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• HTG Explains: Should You Build Your Own PC?

  - by Chris Hoffman

  There was a time when every geek seemed to build their own PC. While the masses bought eMachines and Compaqs, geeks built their own more powerful and reliable desktop machines for cheaper. But does this still make sense? Building your own PC still offers as much flexibility in component choice as it ever did, but prebuilt computers are available at extremely competitive prices. Building your own PC will no longer save you money in most cases. The Rise of Laptops It’s impossible to look at the decline of geeks building their own PCs without considering the rise of laptops. There was a time when everyone seemed to use desktops — laptops were more expensive and significantly slower in day-to-day tasks. With the diminishing importance of computing power — nearly every modern computer has more than enough power to surf the web and use typical programs like Microsoft Office without any trouble — and the rise of laptop availability at nearly every price point, most people are buying laptops instead of desktops. And, if you’re buying a laptop, you can’t really build your own. You can’t just buy a laptop case and start plugging components into it — even if you could, you would end up with an extremely bulky device. Ultimately, to consider building your own desktop PC, you have to actually want a desktop PC. Most people are better served by laptops. Benefits to PC Building The two main reasons to build your own PC have been component choice and saving money. Building your own PC allows you to choose all the specific components you want rather than have them chosen for you. You get to choose everything, including the PC’s case and cooling system. Want a huge case with room for a fancy water-cooling system? You probably want to build your own PC. In the past, this often allowed you to save money — you could get better deals by buying the components yourself and combining them, avoiding the PC manufacturer markup. You’d often even end up with better components — you could pick up a more powerful CPU that was easier to overclock and choose more reliable components so you wouldn’t have to put up with an unstable eMachine that crashed every day. PCs you build yourself are also likely more upgradable — a prebuilt PC may have a sealed case and be constructed in such a way to discourage you from tampering with the insides, while swapping components in and out is generally easier with a computer you’ve built on your own. If you want to upgrade your CPU or replace your graphics card, it’s a definite benefit. Downsides to Building Your Own PC It’s important to remember there are downsides to building your own PC, too. For one thing, it’s just more work — sure, if you know what you’re doing, building your own PC isn’t that hard. Even for a geek, researching the best components, price-matching, waiting for them all to arrive, and building the PC just takes longer. Warranty is a more pernicious problem. If you buy a prebuilt PC and it starts malfunctioning, you can contact the computer’s manufacturer and have them deal with it. You don’t need to worry about what’s wrong. If you build your own PC and it starts malfunctioning, you have to diagnose the problem yourself. What’s malfunctioning, the motherboard, CPU, RAM, graphics card, or power supply? Each component has a separate warranty through its manufacturer, so you’ll have to determine which component is malfunctioning before you can send it off for replacement. Should You Still Build Your Own PC? Let’s say you do want a desktop and are willing to consider building your own PC. First, bear in mind that PC manufacturers are buying in bulk and getting a better deal on each component. They also have to pay much less for a Windows license than the $120 or so it would cost you to to buy your own Windows license. This is all going to wipe out the cost savings you’ll see — with everything all told, you’ll probably spend more money building your own average desktop PC than you would picking one up from Amazon or the local electronics store. If you’re an average PC user that uses your desktop for the typical things, there’s no money to be saved from building your own PC. But maybe you’re looking for something higher end. Perhaps you want a high-end gaming PC with the fastest graphics card and CPU available. Perhaps you want to pick out each individual component and choose the exact components for your gaming rig. In this case, building your own PC may be a good option. As you start to look at more expensive, high-end PCs, you may start to see a price gap — but you may not. Let’s say you wanted to blow thousands of dollars on a gaming PC. If you’re looking at spending this kind of money, it would be worth comparing the cost of individual components versus a prebuilt gaming system. Still, the actual prices may surprise you. For example, if you wanted to upgrade Dell’s $2293 Alienware Aurora to include a second NVIDIA GeForce GTX 780 graphics card, you’d pay an additional $600 on Alienware’s website. The same graphics card costs $650 on Amazon or Newegg, so you’d be spending more money building the system yourself. Why? Dell’s Alienware gets bulk discounts you can’t get — and this is Alienware, which was once regarded as selling ridiculously overpriced gaming PCs to people who wouldn’t build their own. Building your own PC still allows you to get the most freedom when choosing and combining components, but this is only valuable to a small niche of gamers and professional users — most people, even average gamers, would be fine going with a prebuilt system. If you’re an average person or even an average gamer, you’ll likely find that it’s cheaper to purchase a prebuilt PC rather than assemble your own. Even at the very high end, components may be more expensive separately than they are in a prebuilt PC. Enthusiasts who want to choose all the individual components for their dream gaming PC and want maximum flexibility may want to build their own PCs. Even then, building your own PC these days is more about flexibility and component choice than it is about saving money. In summary, you probably shouldn’t build your own PC. If you’re an enthusiast, you may want to — but only a small minority of people would actually benefit from building their own systems. Feel free to compare prices, but you may be surprised which is cheaper. Image Credit: Richard Jones on Flickr, elPadawan on Flickr, Richard Jones on Flickr     

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• Not attending the LUGM mini-meetup - 05. Oct 2013

  Not attending a meeting of the LUGM can be fun, too. It's getting a bit of a habit that Ish is organising small gatherings, aka mini-meetups, of the Linux User Group Mauritius/Meta (LUGM) almost every Saturday. There they mainly discuss and talk about various elements of using Linux as ones main operating systems and the possibilities you are going to have. On top of course, some tips & tricks about mastering the command line and initial steps in scripting or even writing HTML. In general, sounds like a good portion of fun and great spirit of community. Unfortunately, I'm usually quite busy with private and family matters during the weekend and so I already signalised that I wouldn't be around. Well, at least not physically... But this Saturday a couple of things worked out faster than expected and so I was hanging out on my machine. I made virtual contact with one of Pawan's messages over on Facebook... And somehow that kicked off some kind of an online game fun on basic configuration of Apache HTTPd 2.2.x, PHP 5.x and how to improve the overall performance of a newly installed blog based on WordPress. Default configuration files Nitin's website finally came alive and despite the dark theme and the hidden Apple 'fanboy' advertisement I was more interested in the technical situation. As with any new installation there is usually quite some adjustment to be done. And Nitin's page was no exception. Unfortunately, out of the box installations of Apache httpd and PHP are too verbose and expose too much information under the hood. You might think that this isn't really a problem at all, well, think about it again after completely reading this article. First, I checked the HTTP response headers - using either Chrome Developer Tools or Firefox Web Developer extension - of Nitin's page and based on that I advised him to lower the noise levels a little bit. It's not really necessary that detailed information about web server software and scripting language has to be published in every response made. Quite a number of script kiddies and exploits actually check for version specifics prior to an attack. So, removing at least version details hardens the system a little bit. In particular, I'm talking about these response values: Server X-Powered-By How to achieve that? By tweaking the configuration files... Namely, we are going to look into the following ones: apache2.conf httpd.conf .htaccess php.ini The above list contains some additional files, I'm talking about in the next paragraphs. Anyway, those are the ones involved. Tweaking Apache Open your favourite text editor and start to modify the apache2.conf. Eventually, you might like to have a quick peak at the file to see whether it is necessary to adjust it or not. Following is a handy combination of commands to get an overview of your active directives: # sudo grep -v '#' /etc/apache2/apache2.conf | grep -v '^$' | less There you keep an eye on those two Apache directives: ServerSignature Off ServerTokens Prod If that's not the case, change them as highlighted above. In order to activate your modifications you have to restart Apache httpd server. On Debian and Ubuntu you might use apache2ctl for that, on other distributions you might have to use service or run the init-scripts again: # sudo apache2ctl configtestSyntax OK# sudo apache2ctl restart Refresh your website and check the HTTP response header. Tweaking PHP5 (a little bit) Next, check your php.ini file with the following statement: # sudo grep -v ';' /etc/php5/apache2/php.ini | grep -v '^$' | less And check the value of expose_php = Off Again, if it's not as highlighted, change it... Some more Apache love Okay, back to Apache it might also be interesting to improve the situation about browser caching and removing more obsolete information. When you run your website against the usual performance checks like Google Page Speed and Yahoo YSlow you might see those check points with bad grades on a standard, default configuration. Well, this can be done easily. Configure entity tags (ETags) ETags are only interesting when you run your websites on a farm of multiple web servers. Removing this data for your static resources is very simple in Apache. As we are going to deal with the HTTP response header information you have to ensure that Apache is capable to manipulate them. First, check your enabled modules: # sudo ls -al /etc/apache2/mods-enabled/ | grep headers And in case that the 'headers' module is not listed, you have to enable it from the available ones: # sudo a2enmod headers Second, check your httpd.conf file (in case it exists): # sudo grep -v '#' /etc/apache2/httpd.conf | grep -v '^$' | less In newer (better said fresh) installations you might have to create a new configuration file below your conf.d folder with your favourite text editor like so: # sudo nano /etc/apache2/conf.d/headers.conf Then, in order to tweak your HTTP responses either check for those lines or add them: Header unset ETagFileETag None In case that your file doesn't exist or those lines are missing, feel free to create/add them. Afterwards, check your Apache configuration syntax and restart your running instances as already shown above: # sudo apache2ctl configtestSyntax OK# sudo apache2ctl restart Add Expires headers To improve the loading performance of your website, you should take some care into the proper configuration of how to leverage the browser's ability to cache certain resources and files. This is done by adding an Expires: value to the HTTP response header. Generally speaking it is advised that you specify a near-future, read: 1 week or a little bit more, for your static content like JavaScript files or Cascading Style Sheets. One solution to adjust this is to put some instructions into the .htaccess file in the root folder of your web site. Of course, this could also be placed into a more generic location of your Apache installation but honestly, I'd like to keep this at the web site level. Following some adjustments I'm currently using on this blog site: # Turn on Expires and set default to 0ExpiresActive OnExpiresDefault A0 # Set up caching on media files for 1 year (forever?)<FilesMatch "\.(flv|ico|pdf|avi|mov|ppt|doc|mp3|wmv|wav)$">ExpiresDefault A29030400Header append Cache-Control "public"</FilesMatch> # Set up caching on media files for 1 week<FilesMatch "\.(js|css)$">ExpiresDefault A604800Header append Cache-Control "public"</FilesMatch> # Set up caching on media files for 31 days<FilesMatch "\.(gif|jpg|jpeg|png|swf)$">ExpiresDefault A2678400Header append Cache-Control "public"</FilesMatch> As we are editing the .htaccess files, it is not necessary to restart Apache. In case that your web site doesn't load anymore or you're experiencing an error while trying to restart your httpd, check that the 'expires' module is actually an enabled module: # ls -al /etc/apache2/mods-enabled/ | grep expires# sudo a2enmod expires Of course, the instructions above a re not feature complete but I hope that they might provide a better default configuration for your LAMP stack. Resume of the day Within a couple of hours, and while being occupied with an eLearning course on SQL Server 2012, I had some good fun in helping and assisting other LUGM members while they were some kilometers away at Bagatelle. According to other blog articles it seems that Nitin had quite some moments of desperation. Just for the records: At no time it was my intention to either kick his butt or pull a leg on him. Simply, providing some input based on the lessons I've learned over the last couple of years configuring Apache HTTPd and PHP. Check out the other blogs, too: LUGM mini-meetup... Epic! Superb Saturday Linux Meetup And last but not least, the man himself: The end of a new beginning Cheers, and happy community'ing! Updates Due to our weekly Code & Coffee sessions in the MSCC community, I had a chance to talk to Nitin directly and he showed me the problems directly on his machine. This led to update this article hence the paragraphs on enabling the modules 'headers' and 'expires'.

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• A star algorithm implementation problems

  - by bryan226

  I’m having some trouble implementing the A* algorithm in a 2D tile based game. The problem is basically that the algorithm gets stuck when something gets in its direct way (e.g. walls) Note that it only allows Horizontal and Vertical movement. Here's a picture as it works fine across the map without something in its direct way: (Green tile = destination, Blue = In closed list, Green = in open list) This is what happens if I try to walk 'around' a wall: I calculate costs with the F = G + H formula: G = 1 Cost per Step H = 10 Cost per Step //Count how many tiles are between current-tile & destination-tile The functions: short c_astar::GuessH(short Startx,short Starty,short Destinationx,short Destinationy) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Destinationx; Destination.y = Destinationy; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b)*10; } short c_astar::GuessG(short Startx,short Starty,short Currentx,short Currenty) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Currentx; Destination.y = Currenty; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b); } At the end of the loop I check which tile is the cheapest to go according to its F value: Then some quick checks are done for each tile (UP,DOWN,LEFT,RIGHT): //...CX are holding the F value of the TILE specified // Info: C0 = Center (Current) // C1 = UP // C2 = DOWN // C3 = LEFT // C4 = RIGHT //Quick checks if(((C1 < C2) && (C1 < C3) && (C1 < C4))) { Current.y -= 1; bSimilar = false; if(DEBUG) hge->System_Log("C1 < ALL"); } //.. same for C2,C3 & C4 If there are multiple tiles with the same F value: It’s actually a switch for DOWNLEFT,UPRIGHT.. etc. Here’s one of it: case UPRIGHT: { //UP Temporary = Current; Temporary.y -= 1; bTileStatus[0] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[0]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[0] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[0] = true; //RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[1] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[1] = true; //************************************************* // Purpose: ClosedList behavior //************************************************* if(bFoundInClosedList[0] && !bFoundInClosedList[1]) { //UP found in ClosedList. Go RIGHT return RIGHT; } if(!bFoundInClosedList[0] && bFoundInClosedList[1]) { //RIGHT found in ClosedList. Go UP return UP; } if(bFoundInClosedList[0] && bFoundInClosedList[1]) { //Both found in ClosedList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } //************************************************* // Purpose: OpenList behavior //************************************************* if(bFoundInOpenList[0] && !bFoundInOpenList[1]) { //UP found in OpenList. Go RIGHT return RIGHT; } if(!bFoundInOpenList[0] && bFoundInOpenList[1]) { //RIGHT found in OpenList. Go UP return UP; } if(bFoundInOpenList[0] && bFoundInOpenList[1]) { //Both found in OpenList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } } else if(!bTileStatus[1]) { //RIGHT is not walkable OR out of range //Choose UP return UP; } } else if(!bTileStatus[0]) { //UP is not walkable OR out of range //Fast check RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { return RIGHT; } else return FAILED; //Failed, no valid path found! } } break; A log for the second picture: (Cut down to ten passes, because it’s just repeating itself) ----------------------------------------------------- PASS: 1 | C1: 211 | C2: 191 | C3: 211 | C4: 191 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 2 | C1: 200 | C2: 182 | C3: 202 | C4: 182 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 3 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 4 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 5 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 6 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 7 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 8 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- PASS: 9 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 10 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- Its always going after the cheapest F value, which seems to be wrong. If someone could point me to the right direction I'd be thankful. Regards, bryan226

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• Master-slave vs. peer-to-peer archictecture: benefits and problems

  - by Ashok_Ora

  Normal 0 false false false EN-US X-NONE X-NONE Almost two decades ago, I was a member of a database development team that introduced adaptive locking. Locking, the most popular concurrency control technique in database systems, is pessimistic. Locking ensures that two or more conflicting operations on the same data item don’t “trample” on each other’s toes, resulting in data corruption. In a nutshell, here’s the issue we were trying to address. In everyday life, traffic lights serve the same purpose. They ensure that traffic flows smoothly and when everyone follows the rules, there are no accidents at intersections. As I mentioned earlier, the problem with typical locking protocols is that they are pessimistic. Regardless of whether there is another conflicting operation in the system or not, you have to hold a lock! Acquiring and releasing locks can be quite expensive, depending on how many objects the transaction touches. Every transaction has to pay this penalty. To use the earlier traffic light analogy, if you have ever waited at a red light in the middle of nowhere with no one on the road, wondering why you need to wait when there’s clearly no danger of a collision, you know what I mean. The adaptive locking scheme that we invented was able to minimize the number of locks that a transaction held, by detecting whether there were one or more transactions that needed conflicting eyou could get by without holding any lock at all. In many “well-behaved” workloads, there are few conflicts, so this optimization is a huge win. If, on the other hand, there are many concurrent, conflicting requests, the algorithm gracefully degrades to the “normal” behavior with minimal cost. We were able to reduce the number of lock requests per TPC-B transaction from 178 requests down to 2! Wow! This is a dramatic improvement in concurrency as well as transaction latency. The lesson from this exercise was that if you can identify the common scenario and optimize for that case so that only the uncommon scenarios are more expensive, you can make dramatic improvements in performance without sacrificing correctness. So how does this relate to the architecture and design of some of the modern NoSQL systems? NoSQL systems can be broadly classified as master-slave sharded, or peer-to-peer sharded systems. NoSQL systems with a peer-to-peer architecture have an interesting way of handling changes. Whenever an item is changed, the client (or an intermediary) propagates the changes synchronously or asynchronously to multiple copies (for availability) of the data. Since the change can be propagated asynchronously, during some interval in time, it will be the case that some copies have received the update, and others haven’t. What happens if someone tries to read the item during this interval? The client in a peer-to-peer system will fetch the same item from multiple copies and compare them to each other. If they’re all the same, then every copy that was queried has the same (and up-to-date) value of the data item, so all’s good. If not, then the system provides a mechanism to reconcile the discrepancy and to update stale copies. So what’s the problem with this? There are two major issues: First, IT’S HORRIBLY PESSIMISTIC because, in the common case, it is unlikely that the same data item will be updated and read from different locations at around the same time! For every read operation, you have to read from multiple copies. That’s a pretty expensive, especially if the data are stored in multiple geographically separate locations and network latencies are high. Second, if the copies are not all the same, the application has to reconcile the differences and propagate the correct value to the out-dated copies. This means that the application program has to handle discrepancies in the different versions of the data item and resolve the issue (which can further add to cost and operation latency). Resolving discrepancies is only one part of the problem. What if the same data item was updated independently on two different nodes (copies)? In that case, due to the asynchronous nature of change propagation, you might land up with different versions of the data item in different copies. In this case, the application program also has to resolve conflicts and then propagate the correct value to the copies that are out-dated or have incorrect versions. This can get really complicated. My hunch is that there are many peer-to-peer-based applications that don’t handle this correctly, and worse, don’t even know it. Imagine have 100s of millions of records in your database – how can you tell whether a particular data item is incorrect or out of date? And what price are you willing to pay for ensuring that the data can be trusted? Multiple network messages per read request? Discrepancy and conflict resolution logic in the application, and potentially, additional messages? All this overhead, when all you were trying to do was to read a data item. Wouldn’t it be simpler to avoid this problem in the first place? Master-slave architectures like the Oracle NoSQL Database handles this very elegantly. A change to a data item is always sent to the master copy. Consequently, the master copy always has the most current and authoritative version of the data item. The master is also responsible for propagating the change to the other copies (for availability and read scalability). Client drivers are aware of master copies and replicas, and client drivers are also aware of the “currency” of a replica. In other words, each NoSQL Database client knows how stale a replica is. This vastly simplifies the job of the application developer. If the application needs the most current version of the data item, the client driver will automatically route the request to the master copy. If the application is willing to tolerate some staleness of data (e.g. a version that is no more than 1 second out of date), the client can easily determine which replica (or set of replicas) can satisfy the request, and route the request to the most efficient copy. This results in a dramatic simplification in application logic and also minimizes network requests (the driver will only send the request to exactl the right replica, not many). So, back to my original point. A well designed and well architected system minimizes or eliminates unnecessary overhead and avoids pessimistic algorithms wherever possible in order to deliver a highly efficient and high performance system. If you’ve every programmed an Oracle NoSQL Database application, you’ll know the difference! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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• ODEE Green Field (Windows) Part 4 - Documaker

  - by AndyL-Oracle

  Welcome back! We're about nearing completion of our installation of Oracle Documaker Enterprise Edition ("ODEE") in a green field. In my previous post, I covered the installation of SOA Suite for WebLogic. Before that, I covered the installation of WebLogic, and Oracle 11g database - all of which constitute the prerequisites for installing ODEE. Naturally, if your environment already has a WebLogic server and Oracle database, then you can skip all those components and go straight for the heart of the installation of ODEE. The ODEE installation is comprised of two procedures, the first covers the installation, which is running the installer and answering some questions. This will lay down the files necessary to install into the tiers (e.g. database schemas, WebLogic domains, etcetera). The second procedure is to deploy the configuration files into the various components (e.g. deploy the database schemas, WebLogic domains, SOA composites, etcetera). I will segment my posts accordingly! Let's get started, shall we? Unpack the installation files into a temporary directory location. This should extract a zip file. Extract that zip file into the temporary directory location. Navigate to and execute the installer in Disk1/setup.exe. You may have to allow the program to run if User Account Control is enabled. Once the dialog below is displayed, click Next. Select your ODEE Home - inside this directory is where all the files will be deployed. For ease of support, I recommend using the default, however you can put this wherever you want. Click Next. Select the database type, database connection type – note that the database name should match the value used for the connection type (e.g. if using SID, then the name should be IDMAKER; if using ServiceName, the name should be “idmaker.us.oracle.com”). Verify whether or not you want to enable advanced compression. Note: if you are not licensed for Oracle 11g Advanced Compression option do not use this option! Terrible, terrible calamities will befall you if you do! Click Next. Enter the Documaker Admin user name (default "dmkr_admin" is recommended for support purposes) and set the password. Update the System name and ID (must be unique) if you want/need to - since this is a green field install you should be able to use the default System ID. The only time you'd change this is if you were, for some reason, installing a new ODEE system into an existing schema that already had a system. Click Next. Enter the Assembly Line user name (default "dmkr_asline" is recommended) and set the password. Update the Assembly Line name and ID (must be unique) if you want/need to - it's quite possible that at some point you will create another assembly line, in which case you have several methods of doing so. One is to re-run the installer, and in this case you would pick a different assembly line ID and name. Click Next. Note: you can set the DB folder if needed (typically you don’t – see ODEE Installation Guide for specifics. Select the appropriate Application Server type - in this case, our green field install is going to use WebLogic - set the username to weblogic (this is required) and specify your chosen password. This credential will be used to access the application server console/control panel. Keep in mind that there are specific criteria on password choices that are required by WebLogic, but are not enforced by the installer (e.g. must contain a number, must be of a certain length, etcetera). Choose a strong password. Set the connection information for the JMS server. Note that for the 12.3.x version, the installer creates a separate JVM (WebLogic managed server) that hosts the JMS server, whereas prior editions place the JMS server on the AdminServer.  You may also specify a separate URL to the JMS server in case you intend to move the JMS resources to a separate/different server (e.g. back to AdminServer). You'll need to provide a login principal and credentials - for simplicity I usually make this the same as the WebLogic domain user, however this is not a secure practice! Make your JMS principal different from the WebLogic principal and choose a strong password, then click Next. Specify the Hot Folder(s) (comma-delimited if more than one) - this is the directory/directories that is/are monitored by ODEE for jobs to process. Click Next. If you will be setting up an SMTP server for ODEE to send emails, you may configure the connection details here. The details required are simple: hostname, port, user/password, and the sender's address (e.g. emails will appear to be sent by the address shown here so if the recipient clicks "reply", this is where it will go). Click Next. If you will be using Oracle WebCenter:Content (formerly known as Oracle UCM) you can enable this option and set the endpoints/credentials here. If you aren't sure, select False - you can always go back and enable this later. I'm almost 76% certain there will be a post sometime in the future that details how to configure ODEE + WCC:C! Click Next. If you will be using Oracle UMS for sending MMS/text messages, you can enable and set the endpoints/credentials here. As with UCM, if you're not sure, don't enable it - you can always set it later. Click Next. On this screen you can change the endpoints for the Documaker Web Service (DWS), and the endpoints for approval processing in Documaker Interactive. The deployment process for ODEE will create 3 managed WebLogic servers for hosting various Documaker components (JMS, Interactive, DWS, Dashboard, Documaker Administrator, etcetera) and it will set the ports used for each of these services. In this screen you can change these values if you know how you want to deploy these managed servers - but for now we'll just accept the defaults. Click Next. Verify the installation details and click Install. You can save the installation into a response file if you need to (which might be useful if you want to rerun this installation in an unattended fashion). Allow the installation to progress... Click Next. You can save the response file if needed (e.g. in case you forgot to save it earlier!) Click Finish. That's it, you're done with the initial installation. Have a look around the ODEE_HOME that you just installed (remember we selected c:\oracle\odee_1?) and look at the files that are laid down. Don't change anything just yet! Stay tuned for the next segment where we complete and verify the installation. 

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• JBox2D Polygon Collisions Acting Strange

  - by andy

  I have been playing around with JBox2D and Slick2D and made a little demo with a ground object, a box object, and two different polygons. The problem I am facing is that the collision-detection for the polygons seems to be off (see picture below), but the box's collision works fine. My Code: Main Class package main; import org.jbox2d.common.Vec2; import org.jbox2d.dynamics.BodyType; import org.jbox2d.dynamics.World; import org.newdawn.slick.GameContainer; import org.newdawn.slick.Graphics; import org.newdawn.slick.SlickException; import org.newdawn.slick.state.BasicGameState; import org.newdawn.slick.state.StateBasedGame; import shapes.Box; import shapes.Polygon; public class State1 extends BasicGameState{ World world; int velocityIterations; int positionIterations; float pixelsPerMeter; int state; Box ground; Box box1; Polygon poly1; Polygon poly2; Renderer renderer; public State1(int state) { this.state = state; } @Override public void init(GameContainer gc, StateBasedGame game) throws SlickException { velocityIterations = 10; positionIterations = 10; pixelsPerMeter = 1f; world = new World(new Vec2(0.f, -9.8f)); renderer = new Renderer(gc, gc.getGraphics(), pixelsPerMeter, world); box1 = new Box(-100f, 200f, 40, 50, BodyType.DYNAMIC, world); ground = new Box(-14, -275, 50, 900, BodyType.STATIC, world); poly1 = new Polygon(50f, 10f, new Vec2[] { new Vec2(-6f, -14f), new Vec2(0f, -20f), new Vec2(6f, -14f), new Vec2(10f, 10f), new Vec2(-10f, 10f) }, BodyType.DYNAMIC, world); poly2 = new Polygon(0f, 10f, new Vec2[] { new Vec2(10f, 0f), new Vec2(20f, 0f), new Vec2(30f, 10f), new Vec2(30f, 20f), new Vec2(20f, 30f), new Vec2(10f, 30f), new Vec2(0f, 20f), new Vec2(0f, 10f) }, BodyType.DYNAMIC, world); } @Override public void update(GameContainer gc, StateBasedGame game, int delta) throws SlickException { world.step((float)delta / 180f, velocityIterations, positionIterations); } @Override public void render(GameContainer gc, StateBasedGame game, Graphics g) throws SlickException { renderer.render(); } @Override public int getID() { return this.state; } } Polygon Class package shapes; import org.jbox2d.collision.shapes.PolygonShape; import org.jbox2d.common.Vec2; import org.jbox2d.dynamics.Body; import org.jbox2d.dynamics.BodyDef; import org.jbox2d.dynamics.BodyType; import org.jbox2d.dynamics.FixtureDef; import org.jbox2d.dynamics.World; import org.newdawn.slick.Color; public class Polygon { public float x, y; public Color color; public BodyType bodyType; org.newdawn.slick.geom.Polygon poly; BodyDef def; PolygonShape ps; FixtureDef fd; Body body; World world; Vec2[] verts; public Polygon(float x, float y, Vec2[] verts, BodyType bodyType, World world) { this.verts = verts; this.x = x; this.y = y; this.bodyType = bodyType; this.world = world; init(); } public void init() { def = new BodyDef(); def.type = bodyType; def.position.set(x, y); ps = new PolygonShape(); ps.set(verts, verts.length); fd = new FixtureDef(); fd.shape = ps; fd.density = 2.0f; fd.friction = 0.7f; fd.restitution = 0.5f; body = world.createBody(def); body.createFixture(fd); } } Rendering Class package main; import org.jbox2d.collision.shapes.PolygonShape; import org.jbox2d.collision.shapes.ShapeType; import org.jbox2d.common.MathUtils; import org.jbox2d.common.Vec2; import org.jbox2d.dynamics.Body; import org.jbox2d.dynamics.Fixture; import org.jbox2d.dynamics.World; import org.newdawn.slick.Color; import org.newdawn.slick.GameContainer; import org.newdawn.slick.Graphics; import org.newdawn.slick.geom.Polygon; import org.newdawn.slick.geom.Transform; public class Renderer { World world; float pixelsPerMeter; GameContainer gc; Graphics g; public Renderer(GameContainer gc, Graphics g, float ppm, World world) { this.world = world; this.pixelsPerMeter = ppm; this.g = g; this.gc = gc; } public void render() { Body current = world.getBodyList(); Vec2 center = current.getLocalCenter(); while(current != null) { Vec2 pos = current.getPosition(); g.pushTransform(); g.translate(pos.x * pixelsPerMeter + (0.5f * gc.getWidth()), -pos.y * pixelsPerMeter + (0.5f * gc.getHeight())); Fixture f = current.getFixtureList(); while(f != null) { ShapeType type = f.getType(); g.setColor(getColor(current)); switch(type) { case POLYGON: { PolygonShape shape = (PolygonShape)f.getShape(); Vec2[] verts = shape.getVertices(); int count = shape.getVertexCount(); Polygon p = new Polygon(); for(int i = 0; i < count; i++) { p.addPoint(verts[i].x, verts[i].y); } p.setCenterX(center.x); p.setCenterY(center.y); p = (Polygon)p.transform(Transform.createRotateTransform(current.getAngle() + MathUtils.PI, center.x, center.y)); p = (Polygon)p.transform(Transform.createScaleTransform(pixelsPerMeter, pixelsPerMeter)); g.draw(p); break; } case CIRCLE: { f.getShape(); } default: } f = f.getNext(); } g.popTransform(); current = current.getNext(); } } public Color getColor(Body b) { Color c = new Color(1f, 1f, 1f); switch(b.m_type) { case DYNAMIC: if(b.isActive()) { c = new Color(255, 123, 0); } else { c = new Color(99, 99, 99); } break; case KINEMATIC: break; case STATIC: c = new Color(111, 111, 111); break; default: break; } return c; } } Any help with fixing the collisions would be greatly appreciated, and if you need any other code snippets I would be happy to provide them.

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• SOA Suite Integration: Part 3: Loading files

  - by Anthony Shorten

  One of the most common scenarios in SOA Integration is the loading of a file into the product from an external source. In Oracle SOA Suite there is a File Adapter that can process many file types into your BPEL process. For this example I will use the File Adapter to load a file of user and emails to update the user object within the Oracle Utilities Application Framework. Remember you can repeat this process with other objects and other file types. Again I am illustrating the ease of integration. The first thing is to create an empty BPEL process that will hold our flow. In Oracle JDeveloper this can be achieved by specifying the Define Service Later template (as other templates have predefined inputs and outputs and in this case we want to specify those). So I will create simpleFileLoad process to house our process. You will start with an empty canvas so you need to first specify the load part of the process using the File Adapter. Select the File Adapter from the Component Palette under BPEL Services and drag and drop it to the left side Partner Links (left is input). You name the Service. In this case I chose LoadFile. Press Next. We will define the interface as part of the wizard so select Define from operation and schema (specified later). Press Next. We are going to choose Read File to denote that we will read the file and specify the default Operation Name as Read. Press Next. The next step is to tell the Adapter the location of the files, how to process them and what to do with them after they have been processed. I am using hardcoded locations in this example but you can have logical locations as well. Press Next. I am now going to tell the adapter how to recognize the files I want to load. In my case I am using CSV files and more importantly I am tell the adapter to run the process for each record in the file it encounters. Press Next. Now, I tell the adapter how often I want to poll for the files. I have taken the defaults. Press Next. At this stage I have no explanation of the format of the input. So I am going to invoke the Native Format Wizard which will guide me through the process of creating the file input format. Clicking the purple cog icon will start the wizard. After an introduction screen (not shown), you specify the format of the input file. The File Adapter supports multiple format types. For this example, I will use Delimited as I am going to load a CSV file. Press Next. The best way for the wizard to work is with a sample. I have a sample file and the wizard will ask how much of the file to use as a template. I will use the defaults. Note: If you are using a language that has other languages other than US-ASCII, it is at this point you specify the character set to use.  Press Next. The sample contains multiple instances of a single record type. The wizard supports complex types as well. We will use the appropriate setting for our file. Press Next. You have to specify the file element and the record element. This will be used by the input wizard to translate the CSV data into an XML structure (this will make sense later). I am using LoadUsers as my file delimiter (root element) and User Record as my record root element. Press Next. As the file is CSV the delimiter is "," so I will also specify that the End Of Line (EOL) indicator indicates the end of a record. Press Next. Up until this point your have not given the columns their names. In my case my sample includes the column names in the first record. This is not always the case but you can specify the names and formats of columns in this dialog (not shown). Press Next. The wizard now generates the schema for the input file. You can specify a name for the schema. I have used userupdate.xsd. We want to verify the schema so press Test. You can test the schema by specifying an input sample. and pressing the green play button. You will see the delimiters you specified earlier for the file and the records. Press Ok to continue. A confirmation screen will be displayed showing you the location of the schema in your project. Press Finish to return to the File Adapter configuration. You will now see the schema and elements prepopulated from the wizard. Press Next. The File Adapter configuration is now complete. Press Finish. Now you need to receive the input from the LoadFile component so we need to place a Receive node in the BPEL process by drag and dropping the Receive component from the Component Palette under BPEL Constructs onto the BPEL process. We link the receive process with the LoadFile component by dragging the left most connect node of the Receive node to the LoadFile component. Once the link is established you need to name the Receive node appropriately and as in the post of the last part of this series you need to generate input variables for the BPEL process to hold the input records in. You need to now add the product Web Service. The process is the same as described in the post of the last part of this series. You drop the Web Service BPEL Service onto the right side of the process and fill in the details of the WSDL URL . You also have to add an Invoke node to call the service and generate the input and outputs variables for the call in the Invoke node. Now, to get the inputs from File to the service. You have to use a Transform (you can use an Assign action but a Transform action is more flexible). You drag and drop the Transform component from the Component Palette under Oracle Extensions and place it between the Receive and Invoke nodes. We name the Transform Node, Mapper File and associate the source of the mapping the schema from the Receive node and the output will be the input variable from the Invoke node. We now build the transform. We first map the user and email attributes by drag and drop the elements from the left to the right. The reason we needed to use the transform is that we will be telling the AS-User service that we want to issue an update action. Remember when we registered the service we actually used Read as the default. If we do not otherwise inform the service to use the Update action it will use the Read action instead (which is not desired). To specify the update action you need to click on the transactionType node on the right and select Set Text to set the action. You need to specify the transactionType of UPD (for update). The mapping is now complete. The final BPEL process is ready for deployment. You then deploy the BPEL process to the server and to test the service by simply dropping a file, in the same pattern/name as you specified, in the directory you specified in the File Adapter. You will see each record as a separate instance entry in the Fusion Middleware Control console. You can now load files into the product. You can repeat this process for each type of file to process. While this was a simple example it illustrates the method of loading data can be achieved using SOA Suite in conjunction with our products.

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• Accessing your web server via IPv6

  Being able to run your systems on IPv6, have automatic address assignment and the ability to resolve host names are the necessary building blocks in your IPv6 network infrastructure. Now, that everything is in place it is about time that we are going to enable another service to respond to IPv6 requests. The following article will guide through the steps on how to enable Apache2 httpd to listen and respond to incoming IPv6 requests. This is the fourth article in a series on IPv6 configuration: Configure IPv6 on your Linux system DHCPv6: Provide IPv6 information in your local network Enabling DNS for IPv6 infrastructure Accessing your web server via IPv6 Piece of advice: This is based on my findings on the internet while reading other people's helpful articles and going through a couple of man-pages on my local system. Surfing the web - IPv6 style Enabling IPv6 connections in Apache 2 is fairly simply. But first let's check whether your system has a running instance of Apache2 or not. You can check this like so: $ service apache2 status Apache2 is running (pid 2680). In case that you got a 'service unknown' you have to install Apache to proceed with the following steps: $ sudo apt-get install apache2 Out of the box, Apache binds to all your available network interfaces and listens to TCP port 80. To check this, run the following command: $ sudo netstat -lnptu | grep "apache2\W*$"tcp6       0      0 :::80                   :::*                    LISTEN      28306/apache2 In this case Apache2 is already binding to IPv6 (and implicitly to IPv4). If you only got a tcp output, then your HTTPd is not yet IPv6 enabled. Check your Listen directive, depending on your system this might be in a different location than the default in Ubuntu. $ sudo nano /etc/apache2/ports.conf # If you just change the port or add more ports here, you will likely also# have to change the VirtualHost statement in# /etc/apache2/sites-enabled/000-default# This is also true if you have upgraded from before 2.2.9-3 (i.e. from# Debian etch). See /usr/share/doc/apache2.2-common/NEWS.Debian.gz and# README.Debian.gzNameVirtualHost *:80Listen 80<IfModule mod_ssl.c>    # If you add NameVirtualHost *:443 here, you will also have to change    # the VirtualHost statement in /etc/apache2/sites-available/default-ssl    # to <VirtualHost *:443>    # Server Name Indication for SSL named virtual hosts is currently not    # supported by MSIE on Windows XP.    Listen 443</IfModule><IfModule mod_gnutls.c>    Listen 443</IfModule> Just in case that you don't have a ports.conf file, look for it like so: $ cd /etc/apache2/$ fgrep -r -i 'listen' ./* And modify the related file instead of the ports.conf. Which most probably might be either apache2.conf or httpd.conf anyways. Okay, please bear in mind that Apache can only bind once on the same interface and port. So, eventually, you might be interested to add another port which explicitly listens to IPv6 only. In that case, you would add the following in your configuration file: Listen 80Listen [2001:db8:bad:a55::2]:8080 But this is completely optional... Anyways, just to complete all steps, you save the file, and then check the syntax like so: $ sudo apache2ctl configtestSyntax OK Ok, now let's apply the modifications to our running Apache2 instances: $ sudo service apache2 reload * Reloading web server config apache2   ...done. $ sudo netstat -lnptu | grep "apache2\W*$"                                                                                               tcp6       0      0 2001:db8:bad:a55:::8080 :::*                    LISTEN      5922/apache2    tcp6       0      0 :::80                   :::*                    LISTEN      5922/apache2 There we have two daemons running and listening to different TCP ports. Now, that the basics are in place, it's time to prepare any website to respond to incoming requests on the IPv6 address. Open up any configuration file you have below your sites-enabled folder. $ ls -al /etc/apache2/sites-enabled/... $ sudo nano /etc/apache2/sites-enabled/000-default <VirtualHost *:80 [2001:db8:bad:a55::2]:8080>        ServerAdmin [email protected]        ServerName server.ios.mu        ServerAlias server Here, we have to check and modify the VirtualHost directive and enable it to respond to the IPv6 address and port our web server is listening to. Save your changes, run the configuration test and reload Apache2 in order to apply your modifications. After successful steps you can launch your favourite browser and navigate to your IPv6 enabled web server. Accessing an IPv6 address in the browser That looks like a successful surgery to me... Note: In case that you received a timeout, check whether your client is operating on IPv6, too.

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• Why JSF Matters (to You)

  - by reza_rahman

        "Those who have knowledge, don’t predict. Those who predict, don’t have knowledge."                                                                                                    – Lao Tzu You may have noticed Thoughtworks recently crowned the likes AngularJS, etc imminent successors to server-side web frameworks. They apparently also deemed it necessary to single out JSF for righteous scorn. I have to say as I was reading the analysis I couldn't help but remember they also promptly jumped on the Ruby, Rails, Clojure, etc bandwagon a good few years ago seemingly similarly crowing these dynamic languages imminent successors to Java. I remember thinking then as I do now whether the folks at Thoughtworks are really that much smarter than me or if they are simply more prone to the Hipster buzz of the day. I'll let you make the final call on that one. I also noticed mention of "J2EE" in the context of JSF and had to wonder how up-to-date or knowledgeable the person writing the analysis actually was given that the term was basically retired almost a decade ago. There's one thing that I am absolutely sure about though - as a long time pretty happy user of JSF, I had no choice but to speak up on what I believe JSF offers. If you feel the same way, I would encourage you to support the team behind JSF whose hard work you may have benefited from over the years. True to his outspoken character PrimeFaces lead Cagatay Civici certainly did not mince words making the case for the JSF ecosystem - his excellent write-up is well worth a read. He specifically pointed out the practical problems in going whole hog with bare metal JavaScript, CSS, HTML for many development teams. I'll admit I had to smile when I read his closing sentence as well as the rather cheerful comments to the post from actual current JSF/PrimeFaces users that are apparently supposed to be on a gloomy death march. In a similar vein, OmniFaces developer Arjan Tijms did a great job pointing out the fact that despite the extremely competitive server-side Java Web UI space, JSF seems to manage to always consistently come out in either the number one or number two spot over many years and many data sources - do give his well-written message in the JAX-RS user forum a careful read. I don't think it's really reasonable to expect this to be the case for so many years if JSF was not at least a capable if not outstanding technology. If fact if you've ever wondered, Oracle itself is one of the largest JSF users on the planet. As Oracle's Shay Shmeltzer explains in a recent JSF Central interview, many of Oracle's strategic products such as ADF, ADF Mobile and Fusion Applications itself is built on JSF. There are well over 3,000 active developers working on these codebases. I don't think anyone can think of a more compelling reason to make sure that a technology is as effective as possible for practical development under real world conditions. Standing on the shoulders of the above giants, I feel like I can be pretty brief in making my own case for JSF: JSF is a powerful abstraction that brings the original Smalltalk MVC pattern to web development. This means cutting down boilerplate code to the bare minimum such that you really can think of just writing your view markup and then simply wire up some properties and event handlers on a POJO. The best way to see what this really means is to compare JSF code for a pretty small case to other approaches. You should then multiply the additional work for the typical enterprise project to try to understand what the productivity trade-offs are. This is reason alone for me to personally never take any other approach seriously as my primary web UI solution unless it can match the sheer productivity of JSF. Thanks to JSF's focus on components from the ground-up JSF has an extremely strong ecosystem that includes projects like PrimeFaces, RichFaces, OmniFaces, ICEFaces and of course ADF Faces/Mobile. These component libraries taken together constitute perhaps the largest widget set ever developed and optimized for a single web UI technology. To begin to grasp what this really means, just briefly browse the excellent PrimeFaces showcase and think about the fact that you can readily use the widgets on that showcase by just using some simple markup and knowing near to nothing about AJAX, JavaScript or CSS. JSF has the fair and legitimate advantage of being an open vendor neutral standard. This means that no single company, individual or insular clique controls JSF - openness, transparency, accountability, plurality, collaboration and inclusiveness is virtually guaranteed by the standards process itself. You have the option to choose between compatible implementations, escape any form of lock-in or even create your own compatible implementation! As you might gather from the quote at the top of the post, I am not a fan of crystal ball gazing and certainly don't want to engage in it myself. Who knows? However far-fetched it may seem maybe AngularJS is the only future we all have after all. If that is the case, so be it. Unlike what you might have been told, Java EE is about choice at heart and it can certainly work extremely well as a back-end for AngularJS. Likewise, you are also most certainly not limited to just JSF for working with Java EE - you have a rich set of choices like Struts 2, Vaadin, Errai, VRaptor 4, Wicket or perhaps even the new action-oriented web framework being considered for Java EE 8 based on the work in Jersey MVC... Please note that any views expressed here are my own only and certainly does not reflect the position of Oracle as a company.

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• Make a lives display in HUD, Flash AS3 (not text!)

  - by user40404

  I've been searching the internet all day and I can't find the answer I'm looking for. In my HUD I want to use orange dots to represent lives. The user starts off with 5 lives and every time they die, I want a dot to be removed. Pretty straight forward. So far my idea is to make a movie clip that has the five dots in a line. There would be 5 frames on the timeline (because after the last life it goes to a game over screen right away). I would have a variable set up to store the number of lives and a function to keep track of lives. So every hit of an obstacle would result in livesCounter--;. Then I would set up something like this: switch(livesCounter){ case 5: livesDisplay.gotoAndPlay(1); break; case 4: livesDisplay.gotoAndPlay(2); break; case 3: livesDisplay.gotoAndPlay(3); break; case 2: livesDisplay.gotoAndPlay(4); break; case 1: livesDisplay.gotoAndPlay(5); break; } I feel like there has to be an easier way to do this where I could just have a movie clip of a single orange dot that I could replicate across an x value based on the number of lives. Maybe the dots would be stored in an array? When the user loses a life, a dot on the right end of the line is removed. So in the end the counter would look like this: * * * * * * * * * * * * * * * (last life lost results in the end game screen) EDIT: code based on suggestions by Zhafur and Arthur Wolf White package { import flash.display.MovieClip; import flash.events.*; import flash.ui.Multitouch; import flash.ui.MultitouchInputMode; import flash.display.Sprite; import flash.text.*; import flash.utils.getTimer; public class CollisionMouse extends MovieClip{ public var mySprite:Sprite = new Sprite(); Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT; public var replacement:newSprite = new newSprite; public var score:int = 0; public var obstScore:int = -50; public var targetScore:int = 200; public var startTime:uint = 0; public var gameTime:uint; public var pauseScreen:PauseScreen = new PauseScreen(); public var hitTarget:Boolean = false; public var hitObj:Boolean = false; public var currLevel:Number = 1; public var heroLives:int = 5; public var life:Sprite; public function CollisionMouse() { mySprite.graphics.beginFill(0xff0000); mySprite.graphics.drawRect(0,0,40,40); addChild(mySprite); mySprite.x = 200; mySprite.y = 200; pauseScreen.x = stage.width/2; pauseScreen.y = stage.height/2; life = new Sprite(); life.x = 210; stage.addEventListener(MouseEvent.MOUSE_MOVE,followMouse); /*mySprite.addEventListener(TouchEvent.TOUCH_END, onTouchEnd);*/ //checkLevel(); timeCheck(); trackLives(); } public function timeCheck(){ addEventListener(Event.ENTER_FRAME, showTime); } public function showTime(e:Event) { gameTime = getTimer()-startTime; rm1_mc.timeDisplay.text = clockTime(gameTime); rm1_mc.livesDisplay.text = String(heroLives); } public function clockTime(ms:int) { var seconds:int = Math.floor(ms/1000); var minutes:int = Math.floor(seconds/60); seconds -= minutes*60; var timeString:String = minutes+":"+String(seconds+100).substr(1,2); return timeString; } public function trackLives(){ for(var i:int=0; i<heroLives; i++){ life.graphics.lineStyle(1, 0xff9900); life.graphics.beginFill(0xff9900, 1); life.graphics.drawCircle(i*15, 45, 6); life.graphics.endFill(); addChild(life); } } function followMouse(e:MouseEvent){ mySprite.x=mouseX; mySprite.y=mouseY; trackCollisions(); } function trackCollisions(){ if(mySprite.hitTestObject(rm1_mc.obst1) || mySprite.hitTestObject(rm1_mc.obst2)){ hitObjects(); } else if(mySprite.hitTestObject(rm1_mc.target_mc)){ hitTarg(); } } function hitObjects(){ addChild(replacement); mySprite.x ^= replacement.x; replacement.x ^= mySprite.x; mySprite.x ^= replacement.x; mySprite.y ^= replacement.y; replacement.y ^= mySprite.y; mySprite.y ^= replacement.y; stage.removeEventListener(MouseEvent.MOUSE_MOVE, followMouse); removeChild(mySprite); hitObj = true; checkScore(); } function hitTarg(){ addChild(replacement); mySprite.x ^= replacement.x; replacement.x ^= mySprite.x; mySprite.x ^= replacement.x; mySprite.y ^= replacement.y; replacement.y ^= mySprite.y; mySprite.y ^= replacement.y; stage.removeEventListener(MouseEvent.MOUSE_MOVE, followMouse); removeEventListener(Event.ENTER_FRAME, showTime); removeChild(mySprite); hitTarget = true; currLevel++; checkScore(); } function checkScore(){ if(hitObj){ score += obstScore; heroLives--; removeChild(life); } else if(hitTarget){ score += targetScore; } rm1_mc.scoreDisplay.text = String(score); rm1_mc.livesDisplay.text = String(heroLives); trackLives(); } } }

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• How to display a JSON error message?

  - by Tiny Giant Studios

  I'm currently developing a tumblr theme and have built a jQuery JSON thingamabob that uses the Tumblr API to do the following: The user would click on the "post type" link (e.g. Video Posts), at which stage jQuery would use JSON to grab all the posts that's related to that type and then dynamically display them in a designated area. Now everything works absolutely peachy, except that with Tumblr being Tumblr and their servers taking a knock every now and then, the Tumblr API thingy is sometimes offline. Now I can't foresee when this function will be down, which is why I want to display some generic error message if JSON (for whatever reason) was unable to load the post. You'll see I've already written some code to show an error message when jQuery can't find any posts related to that post type BUT it doesn't cover any server errors. Note: I sometimes get this error: Failed to load resource: the server responded with a status of 503 (Service Temporarily Unavailable) It is for this 503 Error message that I need to write some code, but I'm slightly clueless :) Here's the jQuery JSON code: $('ul.right li').find('a').click(function() { var postType = this.className; var count = 0; byCategory(postType); return false; function byCategory(postType, callback) { $.getJSON('{URL}/api/read/json?type=' + postType + '&callback=?', function(data) { var article = []; $.each(data.posts, function(i, item) { // i = index // item = data for a particular post switch(item.type) { case 'photo': article[i] = '<div class="post_wrap"><div class="photo" style="padding-bottom:5px;">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/XSTldh6ds/photo_icon.png" alt="type_icon"/></a>' + '<a href="' + item.url + '" title="{Title}"><img src="' + item['photo-url-500'] + '"alt="image" /></a></div></div>'; count = 1; break; case 'video': article[i] = '<div class="post_wrap"><div class="video" style="padding-bottom:5px;">' + '<a href="' + item.url + '" title="{Title}" class="type_icon">' + '<img src="http://static.tumblr.com/ewjv7ap/nuSldhclv/video_icon.png" alt="type_icon"/></a>' + '<span style="margin: auto;">' + item['video-player'] + '</span>' + '</div></div>'; count = 1; break; case 'audio': if (use_IE == true) { article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/R50ldh5uj/audio_icon.png" alt="type_icon"/></a>' + '<h3><a href="' + item.url + '">' + item['id3-artist'] +' - ' + item['id3-title'] + '</a></h3>' + '</div></div>'; } else { article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/R50ldh5uj/audio_icon.png" alt="type_icon"/></a>' + '<h3><a href="' + item.url + '">' + item['id3-artist'] +' - ' + item['id3-title'] + '</a></h3><div class="player">' + item['audio-player'] + '</div>' + '</div></div>'; }; count = 1; break; case 'regular': article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/dwxldhck1/regular_icon.png" alt="type_icon"/></a><h3><a href="' + item.url + '">' + item['regular-title'] + '</a></h3><div class="description_container">' + item['regular-body'] + '</div></div></div>'; count = 1; break; case 'quote': article[i] = '<div class="post_wrap"><div class="quote">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/loEldhcpr/quote_icon.png" alt="type_icon"/></a><blockquote><h3><a href="' + item.url + '" title="{Title}">' + item['quote-text'] + '</a></h3></blockquote><cite>- ' + item['quote-source'] + '</cite></div></div>'; count = 1; break; case 'conversation': article[i] = '<div class="post_wrap"><div class="chat">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/MVuldhcth/conversation_icon.png" alt="type_icon"/></a><h3><a href="' + item.url + '">' + item['conversation-title'] + '</a></h3></div></div>'; count = 1; break; case 'link': article[i] = '<div class="post_wrap"><div class="link">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/EQGldhc30/link_icon.png" alt="type_icon"/></a><h3><a href="' + item['link-url'] + '" target="_blank">' + item['link-text'] + '</a></h3></div></div>'; count = 1; break; default: alert('No Entries Found.'); }; }) // end each if (!(count == 0)) { $('#content_right') .hide('fast') .html('<div class="first_div"><span class="left_corner"></span><span class="right_corner"></span><h2>Displaying ' + postType + ' Posts Only</h2></div>' + article.join('')) .slideDown('fast') } else { $('#content_right') .hide('fast') .html('<div class="first_div"><span class="left_corner"></span><span class="right_corner"></span><h2>Hmmm, currently there are no ' + postType + ' posts to display</h2></div>') .slideDown('fast') } // end getJSON }); // end byCategory } }); If you'd like to see the demo in action, check out Elegantem but do note that everything might work absolutely fine for you (or not), depending on Tumblr's temperament.

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• login form with java/sqlite

  - by tuxou

  hi I would like to create a login form for my application with the possibility to add or remove users for an sqlite database, i have created the table users(nam, pass) but i can't unclud it in my login form, it someone could help me this is my login code: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class login extends JFrame{ // Variables declaration private JLabel jLabel1; private JLabel jLabel2; private JTextField jTextField1; private JPasswordField jPasswordField1; private JButton jButton1; private JPanel contentPane; // End of variables declaration public login(){ super(); create(); this.setVisible(true); } private void create(){ jLabel1 = new JLabel(); jLabel2 = new JLabel(); jTextField1 = new JTextField(); jPasswordField1 = new JPasswordField(); jButton1 = new JButton(); contentPane = (JPanel)this.getContentPane(); // // jLabel1 // jLabel1.setHorizontalAlignment(SwingConstants.LEFT); jLabel1.setForeground(new Color(0, 0, 255)); jLabel1.setText("username:"); // // jLabel2 // jLabel2.setHorizontalAlignment(SwingConstants.LEFT); jLabel2.setForeground(new Color(0, 0, 255)); jLabel2.setText("password:"); // // jTextField1 // jTextField1.setForeground(new Color(0, 0, 255)); jTextField1.setSelectedTextColor(new Color(0, 0, 255)); jTextField1.setToolTipText("Enter your username"); jTextField1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e){ jTextField1_actionPerformed(e); } }); // // jPasswordField1 // jPasswordField1.setForeground(new Color(0, 0, 255)); jPasswordField1.setToolTipText("Enter your password"); jPasswordField1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e){ jPasswordField1_actionPerformed(e); } }); // // jButton1 // jButton1.setBackground(new Color(204, 204, 204)); jButton1.setForeground(new Color(0, 0, 255)); jButton1.setText("Login"); jButton1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e){ jButton1_actionPerformed(e); } }); // // contentPane // contentPane.setLayout(null); contentPane.setBorder(BorderFactory.createEtchedBorder()); contentPane.setBackground(new Color(204, 204, 204)); addComponent(contentPane, jLabel1, 5,10,106,18); addComponent(contentPane, jLabel2, 5,47,97,18); addComponent(contentPane, jTextField1, 110,10,183,22); addComponent(contentPane, jPasswordField1, 110,45,183,22); addComponent(contentPane, jButton1, 150,75,83,28); // // login // this.setTitle("Login To Members Area"); this.setLocation(new Point(76, 182)); this.setSize(new Dimension(335, 141)); this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); this.setResizable(false); } /** Add Component Without a Layout Manager (Absolute Positioning) */ private void addComponent(Container container,Component c,int x,int y,int width,int height){ c.setBounds(x,y,width,height); container.add(c); } private void jTextField1_actionPerformed(ActionEvent e){ } private void jPasswordField1_actionPerformed(ActionEvent e){ } private void jButton1_actionPerformed(ActionEvent e){ System.out.println("\njButton1_actionPerformed(ActionEvent e) called."); String username = new String(jTextField1.getText()); String password = new String(jPasswordField1.getText()); if(username.equals("") || password.equals("")){// If password and username is empty > Do this >>> jButton1.setEnabled(false); JLabel errorFields = new JLabel("<HTML><FONT COLOR = Blue>You must enter a username and password to login.</FONT></HTML>"); JOptionPane.showMessageDialog(null,errorFields); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); this.setVisible(true); } else{ JLabel optionLabel = new JLabel("<HTML><FONT COLOR = Blue>You entered</FONT><FONT COLOR = RED> <B>"+username+"</B></FONT> <FONT COLOR = Blue>as your username.<BR> Is this correct?</FONT></HTML>"); int confirm =JOptionPane.showConfirmDialog(null,optionLabel); switch(confirm){ // Switch > Case case JOptionPane.YES_OPTION: // Attempt to Login user jButton1.setEnabled(false); // Set button enable to false to prevent 2 login attempts break; case JOptionPane.NO_OPTION: // No Case.(Go back. Set text to 0) jButton1.setEnabled(false); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); break; case JOptionPane.CANCEL_OPTION: // Cancel Case.(Go back. Set text to 0) jButton1.setEnabled(false); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); break; } // End Switch > Case } } public static void main(String[] args){ JFrame.setDefaultLookAndFeelDecorated(true); JDialog.setDefaultLookAndFeelDecorated(true); try{ UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); }catch (Exception ex){ System.out.println("Failed loading L&F: "); System.out.println(ex); } new login(); }; } my connectDb class : public class Connectdb { private static Connection connect; private static String url ="jdbc:sqlite:data.db"; private static Statement st; private static ResultSet rs; /** * Constructeur privé d'une connection à la bd unique */ private ConnectionBd(){ try { Class.forName("org.sqlite.JDBC"); connect = DriverManager.getConnection(url); } catch (ClassNotFoundException ex) { Logger.getLogger(ex.getName()).log(Level.SEVERE, null, ex); } catch (SQLException e) { System.exit(e.getErrorCode()); } } public static Connection getInstance(){ if(connect == null){ new Connectdb(); }else{ } return connect; } /** * @return */ public static void initTable(String query){ try { Statement state = getInstance().createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY); ResultSet res = state.executeQuery(query); res.close(); state.close(); } catch (SQLException e) { JOptionPane.showMessageDialog(null, e.getMessage(), "ERROR ! ", JOptionPane.ERROR_MESSAGE); } }

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• segmentation fault using BaseCode encryption

  - by Natasha Thapa

  i took the code from the links below to encrypt and decrypt a text but i get segmentation fault when trying to run this any ideas?? http://etutorials.org/Programming/secure+programming/Chapter+4.+Symmetric+Cryptography+Fundamentals/4.5+Performing+Base64+Encoding/ http://etutorials.org/Programming/secure+programming/Chapter+4.+Symmetric+Cryptography+Fundamentals/4.6+Performing+Base64+Decoding/ #include <stdlib.h> #include <string.h> #include <stdio.h> static char b64revtb[256] = { -3, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*0-15*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16-31*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /*32-47*/ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1, /*48-63*/ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /*64-79*/ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /*80-95*/ -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /*96-111*/ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /*112-127*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128-143*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*144-159*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*160-175*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*176-191*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*192-207*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*208-223*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*224-239*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 /*240-255*/ }; unsigned char *spc_base64_encode( unsigned char *input , size_t len , int wrap ) ; unsigned char *spc_base64_decode(unsigned char *buf, size_t *len, int strict, int *err); static unsigned int raw_base64_decode(unsigned char *in, unsigned char *out, int strict, int *err); unsigned char *tmbuf = NULL; static char tmpbuffer[] ={0}; int main(void) { memset( tmpbuffer, NULL, sizeof( tmpbuffer ) ); sprintf( tmpbuffer, "%s:%s" , "username", "password" ); tmbuf = spc_base64_encode( (unsigned char *)tmpbuffer , strlen( tmpbuffer ), 0 ); printf(" The text %s has been encrytped to %s \n", tmpbuffer, tmbuf ); unsigned char *decrypt = NULL; int strict; int *err; decrypt = spc_base64_decode( tmbuf , strlen( tmbuf ), 0, err ); printf(" The text %s has been decrytped to %s \n", tmbuf , decrypt); } static char b64table[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz" "0123456789+/"; /* Accepts a binary buffer with an associated size. * Returns a base64 encoded, NULL-terminated string. */ unsigned char *spc_base64_encode(unsigned char *input, size_t len, int wrap) { unsigned char *output, *p; size_t i = 0, mod = len % 3, toalloc; toalloc = (len / 3) * 4 + (3 - mod) % 3 + 1; if (wrap) { toalloc += len / 57; if (len % 57) toalloc++; } p = output = (unsigned char *)malloc(((len / 3) + (mod ? 1 : 0)) * 4 + 1); if (!p) return 0; while (i < len - mod) { *p++ = b64table[input[i++] >> 2]; *p++ = b64table[((input[i - 1] << 4) | (input[i] >> 4)) & 0x3f]; *p++ = b64table[((input[i] << 2) | (input[i + 1] >> 6)) & 0x3f]; *p++ = b64table[input[i + 1] & 0x3f]; i += 2; if (wrap && !(i % 57)) *p++ = '\n'; } if (!mod) { if (wrap && i % 57) *p++ = '\n'; *p = 0; return output; } else { *p++ = b64table[input[i++] >> 2]; *p++ = b64table[((input[i - 1] << 4) | (input[i] >> 4)) & 0x3f]; if (mod = = 1) { *p++ = '='; *p++ = '='; if (wrap) *p++ = '\n'; *p = 0; return output; } else { *p++ = b64table[(input[i] << 2) & 0x3f]; *p++ = '='; if (wrap) *p++ = '\n'; *p = 0; return output; } } } static unsigned int raw_base64_decode(unsigned char *in, unsigned char *out, int strict, int *err) { unsigned int result = 0, x; unsigned char buf[3], *p = in, pad = 0; *err = 0; while (!pad) { switch ((x = b64revtb[*p++])) { case -3: /* NULL TERMINATOR */ if (((p - 1) - in) % 4) *err = 1; return result; case -2: /* PADDING CHARACTER. INVALID HERE */ if (((p - 1) - in) % 4 < 2) { *err = 1; return result; } else if (((p - 1) - in) % 4 == 2) { /* Make sure there's appropriate padding */ if (*p != '=') { *err = 1; return result; } buf[2] = 0; pad = 2; result++; break; } else { pad = 1; result += 2; break; } case -1: if (strict) { *err = 2; return result; } break; default: switch (((p - 1) - in) % 4) { case 0: buf[0] = x << 2; break; case 1: buf[0] |= (x >> 4); buf[1] = x << 4; break; case 2: buf[1] |= (x >> 2); buf[2] = x << 6; break; case 3: buf[2] |= x; result += 3; for (x = 0; x < 3 - pad; x++) *out++ = buf[x]; break; } break; } } for (x = 0; x < 3 - pad; x++) *out++ = buf[x]; return result; } /* If err is non-zero on exit, then there was an incorrect padding error. We * allocate enough space for all circumstances, but when there is padding, or * there are characters outside the character set in the string (which we are * supposed to ignore), then we end up allocating too much space. You can * realloc() to the correct length if you wish. */ unsigned char *spc_base64_decode(unsigned char *buf, size_t *len, int strict, int *err) { unsigned char *outbuf; outbuf = (unsigned char *)malloc(3 * (strlen(buf) / 4 + 1)); if (!outbuf) { *err = -3; *len = 0; return 0; } *len = raw_base64_decode(buf, outbuf, strict, err); if (*err) { free(outbuf); *len = 0; outbuf = 0; } return outbuf; }

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• Plan Caching and Query Memory Part II (Hash Match) – When not to use stored procedure - Most common performance mistake SQL Server developers make.

  - by sqlworkshops

  SQL Server estimates Memory requirement at compile time, when stored procedure or other plan caching mechanisms like sp_executesql or prepared statement are used, the memory requirement is estimated based on first set of execution parameters. This is a common reason for spill over tempdb and hence poor performance. Common memory allocating queries are that perform Sort and do Hash Match operations like Hash Join or Hash Aggregation or Hash Union. This article covers Hash Match operations with examples. It is recommended to read Plan Caching and Query Memory Part I before this article which covers an introduction and Query memory for Sort. In most cases it is cheaper to pay for the compilation cost of dynamic queries than huge cost for spill over tempdb, unless memory requirement for a query does not change significantly based on predicates.   This article covers underestimation / overestimation of memory for Hash Match operation. Plan Caching and Query Memory Part I covers underestimation / overestimation for Sort. It is important to note that underestimation of memory for Sort and Hash Match operations lead to spill over tempdb and hence negatively impact performance. Overestimation of memory affects the memory needs of other concurrently executing queries. In addition, it is important to note, with Hash Match operations, overestimation of memory can actually lead to poor performance.   To read additional articles I wrote click here.   The best way to learn is to practice. To create the below tables and reproduce the behavior, join the mailing list by using this link: www.sqlworkshops.com/ml and I will send you the table creation script. Most of these concepts are also covered in our webcasts: www.sqlworkshops.com/webcasts  Let’s create a Customer’s State table that has 99% of customers in NY and the rest 1% in WA.Customers table used in Part I of this article is also used here.To observe Hash Warning, enable 'Hash Warning' in SQL Profiler under Events 'Errors and Warnings'. --Example provided by www.sqlworkshops.com drop table CustomersState go create table CustomersState (CustomerID int primary key, Address char(200), State char(2)) go insert into CustomersState (CustomerID, Address) select CustomerID, 'Address' from Customers update CustomersState set State = 'NY' where CustomerID % 100 != 1 update CustomersState set State = 'WA' where CustomerID % 100 = 1 go update statistics CustomersState with fullscan go   Let’s create a stored procedure that joins customers with CustomersState table with a predicate on State. --Example provided by www.sqlworkshops.com create proc CustomersByState @State char(2) as begin declare @CustomerID int select @CustomerID = e.CustomerID from Customers e inner join CustomersState es on (e.CustomerID = es.CustomerID) where es.State = @State option (maxdop 1) end go  Let’s execute the stored procedure first with parameter value ‘WA’ – which will select 1% of data. set statistics time on go --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' goThe stored procedure took 294 ms to complete.  The stored procedure was granted 6704 KB based on 8000 rows being estimated.  The estimated number of rows, 8000 is similar to actual number of rows 8000 and hence the memory estimation should be ok.  There was no Hash Warning in SQL Profiler. To observe Hash Warning, enable 'Hash Warning' in SQL Profiler under Events 'Errors and Warnings'.   Now let’s execute the stored procedure with parameter value ‘NY’ – which will select 99% of data. -Example provided by www.sqlworkshops.com exec CustomersByState 'NY' go  The stored procedure took 2922 ms to complete.   The stored procedure was granted 6704 KB based on 8000 rows being estimated.    The estimated number of rows, 8000 is way different from the actual number of rows 792000 because the estimation is based on the first set of parameter value supplied to the stored procedure which is ‘WA’ in our case. This underestimation will lead to spill over tempdb, resulting in poor performance.   There was Hash Warning (Recursion) in SQL Profiler. To observe Hash Warning, enable 'Hash Warning' in SQL Profiler under Events 'Errors and Warnings'.   Let’s recompile the stored procedure and then let’s first execute the stored procedure with parameter value ‘NY’.  In a production instance it is not advisable to use sp_recompile instead one should use DBCC FREEPROCCACHE (plan_handle). This is due to locking issues involved with sp_recompile, refer to our webcasts, www.sqlworkshops.com/webcasts for further details.   exec sp_recompile CustomersByState go --Example provided by www.sqlworkshops.com exec CustomersByState 'NY' go  Now the stored procedure took only 1046 ms instead of 2922 ms.   The stored procedure was granted 146752 KB of memory. The estimated number of rows, 792000 is similar to actual number of rows of 792000. Better performance of this stored procedure execution is due to better estimation of memory and avoiding spill over tempdb.   There was no Hash Warning in SQL Profiler.   Now let’s execute the stored procedure with parameter value ‘WA’. --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' go  The stored procedure took 351 ms to complete, higher than the previous execution time of 294 ms.    This stored procedure was granted more memory (146752 KB) than necessary (6704 KB) based on parameter value ‘NY’ for estimation (792000 rows) instead of parameter value ‘WA’ for estimation (8000 rows). This is because the estimation is based on the first set of parameter value supplied to the stored procedure which is ‘NY’ in this case. This overestimation leads to poor performance of this Hash Match operation, it might also affect the performance of other concurrently executing queries requiring memory and hence overestimation is not recommended.     The estimated number of rows, 792000 is much more than the actual number of rows of 8000.  Intermediate Summary: This issue can be avoided by not caching the plan for memory allocating queries. Other possibility is to use recompile hint or optimize for hint to allocate memory for predefined data range.Let’s recreate the stored procedure with recompile hint. --Example provided by www.sqlworkshops.com drop proc CustomersByState go create proc CustomersByState @State char(2) as begin declare @CustomerID int select @CustomerID = e.CustomerID from Customers e inner join CustomersState es on (e.CustomerID = es.CustomerID) where es.State = @State option (maxdop 1, recompile) end go  Let’s execute the stored procedure initially with parameter value ‘WA’ and then with parameter value ‘NY’. --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' go exec CustomersByState 'NY' go  The stored procedure took 297 ms and 1102 ms in line with previous optimal execution times.   The stored procedure with parameter value ‘WA’ has good estimation like before.   Estimated number of rows of 8000 is similar to actual number of rows of 8000.   The stored procedure with parameter value ‘NY’ also has good estimation and memory grant like before because the stored procedure was recompiled with current set of parameter values.  Estimated number of rows of 792000 is similar to actual number of rows of 792000.    The compilation time and compilation CPU of 1 ms is not expensive in this case compared to the performance benefit.   There was no Hash Warning in SQL Profiler.   Let’s recreate the stored procedure with optimize for hint of ‘NY’. --Example provided by www.sqlworkshops.com drop proc CustomersByState go create proc CustomersByState @State char(2) as begin declare @CustomerID int select @CustomerID = e.CustomerID from Customers e inner join CustomersState es on (e.CustomerID = es.CustomerID) where es.State = @State option (maxdop 1, optimize for (@State = 'NY')) end go  Let’s execute the stored procedure initially with parameter value ‘WA’ and then with parameter value ‘NY’. --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' go exec CustomersByState 'NY' go  The stored procedure took 353 ms with parameter value ‘WA’, this is much slower than the optimal execution time of 294 ms we observed previously. This is because of overestimation of memory. The stored procedure with parameter value ‘NY’ has optimal execution time like before.   The stored procedure with parameter value ‘WA’ has overestimation of rows because of optimize for hint value of ‘NY’.   Unlike before, more memory was estimated to this stored procedure based on optimize for hint value ‘NY’.    The stored procedure with parameter value ‘NY’ has good estimation because of optimize for hint value of ‘NY’. Estimated number of rows of 792000 is similar to actual number of rows of 792000.   Optimal amount memory was estimated to this stored procedure based on optimize for hint value ‘NY’.   There was no Hash Warning in SQL Profiler.   This article covers underestimation / overestimation of memory for Hash Match operation. Plan Caching and Query Memory Part I covers underestimation / overestimation for Sort. It is important to note that underestimation of memory for Sort and Hash Match operations lead to spill over tempdb and hence negatively impact performance. Overestimation of memory affects the memory needs of other concurrently executing queries. In addition, it is important to note, with Hash Match operations, overestimation of memory can actually lead to poor performance.   Summary: Cached plan might lead to underestimation or overestimation of memory because the memory is estimated based on first set of execution parameters. It is recommended not to cache the plan if the amount of memory required to execute the stored procedure has a wide range of possibilities. One can mitigate this by using recompile hint, but that will lead to compilation overhead. However, in most cases it might be ok to pay for compilation rather than spilling sort over tempdb which could be very expensive compared to compilation cost. The other possibility is to use optimize for hint, but in case one sorts more data than hinted by optimize for hint, this will still lead to spill. On the other side there is also the possibility of overestimation leading to unnecessary memory issues for other concurrently executing queries. In case of Hash Match operations, this overestimation of memory might lead to poor performance. When the values used in optimize for hint are archived from the database, the estimation will be wrong leading to worst performance, so one has to exercise caution before using optimize for hint, recompile hint is better in this case.   I explain these concepts with detailed examples in my webcasts (www.sqlworkshops.com/webcasts), I recommend you to watch them. The best way to learn is to practice. To create the above tables and reproduce the behavior, join the mailing list at www.sqlworkshops.com/ml and I will send you the relevant SQL Scripts.  Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   Disclaimer and copyright information:This article refers to organizations and products that may be the trademarks or registered trademarks of their various owners. Copyright of this article belongs to R Meyyappan / www.sqlworkshops.com. You may freely use the ideas and concepts discussed in this article with acknowledgement (www.sqlworkshops.com), but you may not claim any of it as your own work. This article is for informational purposes only; you use any of the suggestions given here entirely at your own risk.   R Meyyappan [email protected] LinkedIn: http://at.linkedin.com/in/rmeyyappan

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• XNA 3D model collision is inaccurate

  - by Daniel Lopez

  I am creating a classic game in 3d that deals with asteriods and you have to shoot them and avoid being hit from them. I can generate the asteroids just fine and the ship can shoot bullets just fine. But the asteroids always hit the ship even it doesn't look they are even close. I know 2D collision very well but not 3D so can someone please shed some light to my problem. Thanks in advance. Code For ModelRenderer: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { class ModelRenderer { private float aspectratio; private Model model; private Vector3 camerapos; private Vector3 modelpos; private Matrix rotationy; float radiansy = 0; private bool isalive; public ModelRenderer(Model m, float AspectRatio, Vector3 initial_pos, Vector3 initialcamerapos) { isalive = true; model = m; if (model.Meshes.Count == 0) { throw new Exception("Invalid model because it contains zero meshes!"); } modelpos = initial_pos; camerapos = initialcamerapos; aspectratio = AspectRatio; return; } public float RadiusOfSphere { get { return model.Meshes[0].BoundingSphere.Radius; } } public BoundingBox BoxBounds { get { return BoundingBox.CreateFromSphere(model.Meshes[0].BoundingSphere); } } public BoundingSphere SphereBounds { get { return model.Meshes[0].BoundingSphere; } } public Vector3 CameraPosition { set { camerapos = value; } get { return camerapos; } } public bool IsAlive { get { return isalive; } } public Vector3 ModelPosition { set { modelpos = value; } get { return modelpos; } } public void RotateY(float radians) { radiansy += radians; rotationy = Matrix.CreateRotationY(radiansy); } public Matrix RotationY { set { rotationy = value; } get { return rotationy; } } public float AspectRatio { set { aspectratio = value; } get { return aspectratio; } } public void Kill() { isalive = false; } public void Draw(float scale) { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } public void Draw() { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } } Code For Game1: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; int score = 0, lives = 5; SpriteBatch spriteBatch; GameState gstate = GameState.OnMenuScreen; Menu menu = new Menu(Color.Yellow, Color.White); SpriteFont font; Texture2D background; ModelRenderer ship; Model b, a; List<ModelRenderer> bullets = new List<ModelRenderer>(); List<ModelRenderer> asteriods = new List<ModelRenderer>(); float time = 0.0f; int framecount = 0; SoundEffect effect; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 796; graphics.ApplyChanges(); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); font = Content.Load<SpriteFont>("Fonts\\Lucida Console"); background = Content.Load<Texture2D>("Textures\\B1_stars"); Model p1 = Content.Load<Model>("Models\\p1_wedge"); b = Content.Load<Model>("Models\\pea_proj"); a = Content.Load<Model>("Models\\asteroid1"); effect = Content.Load<SoundEffect>("Audio\\tx0_fire1"); ship = new ModelRenderer(p1, GraphicsDevice.Viewport.AspectRatio, new Vector3(0, 0, 0), new Vector3(0, 0, 9000)); } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { KeyboardState state = Keyboard.GetState(PlayerIndex.One); switch (gstate) { case GameState.OnMenuScreen: { if (state.IsKeyDown(Keys.Enter)) { switch (menu.SelectedChoice) { case MenuChoices.Play: { gstate = GameState.GameStarted; break; } case MenuChoices.Exit: { this.Exit(); break; } } } if (state.IsKeyDown(Keys.Down)) { menu.MoveSelectedMenuChoiceDown(gameTime); } else if(state.IsKeyDown(Keys.Up)) { menu.MoveSelectedMenuChoiceUp(gameTime); } else { menu.KeysReleased(); } break; } case GameState.GameStarted: { foreach (ModelRenderer bullet in bullets) { if (bullet.ModelPosition.X < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.Z < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.X > (ship.ModelPosition.Z - 4000) && bullet.ModelPosition.Z > (ship.ModelPosition.Z - 4000)) { bullet.ModelPosition += (bullet.RotationY.Forward * 120); } else if (collidedwithasteriod(bullet)) { bullet.Kill(); } else { bullet.Kill(); } } foreach (ModelRenderer asteroid in asteriods) { if (ship.SphereBounds.Intersects(asteroid.BoxBounds)) { lives -= 1; asteroid.Kill(); // This always hits no matter where the ship goes. } else { asteroid.ModelPosition -= (asteroid.RotationY.Forward * 50); } } for (int index = 0; index < asteriods.Count; index++) { if (asteriods[index].IsAlive == false) { asteriods.RemoveAt(index); } } for (int index = 0; index < bullets.Count; index++) { if (bullets[index].IsAlive == false) { bullets.RemoveAt(index); } } if (state.IsKeyDown(Keys.Left)) { ship.RotateY(0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Right)) { ship.RotateY(-0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Up)) { ship.ModelPosition += (ship.RotationY.Forward * 50); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Space)) { time += gameTime.ElapsedGameTime.Milliseconds; if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0.0f; } if ((framecount % 60) == 0) { createasteroid(); framecount = 0; } framecount++; break; } } base.Update(gameTime); } void firebullet() { if (bullets.Count < 3) { ModelRenderer bullet = new ModelRenderer(b, GraphicsDevice.Viewport.AspectRatio, ship.ModelPosition, new Vector3(0, 0, 9000)); bullet.RotationY = ship.RotationY; bullets.Add(bullet); } } void createasteroid() { if (asteriods.Count < 2) { Random random = new Random(); float z = random.Next(-13000, -11000); float x = random.Next(-9000, -8000); Random random2 = new Random(); int degrees = random.Next(0, 45); float radians = MathHelper.ToRadians(degrees); ModelRenderer asteroid = new ModelRenderer(a, GraphicsDevice.Viewport.AspectRatio, new Vector3(x, 0, z), new Vector3(0,0, 9000)); asteroid.RotateY(radians); asteriods.Add(asteroid); } } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (gstate) { case GameState.OnMenuScreen: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); menu.DrawMenu(ref spriteBatch, font, new Vector2(GraphicsDevice.Viewport.Width / 2, GraphicsDevice.Viewport.Height / 2) - new Vector2(50f), 100f); spriteBatch.End(); break; } case GameState.GameStarted: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.DrawString(font, "Score: " + score.ToString() + "\nLives: " + lives.ToString(), Vector2.Zero, Color.White); spriteBatch.End(); ship.Draw(); foreach (ModelRenderer bullet in bullets) { bullet.Draw(); } foreach (ModelRenderer asteroid in asteriods) { asteroid.Draw(0.1f); } break; } } base.Draw(gameTime); } bool collidedwithasteriod(ModelRenderer bullet) { foreach (ModelRenderer asteroid in asteriods) { if (bullet.SphereBounds.Intersects(asteroid.BoxBounds)) { score += 10; asteroid.Kill(); return true; } } return false; } } } }

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• Diving into OpenStack Network Architecture - Part 2 - Basic Use Cases

  - by Ronen Kofman

    rkofman Normal rkofman 4 138 2014-06-05T03:38:00Z 2014-06-05T05:04:00Z 3 2735 15596 Oracle Corporation 129 36 18295 12.00 Clean Clean false false false false EN-US X-NONE HE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi; mso-bidi-language:AR-SA;} In the previous post we reviewed several network components including Open vSwitch, Network Namespaces, Linux Bridges and veth pairs. In this post we will take three simple use cases and see how those basic components come together to create a complete SDN solution in OpenStack. With those three use cases we will review almost the entire network setup and see how all the pieces work together. The use cases we will use are: 1.       Create network – what happens when we create network and how can we create multiple isolated networks 2.       Launch a VM – once we have networks we can launch VMs and connect them to networks. 3.       DHCP request from a VM – OpenStack can automatically assign IP addresses to VMs. This is done through local DHCP service controlled by OpenStack Neutron. We will see how this service runs and how does a DHCP request and response look like. In this post we will show connectivity, we will see how packets get from point A to point B. We first focus on how a configured deployment looks like and only later we will discuss how and when the configuration is created. Personally I found it very valuable to see the actual interfaces and how they connect to each other through examples and hands on experiments. After the end game is clear and we know how the connectivity works, in a later post, we will take a step back and explain how Neutron configures the components to be able to provide such connectivity.  We are going to get pretty technical shortly and I recommend trying these examples on your own deployment or using the Oracle OpenStack Tech Preview. Understanding these three use cases thoroughly and how to look at them will be very helpful when trying to debug a deployment in case something does not work. Use case #1: Create Network Create network is a simple operation it can be performed from the GUI or command line. When we create a network in OpenStack the network is only available to the tenant who created it or it could be defined as “shared” and then it can be used by all tenants. A network can have multiple subnets but for this demonstration purpose and for simplicity we will assume that each network has exactly one subnet. Creating a network from the command line will look like this: # neutron net-create net1 Created a new network: +---------------------------+--------------------------------------+ | Field                     | Value                                | +---------------------------+--------------------------------------+ | admin_state_up            | True                                 | | id                        | 5f833617-6179-4797-b7c0-7d420d84040c | | name                      | net1                                 | | provider:network_type     | vlan                                 | | provider:physical_network | default                              | | provider:segmentation_id  | 1000                                 | | shared                    | False                                | | status                    | ACTIVE                               | | subnets                   |                                      | | tenant_id                 | 9796e5145ee546508939cd49ad59d51f     | +---------------------------+--------------------------------------+ Creating a subnet for this network will look like this: # neutron subnet-create net1 10.10.10.0/24 Created a new subnet: +------------------+------------------------------------------------+ | Field            | Value                                          | +------------------+------------------------------------------------+ | allocation_pools | {"start": "10.10.10.2", "end": "10.10.10.254"} | | cidr             | 10.10.10.0/24                                  | | dns_nameservers  |                                                | | enable_dhcp      | True                                           | | gateway_ip       | 10.10.10.1                                     | | host_routes      |                                                | | id               | 2d7a0a58-0674-439a-ad23-d6471aaae9bc           | | ip_version       | 4                                              | | name             |                                                | | network_id       | 5f833617-6179-4797-b7c0-7d420d84040c           | | tenant_id        | 9796e5145ee546508939cd49ad59d51f               | +------------------+------------------------------------------------+ We now have a network and a subnet, on the network topology view this looks like this: Now let’s dive in and see what happened under the hood. Looking at the control node we will discover that a new namespace was created: # ip netns list qdhcp-5f833617-6179-4797-b7c0-7d420d84040c   The name of the namespace is qdhcp-<network id> (see above), let’s look into the namespace and see what’s in it: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo     inet6 ::1/128 scope host        valid_lft forever preferred_lft forever 12: tap26c9b807-7c: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN     link/ether fa:16:3e:1d:5c:81 brd ff:ff:ff:ff:ff:ff     inet 10.10.10.3/24 brd 10.10.10.255 scope global tap26c9b807-7c     inet6 fe80::f816:3eff:fe1d:5c81/64 scope link        valid_lft forever preferred_lft forever   We see two interfaces in the namespace, one is the loopback and the other one is an interface called “tap26c9b807-7c”. This interface has the IP address of 10.10.10.3 and it will also serve dhcp requests in a way we will see later. Let’s trace the connectivity of the “tap26c9b807-7c” interface from the namespace.  First stop is OVS, we see that the interface connects to bridge  “br-int” on OVS: # ovs-vsctl show 8a069c7c-ea05-4375-93e2-b9fc9e4b3ca1     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-ex         Port br-ex             Interface br-ex                 type: internal     Bridge br-int         Port "int-br-eth2"             Interface "int-br-eth2"         Port "tap26c9b807-7c"             tag: 1             Interface "tap26c9b807-7c"                 type: internal         Port br-int             Interface br-int                 type: internal     ovs_version: "1.11.0"   In the picture above we have a veth pair which has two ends called “int-br-eth2” and "phy-br-eth2", this veth pair is used to connect two bridge in OVS "br-eth2" and "br-int". In the previous post we explained how to check the veth connectivity using the ethtool command. It shows that the two are indeed a pair: # ethtool -S int-br-eth2 NIC statistics:      peer_ifindex: 10 . .   #ip link . . 10: phy-br-eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 . . Note that “phy-br-eth2” is connected to a bridge called "br-eth2" and one of this bridge's interfaces is the physical link eth2. This means that the network which we have just created has created a namespace which is connected to the physical interface eth2. eth2 is the “VM network” the physical interface where all the virtual machines connect to where all the VMs are connected. About network isolation: OpenStack supports creation of multiple isolated networks and can use several mechanisms to isolate the networks from one another. The isolation mechanism can be VLANs, VxLANs or GRE tunnels, this is configured as part of the initial setup in our deployment we use VLANs. When using VLAN tagging as an isolation mechanism a VLAN tag is allocated by Neutron from a pre-defined VLAN tags pool and assigned to the newly created network. By provisioning VLAN tags to the networks Neutron allows creation of multiple isolated networks on the same physical link.  The big difference between this and other platforms is that the user does not have to deal with allocating and managing VLANs to networks. The VLAN allocation and provisioning is handled by Neutron which keeps track of the VLAN tags, and responsible for allocating and reclaiming VLAN tags. In the example above net1 has the VLAN tag 1000, this means that whenever a VM is created and connected to this network the packets from that VM will have to be tagged with VLAN tag 1000 to go on this particular network. This is true for namespace as well, if we would like to connect a namespace to a particular network we have to make sure that the packets to and from the namespace are correctly tagged when they reach the VM network. In the example above we see that the namespace interface “tap26c9b807-7c” has vlan tag 1 assigned to it, if we examine OVS we see that it has flows which modify VLAN tag 1 to VLAN tag 1000 when a packet goes to the VM network on eth2 and vice versa. We can see this using the dump-flows command on OVS for packets going to the VM network we see the modification done on br-eth2: #  ovs-ofctl dump-flows br-eth2 NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18669.401s, table=0, n_packets=857, n_bytes=163350, idle_age=25, priority=4,in_port=2,dl_vlan=1 actions=mod_vlan_vid:1000,NORMAL  cookie=0x0, duration=165108.226s, table=0, n_packets=14, n_bytes=1000, idle_age=5343, hard_age=65534, priority=2,in_port=2 actions=drop  cookie=0x0, duration=165109.813s, table=0, n_packets=1671, n_bytes=213304, idle_age=25, hard_age=65534, priority=1 actions=NORMAL   For packets coming from the interface to the namespace we see the following modification: #  ovs-ofctl dump-flows br-int NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18690.876s, table=0, n_packets=1610, n_bytes=210752, idle_age=1, priority=3,in_port=1,dl_vlan=1000 actions=mod_vlan_vid:1,NORMAL  cookie=0x0, duration=165130.01s, table=0, n_packets=75, n_bytes=3686, idle_age=4212, hard_age=65534, priority=2,in_port=1 actions=drop  cookie=0x0, duration=165131.96s, table=0, n_packets=863, n_bytes=160727, idle_age=1, hard_age=65534, priority=1 actions=NORMAL   To summarize we can see that when a user creates a network Neutron creates a namespace and this namespace is connected through OVS to the “VM network”. OVS also takes care of tagging the packets from the namespace to the VM network with the correct VLAN tag and knows to modify the VLAN for packets coming from VM network to the namespace. Now let’s see what happens when a VM is launched and how it is connected to the “VM network”. Use case #2: Launch a VM Launching a VM can be done from Horizon or from the command line this is how we do it from Horizon: Attach the network: And Launch Once the virtual machine is up and running we can see the associated IP using the nova list command : # nova list +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | ID                                   | Name         | Status | Task State | Power State | Networks        | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | 3707ac87-4f5d-4349-b7ed-3a673f55e5e1 | Oracle Linux | ACTIVE | None       | Running     | net1=10.10.10.2 | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ The nova list command shows us that the VM is running and that the IP 10.10.10.2 is assigned to this VM. Let’s trace the connectivity from the VM to VM network on eth2 starting with the VM definition file. The configuration files of the VM including the virtual disk(s), in case of ephemeral storage, are stored on the compute node at/var/lib/nova/instances/<instance-id>/. Looking into the VM definition file ,libvirt.xml,  we see that the VM is connected to an interface called “tap53903a95-82” which is connected to a Linux bridge called “qbr53903a95-82”: <interface type="bridge">       <mac address="fa:16:3e:fe:c7:87"/>       <source bridge="qbr53903a95-82"/>       <target dev="tap53903a95-82"/>     </interface>   Looking at the bridge using the brctl show command we see this: # brctl show bridge name     bridge id               STP enabled     interfaces qbr53903a95-82          8000.7e7f3282b836       no              qvb53903a95-82                                                         tap53903a95-82    The bridge has two interfaces, one connected to the VM (“tap53903a95-82 “) and another one ( “qvb53903a95-82”) connected to “br-int” bridge on OVS: # ovs-vsctl show 83c42f80-77e9-46c8-8560-7697d76de51c     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-int         Port br-int             Interface br-int                 type: internal         Port "int-br-eth2"             Interface "int-br-eth2"         Port "qvo53903a95-82"             tag: 3             Interface "qvo53903a95-82"     ovs_version: "1.11.0"   As we showed earlier “br-int” is connected to “br-eth2” on OVS using the veth pair int-br-eth2,phy-br-eth2 and br-eth2 is connected to the physical interface eth2. The whole flow end to end looks like this: VM è tap53903a95-82 (virtual interface)è qbr53903a95-82 (Linux bridge) è qvb53903a95-82 (interface connected from Linux bridge to OVS bridge br-int) è int-br-eth2 (veth one end) è phy-br-eth2 (veth the other end) è eth2 physical interface. The purpose of the Linux Bridge connecting to the VM is to allow security group enforcement with iptables. Security groups are enforced at the edge point which are the interface of the VM, since iptables nnot be applied to OVS bridges we use Linux bridge to apply them. In the future we hope to see this Linux Bridge going away rules.  VLAN tags: As we discussed in the first use case net1 is using VLAN tag 1000, looking at OVS above we see that qvo41f1ebcf-7c is tagged with VLAN tag 3. The modification from VLAN tag 3 to 1000 as we go to the physical network is done by OVS  as part of the packet flow of br-eth2 in the same way we showed before. To summarize, when a VM is launched it is connected to the VM network through a chain of elements as described here. During the packet from VM to the network and back the VLAN tag is modified. Use case #3: Serving a DHCP request coming from the virtual machine In the previous use cases we have shown that both the namespace called dhcp-<some id> and the VM end up connecting to the physical interface eth2  on their respective nodes, both will tag their packets with VLAN tag 1000.We saw that the namespace has an interface with IP of 10.10.10.3. Since the VM and the namespace are connected to each other and have interfaces on the same subnet they can ping each other, in this picture we see a ping from the VM which was assigned 10.10.10.2 to the namespace: The fact that they are connected and can ping each other can become very handy when something doesn’t work right and we need to isolate the problem. In such case knowing that we should be able to ping from the VM to the namespace and back can be used to trace the disconnect using tcpdump or other monitoring tools. To serve DHCP requests coming from VMs on the network Neutron uses a Linux tool called “dnsmasq”,this is a lightweight DNS and DHCP service you can read more about it here. If we look at the dnsmasq on the control node with the ps command we see this: dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap26c9b807-7c --except-interface=lo --pid-file=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host --dhcp-optsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/opts --leasefile-ro --dhcp-range=tag0,10.10.10.0,static,120s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal The service connects to the tap interface in the namespace (“--interface=tap26c9b807-7c”), If we look at the hosts file we see this: # cat  /var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host fa:16:3e:fe:c7:87,host-10-10-10-2.openstacklocal,10.10.10.2   If you look at the console output above you can see the MAC address fa:16:3e:fe:c7:87 which is the VM MAC. This MAC address is mapped to IP 10.10.10.2 and so when a DHCP request comes with this MAC dnsmasq will return the 10.10.10.2.If we look into the namespace at the time we initiate a DHCP request from the VM (this can be done by simply restarting the network service in the VM) we see the following: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c tcpdump -n 19:27:12.191280 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:fe:c7:87, length 310 19:27:12.191666 IP 10.10.10.3.bootps > 10.10.10.2.bootpc: BOOTP/DHCP, Reply, length 325   To summarize, the DHCP service is handled by dnsmasq which is configured by Neutron to listen to the interface in the DHCP namespace. Neutron also configures dnsmasq with the combination of MAC and IP so when a DHCP request comes along it will receive the assigned IP. Summary In this post we relied on the components described in the previous post and saw how network connectivity is achieved using three simple use cases. These use cases gave a good view of the entire network stack and helped understand how an end to end connection is being made between a VM on a compute node and the DHCP namespace on the control node. One conclusion we can draw from what we saw here is that if we launch a VM and it is able to perform a DHCP request and receive a correct IP then there is reason to believe that the network is working as expected. We saw that a packet has to travel through a long list of components before reaching its destination and if it has done so successfully this means that many components are functioning properly. In the next post we will look at some more sophisticated services Neutron supports and see how they work. We will see that while there are some more components involved for the most part the concepts are the same. @RonenKofman

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• Delphi Editbox causing unexplainable errors...

  - by NeoNMD

  On a form I have 8 edit boxes that I do the exact same thing with. They are arranged in 2 sets of 4, one is Upper and the other is Lower. I kept getting errors clearing all the edit boxes so I went through clearing them 1 by 1 and found that 1 of the edit boxes just didnt work and when I tried to run the program and change that exit box it caused the debugger to jump to a point in the code with the database (even though the edit boxes had nothing to do with the database and they arent in a procedure or stack with a database in it) and say the program has access violation there. So I then removed all mention of that edit box and the code worked perfectly again, so I deleted that edit box, copied and pasted another edit box and left all values the same, then went through my code and copied the code from the other sections and simply renamed it for the new Edit box and it STILL causes an error even though it is entirely new. I cannot figure it out so I ask you all, what the hell? The editbox in question is "Edit1" unit DefinitionCoreV2; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, SQLiteTable3, StdCtrls; type TDefinitionFrm = class(TForm) GrpCompetition: TGroupBox; CmbCompSele: TComboBox; BtnCompetitionAdd: TButton; BtnCompetitionUpdate: TButton; BtnCompetitionRevert: TButton; GrpCompetitionDetails: TGroupBox; LblCompetitionIDTitle: TLabel; EdtCompID: TEdit; LblCompetitionDescriptionTitle: TLabel; EdtCompDesc: TEdit; LblCompetitionNotesTitle: TLabel; EdtCompNote: TEdit; LblCompetitionLocationTitle: TLabel; EdtCompLoca: TEdit; BtnCompetitionDelete: TButton; GrpSection: TGroupBox; LblSectionID: TLabel; LblGender: TLabel; LblAge: TLabel; LblLevel: TLabel; LblWeight: TLabel; LblType: TLabel; LblHeight: TLabel; LblCompetitionID: TLabel; BtnSectionAdd: TButton; EdtSectionID: TEdit; CmbGender: TComboBox; BtnSectionUpdate: TButton; BtnSectionRevert: TButton; CmbAgeRange: TComboBox; CmbLevelRange: TComboBox; CmbType: TComboBox; CmbWeightRange: TComboBox; CmbHeightRange: TComboBox; EdtSectCompetitionID: TEdit; BtnSectionDelete: TButton; GrpSectionDetails: TGroupBox; EdtLowerAge: TEdit; EdtLowerWeight: TEdit; EdtLowerHeight: TEdit; EdtUpperAge: TEdit; EdtUpperLevel: TEdit; EdtUpperWeight: TEdit; EdtUpperHeight: TEdit; LblAgeRule: TLabel; LblLevelRule: TLabel; LblWeightRule: TLabel; LblHeightRule: TLabel; LblCompetitionSelect: TLabel; LblSectionSelect: TLabel; CmbSectSele: TComboBox; Edit1: TEdit; procedure FormCreate(Sender: TObject); procedure BtnCompetitionAddClick(Sender: TObject); procedure CmbCompSeleChange(Sender: TObject); procedure BtnCompetitionUpdateClick(Sender: TObject); procedure BtnCompetitionRevertClick(Sender: TObject); procedure BtnCompetitionDeleteClick(Sender: TObject); procedure CmbSectSeleChange(Sender: TObject); procedure BtnSectionAddClick(Sender: TObject); procedure BtnSectionUpdateClick(Sender: TObject); procedure BtnSectionRevertClick(Sender: TObject); procedure BtnSectionDeleteClick(Sender: TObject); procedure CmbAgeRangeChange(Sender: TObject); procedure CmbLevelRangeChange(Sender: TObject); procedure CmbWeightRangeChange(Sender: TObject); procedure CmbHeightRangeChange(Sender: TObject); private procedure UpdateCmbCompSele; procedure AddComp; procedure RevertComp; procedure AddSect; procedure RevertSect; procedure UpdateCmbSectSele; procedure ClearSect; { Private declarations } public { Public declarations } end; var DefinitionFrm: TDefinitionFrm; implementation {$R *.dfm} procedure TDefinitionFrm.UpdateCmbCompSele; var slDBpath: string; sldb : TSQLiteDatabase; sltb : TSQLiteTable; sCompTitle : string; bNext : boolean; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try sltb := slDb.GetTable('SELECT * FROM CompetitionTable'); try CmbCompSele.Items.Clear; Repeat begin sCompTitle:=sltb.FieldAsString(sltb.FieldIndex['CompetitionID'])+':'+sltb.FieldAsString(sltb.FieldIndex['Description']); CmbCompSele.Items.Add(sCompTitle); bNext := sltb.Next; end; Until sltb.EOF; finally sltb.Free; end; finally sldb.Free; end; end; procedure TDefinitionFrm.UpdateCmbSectSele; var slDBpath: string; sldb : TSQLiteDatabase; sltb : TSQLiteTable; sSQL : string; sSectTitle : string; bNext : boolean; bLast : boolean; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try sltb := slDb.GetTable('SELECT * FROM SectionTable WHERE CompetitionID = '+EdtCompID.text); If sltb.RowCount =0 then begin sltb := slDb.GetTable('SELECT * FROM SectionTable'); bLast:= sltb.MoveLast; sSQL := 'INSERT INTO SectionTable(SectionID,CompetitionID,Gender,Type) VALUES ('+IntToStr(sltb.FieldAsInteger(sltb.FieldIndex['SectionID'])+1)+','+EdtCompID.text+',1,1)'; sldb.ExecSQL(sSQL); sltb := slDb.GetTable('SELECT * FROM SectionTable WHERE CompetitionID = '+EdtCompID.text); end; try CmbSectSele.Items.Clear; Repeat begin sSectTitle:=sltb.FieldAsString(sltb.FieldIndex['SectionID'])+':'+sltb.FieldAsString(sltb.FieldIndex['Type'])+':'+sltb.FieldAsString(sltb.FieldIndex['Gender'])+':'+sltb.FieldAsString(sltb.FieldIndex['Age'])+':'+sltb.FieldAsString(sltb.FieldIndex['Level'])+':'+sltb.FieldAsString(sltb.FieldIndex['Weight'])+':'+sltb.FieldAsString(sltb.FieldIndex['Height']); CmbSectSele.Items.Add(sSectTitle); //CmbType.Items.Strings[sltb.FieldAsInteger(sltb.FieldIndex['Type'])] Works but has logic errors bNext := sltb.Next; end; Until sltb.EOF; finally sltb.Free; end; finally sldb.Free; end; end; procedure TDefinitionFrm.AddComp; var slDBpath: string; sSQL : string; sldb : TSQLiteDatabase; sltb : TSQLiteTable; bLast : boolean; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try sltb := slDb.GetTable('SELECT * FROM CompetitionTable'); try bLast:= sltb.MoveLast; sSQL := 'INSERT INTO CompetitionTable(CompetitionID,Description) VALUES ('+IntToStr(sltb.FieldAsInteger(sltb.FieldIndex['CompetitionID'])+1)+',"New Competition")'; sldb.ExecSQL(sSQL); finally sltb.Free; end; finally sldb.Free; end; UpdateCmbCompSele; end; procedure TDefinitionFrm.AddSect; var slDBpath: string; sSQL : string; sldb : TSQLiteDatabase; sltb : TSQLiteTable; bLast : boolean; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try sltb := slDb.GetTable('SELECT * FROM SectionTable'); try bLast:= sltb.MoveLast; sSQL := 'INSERT INTO SectionTable(SectionID,CompetitionID,Gender,Type) VALUES ('+IntToStr(sltb.FieldAsInteger(sltb.FieldIndex['SectionID'])+1)+','+EdtCompID.text+',1,1)'; sldb.ExecSQL(sSQL); finally sltb.Free; end; finally sldb.Free; end; UpdateCmbSectSele; end; procedure TDefinitionFrm.RevertComp; var slDBpath: string; sldb : TSQLiteDatabase; sltb : TSQLiteTable; iID : integer; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try If CmbCompSele.Text <> '' then begin iID := StrToInt(Copy(CmbCompSele.Text,0,Pos(':',CmbCompSele.Text)-1)); sltb := slDb.GetTable('SELECT * FROM CompetitionTable WHERE CompetitionID='+IntToStr(iID))//ItemIndex starts at 0, CompID at 1 end else sltb := slDb.GetTable('SELECT * FROM CompetitionTable WHERE CompetitionID=1'); try EdtCompID.Text:=sltb.FieldAsString(sltb.FieldIndex['CompetitionID']); EdtCompLoca.Text:=sltb.FieldAsString(sltb.FieldIndex['Location']); EdtCompDesc.Text:=sltb.FieldAsString(sltb.FieldIndex['Description']); EdtCompNote.Text:=sltb.FieldAsString(sltb.FieldIndex['Notes']); finally sltb.Free; end; finally sldb.Free; end; end; procedure TDefinitionFrm.RevertSect; var slDBpath: string; sldb : TSQLiteDatabase; sltb : TSQLiteTable; iID : integer; sTemp : string; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try If CmbCompSele.Text <> '' then begin iID := StrToInt(Copy(CmbSectSele.Text,0,Pos(':',CmbSectSele.Text)-1)); sltb := slDb.GetTable('SELECT * FROM SectionTable WHERE SectionID='+IntToStr(iID));//ItemIndex starts at 0, CompID at 1 end else sltb := slDb.GetTable('SELECT * FROM SectionTable WHERE CompetitionID='+EdtCompID.Text); try EdtSectionID.Text:=sltb.FieldAsString(sltb.FieldIndex['SectionID']); EdtSectCompetitionID.Text:=sltb.FieldAsString(sltb.FieldIndex['CompetitionID']); Case sltb.FieldAsInteger(sltb.FieldIndex['Type']) of 1 : CmbType.ItemIndex:=0; 2 : CmbType.ItemIndex:=0; 3 : CmbType.ItemIndex:=1; 4 : CmbType.ItemIndex:=1; end; Case sltb.FieldAsInteger(sltb.FieldIndex['Gender']) of 1 : CmbGender.ItemIndex:=0; 2 : CmbGender.ItemIndex:=1; 3 : CmbGender.ItemIndex:=2; end; sTemp := sltb.FieldAsString(sltb.FieldIndex['Age']); if sTemp <> '' then begin //Decode end else begin LblAgeRule.Hide; EdtLowerAge.Text :=''; EdtLowerAge.Hide; EdtUpperAge.Text :=''; EdtUpperAge.Hide; end; sTemp := sltb.FieldAsString(sltb.FieldIndex['Level']); if sTemp <> '' then begin //Decode end else begin LblLevelRule.Hide; Edit1.Text :=''; Edit1.Hide; EdtUpperLevel.Text :=''; EdtUpperLevel.Hide; end; sTemp := sltb.FieldAsString(sltb.FieldIndex['Weight']); if sTemp <> '' then begin //Decode end else begin LblWeightRule.Hide; EdtLowerWeight.Text :=''; EdtLowerWeight.Hide; EdtUpperWeight.Text :=''; EdtUpperWeight.Hide; end; sTemp := sltb.FieldAsString(sltb.FieldIndex['Height']); if sTemp <> '' then begin //Decode end else begin LblHeightRule.Hide; EdtLowerHeight.Text :=''; EdtLowerHeight.Hide; EdtUpperHeight.Text :=''; EdtUpperHeight.Hide; end; finally sltb.Free; end; finally sldb.Free; end; end; procedure TDefinitionFrm.BtnCompetitionAddClick(Sender: TObject); begin AddComp end; procedure TDefinitionFrm.ClearSect; begin CmbSectSele.Clear; EdtSectionID.Text:=''; EdtSectCompetitionID.Text:=''; CmbType.Clear; CmbGender.Clear; CmbAgeRange.Clear; EdtLowerAge.Text:=''; EdtUpperAge.Text:=''; CmbLevelRange.Clear; Edit1.Text:=''; EdtUpperLevel.Text:=''; CmbWeightRange.Clear; EdtLowerWeight.Text:=''; EdtUpperWeight.Text:=''; CmbHeightRange.Clear; EdtLowerHeight.Text:=''; EdtUpperHeight.Text:=''; end; procedure TDefinitionFrm.CmbCompSeleChange(Sender: TObject); begin If CmbCompSele.ItemIndex <> -1 then begin RevertComp; GrpSection.Enabled:=True; CmbSectSele.Clear; ClearSect; UpdateCmbSectSele; end; end; procedure TDefinitionFrm.BtnCompetitionUpdateClick(Sender: TObject); var slDBpath: string; sSQL : string; sldb : TSQLiteDatabase; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try sSQL:= 'UPDATE CompetitionTable SET Description="'+EdtCompDesc.Text+'",Location="'+EdtCompLoca.Text+'",Notes="'+EdtCompNote.Text+'" WHERE CompetitionID ="'+EdtCompID.Text+'";'; sldb.ExecSQL(sSQL); finally sldb.Free; end; end; procedure TDefinitionFrm.BtnCompetitionRevertClick(Sender: TObject); begin RevertComp; end; procedure TDefinitionFrm.BtnCompetitionDeleteClick(Sender: TObject); var slDBpath: string; sSQL : string; sldb : TSQLiteDatabase; iID : integer; begin If CmbCompSele.Text <> '' then begin If (CmbCompSele.Text[1] ='1') and (CmbCompSele.Text[2] =':') then begin MessageDlg('Deleting the last record is a very bad idea :/',mtInformation,[mbOK],0); end else begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try iID := StrToInt(Copy(CmbCompSele.Text,0,Pos(':',CmbCompSele.Text)-1)); sSQL:= 'DELETE FROM SectionTable WHERE CompetitionID='+IntToStr(iID)+';'; sldb.ExecSQL(sSQL); sSQL:= 'DELETE FROM CompetitionTable WHERE CompetitionID='+IntToStr(iID)+';'; sldb.ExecSQL(sSQL); finally sldb.Free; end; CmbCompSele.ItemIndex:=0; UpdateCmbCompSele; RevertComp; CmbCompSele.Text:='Select Competition'; end; end; end; procedure TDefinitionFrm.FormCreate(Sender: TObject); begin UpdateCmbCompSele; end; procedure TDefinitionFrm.CmbSectSeleChange(Sender: TObject); begin RevertSect; end; procedure TDefinitionFrm.BtnSectionAddClick(Sender: TObject); begin AddSect; end; procedure TDefinitionFrm.BtnSectionUpdateClick(Sender: TObject); //change fields values var slDBpath: string; sSQL : string; sldb : TSQLiteDatabase; iTypeCode : integer; iGenderCode : integer; sAgeStr, sLevelStr, sWeightStr, sHeightStr : string; begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try If CmbType.Text='Fighting' then iTypeCode := 1 else iTypeCode := 3; If CmbGender.Text='Male' then iGenderCode := 1 else if CmbGender.Text='Female' then iGenderCode := 2 else iGenderCode := 3; Case CmbAgeRange.ItemIndex of 0:sAgeStr := 'o-'+EdtLowerAge.Text; 1:sAgeStr := 'u-'+EdtLowerAge.Text; 2:sAgeStr := EdtLowerAge.Text+'-'+EdtUpperAge.Text; end; Case CmbLevelRange.ItemIndex of 0:sLevelStr := 'o-'+Edit1.Text; 1:sLevelStr := 'u-'+Edit1.Text; 2:sLevelStr := Edit1.Text+'-'+EdtUpperLevel.Text; end; Case CmbWeightRange.ItemIndex of 0:sWeightStr := 'o-'+EdtLowerWeight.Text; 1:sWeightStr := 'u-'+EdtLowerWeight.Text; 2:sWeightStr := EdtLowerWeight.Text+'-'+EdtUpperWeight.Text; end; Case CmbHeightRange.ItemIndex of 0:sHeightStr := 'o-'+EdtLowerHeight.Text; 1:sHeightStr := 'u-'+EdtLowerHeight.Text; 2:sHeightStr := EdtLowerHeight.Text+'-'+EdtUpperHeight.Text; end; sSQL:= 'UPDATE SectionTable SET Type="'+IntToStr(iTypeCode)+'",Gender="'+IntToStr(iGenderCode)+'" WHERE SectionID ="'+EdtSectionID.Text+'";'; sldb.ExecSQL(sSQL); finally sldb.Free; end; end; procedure TDefinitionFrm.BtnSectionRevertClick(Sender: TObject); begin RevertSect; end; procedure TDefinitionFrm.BtnSectionDeleteClick(Sender: TObject); var slDBpath: string; sSQL : string; sldb : TSQLiteDatabase; begin If CmbSectSele.Text[1] ='1' then begin MessageDlg('Deleting the last record is a very bad idea :/',mtInformation,[mbOK],0); end else begin slDBPath := ExtractFilepath(application.exename)+ 'Competitions.db'; if not FileExists(slDBPath) then begin MessageDlg('Competitions.db does not exist.',mtInformation,[mbOK],0); exit; end; sldb := TSQLiteDatabase.Create(slDBPath); try sSQL:= 'DELETE FROM SectionTable WHERE SectionID='+CmbSectSele.Text[1]+';'; sldb.ExecSQL(sSQL); finally sldb.Free; end; CmbSectSele.ItemIndex:=0; UpdateCmbSectSele; RevertSect; CmbSectSele.Text:='Select Competition'; end; end; procedure TDefinitionFrm.CmbAgeRangeChange(Sender: TObject); begin Case CmbAgeRange.ItemIndex of 0: begin EdtLowerAge.Show; LblAgeRule.Caption:='Over and including'; LblAgeRule.Show; EdtUpperAge.Hide; end; 1: begin EdtLowerAge.Show; LblAgeRule.Caption:='Under and including'; LblAgeRule.Show; EdtUpperAge.Hide; end; 2: begin EdtLowerAge.Show; LblAgeRule.Caption:='LblAgeRule'; LblAgeRule.Hide; EdtUpperAge.Show; end; end; end; procedure TDefinitionFrm.CmbLevelRangeChange(Sender: TObject); begin Case CmbLevelRange.ItemIndex of 0: begin Edit1.Show; LblLevelRule.Caption:='Over and including'; LblLevelRule.Show; EdtUpperLevel.Hide; end; 1: begin Edit1.Show; LblLevelRule.Caption:='Under and including'; LblLevelRule.Show; EdtUpperLevel.Hide; end; 2: begin Edit1.Show; LblLevelRule.Caption:='LblLevelRule'; LblLevelRule.Hide; EdtUpperLevel.Show; end; end; end; procedure TDefinitionFrm.CmbWeightRangeChange(Sender: TObject); begin Case CmbWeightRange.ItemIndex of 0: begin EdtLowerWeight.Show; LblWeightRule.Caption:='Over and including'; LblWeightRule.Show; EdtUpperWeight.Hide; end; 1: begin EdtLowerWeight.Show; LblWeightRule.Caption:='Under and including'; LblWeightRule.Show; EdtUpperWeight.Hide; end; 2: begin EdtLowerWeight.Show; LblWeightRule.Caption:='LblWeightRule'; LblWeightRule.Hide; EdtUpperWeight.Show; end; end; end; procedure TDefinitionFrm.CmbHeightRangeChange(Sender: TObject); begin Case CmbHeightRange.ItemIndex of 0: begin EdtLowerHeight.Show; LblHeightRule.Caption:='Over and including'; LblHeightRule.Show; EdtUpperHeight.Hide; end; 1: begin EdtLowerHeight.Show; LblHeightRule.Caption:='Under and including'; LblHeightRule.Show; EdtUpperHeight.Hide; end; 2: begin EdtLowerHeight.Show; LblHeightRule.Caption:='LblHeightRule'; LblHeightRule.Hide; EdtUpperHeight.Show; end; end; end; end.

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• Is there any fundamental difference between piping in mac and linux?

  - by Mohammad Moghimi

  ps -e | grep bash sample output from a linux machine: 1128 pts/14 00:00:00 bash 7491 pts/7 00:00:00 bash 12651 pts/14 00:00:00 bash 16145 pts/2 00:00:00 bash sample output from a mac machine: 58352 ttys000 0:00.09 login -pfl username /bin/bash -c exec -la bash /bin/bash 58353 ttys000 0:00.02 -bash 58390 ttys000 0:00.00 grep bash 20372 ttys005 0:00.06 login -pfl username /bin/bash -c exec -la bash /bin/bash 20373 ttys005 0:00.18 -bash My question is that why we see "grep bash" in the second case but not the first case.

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• How important are PTR records for Email Servers?

  - by Kyle Brandt

  Does anyone know of any studies done to show how much email will be rejected if there is not ptr record for the SMTP banner name of an email server? Are reverse checks always done when enabled, or is it sometimes configured so if an spam program considers an email 'iffy', the reverse check is done?

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• Windows 7 Group Policy to display message for login tries left before account lock

  - by Vivek

  My requirement is to display the the remaining count left on the login screen when user trying to login using Windows 7 OS before account lock in case user enter invalid password. I am having Active Directory on Windows 2008 R2 server. I set the maximum Lockout count = 5 in GPO policy. Example: If user try login first 1 attempt is failed, next time enter password and login shold show message for remaining attemps left.( my case count 4 left) Please let me know as this is urgent for me.

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• Difference ProxyPass and RewriteRule

  - by Wesho

  I just came across a case where ProxyPass (ProxyPassMatch to be exact) is being used in an Apache configuration file. This mod_proxy rule is being used to proxy from a whole cluster to one specific server, when a certain file is requested which only resides on that server. Now I'm a bit confused since I can't grasp why something like this cannot be achieved using a RewriteRule. So in essence I want to ask: What is the difference between ProxyPassMatch and a RewriteRule in this case?

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• CSMA/CD and CSMA/CA

  - by Zia ur Rahman

  CSMA/CD is used in wired LANs, CSMA means that the computers on the network sense the medium if the medium is idle, the computer transmits otherwise it defers sending.CD refers to collision detection. I don’t want to write about CD because its not related to my Question. Now in case of wireless LANs we use CSMA/CA , here CSMA refers to carrier sensing , the Question is how carrier sensing is done in case of wireless LANs? the collision avoidance is done by sending the control message to the intended receipient.

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• Do I have to 'remove' and 're-attach' Magic Mouse when switching between Snow Leopard and Windows 7?

  - by Teerasej

  I am deciding to buy an Apple Magic Mouse but I am wondering about the method which I have to use with Apple's Mighty Mouse: CASE 1: If I am using OS X and switching to Windows 7: Remove Mighty mouse from Bluetooth device Reboot in Windows 7 Add Mighty mouse as new Bluetooth device in Windows 7 CASE 2: If I need to switch back to OS X: Remove Mighty Mouse from Windows' Bluetooth device list Reboot in OS X Add Mighty mouse as new Bluetooth device in OS X Do I still need to proceed in this way with the Magic Mouse or not?

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• after installing monit when i do monit status myproc i get "error connecting to the monit daemon"

  - by Jason

  after installing monit when i do monit status myproc i get "error connecting to the monit daemon" I read somewhere that The status command won't work in the case that monit is running indaemon mode without its http support - the command 'monit status' in such case tries to get the status from the daemon via http/tcp. To start the http interface you need to add the 'set httpd ...' statement to theconfiguration. is that still correct? that post was from 2005

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• Price drop patterns

  - by doug

  I'm looking to buy a new laptop, and i don't need the top hi-tech because I'll use it for office type applications. In this case, the CPU and RAM are those who are mostly used. For example Intel i3 CPU was launched in Jan 2010 and in this case, the prices for Core Duo technology will drop. Do you know when or which are the signs? Can we talk about such a pattern?

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