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• Disaster Recovery Example

  Previously, I use to work for a small internet company that sells dental plans online. Our primary focus concerning disaster prevention and recovery is on our corporate website and private intranet site. We had a multiphase disaster recovery plan that includes data redundancy, load balancing, and off-site monitoring. Data redundancy is a key aspect of our disaster recovery plan. The first phase of this is to replicate our data to multiple database servers and schedule daily backups of the databases that are stored off site. The next phase is the file replication of data amongst our web servers that are also backed up daily by our collocation. In addition to the files located on the server, files are also stored locally on development machines, and again backed up using version control software. Load balancing is another key aspect of our disaster recovery plan. Load balancing offers many benefits for our system, better performance, load distribution and increased availability. With our servers behind a load balancer our system has the ability to accept multiple requests simultaneously because the load is split between multiple servers. Plus if one server is slow or experiencing a failure the traffic is diverted amongst the other servers connected to the load balancer allowing the server to get back online. The final key to our disaster recovery plan is off-site monitoring that notifies all IT staff of any outages or errors on the main website encountered by the monitor. Messages are sent by email, voicemail, and SMS. According to Disasterrecovery.org, disaster recovery planning is the way companies successfully manage crises with minimal cost and effort and maximum speed compared to others that are forced to make decision out of desperation when disasters occur. In addition Sun Guard stated in 2009 that the first step in disaster recovery planning is to analyze company risks and factor in fixed costs for things like hardware, software, staffing and utilities, as well as indirect costs, such as floor space, power protection, physical and information security, and management. Also availability requirements need to be determined per application and system as well as the strategies for recovery.

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• How does datomic handle "corrections"?

  - by blueberryfields

  tl;dr Rich Hickey describes datomic as a system which implicitly deals with timestamps associated with data storage from my experience, data is often imperfectly stored in systems, and on many occasions needs to retroactively be corrected (ie, often the question of "was a True on Tuesday at 12:00pm?" will have an incorrect answer stored in the database) This seems like a spot where the abstractions behind datomic might break - do they? If they don't, how does the system handle such corrections? Rich Hickey, in several of his talks, justifies the creation of datomic, and explains its benefits. His work, if I understand correctly, is motivated by core the insight that humans, when speaking about data and facts, implicitly associate some of the related context into their work(a date-time). By pushing the work required to manage the implicit date-time component of context into the database, he's created a system which is both much easier to understand, and much easier to program. This turns out to be relevant to most database programmers in practice - his work saves everyone a lot of time managing complex, hard to produce/debug/fix, time queries. However, especially in large databases, data is often damaged/incorrect (maybe it was not input correctly, maybe it eroded over time, etc...). While most database updates are insertions of new facts, and should indeed be treated that way, a non-trivial subset of the work required to manage time-queries has to do with retroactive updates. I have yet to see any documentation which explains how such corrections, or retroactive updates, are handled by datomic; from my experience, they are a non-trivial (and incredibly difficult to deal with) subset of time-related data manipulation that database programmers are faced with. Does datomic gracefully handle such updates? If so, how?

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• A fix for the design time error in MVVM Light V4.1

  - by Laurent Bugnion

  For those of you who installed V4.1 of MVVM Light and created a project for Windows Phone 8, you will have noticed an error showing up in the design surface (either in Visual Studio designer, or in Expression Blend). The error says: “Could not load type ‘System.ComponentModel.INotifyPropertyChanging’ from assembly ‘mscorlib.extensions’” with additional information about version numbers. The error is caused by an incompatibility between versions of System.Windows.Interactivity. Because this assembly is strongly named, any version incompatibility is causing the kind of error shown here (for an interesting discussion on the strong naming issue, see this thread on Codeplex). I managed to resolve the issue for Windows Phone 8 and will publish a cleaned up installer next week. In the mean time, in order to allow you to continue development, please follow the steps: Download the new DLLs zip package (MVVMLight_V4_1_25_WP8). Right click on the Zip file and select Properties from the context menu. Press the “Unblock” button (if available) and then OK. Right click again on the zip package and select “Extract all…”. Select a known location for the new DLLs. Open the MVVM Light project with the design time error in Visual Studio 2012. Open the References folder in the Solution Explorer. Select the following DLLs: GalaSoft.MvvmLight.dll, GalaSoft.MvvmLight.Extras.dll, Microsoft.Practices.ServiceLocation.dll and System.Windows.Interactivity.dll. Press “delete” and confirm to remove the DLLs from your project. Right click on References and select Add Reference from the context menu. Browse to the folder with the new DLLs. Select the four new DLLs and press OK. Rebuild your application, and open it again in Blend or in the Visual Studio designer. The error should be gone now. In the next few days, as time allows, I will publish a new MSI containing a fixed version of the DLLs as well as a few other improvements. This quick fix should however allow you to continue working on your Windows Phone 8 projects in design mode too.   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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• Is file permission secured when it transferred from Ubuntu to Windows?

  - by Gaurav_Java

  I am having 9GB text file which is encrypted . This file contains some confidential data . Which is on my system(Ubuntu) and my external HDD (ntfs) . This file get daily updated and then encrypted . But it has to be shared among 2-3 (Windows) person. I defined permission so that no other person can even read this file(chmod 660). It is too large file, so I can't upload it anywhere and it get updated daily basis. But this file travel on Windows OS and Ubuntu also. Even I am having copy of this on my personal computer. Recently it was deleted by some other user over Windows . I just want to know how can I set permission over that file so that it cannot be deleted from any other operating system. If someone delete this file, then I am having data old for couple of days, which is only on my system. I gone through this question it says there is nothing. And from this question I am not able to understand how can I protect it. Can I do anything for preventing this file from being deleted. Then how can I secure this files from getting deleted any suggestion or software or ideas. Maybe I sound silly or this is stupid question. Please don't close it, thanks for any suggestion or solution.

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• Which approach is the most maintainable?

  - by 2rs2ts

  When creating a product which will inherently suffer from regression due to OS updates, which of these is the preferable approach when trying to reduce maintenance cost and the likelihood of needing refactoring, when considering the task of interpreting system state and settings for a lay user? Delegate the responsibility of interpreting the results of inspecting the system to the modules which perform these tasks, or, Separate the concerns of interpretation and inspection into two modules? The first obviously creates a blob in which a lot of code would be verbose, redundant, and hard to grok; the second creates a strong coupling in which the interpretation module essentially has to know what it expects from inspection routines and will have to adapt to changes to the OS just as much as the inspection will. I would normally choose the second option for the separation of concerns, foreseeing the possibility that inspection routines could be re-used, but a developer updating the product to deal with a new OS feature or something would have to not only write an inspection routine but also write an interpretation routine and link the two correctly - and it gets worse for a developer who has to change which inspection routines are used to get a certain system setting, or worse yet, has to fix an inspection routine which broke after an OS patch. I wonder, is it better to have to patch one package a lot or two packages, each somewhat less so?

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• Simple Interactive Search with jQuery and ASP.Net MVC

  - by Doug Lampe

  Google now has a feature where the search updates as you type in the search box.  You can implement the same feature in your MVC site with a little jQuery and MVC Ajax.  Here's how: Create a javascript global variable to hold the previous value of your search box. Use setTimeout to check to see if the search box has changed after some interval.  (Note: Don't use setInterval since we don't want to have to turn the timer off while Ajax is processing.) Submit the form if the value is changed. Set the update target to display your results. Set the on success callback to "start" the timer again.  This, along with step 2 above will make sure that you don't sent multipe requests until the initial request has finished processing. Here is the code: <script type="text/javascript"> var searchValue = $('#Search').val(); $(function () {     setTimeout(checkSearchChanged, 0.1); }); function checkSearchChanged() {     var currentValue = $('#Search').val();     if ((currentValue) && currentValue != searchValue && currentValue != '') {         searchValue = $('#Search').val();         $('#submit').click();     }     else {         setTimeout(checkSearchChanged, 0.1);     } } </script> <h2>Search</h2> <% using (Ajax.BeginForm("SearchResults", new AjaxOptions { UpdateTargetId = "searchResults", OnSuccess = "checkSearchChanged" })) { %>     Search: <%   = Html.TextBox("Search", null, new { @class = "wide" })%><input id="submit" type="submit" value="Search" /> <% } %> <div id="searchResults"></div> That's it!

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• How should I create a mutable, varied jtree with arbitrary/generic category nodes?

  - by Pureferret

  Please note: I don't want coding help here, I'm on Programmers for a reason. I want to improve my program planning/writing skills not (just) my understanding of Java. I'm trying to figure out how to make a tree which has an arbitrary category system, based on the skills listed for this LARP game here. My previous attempt had a bool for whether a skill was also a category. Trying to code around that was messy. Drawing out my tree I noticed that only my 'leaves' were skills and I'd labeled the others as categories. Explanation of tree: The Tree is 'born' with a set of hard coded highest level categories (Weapons, Physical and Mental, Medical etc.). Fro mthis the user needs to be able to add a skill. Ultimately they want to add 'One-handed Sword Specialisation' for instance. To do so you'd ideally click 'add' with Weapons selected and then select One-handed from a combobox, then click add again and enter a name in a text field. Then click add again to add a 'level' or 'tier' first proficiency, then specialisation. Of course if you want to buy a different skill it's completely different, which is what I'm having trouble getting my head around let alone programming in. What is a good system for describing this sort of tree in code? All the other JTree examples I've seen have some predictable pattern, and I don't want to have to code this all in 'literals'. Should I be using abstract classes? Interfaces? How can I make this sort of cluster of objects extensible when I add in other skills not listed above that behave differently? If there is not a good system to use, if there a good process for working out how to do this sort of thing?

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• Will you choose JavaFX for Development?

  - by javafx4you

  A few weeks ago, a poll on the home page of java.net caught my eyes, because it was related to JavaFX. Its title: Will you use JavaFX for development once it's fully ported to Mac and Linux platforms? Usually, the results for this type of polls are published on the editor's Daily Blog soon after the poll closes. For some reason, this didn't happen for the JavaFX poll, so I'll take a shot at interpreting the results.  The results found on java.net look pretty close to the following: Although this way to look at the results already gives us an idea of how much traction JavaFX is getting, there are just too many type of answers that make it hard to read. The answers "maybe" and "I don't know" are awfully similar, so I'm tempted to collapse these together. Then there is "No, I don't do that type of development" that just doesn't belong here, as obviously developers who ave chosen this answer don't develop Rich Internet Apps, and therefore I will adapt the % results accordingly. Finally, I've been tempted to combine the top three categories just t simplify the results. This gives me the following chart:  Whether you prefer the original graph, or my simplified take on it, one thing is sure:  less than 10% of developers who have taken this poll plan to stick to another toolkit (presumably Swing or SWT), while the vast majority is inclined to use JavaFX. When you take into account that JavaFX 2.0 is pretty much a "new" API (no more JavaFX Script), I think these are some pretty good results, 6 months after the official release of JavaFX 2.0.

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• FOSS Development: Who develops the OS-specific packages?

  - by achristi

  I have a couple of FOSS projects. They can be a bit of a pain to get running unless you've got dependencies in place already, which I figure is par for the course for FOSS projects. We know that each free operating system out there has its own package management systems. A few of them, such as homebrew on Mac OS or AUR on Arch linux are very friendly to community contributions. What I am wondering is, who exactly is expected to contribute packages? Primarily I am concerned with the case of small or developing projects, since it's pretty standard for the big projects to be put in there by the OS maintainers. From my perspective, it is something of a chicken-egg problem, because your software will not make its way into a package system if it does not have users, and it is less likely to gain users if it is not easy to install and use. For the sake of discussion, let's assume that the software in question is actually legitimately useful. I can see where people could create crapware or spam and that should obviously be kept out of any package system. So, in summary, whose job is this? Is it spammy for a FOSS software dev to put his own work into various OS package repositories?

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• Worthless Anti-Spam (What can we learn)

  - by smehaffie

  I recently can across a site that had a “anti-spam” field at the bottom of the entry from.  The first issue I had with it was that at 1280X800 you could not read the value you were suppose to enter (see below).  You tell me, should you enter div, dlv, piv, or plv. But even worse than not being readable at high resolutions is the fact that the programmer who coded it really did not understand what this was used for.  An anti-spam (aka: catpcha) entry field should not be able to be read by looking at the HTML DOM object (so entry of value cannot be scripted).  In this case the value is simply a disabled text input filed that has the value you need to type.  So a hacker would simply need to search for text input field named “spam2” and then they could flood the site with spam. 1: <td> 2: <label> 3: <input name="spam1" type="text" class="small" id="spam1" size="6" maxlength="3" /> 4: <input name="spam2" type="text" class="small" id="spam2" value="plv" 5: disabled="disabled" size="6" maxlength="3" /> 6: * <span class="small">- Anti-SPAM key - please enter matching value</span> 7: </label> 8: </td>   There are some things to learn from this example: 1) Always make sure you understand why you are coding a feature/function for any program you write.  Just following the requirements without realizing the “why” will sooner or later come back to bite you.  I think the above example appears to be an example of this. 2) Always check how the screen appears in different resolutions.  In this case it was pretty much unreadable in 1280x800, but you could read it in 800X600 (but most people I know do not have their resolution set that low).  Lucky for me I could “View Source” and get the value I needed to enter.

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• Proper method to update and draw from game loop?

  - by Lost_Soul

  Recently I've took up the challenge for myself to create a basic 2d side scrolling monster truck game for my little brother. Which seems easy enough in theory. After working with XNA it seems strange jumping into Java (which is what I plan to program it in). Inside my game class I created a private class called GameLoop that extends from Runnable, then in the overridden run() method I made a while loop that handles time and such and I implemented a targetFPS for drawing as well. The loop looks like this: @Override public void run() { long fpsTime = 0; gameStart = System.currentTimeMillis(); lastTime = System.currentTimeMillis(); while(game.isGameRunning()) { currentTime = System.currentTimeMillis(); long ellapsedTime = currentTime - lastTime; if(mouseState.leftIsDown) { que.add(new Dot(mouseState.getPosition())); } entities.addAll(que); game.updateGame(ellapsedTime); fpsTime += ellapsedTime; if(fpsTime >= (1000 / targetedFPS)) { game.drawGame(ellapsedTime); } lastTime = currentTime; } The problem I've ran into is adding of entities after a click. I made a class that has another private class that extends MouseListener and MouseMotionListener then on changes I have it set a few booleans to tell me if the mouse is pressed or not which seems to work great but when I add the entity it throws a CME (Concurrent Modification Exception) sometimes. I have all the entities stored in a LinkedList so later I tried adding a que linkedlist where I later add the que to the normal list in the update loop. I think this would work fine if it was just the update method in the gameloop but with the repaint() method (called inside game.drawGame() method) it throws the CME. The only other thing is that I'm currently drawing directly from the overridden paintComponent() method in a custom class that extends JPanel. Maybe there is a better way to go about this? As well as fix my CME? Thanks in advance!!!

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• eSTEP Newsletter for the technical EMEA partner community

  - by mseika

  We are pleased to present to you the first issue of the eSTEP Newsletter, which is dedicated to support the technical EMEA partner community in the effort to provide more information on what is going on within the corporation, what is the technical news regarding Hardware, events and all the important things which we think may be of interest to you. Invitation: STEP TechCast: Oracle Solaris 11 Express Get an insight on how Oracle Solaris 11 Express has raised the bar on the innovation introduced in Oracle Solaris 10. Learn about the new integrated features such as: network based package management tools improvements to built-in virtualization new virtualised network architecture security enhancements file system evolution  Learn how Oracle Solaris 11 Express provides greatly decreased planned system downtime, performs a completely safe system upgrade, achieves an unprecedented level of flexibility for application consolidation, and provides the highest levels of security in your datacenter. Date and time: Thursday, 7. July 2011, 13:00 - 14:00 CEST Speaker: Joost Pronk van Hoogeveen Target audience: Tech Presales Webcast Coordinates: You will find the coordinates in the eSTEP portal under the Events tab. Use your email-adress and PIN: eSTEP_2011 to get access. We are happy to get your comments and feedback.

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• keyPressed is not working after adding ActionListener to JButton

  - by Yehonatan

  I have a serious problem while trying to build a menu for my game. I've added two JButton to a main JPanel and added an ActionListener for each of them. The main JPanel also contains the game JPanel which have the keyPressed method inside keyController. That's how it looks - Main -       JPanel -         JButton, JButton,         JPanel which contains the game and keyPressed function inside KeyController class which worked fine before I added the ActionListener for JButton. For some reason after I added an ActionListener for each of the button, the game JPanel is not getting any keyPreseed events nor KeyRealesed. Does anyone know the solution for my situation? Thank you very much! Main window - Scanner in = new Scanner(System.in); JFrame f = new JFrame("Square V.S Circles"); f.setUndecorated(true); f.setResizable(false); f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); f.add(new JPanelHandler()); f.pack(); f.setVisible(true); f.setLocationRelativeTo(null); JPanelHandler(main JPanel) - super.setFocusable(true); JButton mybutton = new JButton("Quit"); JButton sayhi = new JButton("Say hi"); sayhi.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { System.out.println("Hi"); } }); mybutton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { System.exit(0); } }); add(mybutton); add(sayhi); add(new Board(2)); Board KeyController(The code inside is working so it's unnecessary to put it here) - private class KeyController extends KeyAdapter { public KeyController() { ..Code } @Override public void keyPressed(KeyEvent e) { ...Code } @Override public void keyReleased(KeyEvent e){ ...Code } }

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• Should I use a config file or database for storing business rules?

  - by foiseworth

  I have recently been reading The Pragmatic Programmer which states that: Details mess up our pristine code—especially if they change frequently. Every time we have to go in and change the code to accommodate some change in business logic, or in the law, or in management's personal tastes of the day, we run the risk of breaking the system—of introducing a new bug. Hunt, Andrew; Thomas, David (1999-10-20). The Pragmatic Programmer: From Journeyman to Master (Kindle Locations 2651-2653). Pearson Education (USA). Kindle Edition. I am currently programming a web app that has some models that have properties that can only be from a set of values, e.g. (not actual example as the web app data confidential): light-type = sphere / cube / cylinder The light type can only be the above three values but according to TPP I should always code as if they could change and place their values in a config file. As there are several incidents of this throughout the app, my question is: Should I store possibly values like these in: a config file: 'light-types' = array(sphere, cube, cylinder), 'other-type' = value, 'etc = etc-value a single table in a database with one line for each config item a database with a table for each config item (e.g. table: light_types; columns: id, name) some other way? Many thanks for any assistance / expertise offered.

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• correct way to implement auth/acl in mvc

  - by WiseStrawberry

  I am looking into making a correctly laid out MVC auth/acl system. I think I want the authentication of a user (and the session handling) to be seperate from the ACL system. (I don't know why but this seems a good idea from the things I've read) What does mvc have to do with this question you ask? Because I wish for the application to be well integrated with my acl. An example of a controller (CodeIgniter) <?php class forums extends MX_Controller { $allowed = array('users', 'admin'); $need_login = true; function __construct() { //example of checking if logged in. if($this->auth->logged_in() && $this->auth->is_admin()) { echo "you're logged in!"; } } public function add_topic() { if($this->auth->allowed('add_topic') { //some add topic things. } else { echo 'not allowed to add topic'; } } } ?> My thoughts $this->auth would be autoloaded in the system. I would like to check the $allowed array against the user currently (not) logged in and react accordingly. Is this a good way of doing things? I haven't seen much literature on mvc integration and auth. I want to make things as easy as possible.

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• Banshee doesn't like opening websites

  - by Allan

  I have come across two bugs (which will be added to launchpad if it's not resolved here) When I open any of the websites in Banshee Amazon or Miro Guide as soon as the site is finished loading it crashes Banshee. If I play any video local or remote it will show 1 frame maybe 0.5 sec of video then I get a black screen and audio continues in the backgound. Specs & Details I have a Fujitsu Amilo 1718 laptop with 2 gig of ram (original 1 gig) graphics is provided by ATI Radeon Xpress 200M (don't laugh it works with compiz....just) I have a link to the output of banshee --debug Here Don't have time to read? Here are the Highlights [2 Warn 11:52:34.814] Caught an exception - System.ArgumentNullException: Argument cannot be null. then abit later Debug info from gdb: Could not attach to process. If your uid matches the uid of the target process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try again as the root user. For more details, see /etc/sysctl.d/10-ptrace.conf ptrace: Operation not permitted. ================================================================= Got a SIGSEGV while executing native code. This usually indicates a fatal error in the mono runtime or one of the native libraries used by your application. ================================================================= Aborted Not music to my ears as you can expect. The version I am using is 1.9.4 from the daily ppa but these bugs happen in any version of banshee from 1.8.1 and up. So if any one has come across a fix for this problem please share!! additional info Both VLC and Miro work on my system so there isn't a system wide problem with video and I haven't mentioned mono so no trolling it will get voted down.

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• 11.10 install hangs at different places

  - by TreefrogInc

  I've been trying to install Oneiric for some time now, and I've looked everywhere for a solution to the problems I've been having. So far, I've attempted four times to install it, so now I'm up to a point of panic. So I grabbed the 11.10 x64 iso from the website, and after verifying that the md5 hash is correct, I burned that onto my last remaining clean CD. On my first attempt, everything went perfectly up to the middle of the installation, and the progress bar stopped when it said: "configuring target system." I could do everything else, only the installation seemed to have stopped. After I googled my problem, I went and used the "check disc for errors" option, which said everything was fine. Then I tried the installation again, only this time, I selected "Install Ubuntu Now" instead of the "try before installing". Again, the same problem. My second and third tries didn't even reach the installation phase. It just stopped at the 5 blinking dots and never went any further. I used the same non-rewritable cd for all the attempts, as the error check didn't show any problems and because I'm currently out of usable cds. System: Core i3 CPU @ 3.4 GHz, 500 GB HDD (250g used for Win7, 70g used for preexisting system partitions, 180g unallocated).

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• Quickly ubuntu-application + indicator template don't work

  - by aliasbody

  I've started to work with quickly and python (because I wanted to have some GTk3 integration and create and appindicator), and so I create the projecto like this : quickly create ubuntu-application ualarm cd ualarm quickly run And the application launched. But then I tried to add the appindicator like this : quickly add indicator And since then the application doesn't start anymore and this error appear : aliasbody@BodyUbuntu-PC:~/Projectos/ualarm$ quickly run (ualarm:8515): Gtk-WARNING **: Theme parsing error: gnome-panel.css:28:11: Not using units is deprecated. Assuming 'px'. /usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py:391: Warning: g_object_set_property: construct property "type" for object `Window' can't be set after construction Gtk.Window.__init__(self, type=type, **kwds) Traceback (most recent call last): File "bin/ualarm", line 33, in <module> ualarm.main() File "/home/aliasbody/Projectos/ualarm/ualarm/__init__.py", line 33, in main window = UalarmWindow.UalarmWindow() File "/home/aliasbody/Projectos/ualarm/ualarm_lib/Window.py", line 35, in __new__ new_object.finish_initializing(builder) File "/home/aliasbody/Projectos/ualarm/ualarm/UalarmWindow.py", line 24, in finish_initializing super(UalarmWindow, self).finish_initializing(builder) File "/home/aliasbody/Projectos/ualarm/ualarm_lib/Window.py", line 75, in finish_initializing self.indicator = indicator.new_application_indicator(self) File "/home/aliasbody/Projectos/ualarm/ualarm/indicator.py", line 52, in new_application_indicator ind = Indicator(window) File "/home/aliasbody/Projectos/ualarm/ualarm/indicator.py", line 20, in __init__ self.indicator = AppIndicator3.Indicator('ualarm', '', AppIndicator3.IndicatorCategory.APPLICATION_STATUS) TypeError: GObject.__init__() takes exactly 0 arguments (3 given) How can I solve this problem ?

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• Floating point undesirable in highly critical code?

  - by Kirt Undercoffer

  Question 11 in the Software Quality section of "IEEE Computer Society Real-World Software Engineering Problems", Naveda, Seidman, lists fp computation as undesirable because "the accuracy of the computations cannot be guaranteed". This is in the context of computing acceleration for an emergency braking system for a high speed train. This thinking seems to be invoking possible errors in small differences between measurements of a moving object but small differences at slow speeds aren't a problem (or shouldn't be), small differences between two measurements at high speed are irrelevant - can there be a problem with small roundoff errors during deceleration for an emergency braking system? This problem has been observed with airplane braking systems resulting in hydroplaning but could this actually happen in the context of a high speed train? The concern about fp errors seems to not be well-founded in this context. Any insight? The fp is used for acceleration so perhaps the concern is inching over a speed limit? But fp should be just fine if they use a double in whatever implementation language. The actual problem in the text states: During the inspection of the code for the emergency braking system of a new high speed train (a highly critical, real-time application), the review team identifies several characteristics of the code. Which of these characteristics are generally viewed as undesirable? The code contains three recursive functions (well that one is obvious). The computation of acceleration uses floating point arithmetic. All other computations use integer arithmetic. The code contains one linked list that uses dynamic memory allocation (second obvious problem). All inputs are checked to determine that they are within expected bounds before they are used.

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• How to indicate to a web server the language of a resource

  - by Nik M

  I'm writing an HTTP API to a publishing server, and I want resources with representations in multiple languages. A user whose client GETs a resource which has Korean, Japanese and Trad. Chinese representations, and sends Accept-Language: en, ja;q=0.7 should get the Japanese. One resource, identified by one URI, will therefore have a number of different language representations. This seems to me like a totally orthodox use of content negotiation and multiple resource representations. But when each translator comes to provide these alternate language representations to the server, what's the correct way to instruct the server which language to store the representation under? I'm having the translators PUT the representation in its entirety to the same URI, but I can't find out how to do this elegantly. Content-Language is a response header, and none of the request headers seem to fit the bill. It seems my options are Invent a new request header Supply additional metadata in a multipart/related document Provide language as a parameter to the Content-Type of the request, like Content-Type: text/html;language=en I don't want to get into the business of extending HTTP, and I don't feel great about bundling extra metadata into the representation. Neither approach seems friendly to HTTP caches either. So option 3 seems like the best way that I can think of, but even then it's decidedly non-standard to put my own specific parameters on a very well established content type. Is there any by-the-book way of achieving this?

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• New SPC2 benchmark- The 7420 KILLS it !!!

  - by user12620172

  This is pretty sweet. The new SPC2 benchmark came out last week, and the 7420 not only came in 2nd of ALL speed scores, but came in #1 for price per MBPS. Check out this table. The 7420 score of 10,704 makes it really fast, but that's not the best part. The price one would have to pay in order to beat it is ridiculous. You can go see for yourself at http://www.storageperformance.org/results/benchmark_results_spc2The only system on the whole page that beats it was over twice the price per MBPS. Very sweet for Oracle. So let's see, the 7420 is the fastest per $. The 7420 is the cheapest per MBPS. The 7420 has incredible, built-in features, management services, analytics, and protocols. It's extremely stable and as a cluster has no single point of failure. It won the Storage Magazine award for best NAS system this year. So how long will it be before it's the number 1 NAS system in the market? What are the biggest hurdles still stopping the widespread adoption of the ZFSSA? From what I see, it's three things: 1. Administrator's comfort level with older legacy systems. 2. Politics 3. Past issues with Oracle Support.   I see all of these issues crop up regularly. Number 1 just takes time and education. Number 3 takes time with our new, better, and growing support team. many of them came from Oracle and there were growing pains when they went from a straight software-model to having to also support hardware. Number 2 is tricky, but it's the job of the sales teams to break through the internal politics and help their clients see the value in oracle hardware systems. Benchmarks like this will help.

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• WiFi slow sometimes, reboot helps, how do I debug it?

  - by January

  Ubuntu 12.04.1 with all updates installed. Laptop Lenovo Thinkpad X230 with Intel Corporation Centrino Advanced-N 6205. WiFi sometimes becomes extremely slow. Often this occurs when I wake the system from suspend and connect to a different network. I find no obvious clues in system logs. /etc/init.d/network-manager restart doesn't help, but a reboot does. How can I go on with debugging this issue? In specific, which parts of the system should I try to restart (without a complete reboot)? I know of problems with Intel WiFi (see for example this question and the instructions here), but if that was the problem, I would expect the WiFi to be slow at all times, and not just sometimes. Also, I have a gut feeling that it might be a DNS issue (for example, getting a page from a known server is faster than accessing a new server), but I don't know how to tackle it. Update: despite numerous updates in the meanwhile, I still observe this behavior. It happens always when I access my WiFi router at home after returning from work; when I reboot my laptop, the connection speed is good again.

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• What's hot in Oracle Premier Support News for Solaris, Storage and Systems - How to Patch!

  - by user12244613

  Struggling with locating patches for Sun products? Can't find your Oracle System Drivers? This question has been raised many times by customers and was the source of a short video in the Oracle System Support Newsletter in February 2012. The transition between SunSolve and My Oracle Support is to change how you think about the type of patch your looking for. For example, in SunSolve you might have typed e1000g if looking for an Enternet Driver.. but entering e1000g will not find anything in My Oracle Support - Patches and Update Menu. As you need to use the Product (Advanced) search which is driven of the Product Name, therefore you need to type "Ethernet" and select the ethernet product you are looking for to locate the patches for this product. Just to recap that video: If you are looking for the e1000g Ethernet Driver - You need to use Advance Search and search for Enternet 1. Log into My Oracle Support - Select Patches and Updates - Select Product or Family (Advanced Search). 2. In the product line enter: Ethernet and select the product name from the menu. 3. Check remove supersede patches - that ensure you only get relevant current patches in the results. 4. Select Search and the results are displayed. Now you have more options to include the platform (Solaris,Linux etc.) if want to further narrow the search. Need more information? Log into My Oracle Support and what a short 90sec video I put together. View the 7 minute Video using Firefox/chrome – It shows searching for individual patches, Solaris, Firmware etc. If you are not receiving the Oracle System Support Newsletter: Option (a) Within My Oracle Support, make document id: 1363390.1 a favourite and revisit it on the 2nd of each month for the latest content. Option (b) By default the Newsletter  is sent to all customers who have logged a Service Request on an Oracle Systems Hardware Product during the last 12months, unless you have opted out to receiving Oracle Communications on your profile on http://oracle.com

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• Win7 no longer available after installing 12.04

  - by Michael

  I have installed Ubuntu 12.04 but my Windows 7 partition seems to have been lost. It is in sda2. Can anyone help me how to get this Windows 7 partition back without having to reinstall Windows 7? Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xd45cd45c Device Boot Start End Blocks Id System /dev/sda1 2048 61433855 30715904 83 Linux /dev/sda2 * 61433856 122873855 30720000 7 HPFS/NTFS/exFAT /dev/sda3 122873856 976769023 426947584 7 HPFS/NTFS/exFAT Disk /dev/sdb: 203.9 GB, 203928109056 bytes 255 heads, 63 sectors/track, 24792 cylinders, total 398297088 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x03ee03ee Device Boot Start End Blocks Id System /dev/sdb1 * 63 20482874 10241406 c W95 FAT32 (LBA) /dev/sdb2 20482875 40965749 10241437+ 1c Hidden W95 FAT32 (LBA) /dev/sdb3 40965750 398283479 178658865 f W95 Ext'd (LBA) /dev/sdb5 40965813 76694309 17864248+ 7 HPFS/NTFS/exFAT /dev/sdb6 76694373 108856439 16081033+ 7 HPFS/NTFS/exFAT /dev/sdb7 108856503 398283479 144713488+ 7 HPFS/NTFS/exFAT Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 240 heads, 63 sectors/track, 129201 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000001 Device Boot Start End Blocks Id System /dev/sdc1 * 63 20480543 10240240+ 82 Linux swap / Solaris /dev/sdc2 20480605 1953519119 966519257+ f W95 Ext'd (LBA) /dev/sdc5 20480607 1953519119 966519256+ 7 HPFS/NTFS/exFAT

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• Sub-systems in game engines

  - by Hillel

  So here's the problem- I'm writing my own engine library, and it works fine with stuff like menus and the actual game screen. The thing is, I can't really figure out how to integrate something like an intro or dialogue preceding certain levels into this system. Let's look at another example- say I have a game-specific engine which gets a Level object and runs it. Engine would have its own collision and physics system, all hard coded. Now, what if at some point in a level, I want the player to enter a mini-game with different rules? How do I morph the Engine class to support these sub-systems without having to deal with their code all the time (as in: if(regular game) ... else if(mini game) ...)? And what if I want an intro animation at the start of a level, and I want the player to be able to assume control of his character once the animation ends, do I implement the animation into the Engine class itself? Or maybe I need to run another class, CutScene, and when it ends, it calls Engine and starts the level? What if I want to add a dialogue system, where at the start of each level there's a short dialogue and the player can't control his character, and once it ends, he can? Would I then run the dialogue code inside the Engine code? Maybe these sub-systems should all be scripted? I don't know anything about scripting, is it necessary for this kind of situation? Any help would be appreciated.

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