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• Ubuntu 12.04 won't load - hangs at Busybox v1.18.5 / initramfs

  - by Marty

  I want to start by saying that I am very new with Linux (about 1 month using it). I have had no problems up until now. I am running Ubuntu 12.04 from a Toshiba laptop with 250 GB hard drive and 3 GB of ram. Everything worked fine yesterday. The only changes I made was was that I downloaded Banshee to try as a replacement for Rhythmbox and did a few recommended updates. This morning I tried to boot and it took a long time and I finally got this error: mount: mounting /dev/disk/by-uuid/02bc41cc-1e21-4700-a179-be2805a658c4 on /root failed: Invalid argument mount: mounting /dev on /root/dev failed: No such file or directory mount: mounting /sys on /root/sys failed: No such file or directory mount: mounting /proc on /root/proc failed: No such file or directory Target filesystem doesn't have requested /sbin/init. No init found. Try passing init= bootarg. BusyBox v1.18. (Ubuntu 1:1.18.5-1ubuntu4) built-in shell (ash) Enter 'help' for a list of built-in commands (initramfs) I'm not sure what to do beyond this point. I have read around on here and haven't found the help I need. I did try to boot it from the Live CD. I can boot up to the Try Ubuntu/Install Ubuntu screen. When I go through the Try Ubuntu selection I can't access my hard disk. When I clicked on it I got this error: Unable to mount 247 GB Filesystem Error mounting: mount: wrong fs type, bad option, bad superblock on /dev/sda/1, missing codepage or helper program, or other error. In some cases useful info is found in syslog - try dmesg|tail or so. I tried dmesg|tail and saw a string of values but nothing that looked helpful. I have also tried to boot from the GRUB screen as recovery mode and previous Linux version but they didn't work either. I tried to load Windows Recovery Environment (loader) (on /dev/sdc3) and got this message: error: no such device: 268057B1805785E9 error: hd1 cannot get C/H/S values I had saw somewhere that I could fix this with the Live CD but my knowledge isn't good enough to try. I tried something with Gpart that I had read, but the system told me that I didn't have Gpart. Could someone please explain to me what I need to do and/or haven't tried yet. Thanks so much!

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• Are there deprecated practices for multithread and multiprocessor programming that I should no longer use?

  - by DeveloperDon

  In the early days of FORTRAN and BASIC, essentially all programs were written with GOTO statements. The result was spaghetti code and the solution was structured programming. Similarly, pointers can have difficult to control characteristics in our programs. C++ started with plenty of pointers, but use of references are recommended. Libraries like STL can reduce some of our dependency. There are also idioms to create smart pointers that have better characteristics, and some version of C++ permit references and managed code. Programming practices like inheritance and polymorphism use a lot of pointers behind the scenes (just as for, while, do structured programming generates code filled with branch instructions). Languages like Java eliminate pointers and use garbage collection to manage dynamically allocated data instead of depending on programmers to match all their new and delete statements. In my reading, I have seen examples of multi-process and multi-thread programming that don't seem to use semaphores. Do they use the same thing with different names or do they have new ways of structuring protection of resources from concurrent use? For example, a specific example of a system for multithread programming with multicore processors is OpenMP. It represents a critical region as follows, without the use of semaphores, which seem not to be included in the environment. th_id = omp_get_thread_num(); #pragma omp critical { cout << "Hello World from thread " << th_id << '\n'; } This example is an excerpt from: http://en.wikipedia.org/wiki/OpenMP Alternatively, similar protection of threads from each other using semaphores with functions wait() and signal() might look like this: wait(sem); th_id = get_thread_num(); cout << "Hello World from thread " << th_id << '\n'; signal(sem); In this example, things are pretty simple, and just a simple review is enough to show the wait() and signal() calls are matched and even with a lot of concurrency, thread safety is provided. But other algorithms are more complicated and use multiple semaphores (both binary and counting) spread across multiple functions with complex conditions that can be called by many threads. The consequences of creating deadlock or failing to make things thread safe can be hard to manage. Do these systems like OpenMP eliminate the problems with semaphores? Do they move the problem somewhere else? How do I transform my favorite semaphore using algorithm to not use semaphores anymore?

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• Book review: Peopleware: Productive Projects and Teams

  - by DigiMortal

     Peopleware by Tom DeMarco and Timothy Lister is golden classic book that can be considered as mandatory reading for software project managers, team leads, higher level management and board members of software companies. If you make decisions about people then you cannot miss this book. If you are already good on managing developers then this book can make you even better – you will learn new stuff about successful development teams for sure. Why peopleware? Peopleware gives you very good hints about how to build up working environment for project teams where people can really do their work. Book also covers team building topics that are also important reading. As software developer I found practically all points in this book to be accurate and valid. Many times I have found my self thinking about same things and Peopleware made me more confident about my opinions. Peopleware covers also time management and planning topics that help you do way better job on using developers time effectively by minimizing the amount of interruptions by phone calls, pointless meetings and i-want-to-know-what-are-you-doing-right-now questions by managers who doesn’t write code anyway. I think if you follow suggestions given by Peopleware your developers are very happy. I suggest you to also read another great book – Death March by Edward Yourdon. Death March describes you effectively what happens when good advices given by Peopleware are totally ignored or worse yet – people are treated exactly opposite way. I consider also Death March as golden classics and I strongly recommend you to read this book too. Table of Contents Acknowledgments Preface to the Second Edition Preface to the First Edition Part 1: Managing the Human Resource Chapter 1: Somewhere Today, a Project Is Failing Chapter 2: Make a Cheeseburger, Sell a Cheeseburger Chapter 3: Vienna Waits for You Chapter 4: Quality-If Time Permits Chapter 5: Parkinson's Law Revisited Chapter 6: Laetrile Part II: The Office Environment Chapter 7: The Furniture Police Chapter 8: "You Never Get Anything Done Around Here Between 9 and 5" Chapter 9: Saving Money on Space Intermezzo: Productivity Measurement and Unidentified Flying Objects Chapter 10: Brain Time Versus Body Time Chapter 11: The Telephone Chapter 12: Bring Back the Door Chapter 13: Taking Umbrella Steps Part III: The Right People Chapter 14: The Hornblower Factor Chapter 15: Hiring a Juggler Chapter 16: Happy to Be Here Chapter 17: The Self-Healing System Part IV: Growing Productive Teams Chapter 18: The Whole Is Greater Than the Sum of the Parts Chapter 19: The Black Team Chapter 20: Teamicide Chapter 21: A Spaghetti Dinner Chapter 22: Open Kimono Chapter 23: Chemistry for Team Formation Part V: It't Supposed to Be Fun to Work Here Chapter 24: Chaos and Order Chapter 25: Free Electrons Chapter 26: Holgar Dansk Part VI: Son of Peopleware Chapter 27: Teamicide, Revisited Chapter 28: Competition Chapter 29: Process Improvement Programs Chapter 30: Making Change Possible Chapter 31: Human Capital Chapter 32:Organizational Learning Chapter 33: The Ultimate Management Sin Is Chapter 34: The Making of Community Notes Bibliography Index About the Authors

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• Rewriting code under BSD license

  - by Frank

  I am currently studding OpengGL with OpenGL Supebible 5th edition. I've found interested for me some C++ code that is distributed with the book (see also on google code). That code is under New BSD License. I am writing my software on C# with SharpGL wrapper and I'd like to know following things: Can I rewrite that C++ to C#? edid: I'am interesting in using such things like GLBatch, GLShaderManager and some other thing from GLTools. Problem is that library is on C++, but I use C#. How do I have to mark my source code if I put it somewhere like to my github account? What disclaimer should be? Original disclaimer looks like: /* GLShaderManager.h Copyright (c) 2009, Richard S. Wright Jr. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of Richard S. Wright Jr. nor the names of other contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ Edit: Should my copyright looks like after rewriting something like that? Copyright (c) 2014, My Name Copyright (c) 2009, Richard S. Wright Jr. All rights reserved. Redistribution...................

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• Using INotifyPropertyChanged in background threads

  - by digitaldias

  Following up on a previous blog post where I exemplify databinding to objects, a reader was having some trouble with getting the UI to update. Here’s the rough UI: The idea is, when pressing Start, a background worker process starts ticking at the specified interval, then proceeds to increment the databound Elapsed value. The problem is that event propagation is limeted to current thread, meaning, you fire an event in one thread, then other threads of the same application will not catch it. The Code behind So, somewhere in my ViewModel, I have a corresponding bethod Start that initiates a background worker, for example: public void Start( ) { BackgroundWorker backgroundWorker = new BackgroundWorker( ); backgroundWorker.DoWork += IncrementTimerValue; backgroundWorker.RunWorkerAsync( ); } protected void IncrementTimerValue( object sender, DoWorkEventArgs e ) { do { if( this.ElapsedMs == 100 ) this.ElapsedMs = 0; else this.ElapsedMs++; }while( true ); } Assuming that there is a property: public int ElapsedMs { get { return _elapsedMs; } set { if( _elapsedMs == value ) return; _elapsedMs = value; NotifyThatPropertyChanged( "ElapsedMs" ); } } The above code will not work. If you step into this code in debug, you will find that INotifyPropertyChanged is called, but it does so in a different thread, and thus the UI never catches it, and does not update. One solution Knowing that the background thread updates the ElapsedMs member gives me a chance to activate BackgroundWorker class’ progress reporting mechanism to simply alert the main thread that something has happened, and that it is probably a good idea to refresh the ElapsedMs binding. public void Start( ) { BackgroundWorker backgroundWorker = new BackgroundWorker( ); backgroundWorker.DoWork += IncrementTimerValue; // Listen for progress report events backgroundWorker.WorkerReportsProgress = true; // Tell the UI that ElapsedMs needs to update backgroundWorker.RunWorkerCompleted += ( sender, e ) => { NotifyThatPropertyChanged( "ElapsedMs" ) }; backgroundWorker.RunWorkerAsync( ); } protected void IncrementTimerValue( object sender, DoWorkEventArgs e ) { do { if( this.ElapsedMs == 100 ) this.ElapsedMs = 0; else this.ElapsedMs++; // report any progress ( sender as BackgroundWorker ).ReportProgress( 0 ); }while( true ); } What happens above now is that I’ve used the BackgroundWorker cross thread mechanism to alert me of when it is ok for the UI to update it’s ElapsedMs field. Because the property itself is being updated in a different thread, I’m removing the NotifyThatPropertyChanged call from it’s Set method, and moving that responsability to the anonymous method that I created in the Start method. This is one way of solving the issue of having a background thread update your UI. I would be happy to hear of other cross-threading mechanisms for working in a MCP/MVC/MVVM pattern.

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• Music Notation Editor - Refactoring view creation logic elseware

  - by Cyril Silverman

  Let me preface by saying that knowing some elementary music theory and music notation may be helpful in grasping the problem at hand. I'm currently building a Music Notation and Tablature Editor (in Javascript). But I've come to a point where the core parts of the program are more or less there. All functionality I plan to add at this point will really build off the foundation that I've created. As a result, I want to refactor to really solidify my code. I'm using an API called VexFlow to render notation. Basically I pass the parts of the editor's state to VexFlow to build the graphical representation of the score. Here is a rough and stripped down UML diagram showing you the outline of my program: In essence, a Part has many Measures which has many Notes which has many NoteItems (yes, this is semantically weird, as a chord is represented as a Note with multiple NoteItems, individual pitches or fret positions). All of the relationships are bi-directional. There are a few problems with my design because my Measure class contains the majority of the entire application view logic. The class holds the data about all VexFlow objects (the graphical representation of the score). It contains the graphical Staff object and the graphical notes. (Shouldn't these be placed somewhere else in the program?) While VexFlowFactory deals with actual creation (and some processing) of most of the VexFlow objects, Measure still "directs" the creation of all the objects and what order they are supposed to be created in for both the VexFlowStaff and VexFlowNotes. I'm not looking for a specific answer as you'd need a much deeper understanding of my code. Just a general direction to go in. Here's a thought I had, create an MeasureView/NoteView/PartView classes that contains the basic VexFlow objects for each class in addition to any extraneous logic for it's creation? but where would these views be contained? Do I create a ScoreView that is a parallel graphical representation of everything? So that ScoreView.render() would cascade down PartView and call render for each PartView and casade down into each MeasureView, etc. Again, I just have no idea what direction to go in. The more I think about it, the more ways to go seem to pop into my head. I tried to be as concise and simplistic as possible while still getting my problem across. Please feel free to ask me any questions if anything is unclear. It's quite a struggle trying to dumb down a complicated problem to its core parts.

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• Alternatives for comparing data from different databases

  - by Alex

  I have two huge tables on separate databases. One of them has the information of all the SMS that passed through the company's servers while the other one has the information of the actual billing of those SMS. My job is to compare samples of both of these tables (for example, the records between 1 and 2 pm) to see if there are any differences: SMS that were sent but not charged to the user for whatever reason that may be happening. The columns I will be using to compare are the remitent's phone number and the exact date the SMS was sent. An issue here is that dates usually are the same on both sides, but in many cases differ by 1 or 2 seconds. I have, so far, two alternatives to do this: (PL/SQL) Create two tables where i'm going to temporarily store all the records of that 1hour sample. One for each of the main tables. Then, for each distinct phone number, select the time of every SMS sent from that phone from both my temporary tables and start comparing one by one using cursors. In this case, the procedure would be ran on the server where one of the sources is so the contents of the other one would be looked up using a dblink. (sqlplus + c++) Instead of storing the 1hour samples in new tables, output the query to a text file. I will have two text files, one for each source. Then, open the first file and load all of it's content on a hash_map (key-value) using c++, where the key will be the phone number and the value a list of times of SMS sent from that phone. Finally, open the second file, grab each line (in this format: numberX timeX), look for numberX's entry on the hash_map (wich will be a list of times) and then check if timeX is on that list. If it isn't, save it somewhere to finally store it on a "uncharged" table (this would also be the final step on case 1) My main concern is efficiency. These samples have about 2 million records on each source, so just grabbing one record on one side and looking it up on the other would not be possible. That's the reason I wanted to use hash_maps Which do you think is a better option?

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• How to integrate Java ME SDK 3.2 with NetBeans

  - by SungmoonCho

  Many people like to use Java ME SDK with IDEs. We provided instructions on how to integrate the SDK with NetBeans through the download page, and also through the release note, however, let me explain it here once again with some screen shots. 1. Download Java ME SDK and NetBeans plugin from here. 2. Install Java ME SDK first. You will have the emulator and the runtime on your machine. Also please unarchive the NetBeans plugin somewhere. 3. Launch NetBeans. 4. Go to "Tools" - "Plugins". 5. Check out the "Installed" tab. Check "Show details". If you see the previous version of Java ME SDK Tools installed already. Check those to uninstall them. 6. Go to "Settings" tab. 7. Click "Add", and provide the location of NetBeans plugin. In my case, it is "file:/C:/Users/sungcho/Downloads/nb-me-sdk-plugins-uc/updates.xml". Don't forget to add "updates.xml" at the end. 8. Click "Okay" 9. Click "Available Plugins" tab. 10. If you scroll down, you will see three Java ME SDK Tools. Check "Java ME SDK Tools" plugin. Also check others as you desire. 11. Follow the instruction and install them. 12. Restart NetBeans 13. That is it. Done. Now you will see Oracle Java ME SDK 3.2 in your Java Platform list.

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• PowerShell – Show a Notification Balloon

  - by BuckWoody

  In my presentations for PowerShell I sometimes want to start a process (like a backup) that will take some time. I normally pop up a notification “balloon” at the start, and then do the bulk of the work, and then pop up a balloon at the end to let me know it’s done. You can actually try out this little sample (on a test system, of course) without any other code to see what it does. Then just put the other PowerShell commands in the #Do Some Work part. Oh – throw an icon (.ico file) in a c:\temp directory or point that somewhere else. (No, this probably isn’t original. Can’t remember where I saw the original code, but I’ve modified it a bit anyway, so if you’re the original author and this looks slightly familiar, post a comment.) [void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms") $objBalloon = New-Object System.Windows.Forms.NotifyIcon $objBalloon.Icon = "C:\temp\Folder.ico" # You can use the value Info, Warning, Error $objBalloon.BalloonTipIcon = "Info" # Put what you want to say here for the Start of the process $objBalloon.BalloonTipTitle = "Begin Title" $objBalloon.BalloonTipText = "Begin Message" $objBalloon.Visible = $True $objBalloon.ShowBalloonTip(10000) # Do some work # Put what you want to say here for the completion of the process $objBalloon.BalloonTipTitle = "End Title" $objBalloon.BalloonTipText = "End Message" $objBalloon.Visible = $True $objBalloon.ShowBalloonTip(10000) Script Disclaimer, for people who need to be told this sort of thing: Never trust any script, including those that you find here, until you understand exactly what it does and how it will act on your systems. Always check the script on a test system or Virtual Machine, not a production system. Yes, there are always multiple ways to do things, and this script may not work in every situation, for everything. It’s just a script, people. All scripts on this site are performed by a professional stunt driver on a closed course. Your mileage may vary. Void where prohibited. Offer good for a limited time only. Keep out of reach of small children. Do not operate heavy machinery while using this script. If you experience blurry vision, indigestion or diarrhea during the operation of this script, see a physician immediately. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Stop trying to be perfect

  - by Kyle Burns

  Yes, Bob is my uncle too.  I also think the points in the Manifesto for Software Craftsmanship (manifesto.softwarecraftsmanship.org) are all great.  What amazes me is that tend to confuse the term “well crafted” with “perfect”.  I'm about to say something that will make Quality Assurance managers and many development types as well until you think about it as a craftsman – “Stop trying to be perfect”. Now let me explain what I mean.  Building software, as with building almost anything, often involves a series of trade-offs where either one undesired characteristic is accepted as necessary to achieve another desired one (or maybe stave off one that is even less desirable) or a desirable characteristic is sacrificed for the same reasons.  This implies that perfection itself is unattainable.  What is attainable is “sufficient” and I think that this really goes to the heart both of what people are trying to do with Agile and with the craftsmanship movement.  Simply put, sufficient software drives the greatest business value.   I've been in many meetings where “how can we keep anything from ever going wrong” has become the thing that holds us in analysis paralysis.  I've also been the guy trying way too hard to perfect some function to make sure that every edge case is accounted for.  Somewhere in there, something a drill instructor said while I was in boot camp occurred to me.  In response to being asked a question by another recruit having to do with some edge case (I can barely remember the context), he said “What if grasshoppers had machine guns?  Would the birds still **** with them?”  It sounds funny, but there's a lot of wisdom in those words.   “Sufficient” is different for every situation and it’s important to understand what sufficient means in the context of the work you’re doing.  If I’m writing a timesheet application (and please shoot me if I am), I’m going to have a much higher tolerance for imperfection than if you’re writing software to control life support systems on spacecraft.  I’m also likely to have less need for high volume performance than if you’re writing software to control stock trading transactions.   I’d encourage anyone who has read this far to instead of trying to be perfect, try to create software that is sufficient in every way.  If you’re working to make a component that is sufficient “better”, ask yourself if there is any component left that is not yet sufficient.  If the answer is “yes” you’re working on the wrong thing and need to adjust.  If the answer is “no”, why aren’t you shipping and delivering business value?

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• GWT: Generate more complete crawl error report

  - by Mike

  I'm a developer in charge of managing Webmasters and related issues (including correcting crawl errors) for dozens (hundreds, maybe?) of active sites and as part of my duties I create a report of every discrepancy, including all pages generating a 404 and all pages that link to those pages. Currently within Webmaster Tools I'm able to download a csv file of all pages with a 404 response, but I'm then having to manually click on every single one of those links and copy the "linked from" field to paste into my spreadsheet. This is extremely tedious and seems unnecessary; I would expect the ability to download all that data at once. I'm ultimately looking for the end result of one csv file that has every url with a 404, but also has every url that links to each one of them. Am I overlooking this functionality somewhere or does anyone have a good solution? Edit 1 (2/11/2013): Example of what the csv output looks like now: URL,Response Code,News Error,Detected,Category http://www.abcdef.com/123.php,404,,11/12/13,Not found http://www.abcdef.com/456.php,404,,11/12/13,Not found Which is great, but let's say 123.php has 5 pages that link to it. Now I have to duplicate that row in my spreadsheet 4 more times, then go into Webmasters, get all the url's that link to the page, and add that data to my spreadsheet. The output I would prefer: URL,Response Code,Linked From,News Error,Detected,Category http://www.abcdef.com/123.php,404,http://www.ghijkl.com/naughtypage1.php,,11/12/13,Not found http://www.abcdef.com/123.php,404,http://www.ghijkl.com/naughtypage2.php,,11/12/13,Not found http://www.abcdef.com/123.php,404,http://www.ghijkl.com/naughtypage3.php,,11/12/13,Not found http://www.abcdef.com/456.php,404,http://www.ghijkl.com/naughtypage1.php,,11/12/13,Not found http://www.abcdef.com/456.php,404,http://www.ghijkl.com/naughtypage2.php,,11/12/13,Not found http://www.abcdef.com/456.php,404,http://www.ghijkl.com/naughtypage3.php,,11/12/13,Not found Note the (hypothetical) addition of a "Linked From" column, as well as the fact there are only 2 unique URL's now (like before) but all of the "Linked To" pages are shown in one report. Edit 2 (2/12/2013): To clarify, my question is less about detecting and correcting 404's, but more about generating a report of what Google has listed as errors. Oftentimes, these errors aren't even valid anymore but I still need documentation to show that Google detected a problem and that problem is now fixed. Many of the "linked from" url's I find are actually outdated, cached resources. For example, I'll frequently see that the linked-from url is the sitemap, which is actually an old sitemap cached by Google that points to an old page. Neither the sitemap or old page exist, but they still appear in my crawl error reports because they are cached resources.

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• Drawing lots of tiles with OpenGL, the modern way

  - by Nic

  I'm working on a small tile/sprite-based PC game with a team of people, and we're running into performance issues. The last time I used OpenGL was around 2004, so I've been teaching myself how to use the core profile, and I'm finding myself a little confused. I need to draw in the neighborhood of 250-750 48x48 tiles to the screen every frame, as well as maybe around 50 sprites. The tiles only change when a new level is loaded, and the sprites are changing all the time. Some of the tiles are made up of four 24x24 pieces, and most (but not all) of the sprites are the same size as the tiles. A lot of the tiles and sprites use alpha blending. Right now I'm doing all of this in immediate mode, which I know is a bad idea. All the same, when one of our team members tries to run it, he gets very bad frame rates (~20-30 fps), and it's much worse when there are more tiles, especially when a lot of those tiles are the kind that are cut into pieces. This all makes me think that the problem is the number of draw calls being made. I've thought of a few possible solutions to this, but I wanted to run them by some people who know what they're talking about so I don't waste my time on something stupid: TILES: When a level is loaded, draw all the tiles once into a frame buffer attached to a big honking texture, and just draw a big rectangle with that texture on it every frame. Put all the tiles into a static vertex buffer when the level is loaded, and draw them that way. I don't know if there's a way to draw objects with different textures with a single call to glDrawElements, or if this is even something I'd want to do. Maybe just put all the tiles into a big giant texture and use funny texture coordinates in the VBO? SPRITES: Draw each sprite with a separate call to glDrawElements. Use a dynamic VBO somehow. Same texture question as number 2 above. Point sprites? This is probably silly. Are any of these ideas sensible? Is there a good implementation somewhere I could look over?

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• Calling home, receiving calls and smartphone data from the US

  - by Rob Farley

  I got asked about calling home from the US, by someone going to the PASS Summit. I found myself thinking “there should be a blog post about this”... The easiest way to phone home is Skype - no question. Use WiFi, and if you’re calling someone who has Skype on their phone at the other end, it’s free. Even if they don’t, it’s still pretty good price-wise. The PASS Summit conference centre has good WiFI, as do the hotels, and plenty of other places (like Starbucks). But if you’re used to having data all the time, particularly when you’re walking from one place to another, then you’ll want a sim card. This also lets you receive calls more easily, not just solving your data problem. You’ll need to make sure your phone isn’t locked to your local network – get that sorted before you leave. It’s no trouble to drop by a T-mobile or AT&T store and getting a prepaid sim. You can’t get one from the airport, but if the PASS Summit is your first stop, there’s a T-mobile store on 6th in Seattle between Pine & Pike, so you can see it from the Sheraton hotel if that’s where you’re staying. AT&T isn’t far away either. But – there’s an extra step that you should be aware of. If you talk to one of these US telcos, you’ll probably (hopefully I’m wrong, but this is how it was for me recently) be told that their prepaid sims don’t work in smartphones. And they’re right – the APN gets detected and stops the data from working. But luckily, Apple (and others) have provided information about how to change the APN, which has been used by a company based in New Zealand to let you get your phone working. Basically, you send your phone browser to http://unlockit.co.nz and follow the prompts. But do this from a WiFi place somewhere, because you won’t have data access until after you’ve sorted this out... Oh, and if you get a prepaid sim with “unlimited data”, you will still need to get a Data Feature for it. And just for the record – this is WAY easier if you’re going to the UK. I dropped into a T-mobile shop there, and bought a prepaid sim card for five quid, which gave me 250MB data and some (but not much) call credit. In Australia it’s even easier, because you can buy data-enabled sim cards that work in smartphones from the airport when you arrive. I think having access to data really helps you feel at home in a different place. It means you can pull up maps, see what your friends are doing, and more. Hopefully this post helps, but feel free to post comments with extra information if you have it. @rob_farley

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• Ubuntu hangs on booting up after a update

  - by alFReD NSH

  I've made a clean install yesterday, for the first time restarted, everything went good and then after I updated packages and copied my old home directory to replace the new one, when I restarted it hung when it was booting. I tried reinstalling again and doing the same thing, but again same thing happened. Here's what I see, before when the Ubuntu logo with the five dots is shown: Then after that, 3 or 4 of the dots will load and hangs there. If I press arrow up before that, this will be shown I started my laptop again today(the pictures are for the day before) and after that, boot up with live CD and got the logs. dmesg: http://pastebin.com/aVxV7BQF syslog: http://pastebin.com/4E2BrRUK And some info: alfred@alFitop:~$ uname -a Linux alFitop 3.2.0-24-generic #39-Ubuntu SMP Mon May 21 16:52:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux lshw: http://pastebin.com/AZbKJmsT sources.list : http://pastebin.com/2HazmuyV My problem is a bit similar to here: http://ubuntuforums.org/showthread.php?t=1918271 Though I didn't change my x.org config. Only changed home directory and updated packages. I've tried memtest and fschk, both passed. In the recovery mode boot option, I've also realized that same things happen in failsafe graphical mode. But when I go into the network mode, I can boot up my system, but of course same the graphics are just basic. Adding blacklist intel_ips to /etc/modprobe.d/blacklist.conf solves the first message, but still I get the broken pipe and CPU stack traces. The current kernel version is 3.2.0-25, I've tried booting up in the 3.2.0-23(the one the installer came with, but same results.) Also uninstalled apparmor, didn't help. I've installed Ubuntu again, this time without copying the home directory, also same result. --- UPDATE --- This problem was solved before with removing backports, but its back again! I've updated my laptop last night and the problem came back. It's definitely one of these packages. My /var/log/apt/term.log and /var/log/apt/history.log. I'm almost having the same situation. --- UPDATE --- I realized this also have happened on times that I have updated(haven't restarted after it) and my computer power has been cut off and its shutdown due to lack of power. And I realized if I just do as I answered but not in somewhere without GUI(networking mode has the GUI) it wouldn't work.

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• Setting up port forwarding for 7000 appliance VM in VirtualBox

  - by uejio

  I've been using the 7000 appliance VM for a lot of testing lately and relied on others to set up the networking for the VM for me, but finally, I decided to take the dive and do it myself.  After some experimenting, I came up with a very brief number of steps to do this all using the VirtualBox CLI instead of the GUI. First download the VM image and unpack it somewhere.  I put it in /var/tmp. Then, set your VBOX_USER_HOME to some place with lots of disk space and import the VM: export VBOX_USER_HOME=/var/tmp/MyVirtualBoxVBoxManage import /var/tmp/simulator/vbox-2011.1.0.0.1.1.8/Sun\ ZFS\ Storage\ 7000.ovf (go get a cup of tea...) Then, set up port forwarding of the VM appliance BUI and shell:First set up port as NAT:VBoxManage modifyvm Sun_ZFS_Storage_7000 --nic1 nat Then set up rules for port forwarding (pick some unused port numbers):VBoxManage modifyvm Sun_ZFS_Storage_7000 --natpf1 "guestssh,tcp,,4622,,22"VBoxManage modifyvm Sun_ZFS_Storage_7000 --natpf1 "guestbui,tcp,,46215,,215" Verify the settings using:VBoxManage showvminfo Sun_ZFS_Storage_7000 | grep -i nic Start the appliance:$ VBoxHeadless --startvm Sun_ZFS_Storage_7000 & Connect to it using your favorite RDP client.  I use a Sun Ray, so I use the Sun Ray Windows Connector client: $ /opt/SUNWuttsc/bin/uttsc -g 800x600 -P <portnumber> <your-hostname> & The portnumber is displayed in the output of the --startvm command.(This did not work after I updated to VirtualBox 4.1.12, so maybe at this point, you need to use the VirtualBox GUI.) It takes a while to first bring up the VM, so please be patient. The longest time is in loading the smf service descriptions, but fortunately, that only needs to be done the first time the VM boots.  There is also a delay in just booting the appliance, so give it some time. Be sure to set the NIC rule on only one port and not all ports otherwise there will be a conflict in ports and it won't work. After going through the initial configuration screen, you can connect to it using ssh or your browser: ssh -p 45022 root@<your-host-name> https://<your-host-name>:45215 BTW, for the initial configuration, I only had to set the hostname and password.  The rest of the defaults were set by VirtualBox and seemed to work fine.

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• Editing /.config/dconf/user

  - by user86322

  I am having a problem with Gnome3 (actually, I have it set to fallback mode, or Gnome 2). I have two displays and I need an X screen (I used nvidia-xconfig and nvidia-settings to do this) for each screen. However, every time I either restart X or log in, Gnome seems to be adding the objects values under /gnome/gnome-panel/layouts (ex. first time I set the two separate X screens I had clock, then log out/in, there was clock and clock1 under objects, and then log out/in there were three, clock, clock1, clock2,.......log out/in, ............30 times....clock, clock1, clock2, ......clock 42.....!! The same thing goes for top-panels, menu-bars, etc.) After a while, I found out I could remove all those using the dconf-editor, going to /gnome/gnome-panel/layouts, removing all the repetitions under fields objects-id-list and top-id-list and leaving one value of each object. This is not a solution but at least allow me to keep using Linux without so much problem. However, the problem persists every time I restart X or log in. I now finally learned about "dconf" and where the user profile settings are located (~/.config/dconf/user) and one can use "dconf" to see the keys. In my case, I need to change/remove many keys (all those clocksX, workspace-X, menu-bar-X, etc., where goes from 1 to 42 and still counting) so it's really tedious and boring to be changing one by one using "dconf write". So I found "dconf dump", which actually allow me to dump everything into a .txt file and edit the file really quick (i.e, "dconf dump / >> dump_user.txt"). The problems? Two of them: How do I "load" back "dump_user.txt" I edited into the user profile? (I read somewhere there was a "dconf reload" but reload doesn't exist as a command under "dconf") How do I stop Gnome from keep adding more objects to my desktop environment every time I log in/restart X? NOTE: The problem doesn't occur when I set the displays to use TwinView feature (i.e., the desktop is extended/shared by both displays). However, for my case I need two separate X's. Any help/suggestion would be greatly appreciated. Thanks

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• Dark Sun Dispatch 001.5 (a review of City Under The Sand)

  - by Chris Williams

  City Under The Sand - a review I'm moderately familiar with the Dark Sun setting. I've read the other Dark Sun novels, ages ago and I recently started running a D&D 4.0 campaign in the Dark Sun world, so I picked up this book to help re-familiarize myself with the setting. Overall, it did accomplish that, in a limited way. The book takes place in Nibenay and a neighboring expanse of desert that includes a formerly buried city, a small town and a bandit outpost. The book does a more interesting job of describing Nibenese politics and the court of the ruling Sorcerer King, his templars and the expected jockeying for position that occurs between the Templar Wives. There is a fair amount of combat, which was interesting and fairly well detailed. The ensemble cast is introduced and eventually brought together over the first few chapters. Not a lot of backstory on most of the characters, but you get a feel for them fairly quickly. The storyline was somewhat predictable after the first third of the book. Some of the reviews on Amazon complain about the 2-dimensional characterizations, and yes there were some... but it's easy to ignore because there is a lot going on in the book... several interwoven plotlines that all eventually converge. Where the book falls short... First, it appears to have been edited by a 4th grader who knows how to use spellcheck but lacks the attention to detail to notice the frequent occurence of incorrect words that often don't make sense or change the context of the entire sentence. It happened just enough to be distracting, and honestly I expect better from WOTC. Second, there is a lot of buildup to the end of the story... the big fight, the confrontation between good and evil, etc... which is handled in just a few pages and then the story basically just ends. Kind of a letdown, honestly. There wasn't a big finish, and it wasn't a cliffhanger, it just wraps up neatly and ends. It felt pretty rushed. Overall, aside from the very end, I enjoyed it. I really liked the insight into that region of Athas and it gave me some good ideas for fleshing out my own campaign. In that sense, the book served its purpose for me. If you're looking for a light read (got a 5-6 hour flight somewhere?) or you want to learn more about the Dark Sun setting, then I'd recommend this book.

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• What layer to introduce human readable error messages?

  - by MrLane

  One of the things that I have never been happy with on any project I have worked on over the years and have really not been able to resolve myself is exactly at what tier in an application should human readable error information be retrieved for display to a user. A common approach that has worked well has been to return strongly typed/concrete "result objects" from the methods on the public surface of the business tier/API. A method on the interface may be: public ClearUserAccountsResult ClearUserAccounts(ClearUserAccountsParam param); And the result class implementation: public class ClearUserAccountsResult : IResult { public readonly List<Account> ClearedAccounts{get; set;} public readonly bool Success {get; set;} // Implements IResult public readonly string Message{get; set;} // Implements IResult, human readable // Constructor implemented here to set readonly properties... } This works great when the API needs to be exposed over WCF as the result object can be serialized. Again this is only done on the public surface of the API/business tier. The error message can also be looked up from the database, which means it can be changed and localized. However, it has always been suspect to me, this idea of returning human readable information from the business tier like this, partly because what constitutes the public surface of the API may change over time...and it may be the case that the API will need to be reused by other API components in the future that do not need the human readable string messages (and looking them up from a database would be an expensive waste). I am thinking a better approach is to keep the business objects free from such result objects and keep them simple and then retrieve human readable error strings somewhere closer to the UI layer or only in the UI itself, but I have two problems here: 1) The UI may be a remote client (Winforms/WPF/Silverlight) or an ASP.NET web application hosted on another server. In these cases the UI will have to fetch the error strings from the server. 2) Often there are multiple legitimate modes of failure. If the business tier becomes so vague and generic in the way it returns errors there may not be enough information exposed publicly to tell what the error actually was: i.e: if a method has 3 modes of legitimate failure but returns a boolean to indicate failure, you cannot work out what the appropriate message to display to the user should be. I have thought about using failure enums as a substitute, they can indicate a specific error that can be tested for and coded against. This is sometimes useful within the business tier itself as a way of passing via method returns the specifics of a failure rather than just a boolean, but it is not so good for serialization scenarios. Is there a well worn pattern for this? What do people think? Thanks.

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• Should I install ubuntu on USB instead of HDD dual-boot?

  - by user2147243

  I had Ubuntu 12.04 installed as dual-boot OS on top of Vista on my laptop. Hacked the grub settings to default to Vista (instead of the default Ubuntu -- pain) on startup, and all was OK for occasional Ubuntu use for past 6 months. Then last week I got a strange message about 'lack of disk space' (~50MB free) when installing pxyplot, even though there was still about 6GB free disk space when I checked later. Then today the Ubuntu wouldn't load at all, and checking the HDD partitions in Vista it looked like the 15GB Ubuntu partition was now three smaller partitions! So, I got rid of those partitions and expanded the Vista partition to use the reclaimed space. Now can't restart ('grub rescue' appears and doesn't 'rescue' anything), so I'll have to do a boot recovery using a Vista installation CD. (Not a particularly user-friendly failure mode of the dual-boot installation!) I now have to decide to either a) try installing ubuntu on the HDD again, but don't want to stuff up my Vista ever again, as that is my most used OS, or b) install Ubuntu on a 16GB USB 3.0 stick. Apparently performance from USB won't be as good as from HDD, and running OS from USB stick does lots of r/w so the stick may fail after a few years! Perhaps installing Ubuntu on live USB and setup to then run in RAM would alleviate the performance/USB lifespan problems? If I create a live-USB for Ubuntu OS, will it boot off that when I restart the laptop with it plugged in? Or will I have to change the laptop setting for boot-order whenever I want to boot Ubuntu instead of Vista (that would be even more painful than the grub default boot order putting Ubuntu ahead of the existing Vista OS!) -- update: I recovered my Vista setup using Iolo SystemMechanic Disaster Recovery Tool, and created a bootable USB of Ubuntu 13.10 on an 8GB USB3.0 pendrive, with 4GB of 'persistence' to allow saving of settings, install some packages etc. It worked OK for a couple of test boots, but once I changed the time and desktop wallpaper, the next Ubuntu reboot crashed and I then couldn't get it to boot successfully. So I decided to install Ubuntu 12.04 LTS as a dual-boot again, but this time instead of partitioning the HDD and installing from an ISO DVD I used the wubi.exe tool to install Ubuntu as a dual-boot. Worked very well, although one oddity was that, despite asking how big the make the partition (20GB), the installed Ubuntu appears to be happily installed somewhere within the Vista NTFS file system (no partition shows up in Windows disk manager, and in Ubuntu disk management tool the entire 133 GB of HDD is showing, with ~40GB free space). A nice feature of installing the dual-boot using wubi is that the laptop now uses Windows boot manager on startup, with Vista as the default OS and Ubuntu happily listed as second on the list. So far so good.

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• How to force a clock update using ntp?

  - by ysap

  I am running Ubuntu on an ARM based embedded system that lacks a battery backed RTC. The wake-up time is somewhere during 1970. Thus, I use the NTP service to update the time to the current time. I added the following line to /etc/rc.local file: sudo ntpdate -s time.nist.gov However, after startup, it still takes a couple of minutes until the time is updated, during which period I cannot work effectively with tar and make. How can I force a clock update at any given time? UPDATE 1: The following (thanks to Eric and Stephan) works fine from command line, but fails to update the clock when put in /etc/rc.local: $ date ; sudo service ntp stop ; sudo ntpdate -s time.nist.gov ; sudo service ntp start ; date Thu Jan 1 00:00:58 UTC 1970 * Stopping NTP server ntpd [ OK ] * Starting NTP server [ OK ] Thu Feb 14 18:52:21 UTC 2013 What am I doing wrong? UPDATE 2: I tried following the few suggestions that came in response to the 1st update, but nothing seems to actually do the job as required. Here's what I tried: Replace the server to us.pool.ntp.org Use explicit paths to the programs Remove the ntp service altogether and leave just sudo ntpdate ... in rc.local Remove the sudo from the above command in rc.local Using the above, the machine still starts at 1970. However, when doing this from command line once logged in (via ssh), the clock gets updated as soon as I invoke ntpdate. Last thing I did was to remove that from rc.local and place a call to ntpdate in my .bashrc file. This does update the clock as expected, and I get the true current time once the command prompt is available. However, this means that if the machine is turned on and no user is logged in, then the time never gets updates. I can, of course, reinstall the ntp service so at least the clock is updated within a few minutes from startup, but then we're back at square 1. So, is there a reason why placing the ntpdate command in rc.local does not perform the required task, while doing so in .bashrc works fine?

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• Has test driven development (TDD) actually benefited a real world project?

  - by James

  I am not new to coding. I have been coding (seriously) for over 15 years now. I have always had some testing for my code. However, over the last few months I have been learning test driven design/development (TDD) using Ruby on Rails. So far, I'm not seeing the benefit. I see some benefit to writing tests for some things, but very few. And while I like the idea of writing the test first, I find I spend substantially more time trying to debug my tests to get them to say what I really mean than I do debugging actual code. This is probably because the test code is often substantially more complicated than the code it tests. I hope this is just inexperience with the available tools (RSpec in this case). I must say though, at this point, the level of frustration mixed with the disappointing lack of performance is beyond unacceptable. So far, the only value I'm seeing from TDD is a growing library of RSpec files that serve as templates for other projects/files. Which is not much more useful, maybe less useful, than the actual project code files. In reading the available literature, I notice that TDD seems to be a massive time sink up front, but pays off in the end. I'm just wondering, are there any real world examples? Does this massive frustration ever pay off in the real world? I really hope I did not miss this question somewhere else on here. I searched, but all the questions/answers are several years old at this point. It was a rare occasion when I found a developer who would say anything bad about TDD, which is why I have spent as much time on this as I have. However, I noticed that nobody seems to point to specific real-world examples. I did read one answer that said the guy debugging the code in 2011 would thank you for have a complete unit testing suite (I think that comment was made in 2008). So, I'm just wondering, after all these years, do we finally have any examples showing the payoff is real? Has anybody actually inherited or gone back to code that was designed/developed with TDD and has a complete set of unit tests and actually felt a payoff? Or did you find that you were spending so much time trying to figure out what the test was testing (and why it was important) that you just tossed out the whole mess and dug into the code?

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• Real-Time Multi-User Gaming Platform

  - by Victor Engel

  I asked this question at Stack Overflow but was told it's more appropriate here, so I'm posting it again here. I'm considering developing a real-time multi-user game, and I want to gather some information about possibilities before I do some real development. I've thought about how best to ask the question, and for simplicity, the best way that occurred to me was to make an analogy to the field (or playground) game darebase. In the field game of darebase, there are two or more bases. To start, there is one team on each base. The game is a fancy game of tag. When two people meet out in the field, the person who left his base most recently timewise captures the other person. They then return to that person's base. Play continues until everyone is part of the same team. So, analogizing this to an online computer game, let's suppose there are an indefinite number of bases. When a person starts up the game, he has a team that is located at, for example, his current GPS coordinates. It could be a virtual world, but for sake of argument, let's suppose the virtual world corresponds to the player's actual GPS coordinates. The game software then consults the database to see where the closest other base is that is online, and the two teams play their game of virtual tag. Note that the user of the other base could have a different base than the one run by the current user as the closest base to him, in which case, he would be in two simultaneous battles, one with each base. When they go offline, the state of their players is saved on a server somewhere. Game logic calls for the players to have some automaton-logic of some sort, so they can fend for themselves in a limited way using basic rules, until their user goes online again. The user doesn't control the players' movements directly, but issues general directives that influence the players' movement logic. I think this analogy is good enough to frame my question. What sort of platforms are available to develop this sort of game? I've been looking at smartfoxserver, but I'm not convinced yet that it is the best option or even that it will work at all. One possibility, of course, would be to roll out my own web server, but I'd rather not do that if there is an existing service out there already that I could tap into. I will be developing for iOS devices at first. So any suggestions would be greatly appreciated. I think I need to establish the architecture first before proceeding with this project. Note that darbase is not the game I intend to implement, but, upon reflection, that might not be a bad idea either.

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• Incorrect results for frustum cull

  - by DeadMG

  Previously, I had a problem with my frustum culling producing too optimistic results- that is, including many objects that were not in the view volume. Now I have refactored that code and produced a cull that should be accurate to the actual frustum, instead of an axis-aligned box approximation. The problem is that now it never returns anything to be in the view volume. As the mathematical support library I'm using does not provide plane support functions, I had to code much of this functionality myself, and I'm not really the mathematical type, so it's likely that I've made some silly error somewhere. As follows is the relevant code: class Plane { public: Plane() { r0 = Math::Vector(0,0,0); normal = Math::Vector(0,1,0); } Plane(Math::Vector p1, Math::Vector p2, Math::Vector p3) { r0 = p1; normal = Math::Cross((p2 - p1), (p3 - p1)); } Math::Vector r0; Math::Vector normal; }; This class represents one plane as a point and a normal vector. class Frustum { public: Frustum( const std::array<Math::Vector, 8>& points ) { planes[0] = Plane(points[0], points[1], points[2]); planes[1] = Plane(points[4], points[5], points[6]); planes[2] = Plane(points[0], points[1], points[4]); planes[3] = Plane(points[2], points[3], points[6]); planes[4] = Plane(points[0], points[2], points[4]); planes[5] = Plane(points[1], points[3], points[5]); } Plane planes[6]; }; The points are passed in order where (the inverse of) each bit of the index of each point indicates whether it's the left, top, and back of the frustum, respectively. As such, I just picked any three points where they all shared one bit in common to define the planes. My intersection test is as follows (based on this): bool Intersects(Math::AABB lhs, const Frustum& rhs) const { for(int i = 0; i < 6; i++) { Math::Vector pvertex = lhs.TopRightFurthest; Math::Vector nvertex = lhs.BottomLeftClosest; if (rhs.planes[i].normal.x <= -0.0f) { std::swap(pvertex.x, nvertex.x); } if (rhs.planes[i].normal.y <= -0.0f) { std::swap(pvertex.y, nvertex.y); } if (rhs.planes[i].normal.z <= -0.0f) { std::swap(pvertex.z, nvertex.z); } if (Math::Dot(rhs.planes[i].r0, nvertex) < 0.0f) { return false; } } return true; } Also of note is that because I'm using a left-handed co-ordinate system, I wrote my Cross function to return the negative of the formula given on Wikipedia. Any suggestions as to where I've made a mistake?

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• Architecture for a template-building, WYSIWIG application

  - by Sam Selikoff

  I'm building a WYSIWYG designer in Ember.js. The designer will allow users to create campaigns - think MailChimp. To build a campaign, users will choose an existing template. The template will have a defined layout. The user will then be taken to the designer, where he will be able to edit the text and style, and additionally change some layout options. I've been thinking about how best to go about structuring this app, and there are a few hurdles. Specifically, the output of the campaign will be dynamic: eventually, it will be published somewhere, and when the consumers (not my users, but the people clicking on the campaign that my user created) visit the campaign, certain pieces of data will change, depending on the type of consumer viewing the campaign. That means the ultimate output of the designer will be a dynamic site. The data that is dynamic for this site - the end product - will not be manipulated by the user in the designer. However, the data that will be manipulated by the user in the designer are things like copy, styles, layout options, etc. I'll call the first set of variables server-side data, and the second client-side data. It seems, then, that the process will go something like this: I'll need to create templates for this designer that have two dynamic segments. For instance, the server-side data could be Liquid expressions, and the client-side data Handlebars expressions. When the user creates a campaign, I would compile the template on the back end using some dummy data for the server-side variables, and serve up a handlebars template to the Ember app. The user would then edit the template, and the Ember app would save all his edits to the JS variables that were powering the template. This way he'd be able to preview the template. When he saves, he'll send back the selected template, along with all the data and options he's made. When it comes time to publish, the back-end system will have to do two things: compile the template with Handlebars using the campaign data, and then compile the template with Liquid using the server-side data Is my thinking roughly accurate about this, or is there a simpler way?

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• Are there any concerns with using a static read-only unit of work so that it behaves like a cache?

  - by Rowan Freeman

  Related question: How do I cache data that rarely changes? I'm making an ASP.NET MVC4 application. On every request the security details about the user will need to be checked with the area/controller/action that they are accessing to see if they are allowed to view it. The security information is stored in the database. For example: User Permission UserPermission Action ActionPermission A "Permission" is a token that is applied to an MVC action to indicate that the token is required in order to access the action. Once a user is given the permission (via the UserPermission table) then they have the token and can therefore access the action. I've been looking in to how to cache this data (since it rarely changes) so that I'm only querying in-memory data and not hitting a database (which is a considerable performance hit at the moment). I've tried storing things in lists, using a caching provider but I either run in to problems or performance doesn't improve. One problem that I constantly run in to is that I'm using lazy loading and dynamic proxies with EntityFramework. This means that even if I ToList() everything and store them somewhere static, the relationships are never populated. For example, User.Permissions is an ICollection but it's always null. I don't want to Include() everything because I'm trying to keep things simple and generic (and easy to modify). One thing I know is that an EntityFramework DbContext is a unit of work that acts with 1st-level caching. That is, for the duration of the unit of work, everything that is accessed is cached in memory. I want to create a read-only DbContext that will exist indefinitely and will only be used to read about permission data. Upon testing this it worked perfectly; my page load times went from 200ms+ to 20ms. I can easily force the data to refresh at certain intervals or simply leave it to refresh when the application pool is recycled. Basically it will behave like a cache. Note that the rest of the application will interact with other contexts that exist per request as normal. Is there any disadvantage to this approach? Could I be doing something different?

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