display]{texpower} \usepackage{manfnt} \usepackage{hypbmsec} \usepackage{pause} \usepackage{amssymb, latexcad, lgrind} \usepackage{tikz} \usepackage{amsmath} — Preceding unsigned comment added by 182.187.55.132 (talk) 23:40, 27 October 2014 (UTC)[reply]

There really isn't enough info here, unless someone happens to have had the exact same problem (unlikely). Please try to give us a complete minimal example of your problem, as described here [5]. Often the process of making the minimal example will help you solve your own problem. If not, then at least it helps us help you. Also you could post the exact error message. You might also try asking this question at latex.stackexchange.com. If you are getting an error message and the code is not compiling, it could be a package conflict, but it is more likely a syntax error. Pending any more information from you, I'd recommend trying the Beamer_(LaTeX) package for presentations. It plays well with most other packages, but gives completely useless error logs :) SemanticMantis (talk) 15:38, 28 October 2014 (UTC)[reply]

It is not a syntax error, and surly a package conflict. Same code works when pasted in an other tex file with different package. I think userpackage CJK, hyperref or background are creating problems. I want to write a some command for matrix which run with these packages .

October 28

Key-agreement protocols not based around Diffie-Hellman

I've always thought the way the Diffie-Hellman protocol worked was kind of neat, but I'm disappointed to see that most key-agreement protocols, barring the types that use public-key cryptography, are just variations on it. Are there any key-agreement protocols like DH in that each participant has a secret number and a number they exchange not based around DH? — Melab±1 ☎ 05:10, 28 October 2014 (UTC)[reply]

The key exchange article discusses some. 209.149.115.7 (talk) 19:51, 28 October 2014 (UTC)[reply]

Internet don't work, Proxy-server don't respond... help?

On my laptop, I suddenly can't go on the internet anymore. My connection is just fine, but when I open the Internet explorer, I get "Proxy-Server don't respond" error-message. There's nothing I can do to search for problems or click anything that might work..

I've tried restart the computer a few times, and every time I get a strange error message which I *think* is about the root to the problem. That message also started today.. Translated to English it pretty much reads as follows; "Can't load Sorttbls.nlp or any associated files." Last time I rebooted I also got another error-message that said 'Client.exe' didn't work or couldn't run or something. I don't know what these messages mean but I can only assume they are the root to the internet problems. The laptop otherwise seem to work, after a fashion at least.

Any useful insight here, and any know-hows as to what can be done? 84.211.153.120 (talk) 09:47, 28 October 2014 (UTC)[reply]

Do you use a proxy server? Is anything non-internet related different or not working? This may be of help for sorttbls.nlp, [6]. Have you made any recent changes to your system, had any symptoms of malware, etc.?Phoenixia1177 (talk) 09:57, 28 October 2014 (UTC)[reply]

I've had some bad symptoms, yes, but whether they are due to malware, I can't say.. I'm frequently using anti-virus, but today and yesterday I can't run it, it gets stuck on 10%. Coincidence that it happens now? No, it can't be. No real changes to system, computer have crashed many times lately and presented me with the chance to go back to "previous adjustments on the computer" and it hasn't made any difference. I don't think I'm using a proxy, if I have understood the meaning of it correctly. Standard fiber-net provided to the whole street by the same company. Beyond that, I don't have the skills or know-hows on computers to be using any advanced stuff. I open the explorer and browse the net for news etc. and stream football and cycling broadcasts as well as downloading the odd movie or tv-series... that's what I do. I'm a very simple internet user. I suppose the only option is to take the laptop in for repair then. 84.211.153.120 (talk) 11:00, 28 October 2014 (UTC)[reply]

If you can move files onto the malfunctioning machine, via usb, I could try to talk you through some various things you can do - though, depending on the cost to get it fixed, you might be better going that route; then someone is liable if anything goes wrong and you don't have to worry about a detail getting lost in communication. Drop me a line on my talk page if you would like. If not, best of luck, hopefully you'll be up and running soon:-)Phoenixia1177 (talk) 14:15, 28 October 2014 (UTC)[reply]

Presuming you are running Windows, try resetting TCP/IP: http://support.microsoft.com/kb/299357 -- Gadget850^talk 17:33, 28 October 2014 (UTC)[reply]

Largest computer

At [7] they talk about the new British Meteorological Office computer is going to weigh 140 tons. I'm sure it is quite a bit smaller than the Chinese Tianhe-2 computer though I don't know how much that would weigh, and there might be earlier ones that were physically larger. Some sources talk about the SAGE computers being the biggest, they weighed 250 tons each and there were two of them per centre. So anybody have an idea what was or is the single largest computer? Dmcq (talk) 12:49, 28 October 2014 (UTC)[reply]

How about by power requirement? That would probably be a good proxy for size. Dmcq (talk) 11:52, 29 October 2014 (UTC)[reply]

Windows 7 driver installation

I'm having a problem installing a device driver (Windows 7 64-bit). In Event Viewer, the appropriate message from UserPnP contains an error code of 0xE0000219, No Associated Service. According to Microsoft here, "This error is usually the result of incorrectly editing the .inf file." (which I haven't), and "If you did not edit the .inf file, then contact the vendor of the device for an updated device driver package." (I'm using the latest driver, which has installed successfully on another system). I'm not an expert on INF files, but I've compared the one that doesn't work to another one (from the same manufacturer) that does, and they appear to be identical apart from the hardware ID - in particular, the <Device>_Inst.Services section in both files contains the same value for the AddService key. Does anyone here know what the error message actually means? That is, _what_ is Windows trying to do that hasn't worked, rather than the reason _why_ it hasn't worked? Any help would be most appreciated. Tevildo (talk) 15:22, 28 October 2014 (UTC)[reply]

What device are you installing? What is the other OS this is installed on? -- Gadget850^talk 15:37, 28 October 2014 (UTC)[reply]

This is a PXI device. The good system also has Windows 7 64-bit, but an older version of NI-VISA. I've tried taking the bad system back to the version of VISA that's on the good system, but it hasn't fixed the problem. Tevildo (talk) 17:22, 28 October 2014 (UTC)[reply]

On the good system, search the registry for the device name and export all the settings, the import into the problem system. -- Gadget850^talk 17:30, 28 October 2014 (UTC)[reply]

That won't work, as the PCI addresses are different between the systems. In any case, it's more important at this stage to track down the source of the error, rather than the solution - if I have to reformat the system, that won't be a major problem, but it would be useful to establish what's going wrong first. Tevildo (talk) 18:31, 28 October 2014 (UTC)[reply]

Possibly Absurd Question, Naked Power Supply and Risk

I preface this with: I know nothing about electronics, beyond how to follow what connects to what and diagrams. So, I had a few vacation days to use and nothing to do, so I bought a bunch of survival horror games, for the holiday (my partner is out of town) and took the week off; of course, my 360's power supply brick fan broke and now overheats and shuts off power every 30 minutes (and ordering a new one takes ten days+). So, I opened it up, cleaned out a bunch of horrid dust from the fan, and anywhere else, and the unit still displays the same behaviour (I get about ten more minutes out of it). So, two questions. 1.) Is it possible the fan doesn't spin at all because the motor burned out from being clogged - or might it just need more cleaning? 2.) If I remove the top part of the case, set it somewhere out of the way, and use a small fan to blow over top of it, will it give off harmful something or anothers, or light on fire, or etc. because the case is missing? I intend to unplug it when I am not using it and never leave it by itself; I'm mainly concerned with the case somehow protecting me from more than touching a live wire, and that it will still overheat anyway. Any help would be appreciated, thank you for indulging what may be a quite stupid question:-)Phoenixia1177 (talk) 19:50, 28 October 2014 (UTC)[reply]

My power supply is out in the open (technically, it is mounted to the bottom of my desk, behind the file drawer - similar to my motherboard, also mounted to the bottom of the desk). As long as you don't touch it, drop things on it, spill things on it, etc..., you are fine. The deal is how the power supply monitors the fan. Most power supplies that I've had will not run if they do not detect that the fan is spinning. So, if the fan is not spinning (which means it is dead), the power supply will shut off - even if it is not hot. A fan is cheap. So, it is trivial to pop over to some store that sells them solder a new one in where the old one was. It doesn't have to be the same size and mount in exactly the same spot. You just need the load to show it is spinning. You *could* use a resistor instead to give it load, but it is harder to figure out the ohms and you'd still have to run down to the electronics store and solder the resistor in. So, I suggest just replacing the fan. 209.149.115.7 (talk) 19:56, 28 October 2014 (UTC)[reply]

~~Nothing can possibly go wrong if you solder home-made parts in to the AC-DC supply that powers your expensive computer/console/toy!~~

This is a great way to:

electrocute yourself
set fire to your house
permanently destroy your expensive computer/console/toy.

If a power cord or PSU becomes damaged in any way, stop using it immediately and contact Xbox Customer Support for a replacement. You already know this. Don't try to "home-brew" a solution. Residential AC/DC power-supplies carry enough energy to kill an adult human.

Without a detailed schematic, and an expert familiar with this specific power supply design, there is no way to know what has gone wrong. Do not try to fix it yourself. Do not try to operate it. It is not clear whether the observed overheating is a cause or a symptom of a more serious problem - like a short-circuit or a damaged high-energy component.

Nimur (talk) 21:20, 28 October 2014 (UTC)[reply]

I will wait for the replacement, then - I'm going to give cleaning it one more go, though.Phoenixia1177 (talk) 21:22, 28 October 2014 (UTC)[reply]

NFC for photography?

I was in an electronics store today and I noticed several point-and-shoot cameras that are near-field communication (NFC) enabled. I don't understand what NFC brings to cameras as its range is so limited. Any ideas? --76.168.132.112 (talk) 20:28, 28 October 2014 (UTC)[reply]

From this web page: There’s also NFC (Near Field Communication), which is starting to be rolled out across more cameras and works on the basis of touching devices together to transfer images. Search engines are awesome. ‑‑Mandruss ☎ 20:51, 28 October 2014 (UTC)[reply]

It saves users the hassle of taking the SD card out of the camera to then transfer them onto their computer. Dismas|^(talk) 04:03, 29 October 2014 (UTC)[reply]

October 29

Facebook groups

I've taken the liberty of moving this from the Science Refdesk. Wnt (talk) 03:21, 29 October 2014 (UTC)[reply]

what is suggested groups in facebook and how is the suggested groups list created , what is the algorithm behind it .I see that a person whose timeline i am frequently visitng and who was never my friend on fb and do not share any common friend with me that is a member of public but the groups to which that belong are appearing in my suggested groups list how and why is this happening.I have graph search enabled or turned on.Can that person sense somehow directly/indirectly that i am very frequently visiting that guys page whenever i type the first letter of his name in search box on top i am getting his name with profile and pic as suggested searck although he is a member of public in fb terms whats the reason for this and how is it so what is the significance. — Preceding unsigned comment added by 117.194.240.19 (talk) 03:15, 29 October 2014 (UTC)[reply]

Companies like Facebook tend to try to keep those algorithms secret in order to prevent people from trying to game the system for whatever reason. So I doubt we'll have an answer for you on this one. SteveBaker (talk) 15:28, 29 October 2014 (UTC)[reply]

From what I understand, it works along the lines of the predictive text function on smartphones, so it "learns" the common words you search for and provides those words as the first suggestions for what you are searching for. The person you are searching for will have no idea you are searching for him. As to the suggested groups list, I believe it's based on the groups your friends are a member of, rather than on random groups coming up. --TammyMoet (talk) 15:46, 29 October 2014 (UTC)[reply]

linux test command: how to negate a composite result

Hello everyone, if i can use the command test instead of [ i test to use the former. The problem arise with composite expressions. For example if i want to negate
test "a" != "b" && test "a" != "c" && test "a" != "d"
i have no idea of how can i do that. I tried, of course, to write
! test "a" != "b" && test "a" != "c" && test "a" != "d"
or test ! "a" != "b" && test "a" != "c" && test "a" != "d"
but it negates just the first test (as expected).

How can i group and negate the entire result? With the [ version i would just use
[ ! $ "a" != "b" -a "a" != "c" -a "a" != "d" $ ]
or in an equivalent way test ! $ "a" != "b" -a "a" != "c" -a "a" != "d" $ .

I appreciate suggestion of other way to evaluate conditional expression but i would like to ask you if you are kind enough to provide a solution that involves a combination of test one_expression and shell operators (as i wrote at the start, with 3 test commands with && shell operators). Pier4r (talk) 15:18, 29 October 2014 (UTC)[reply]

Follow-up: AT&T data throttling

See Wikipedia:Reference_desk/Archives/Computing/2014_October_23#AT.26T_behavior. They've just been charged with illegal data throttling, so apparently I'm not the only one they did this to. StuRat (talk) 15:34, 29 October 2014 (UTC)[reply]

@@ Line 193: / Line 193: @@
 :There really isn't enough info here, unless someone happens to have had the exact same problem (unlikely). Please try to give us a complete minimal example of your problem, as described here [http://stackoverflow.com/questions/4057778/good-newbie-instructions-for-creating-minimal-complete-bug-examples]. Often the process of making the minimal example will help you solve your own problem. If not, then at least it helps us help you. Also you could post the exact error message. You might also try asking this question at latex.stackexchange.com. If you are getting an error message and the code is not compiling, it ''could'' be a package conflict, but it is more likely a syntax error. Pending any more information from you, I'd recommend trying the [[Beamer_(LaTeX)]] package for presentations. It plays well with most other packages, but gives completely useless error logs :) [[User:SemanticMantis|SemanticMantis]] ([[User talk:SemanticMantis|talk]]) 15:38, 28 October 2014 (UTC)
+It is not a syntax error, and surly a package conflict. Same code works when pasted in an other tex file with different package. I think userpackage CJK,  hyperref or background are creating problems. I want to write a some command for matrix which run with these packages .
 = October 28 =