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  • How do you avoid name similarities between your classes and the native ones?

    - by Oscar
    I just ran into an "interesting problem", which I would like your opinion about: I am developing a system and for many reasons (meaning: abstraction, technology independence, etc) we create our own types for exchanging information. For instance: if there is a method which is called SendEmail and is invoked by the business logic, it way have a parameter of type OurCompany.EMailMessage, which is an object which is completely technology independent and contains only "business relevant data" (for instance, no information abut head encoding). Inside the SendEmail function, we get this information from our EMailMEssage object and create a MailMessage (this one is technolgy specific) object so it can be sent over the network. As you can already notice, our class has a very similar name to the "native" language class. The problem is: this is exactly what they are, email messages, so it is hard to find another meaningful name for them. Do you have this problem often? How do you manage it? Edit: @mgkrebbs just commented about using fully qualified names. This is our current approach, but a little bit too verbose, IMHO. I would like something cleaner, if possible.

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  • Handling exceptions raised in observers

    - by sparky
    I have a Rails (2.3.5) application where there are many groups, and each Group has_many People. I have a Group edit form where users can create new people. When a new person is created, they are sent an email (the email address is user entered on the form). This is accomplished with an observer on the Person model. The problem comes when ActionMailer throws an exception - for example if the domain does not exist. Clearly that cannot be weeded out with a validation. There would seem to be 2 ways to deal with this: A begin...rescue...end block in the observer around the mailer. The problem with this is that the only way to pass any feedback to the user would be to set a global variable - as the observer is out of the MVC flow, I can't even set a flash[:error] there. A rescue_from in the Groups controller. This works fine, but has 2 problems. Firstly, there is no way to know which person threw the exception (all I can get is the 503 exception, no way to know which person caused the problem). This would be useful information to be able to pass back to the user - at the moment, there is no way for me to let them know which email address is the problem - at the moment, I just have to chuck the lot back at them, and issue an unhelpful message saying that one of them is not correct. Secondly (and to a certain extent this make the first point moot) it seems that it is necessary to call a render in the rescue_from, or it dies with a rather bizarre "can't convert Array into String" error from webbrick, with no stack trace & nothing in the log. Thus, I have to throw it back to the user when I come across the first error and have to stop processing the rest of the emails. Neither of the solutions are optimal. It would seem that the only way to get Rails to do what I want is option 1, and loathsome global variables. This would also rely on Rails being single threaded. Can anyone suggest a better solution to this problem?

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  • Does unit testing lead to premature generalization (specifically in the context of C++)?

    - by Martin
    Preliminary notes I'll not go into the distinction of the different kinds of test there are, there are already a few questions on these sites regarding that. I'll take what's there and that says: unit testing in the sense of "testing the smallest isolatable unit of an application" from which this question actually derives The isolation problem What is the smallest isolatable unit of a program. Well, as I see it, it (highly?) depends on what language you are coding in. Micheal Feathers talks about the concept of a seam: [WEwLC, p31] A seam is a place where you can alter behavior in your program without editing in that place. And without going into the details, I understand a seam -- in the context of unit testing -- to be a place in a program where your "test" can interface with your "unit". Examples Unit test -- especially in C++ -- require from the code under test to add more seams that would be strictly called for for a given problem. Example: Adding a virtual interface where non-virtual implementation would have been sufficient Splitting -- generalizing(?) -- a (smallish) class further "just" to facilitate adding a test. Splitting a single-executable project into seemingly "independent" libs, "just" to facilitate compiling them independently for the tests. The question I'll try a few versions that hopefully ask about the same point: Is the way that Unit Tests require one to structure an application's code "only" beneficial for the unit tests or is it actually beneficial to the applications structure. Is the generalization code need to exhibit to be unit-testable useful for anything but the unit tests? Does adding unit tests force one to generalize unnecessarily? Is the shape unit tests force on code "always" also a good shape for the code in general as seen from the problem domain? I remember a rule of thumb that said don't generalize until you need to / until there's a second place that uses the code. With Unit Tests, there's always a second place that uses the code -- namely the unit test. So is this reason enough to generalize?

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  • Using EC2 instance as main development platform

    - by David
    My problem I am working as a consultant for various companies. Each company provides me with a laptop where with their software on and I also have my own where I have my development environment. I tend to buy a new laptop every second year and find myself spending lots of time configuring and installing software. I also sometimes spend a lot of time waiting for my laptop to process things. To solve all these issues, I am now considering using EC2 (running windows instances) as my main development platform and just access this from any PC I happen to be at. I calculated that running the High-CPU On-Demand Instances (medium) for 8 hours a day for a year costs me 580$, which is acceptable. I imagine that when I approach the workplace each day, I will make a single click my phone to fire up the instance, so it is ready when I get to work. I should have different icons on my phone to fire up the various instance types. The same software should of course automatically be loaded on the various hardware (sometimes I would even need their instance with 68.4 GB of memory). Another advantage is that if I am having a specific problem with my instance, I could fire up another instance and have someone look into the problem and update the image. My question: Does anyone have experience with such a setup on EC2? What kind of problems do you forsee?

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  • Are injectable classes allowed to have constructor parameters in DI?

    - by Songo
    Given the following code: class ClientClass{ public function print(){ //some code to calculate $inputString $parser= new Parser($inputString); $result= $parser->parse(); } } class Parser{ private $inputString; public __construct($inputString){ $this->inputString=$inputString; } public function parse(){ //some code } } Now the ClientClass has dependency on class Parser. However, if I wanted to use Dependency Injection for unit testing it would cause a problem because now I can't send the input string to the parser constructor like before as its calculated inside ClientCalss itself: class ClientClass{ private $parser; public __construct(Parser $parser){ $this->parser=$parser; } public function print(){ //some code to calculate $inputString $result= $this->parser->parse(); //--> will throw an exception since no string was provided } } The only solution I found was to modify all my classes that took parameters in their constructors to utilize Setters instead (example: setInputString()). However, I think there might be a better solution than this because sometimes modifying existing classes can cause much harm than benefit. So, Are injectable classes not allowed to have input parameters? If a class must take input parameters in its constructor, what would be the way to inject it properly? UPDATE Just for clarification, the problem happens when in my production code I decide to do this: $clientClass= new ClientClass(new Parser($inputString));//--->I have no way to predict $inputString as it is calculated inside `ClientClass` itself. UPDATE 2 Again for clarification, I'm trying to find a general solution to the problem not for this example code only because some of my classes have 2, 3 or 4 parameters in their constructors not only one.

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  • Lenovo Y460 Intel Driver Secondary Display Flickering

    - by ultimatebuster
    This is a part of the massive dump of problems I'm encountering with my Lenovo Y460 and Ubuntu. Problem: ATI PowerXpress doesn't really work. Doesn't work as I have to use the open source driver with hacks. Turned off ATI card at boot Details on how I accomplished that: http://ubuntuforums.org/showthread.php?p=10955831#post10955831 Installing the ATI drivers results in a failure of the intel drivers to work with Ubuntu Class (all animations have to turned off). Anyway to fix this problem to allow switchable graphics to work? The problem above has been fixed by FGLRX (Catalyst 11.6) is it compatible with kernel 2.6.39? However, there's another issue. If I connect my secondary monitor (VGA 17'') while using the Intel driver, I would not be able to use that screen as there's flickering and tearing, making the screen blurry and usable. Here's the fglrxinfo: $ fglrxinfo display: :0.0 screen: 0 OpenGL vendor string: Tungsten Graphics, Inc OpenGL renderer string: Mesa DRI Intel(R) Ironlake Mobile GEM 20100330 DEVELOPMENT OpenGL version string: 1.4 (2.1 Mesa 7.10.2) Any fixes for that? Potential related bug report on launchpad: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/750259 However I can't confirm because the video showing that is much more dramatic than what I have, mine are tiny flickering that won't be captured by video cameras as I've tried, but enough to make it blurry for humans.

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  • SSD on USB 3.0 doesnt always mount

    - by juergen
    I would like to ask you for some support for this issue. The SSD I use is apparently slightly damaged. Atm it shows this popular Corsair Series 3 problem. symptom: the disk is working for some minutes and then just suddenly stops. Two months ago it worked like a charm. This was my boot device in these days. So now I still need to copy some data out of the device which leads me to my question. Usually the SSD is working again for some minutes, when i unplug and replug its power. It gets detected by the system again and I can continue my backup. The problem on Ubuntu is, that it is not recognized again after two or three replugs. I have to reboot to bring it back. To specify this situation: when i unplug and replug my USB mouse before i reboot it is not recognized as well. So something seems to be wrong with the system also. my question: how do i fix this rebooting issue? I will post all the logs you need to analyse. The problem doesnt depend on the interface. I tried USB3.0, 2.0 and Sata already. Thank you! cheers my system: Ubuntu 11.10, Gigabyte G41MT-S2P, Intel E6750 Corsair Force Series 2 - F120, Digitus USB 3.0 Adapter, USB 3.0 interface card

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  • Source code not matching uploaded HTML file

    - by benhowdle89
    I'm not sure if this is the right place to ask but i'm having a hugely frustrating problem with Coda and my website (i'm not sure which one is causing the issue) I'm using Coda to make changes to my website, Coda uses built in FTP to save changes to your web page. So when you hit Save, it uploads the new file. I've been using Coda for months and never had a problem until now. I am making changes in the html of my index.php and hitting save, it's successfully uploading the file but no changes are reflected in the source code in ANY browser. I even logged into cPanel on my website, ie. www.example.com:2082 and looked at the file - the changes have been made successfully. But the actual webpage in browser's source code, no changes?? I have tried adding which made no difference. Interestingly i make changes to style.css and the changes are instant. I have emptied the cache on all of my browsers but i'm still having an issue. Does this sound like a Coda problem or has anyone heard of such a thing?

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  • Choppy USB mice on just one of USB ports

    - by user20532
    I've got Lenovo b560 laptop with latest, properly updated Kubuntu on it (11.04 natty, kernel 2.6.38-8-generic). It has three USB2.0 ports onboard. I usually plug a mouse into one of them (I've got 3 different mice - in office, at home and for when on the go). Sometimes, usually after laptop awakening from sleep, the mouse still works but cursor movements are choppy, as if the processor was extremely loaded (it's usually not). I found that if I re-plug the mouse cord into the other USB port, it works just fine. If I plug it back to problematic port, it is still choppy and remains choppy until next boot. Of course I want my mice to always work fine. Problem is: I cannot reproduce this behavior for sure, it happens sporadically but regularly. I use different USB ports (problem has ever happened on each of them since), I use different mice (each has failed me this way at least once), I cannot generally find what exactly is going wrong and why plugging to different port fixes the mouse instantly. So I'd like to hear at least clues where to look at, what to try to identify my problem. A bit of update: while beginning this post, I had the issue once again. I have just replugged the mouse back to problematic port and it is not recognized at all. On the other port it works smoothly.

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  • ISA Proxy server

    - by user59931
    Have a proxy at work that runs Microsoft ISA. i used to be able to connect using 11.10 with firefox no problem at all. i could either put the settings in firefox or the settings in ubuntu network proxy settings. this would give me a connection no problem ( slow due to the work network being really lame) since i upgraded with 12.10 firefox just crashes if i have any proxy settings (manual added the proxy settings). if i connect to a diffrent network without the proxy settings it works fine and doesn't crash i tried chrome to see if that would work... simular problem. chrome doesn't crash but is so slow it just times out all the time and can take 10min for a page to load.... not really sure where to go with this? i have tried a clean install of 12.04 on 2 diffrent computers and also both tried just upgrading from 11.10. Only answer i can see at the moment is role back to 11.10 :( i have tried all sorts like turning of IPv6 to see if that would make any diffrence but no joy... really am lost now. whats weird is the repositys are also really really slow through 12.04. 50 megs took an hour to download (ISA server has Ubuntu rep servers enables without authenication). really am lost

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  • Can't Log Into Ubuntu 12.04

    - by Razick
    Yesterday, after turning on Ubuntu, I logged into a Gnome session. A few minutes later, I tried switching to Unity for a change. Unfortunately, the background and my desktop icons loaded, but the system bar and launcher failed to load even after several minutes. Unity had always worked fine for me. I then tried the guest account, and it worked fine on both Unity and Gnome. However, the problem with my account got worse; I couldn't log into any desktop at all anymore. I would type in my password and press enter and it would just sit there doing nothing. The computer no longer responded in any way, so I had to hold the power button and reboot. The same problem happened repeatedly. Earlier today, I tried to get on again. I found that I hadthe same problem, when I tried to log in, the computer no longer locked up, but instead flashed a black screen with theconsole output and what seemed to be an error message before returning to the log in screen. It was to quick for me to read, about 1/4-1/2 second. I'd really appreciate some help as I have some important files that are not backed up yet. I can't transfer the files to a new account, or even make a new account because I tried taking the password off my account so now I can't authenticate from the guest to perform root functions. I'd really appreciate some help as I have some important files that are not backed up yet. Thanks.

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  • linq to sql with nservicebus table lock issue

    - by IGoor
    I am building a system using NServiceBus and my DataLayer is using Linq 2 SQL. The system is made up of 2 services. Service1 receives messages from NSB. It will query Table1 in my database and inserts a record into Table1 If a certain condition is met a new NSB message is sent to the 2nd service Service2 will update records also in Table1 when it receives messages from Service1 and it does some other non database related work. Service2 is a long running process. The problem I am having is the moment Service2 updates a record in Table1, the table is locked. The lock seems to be in place until Service2 has completed all it is processing. i.e. The lock is not released after my datacontext is disposed. This causes the query in Service1 to timeout. Once Service2 completes processing, Service1 resumes processing again without problem. So for example Service1 code may look like: int x =0; using (DataContext db = new DataContext()) { x = (from dp in db.Table1 select dp).Count(); // this line will timeout while service2 is processing Table1 t = new Table1(); t.Data = "test"; db.Table1.InsertOnSubmit(t); db.SubmitChanges(); } if(x % 50 == 0) CallService2(); The code in service2 may look like: using (DataContext db = new DataContext()) { Table1 t = db.Table1.Where(t => t.id == myId); t.Data = "updated"; db.SubmitChanges(); } // I would have expected the lock to have been released at this point, but this is not the case. DoSomeLongRunningTasks(); // lock will be released once service2 exits I don't understand why the lock is not released when the datacontext is disposed in Service2. To get around the problem I have been calling: db.ExecuteCommand("SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED"); and this works, but I am not happy using it. I want to solve this problem properly. Has any one experienced this sort of problem before and does any one know how to solve it? Why is the lock not released after the datacontext has been disposed? Thanks in advance. p.s. sorry for the extremely long post.

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  • How do I interpolate air drag with a variable time step?

    - by Valentin Krummenacher
    So I have a little game which works with small steps, however those steps vary in time, so for example I sometimes have 10 Steps/second and then I have 20 Steps/second. This changes automatically depending on how many steps the user's computer can take. To avoid inaccurate positioning of the game's player object I use y=v0*dt+g*dt^2/2 to determine my objects y-position, where dt is the time since the last step, v0 is the velocity of my object in the beginning of my step and g is the gravity. To calculate the velocity in the end of a step I use v=v0+g*dt what also gives me correct results, independent of whether I use 2 steps with a dt of for example 20ms or one step with a dt of 40ms. Now I would like to introduce air drag. For simplicity's sake I use a=k*v^2 where a is the air drag's acceleration (I am aware that it would usually result in a force, but since I assume 1kg for my object's mass the force is the same as the resulting acceleration), k is a constant (in this case I'm using 0.001) and v is the speed. Now in an infinitely small time interval a is k multiplied by the velocity in this small time interval powered by 2. The problem is that v in the next time interval would depend on the drag of the last which again depends on the v of the last interval and so on... In other words: If I use a=k*v^2 I get different results for my position/velocity when I use 2 steps of 20ms than when I use one step of 40ms. I used to have this problem for my position too, but adding +g*dt^2/2 to the formula for my position fixed the problem since it takes into account that the position depends on the velocity which changes slightly in every infinitely small time interval. Does something like that exist for air drag too? And no, I dont mean anything like Adding air drag to a golf ball trajectory equation or similar, for that kind of method only gives correct results when all my steps are the same. (I hope you can understand my intermediate english, it's not my main language so I would like to say sorry for all the silly mistakes I might have made in my question)

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  • Internet unusably slow with Realtek Semiconductor Co., Ltd. RTL8111/8168B card

    - by user42424
    So I have recently installed Ubuntu 11.10 for a dual boot with wind 7. After the install I had like 300 updates, so I installed them. At first I could use the internet, although it was extremely slow. However now I cannot, sometimes it will load and others it will simply time out. When I try to download something it will either take forever or will not at all. This is a wired system. On Windows side my speeds are fine. Any help would be greatly appreciated. Also like I said I am new to Linux/Ubuntu so please be nice. One last thing, I also installed 11.10 for same dual boot on my laptop, and wireless speed is the same as on Windows? Only the wired desktop gives me the problem? Hear is some hardware info.. Hope it helps. Mobo: Gigabyte GA=880GMA- AMD / CPU: AMD Phenom (tm) IIx4 965 / 16 GB Ram / Realtek PCIe GBE Family Controller / Cisco Linksys E2000 / Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06) / eth0 Link encap:Ethernet HWaddr 50:e5:49:33:64:cf inet addr:192.168.1.118 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::52e5:49ff:fe33:64cf/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:76722 errors:0 dropped:76722 overruns:0 frame:76722 TX packets:49692 errors:0 dropped:65 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:107956638 (107.9 MB) TX bytes:4342553 (4.3 MB) Interrupt:44 Base address:0x2000 thanks to roadmr problem solved! I powered down PC, un plugged power from pc end, waited a few (maybe 3)minutes. plugged power back in, pushed and held power button for 30 + seconds. Let go, powered on PC, and my Internet is fine! downloads and web speed blaze, just like on my Win 7 boot, maybe even faster. Problem Solved, Thanks to all!! **

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  • Sun Java crashing, mostly with jboss

    - by Joel
    I'm on Ubuntu 10.10. I keep having problems with Sun Java crashing on me. I mostly have it crashing on my Jboss server, but I've had it crash MANY MANY times running ANT tasks or the IntelliJ IDE. Here's what it prints: # # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x00007f67e665d440, pid=21260, tid=140082772170512 # # JRE version: 6.0_22-b04 # Java VM: Java HotSpot(TM) 64-Bit Server VM (17.1-b03 mixed mode linux-amd64 ) # Problematic frame: # V [libjvm.so+0x2f2440] # # An error report file with more information is saved as: # /home/blah/blah/blah/hs_err_pid21260.log # # If you would like to submit a bug report, please visit: # http://java.sun.com/webapps/bugreport/crash.jsp # Aborted A co-worker of mine who has the same version of Ubuntu has had the same problem, but has only happened to him once. (I get this probably 2 or 3 times a day, if not more). I have another machine running Ubuntu 10.04 with Sun Java and I have yet to see this problem. 1.0.6_20 is the java version on the 10.04 machine. My machine is running 1.6.0_22. Has anyone else had this problem? Anyone know how to keep it from happening? Also: I have tried reinstalling it and I can't use OpenJDK.

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  • Video freezes when larger than a certain size

    - by Poyan
    I have a weird problem playing video files. I have a fairly new (a few years old) graphic card that should and has played up to 1080p video files without much a lot of trouble. I seem to be having a weird issue where the video plays back fine if the window is below a certain size, but as soon as the windowsize increases, the picture freezes. The audio still plays. Usually this is mitigated by killing som applications. Especially GTK (?) apps seem to cause this lag, like having a Nautilus window open usually triggers this error for me. With hardware rendering I get the error regardless of application. I have tried enabling software rendering in VLC and that eliminates the problem (but I get other problems using software rendering, so I've avoided it). I know this is pretty fuzzy, but I'm not sure how to approach this problem. Do you have any idea? EDIT: Some more information. I have the correct and latest drivers installed. My graphics card is a Nvidia 7600 GT.

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  • Groovy Grapes in NetBeans IDE

    - by Geertjan
    The start of Groovy Grapes support in NetBeans IDE. Below you see a pure Groovy project, with the Groovy JAR and the Ivy JAR automatically on its classpath. There's also a Groovy script that makes use of a @Grab annotation. In the bottom left, in the Services window, you also see a Grape Repository browser, i.e., showing you the JARs that are currently in ".groovy/grapes". Click the images below to get a better look at them. Next, you see what happens when the project is run. The @Grab annotation automatically starts downloading the JARs that are needed and puts them into the ".groovy/grapes" folder. However, the "no suitable classloader found for grab" error message (which Google shows is a problem for lots of developers) prevents the application from running successfully: The final screenshot shows that I've put the JARs that I need onto the classpath of the project. I did that manually, hoping to learn from the NetBeans Maven project or the NetBeans Gradle project how to do that automatically. Also note that the @Grab annotation has been commented out. Now the error message about the classloader is avoided and the project runs. What needs to happen for Groovy Grapes support to be complete in NetBeans IDE: Figure out how to add the downloaded JARs to the project classpath automatically. Fix the refresh problem in the Grape Repository browser, i.e., right now the refresh doesn't happen automatically yet. Hopefully find a way to get around the grab classloader problem, i.e., it's not ideal that one needs to comment out the annotation. Let the user specify a different Grape repository, i.e., right now ".groovy/grapes" is assumed, but the user should be able to point the repository browser to something different. Maybe there should be support for multiple Grape repositories? Comments/feedback/help is welcome.

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  • Ubuntu boots in read-only filesystem after upgrade!

    - by akatzbreaker
    I got a serious problem here: I recently upgraded to the Latest Version of Ubuntu. Now, I boot to my Ubuntu Partition, and I get a Low-Graphics error! I boot to a Recovery-Mode to see what the Problem is. Then, I try to Fix any Damaged Packages, to run fsck but nothing solved the Problem. Then, from the Recovery Menu, I open a Root Shell. I try to create a File and I understand that the Filesystem is Read-Only. Then, I run: mount -o remount,rw / and it Worked for that Terminal Session! When I go back to recovery, I select to resume Boot Normally but I get the Same Error! a I also tried to Boot to my Root Shell again, remount as Read-Write and Start Gnome from there. It Worked! (But the user is ROOT, and is quite Dangerous!) However, I can't do all this proccess at every boot! Any Solution? (Note that when I try to create a new File in my Ubuntu Partition from another OS, I don't get any Errors!)

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  • Can't login to Unity 3d after enabling Xinerama for a short moment

    - by Amir Adar
    Today I connected a second monitor to my computer. I set it up using nVidia's control panel, and all was working quite well, so I figured it won't be a problem to try Xinerama, just to see the difference between that and twinview. After enabling Xinerama and restarting the X session, I saw that I was logged into a Unity 2d session. I thought it was a problem with Xinerama, so I switched back to twinview, but it still logged me into Unity 2d. I tried disconnecting the second monitor, no luck: still Unity 2d. I tried changing GPU drivers and installing drivers from a separate ppa, and still I was logged into Unity 2d. Up until this point, I didn't have any problem logging into Unity 3d. It only happened after I tried using Xinerama. I should note that I was doing all this while updates were going on in the background, so it could be something related to that, though I can't imagine what (I tried booting with another kernel, but no luck). So what exactly happened? Did changing the mode to Xinerama triggered some other changes that I'm not aware of? Did these updates cause a certain malfunction in the driver? Is it something else?

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  • Why is math taught "backwards"? [closed]

    - by Yorirou
    A friend of mine showed me a pretty practical Java example. It was a riddle. I got excited and quickly solved the problem. After it, he showed me the mathematical explanation of my solution (he proved why is it good), and it was completely clear for me. This seems like natural approach for me: solve problems, and generalize. This is very familiar to me, I do it all the time when I am programming: I write a function. When I have to write a similar function, I generalize the problem, grab the generic parts, and refactor them to a function, and solve the original problems as a specialization of the general function. At the university (or at least where I study), things work backwards. The professors shows just the highest possible level of the solutions ("cryptic" mathematical formulas). My problem is that this is too abstract for me. There is no connection of my previous knowledge (== reality in my sense), so even if I can understand it, I can't really learn it properly. Others are learning these formulas word-by-word, and get good grades, since they can write exactly the same to the test, but this is not an option for me. I am a curious person, I can learn interesting things, but I can't learn just text. My brain is for storing toughts, not strings. There are proofs for the theories, but they are also really hard to understand because of this, and in most of the cases they are omitted. What is the reason for this? I don't understand why is it a good idea to show the really high level of abstraction and then leave the practical connections (or some important ideas / practical motivations) out?

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  • which way is correct to retrive data from oracle??

    - by rima
    before answer me plz thinking about the futures of these kind of program and answer me plz. I wanna get some data from oracle server like: 1-get all the function,package,procedure and etc for showing them or drop them & etc... 2-compile my *.sql files,get the result if they have problem & etc... becuz I was beginner in oracle first of all I for solve the second problem I try to connect to sqlPlus by RUN sqlplus and trace the output(I mean,I change the output stream of shell and trace what happend and handle the assigned message to customer. NOW THIS PART SUCCEED. just a little bit I have problem with get all result because the output is asynchronous.any way... [in this case I log in to oracle Server by send argument to the sqlplus by make a process in c#] after that I try to get all function,package or procedure name,but I have problem in speed!so I try to use oracle.DataAccess.dll to connect the database. now I m so confusing about: which way is correct way to build a program that work like Oracle Developer! I do not have any experience for like these program how work. If Your answer is I must use the second way follow this part plz: I search a little bit the Golden,PLedit (Benthic software),I have little bit problem how I must create the connection string?because I thinking about how I can find the host name or port number that oracle work on them?? am I need read the TNSNames.Ora file? IF your answer is I must use the first way follow this part plz: do u have any Idea for how I parse the output?because for example the result of a table is so confusing...[i can handle & program it but I really need someone experience,because the important things to me learn how such software work so nice and with quick response?] All of the has different style in output... If you are not sure Can u help me which book can help me in this way i become expert? becuz for example all the C# write just about how u can connect to DB and the DB books write how u can use this DB program,I looking for a book that give me some Idea how develop an interface for do transaction between these two.not simple send and receive data,for example how write a compiler for them. the language of book is not different for me i know C#,java,VB,sql,Oracle Thanks.

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  • Wifi won't connect to certain networks

    - by Dave M G
    As I write this, I'm in a coffee shop on my laptop, and I am trying to connect to the free wifi network they offer. Every time I select their network from the wifi applet drop down menu, it connects for a second and then disconnects. At the same time, I have my Android phone with me, and it connects to the coffee shop's network without problem. There are a couple of people around me also using the same network with no issues. I asked the staff to check and as far as they can tell there is no problem with their router or anything. I have tried rebooting, but it has not made a difference. I have double and triple checked that I am using the correct WEP password. As an added wrinkle, when I connect to another network, it seems to connect (although I can't use them because they are paid gateway services). So I'm able to ask this question now because I have tethered my laptop to my phone, but it's slow and a workaround, not a solution. All indications are that it's a problem with my computer against this one network. Why would that be and how can I fix it?

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  • Never Bet Against the Impossible

    - by BuckWoody
    My uncle used to say “If a man tells you that his car squirts milk in his eye when you lift the hood, don’t bet against that. You’ll end up with milk in your eye.” My friend Allen White tells me this is taken from a play (and was said about playing cards), but I think the sentiment holds, even in database work. I mentioned the other day that you should allow the other person to talk and actively listen before you propose a solution. Well, I saw a consultant “bet against the impossible”  the other day – and it bit her. She explained to the person telling her the problem that the situation simply couldn’t exist that way, and he proceeded to show her that it did. She got silent, typed a few things, muttered a little, and then said “well, must be something else.” She just couldn’t admit she was wrong. So don’t go there. If someone explains a problem to you with their database, listen with purpose, and then explore the troubleshooting steps you know to find the problem. But keep your absolutes to yourself. In fact, I have a friend that has recently sent me one of those. He connects to a system with SQL Server Management Studio (SSMS) version 2008 (if I recall correctly) and it shows a certain version number of the target system in the connection tab. Then he connects to it using SSMS 2008 R2 and gets a different number. Now, as far as I know, we didn’t change the connection string information, and that’s provided by the target system, so this is impossible. But I won’t tell him that. Not until I look a little more. :) Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Password not working for sudo ("Authentication failure")

    - by Souta
    Before I mention anything further, DO NOT give me a response saying that terminal won't show password input. I'm AWARE of that. I'm typing my user password in (not a capslock issue), and for some reason it still says 'Authentication Failure'. Is there some other password (one I'm not aware of) I'm supposed to be using other than my user password? I've had this ubuntu before, on another hard drive and I didn't have this problem. (And it was the same ubuntu, ubuntu 12.04 LTS) ai@AiNekoYokai:~$ groups ai adm cdrom sudo dip plugdev lpadmin sambashare ai@AiNekoYokai:~$ lsb_release -rd Description: Ubuntu 12.04 LTS Release: 12.04 ai@AiNekoYokai:~$ pkexec cat /etc/sudoers # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults env_reset Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" # Host alias specification # User alias specification # Cmnd alias specification # User privilege specification root ALL=(ALL:ALL) ALL # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL # Allow members of group sudo to execute any command %sudo ALL=(ALL:ALL) ALL # See sudoers(5) for more information on "#include" directives: #includedir /etc/sudoers.d I can log in with my password, but it's not accepted as valid for authentication <-- That is pretty much my issue. (Although, I haven't gone into recovery mode.) I've ran: ai@AiNekoYokai:~$ ls /etc/sudoers.d README And also reinstalled sudo with: pkexec apt-get update pkexec apt-get --purge --reinstall install sudo pkexec usermod -a -G admin $USER <- Says admin does not exist su $USER <- worked for me, however, my password still does not do much (in sense of not working for other things) I changed my password with pkexec passwd $USER. I was able to change it no problem. gksudo xclock was something I was able to get into, no problem. (Clock showed) ai@AiNekoYokai:~$ gksudo xclock

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  • Should sanity be a property of a programmer or a program?

    - by toplel32
    I design and implement languages, that can range from object notations to markup languages. In many cases I have considered restrictions in favor of sanity (common knowledge), like in the case of control characters in identifiers. There are two consequences to consider before doing this: It takes extra computation It narrows liberty I'm interested to learn how developers think of decisions like this. As you may know Microsoft C# is very open on the contrary. If you really want to prefix your integer as Long with 'l' instead of 'L' and so risk other developers of confusing '1' and 'l', no problem. If you want to name your variables in non-latin script so they will contrast with C#'s latin keywords, no problem. Or if you want to distribute a string over multiple lines and so break a series of indentation, no problem. It is cheap to ensure consistency with restrictions and this makes it tempting to implement. But in the case of disallowing non-latin characters (concerning the second example), it means a discredit to Unicode, because one would not take full advantage of its capacity.

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