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  • What is the easiest and fastest way to display an SDL_Surface in a window with SDL2?

    - by Semmu
    I would like to have an SDL_Surface representing the contents of the window, just like in the old days with SDL1.2. What is the best and fastest way to do it in SDL2? What I found is that I need an SDL_Window, an SDL_Renderer for that window, an SDL_Texture to render, and an SDL_Surface to create a texture from. This seems a bit too much to me, since I just want to display a single image on the screen. Not to mention the impact on the performance. On my machine (Lenovo Y510p laptop) this whole procedure takes 9ms, without any memory allocation, only using pre-allocated variables and totally black SDL_Surface. Is there a way I could speed up things?

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  • j2me sprite array

    - by danis
    I`ve tried to put the same Image into an array (array contains 22 Images) to form inventory. for(int i=0;i>22;i++){ invSprite[i] = new Sprite(ingame); invSprite[i].defineReferencePixel(0,0); } and if(inventory){ for(int i=0;i>22;i++){ if(i>=11){ invSprite[i].setRefPixelPosition(0+15*i, 27); }else{ invSprite[i].setRefPixelPosition(0+15*i, 42); } invSprite[i].paint(g); } } If the inventory is on it will show those Images but it`s not. PS if I would try invSprite[0].setRefPixelPosition(10, 27); invSprite[0].paint(g); it would throw an java/lang/NullPointerException

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  • How would I go about updating my electronic circuit simulator's 'electricity'?

    - by liqwidice
    I have made an application which allows the user to place down wires, power sources, and inverters on a virtual circuit board. All connections between tiles are automatic, as shown here: As you can see in the last image, the updating of power throughout this grid is not yet functioning. I think I understand how to do this updating conceptually, but getting it to work in my program is appearing to be much more difficult than I first imagined. My source code can be found here. If you have any tips as to how to I might approach this monstrous task, please let me know. EDIT The goal here is to simply get a working application. Getting tiles to pass on power to their neighbors is quite easy, but the tricky part is getting wires to "unpower" after the removal of a power source. The size of the grid is just 18x18, so efficiency really isn't a factor, for those wondering.

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  • Dual booting Windows 7 and Ubuntu 12.10 on UEFI laptop

    - by fccoelho
    I have a notebook pre-installed with Windows7 and I installed Ubuntu 12.10 on it following the standard installation steps in the installation image. The only problem is that on reboot the machine continues to boot Windows ignoring the presence of Ubuntu (Grub never comes up). My partition scheme is this sda1: NTFS 612MB sda2: NTFS 50GB (after resizing during Ubuntu installation. This is the main windows partition) sda4: extended sda5: ext4 /boot sda6: btrfs / I have tried Boot-repair and it didn't help. Tried rEFInd boot manager but it doesn't support NTFS partitions. I don't know what else to try. My next attempt is to try to install GRUB by hand to the MBR. Any other Ideas?

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  • Relationship between databases [closed]

    - by user1525474
    Hi I am getting ready to create my first web aplication.I have some knowledge of databases but I have never used databases with relationship created beetween them and also I am not sure how to acces the data in the relationship.My experience is limited to basic CRUD applications and working on simple tables with no realtionship using PHP and MySql. For example I will be creating a login system and for each user I would like to create a profile page that store different data(name , address , profile image etc.).Some of the info will be the same in both tables so there is no point in creating the same table twice. What I would like is if anyone can tell of some tutorials so I can better understand the concept?

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  • how to split data using mysql [closed]

    - by user75238
    I want to display images on left side and right side on my website. For example in this code I have 8 images and I want to split them 4 on the left side and 4 on the right side. In between them I want to put text. How can I do this? $display_image2=mysql_query("select id_topic,topic_title,image2 from topics where image2 not like '' order by id_topic desc limit 8")or die (mysql_error()); This is an image clarify what I want to do: http://oi50.tinypic.com/wsok1t.jpg

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  • How can I center XHTML content with CSS?

    - by drea
    so I recently converted a website of mine from a table content format to a div content format. Table format Version: Table version of the website: here. Table version style CSS: body { width: 1020px; margin: 0 auto; background-image: url(images/bg.png); } .logo{ width:301px; height:151px; background:url(images/logo.png); text-indent:-9999px; border:none; cursor:pointer; } .logo:hover { opacity:0.9; } .signin{ width:69px; height:30px; background:url(images/signin.png); text-indent:-9999px; border:none; cursor:pointer; } .signin:hover { opacity:0.9; } .register{ width:79px; height:30px; background:url(images/register.png); text-indent:-9999px; border:none; cursor:pointer; } .register:hover { opacity:0.9; } .Contact_Us{ width:53px; height:9px; background:url(images/Contact_Us.png); text-indent:-9999px; border:none; cursor:pointer; } .Contact_Us:hover { opacity:0.9; } .Code_of_Conduct{ width:84px; height:9px; background:url(images/Code_of_Conduct.png); text-indent:-9999px; border:none; cursor:pointer; } .Code_of_Conduct:hover { opacity:0.9; } .Privacy_Policy{ width:65px; height:12px; background:url(images/Privacy_Policy.png); text-indent:-9999px; border:none; cursor:pointer; } .Privacy_Policy:hover { opacity:0.9; } .Copyright{ width:149px; height:9px; background:url(images/Copyright.png); text-indent:-9999px; border:none; cursor:pointer; } .Copyright:hover { opacity:0.9; } .slideshow{ width:301px; height:151px; background: url(slideshow.png), url(minecraft.png), url(tf2.png), url(CSS.png), url(GM.png), url(aos.png), url(CSGO.png), url(voip.png), text-indent:-9999px; border:none; cursor:pointer; } .slideshow:hover { opacity:0.9; } Table version source: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head profile="http://www.w3.org/2005/10/profile"> <link rel="icon" type="image/png" href="http://www.xodusen.com/resources/images/favicon.png"> <title>Welcome to XodusEN</title> <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script> <script type="text/javascript" src="http://cloud.github.com/downloads/malsup/cycle/jquery.cycle.all.latest.js"></script> <script type="text/javascript"> $(document).ready(function() { $('.slideshow').cycle({ fx: 'fade' // choose your transition type, ex: fade, scrollUp, shuffle, etc... }); }); </script> <meta name="description" content="This is the homepage of XodusEN. Xodus Entertainment Network is a unique & friendly Gaming Community that welcomes & realises the potential, and value within any user regardless of their origin. " > <meta name="keywords" content="XeN, Xodus, XEN, xen, Xodus Entertainment Network, gaming, community, PC, Steam, XBL, Xbox 360, PSN, Playstation, games, Gaming, Community, XodusEN, Gaming Network, Network, TF2, Server, CS:S, Minecraft, premium, servers, Counter-Strike: Source, Website, Homepage, Minecraftia" > <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <link href="style.css" rel="stylesheet" type="text/css"> <!--[if IE]> <script type="text/javascript"> window.location = "http://www.xodusen.com/ie/"; </script> <![endif]--> </head> <body bgcolor="#d7d7d7"> <table id="Table_01" border="0" cellpadding="0" cellspacing="0"> <tr> <td colspan="18"> <img src="images/index_01.png" width="1020" height="9" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="9" alt=""></td> </tr> <tr> <td colspan="11" rowspan="2"> <img src="images/index_02.png" width="826" height="252" alt=""></td> <td> <a id="signin" class="signin" href="http://s.xodusen.com/VrtqYm"> <img src="images/signin.png" width="69" height="30" border="0" alt=""></a> <td rowspan="6"> <img src="images/index_04.png" width="3" height="643" alt=""></td> <td colspan="3"> <a id="register" class="register" href="http://s.xodusen.com/WW3rpZ"> <img src="images/Register.png" width="79" height="30" border="0" alt=""></a> <td colspan="2" rowspan="6"> <img src="images/index_06.png" width="43" height="643" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="30" alt=""></td> </tr> <tr> <td rowspan="5"> <img src="images/index_07.png" width="69" height="613" alt=""></td> <td colspan="3" rowspan="5"> <img src="images/index_08.png" width="79" height="613" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="222" alt=""></td> </tr> <tr> <td colspan="5"> <img src="images/index_09.png" width="385" height="53" alt=""></td> <td> <img src="images/index_10.png" width="250" height="53" alt=""></td> <td colspan="5"> <img src="images/index_11.png" width="191" height="53" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="53" alt=""></td> </tr> <tr> <td colspan="4" rowspan="3"> <img src="images/index_09-13.png" width="360" height="338" alt=""></td> <td colspan="3"> <a id="logo" class="logo" href="http://www.xodusen.com/community"> <img src="images/logo.png" alt=""></a> </td> <td colspan="4" rowspan="3"> <img src="images/index_11-15.png" width="165" height="338" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="151" alt=""></td> </tr> <tr> <td rowspan="2"> <img src="images/index_09-16.png" width="25" height="187" alt=""></td> <td> <img src="images/index_16.png" width="250" height="46" alt=""></td> <td rowspan="2"> <img src="images/index_11-18.png" width="26" height="187" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="46" alt=""></td> </tr> <tr> <td> <img src="images/index_12.png" width="250" height="141" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="141" alt=""></td> </tr> <tr> <td rowspan="7"> <img src="images/index_13.png" width="27" height="548" alt=""></td> <td colspan="16" id="slideshow" class="slideshow"> <a href="http://www.xodusen.com/community"><img src="images/slideshow.png" width="960" height="305" alt=""></a> <a href="http://www.xodusen.com/mcurl"><img src="images/minecraft.png" width="960" height="305" alt=""></a> <a href="steam://connect/74.121.188.194:27015"><img src="images/tf2.png" width="960" height="305" alt=""></a> <a href="steam://connect/74.121.188.195:27015"><img src="images/CSS.png" width="960" height="305" alt=""></a> <a href="steam://connect/74.121.188.197:27015"><img src="images/GM.png" width="960" height="305" alt=""></a> <a href="aos://3267131722:32887"><img src="images/aos.png" width="960" height="305" alt=""></a> <a href="steam://connect/74.121.188.196:27015"><img src="images/CSGO.png" width="960" height="305" alt=""></a></td> <td rowspan="7"> <img src="images/index_15.png" width="33" height="548" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="305" alt=""></td> </tr> <tr> <td colspan="16"> <img src="images/index_16-23.png" width="960" height="155" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="155" alt=""></td> </tr> <tr> <td rowspan="5"> <img src="images/index_17.png" width="38" height="88" alt=""></td> <td rowspan="2"> <a id="Copyright" class="Copyright" href="http://www.xodusen.com/community"> <img src="images/Copyright.png" width="149" height="9" border="0" alt=""></a></td> <td colspan="14"> <img src="images/index_25.png" width="773" height="5" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="5" alt=""></td> </tr> <tr> <td colspan="5" rowspan="4"> <img src="images/index_20.png" width="527" height="83" alt=""></td> <td rowspan="3"> <a id="Privacy_Policy" class="Privacy_Policy" href="http://s.xodusen.com/VhGEkH"> <img src="images/Privacy_Policy.png" width="65" height="12" border="0" alt=""></a></td> <td rowspan="4"> <img src="images/index_28.png" width="8" height="83" alt=""></td> <td colspan="3" rowspan="2"> <a id="Code_of_Conduct" class="Code_of_Conduct" href="http://s.xodusen.com/Tf5Gz7"> <img src="images/Code_of_Conduct.png" width="84" height="9" border="0" alt=""></a></td> <td rowspan="4"> <img src="images/index_30.png" width="6" height="83" alt=""></td> <td rowspan="2"> <a id="Contact_Us" class="Contact_Us" href="http://s.xodusen.com/T5EYsG"> <img src="images/Contact_Us.png" width="53" height="9" border="0" alt=""></a></td> <td colspan="2" rowspan="4"> <img src="images/index_26.png" width="30" height="83" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="4" alt=""></td> </tr> <tr> <td rowspan="3"> <img src="images/index_27.png" width="149" height="79" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="5" alt=""></td> </tr> <tr> <td colspan="3" rowspan="2"> <img src="images/index_28-35.png" width="84" height="74" alt=""></td> <td rowspan="2"> <img src="images/index_29.png" width="53" height="74" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="3" alt=""></td> </tr> <tr> <td> <img src="images/index_30-37.png" width="65" height="71" alt=""></td> <td> <img src="images/spacer.gif" width="1" height="71" alt=""></td> </tr> <tr> <td> <img src="images/spacer.gif" width="27" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="38" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="149" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="146" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="25" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="250" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="26" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="80" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="65" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="8" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="12" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="69" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="3" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="6" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="53" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="20" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="10" height="1" alt=""></td> <td> <img src="images/spacer.gif" width="33" height="1" alt=""></td> <td></td> </tr> </table> </body> </html> Div format Version: Div version of the website: here. Div version style CSS: body { width: 1020px; margin: 0 auto; background-image: url(images/bg.png); } #Table_01 { position:absolute; left:0px; top:0px; width:1020px; height:1200px; } #index-01_ { position:absolute; left:0px; top:0px; width:1020px; height:9px; } #index-02_ { position:absolute; left:0px; top:9px; width:826px; height:305px; } #Signin_ { position:absolute; left:826px; top:9px; width:69px; height:30px; } #index-04_ { position:absolute; left:895px; top:9px; width:3px; height:643px; } #Register_ { position:absolute; left:898px; top:9px; width:79px; height:30px; } #index-06_ { position:absolute; left:977px; top:9px; width:43px; height:643px; } #index-07_ { position:absolute; left:826px; top:39px; width:69px; height:613px; } #index-08_ { position:absolute; left:898px; top:39px; width:79px; height:613px; } #index-09_ { position:absolute; left:0px; top:314px; width:360px; height:338px; } #Logo_ { position:absolute; left:360px; top:314px; width:301px; height:151px; } #index-11_ { position:absolute; left:661px; top:314px; width:165px; height:338px; } #index-12_ { position:absolute; left:360px; top:465px; width:301px; height:187px; } #index-13_ { position:absolute; left:0px; top:652px; width:27px; height:548px; } #Slideshow_ { position:absolute; left:27px; top:652px; width:960px; height:305px; } #index-15_ { position:absolute; left:987px; top:652px; width:33px; height:548px; } #index-16_ { position:absolute; left:27px; top:957px; width:960px; height:155px; } #index-17_ { position:absolute; left:27px; top:1112px; width:39px; height:88px; } #Copyright_ { position:absolute; left:66px; top:1112px; width:148px; height:13px; } #index-19_ { position:absolute; left:214px; top:1112px; width:773px; height:5px; } #index-20_ { position:absolute; left:214px; top:1117px; width:526px; height:83px; } #Privacy-Policy_ { position:absolute; left:740px; top:1117px; width:68px; height:23px; } #index-22_ { position:absolute; left:808px; top:1117px; width:6px; height:83px; } #Code-of-Conduct_ { position:absolute; left:814px; top:1117px; width:84px; height:23px; } #index-24_ { position:absolute; left:898px; top:1117px; width:2px; height:83px; } #Contact-Us_ { position:absolute; left:900px; top:1117px; width:57px; height:23px; } #index-26_ { position:absolute; left:957px; top:1117px; width:30px; height:83px; } #index-27_ { position:absolute; left:66px; top:1125px; width:148px; height:75px; } #index-28_ { position:absolute; left:740px; top:1140px; width:68px; height:60px; } #index-29_ { position:absolute; left:814px; top:1140px; width:84px; height:60px; } #index-30_ { position:absolute; left:900px; top:1140px; width:57px; height:60px; } .logo{ width:301px; height:151px; background:url(images/logo.png); text-indent:-9999px; border:none; cursor:pointer; } .logo:hover { opacity:0.9; } .signin{ width:69px; height:30px; background:url(images/signin.png); text-indent:-9999px; border:none; cursor:pointer; } .signin:hover { opacity:0.9; } .register{ width:79px; height:30px; background:url(images/register.png); text-indent:-9999px; border:none; cursor:pointer; } .register:hover { opacity:0.9; } .contact_Us{ width:53px; height:9px; background:url(images/Contact_Us.png); text-indent:-9999px; border:none; cursor:pointer; } .contact_Us:hover { opacity:0.9; } .code_of_Conduct{ width:84px; height:9px; background:url(images/Code_of_Conduct.png); text-indent:-9999px; border:none; cursor:pointer; } .code_of_Conduct:hover { opacity:0.9; } .privacy_policy{ width:65px; height:12px; background:url(images/Privacy_Policy.png); text-indent:-9999px; border:none; cursor:pointer; } .privacy_policy:hover { opacity:0.9; } .copyright{ width:148px; height:13px; background:url(images/Copyright.png); text-indent:-9999px; border:none; cursor:pointer; } .copyright:hover { opacity:0.9; } .slideshow{ width:301px; height:151px; background: url(slideshow.png), url(minecraft.png), url(tf2.png), url(CSS.png), url(GM.png), url(aos.png), url(CSGO.png), url(voip.png), text-indent:-9999px; border:none; cursor:pointer; } .slideshow:hover { opacity:0.9; } Div version source: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <script type="text/javascript"> //<![CDATA[ window.__CF=window.__CF||{};window.__CF.AJS={"vig_key":{"sid":"c6d1454039dd49b1c8400bbfdf74df7a"},"trumpet":{"message":"XodusEN is undergoing background maintenance, that will provide performance & graphical improvements to our system, but will not hinder your experience across our services."},"ga_key":{"ua":"UA-35779435-1","ga_bs":"2"},"exprmntly":{"service_id":"7967"},"cdnjs":{"__h":"1","cdnjs":"MO,GF,FX,CS,JS"},"abetterbrowser":{"ie":"10"}}; //]]> </script> <script type="text/javascript"> //<![CDATA[ try{if (!window.CloudFlare) { var CloudFlare=[{verbose:0,p:0,byc:0,owlid:"cf",mirage:{responsive:0,lazy:0},oracle:0,paths:{cloudflare:"/cdn-cgi/nexp/aav=1870252173/"},atok:"d6e39f49946fcb6d690f0d10d5a963f3",zone:"xodusen.com",rocket:"a",apps:{"vig_key":{"sid":"c6d1454039dd49b1c8400bbfdf74df7a"},"trumpet":{"message":"XodusEN is undergoing background maintenance, that will provide performance & graphical improvements to our system, but will not hinder your experience across our services."},"ga_key":{"ua":"UA-35779435-1","ga_bs":"2"},"exprmntly":{"service_id":"7967"},"cdnjs":{"__h":"1","cdnjs":"MO,GF,FX,CS,JS"},"abetterbrowser":{"ie":"10"}}}];document.write('<script type="text/javascript" src="//ajax.cloudflare.com/cdn-cgi/nexp/aav=4114775854/cloudflare.min.js"><'+'\/script>')}}catch(e){}; //]]> </script> <script type="text/javascript" src="//ajax.cloudflare.com/cdn-cgi/nexp/aav=1566821048/appsh.min.js"></script><script type="text/javascript">__CF.AJS.inith();</script><link rel="icon" type="image/png" href="http://www.xodusen.com/resources/images/favicon.png"> <title>Welcome to XodusEN</title> <meta name="description" content="This is the homepage of XodusEN. Xodus Entertainment Network is a unique & friendly Gaming Community that welcomes & realises the potential, and value within any user regardless of their origin. 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I have done some research to no avail, so I'd thought given the reputation of this site, that i'd post my issue here. Thank you in advance, ~ drea.

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  • Suggestions for duplicate file finder algorithm (using C)

    - by Andrei Ciobanu
    Hello, I wanted to write a program that test if two files are duplicates (have exactly the same content). First I test if the files have the same sizes, and if they have i start to compare their contents. My first idea, was to "split" the files into fixed size blocks, then start a thread for every block, fseek to startup character of every block and continue the comparisons in parallel. When a comparison from a thread fails, the other working threads are canceled, and the program exits out of the thread spawning loop. The code looks like this: dupf.h #ifndef __NM__DUPF__H__ #define __NM__DUPF__H__ #define NUM_THREADS 15 #define BLOCK_SIZE 8192 /* Thread argument structure */ struct thread_arg_s { const char *name_f1; /* First file name */ const char *name_f2; /* Second file name */ int cursor; /* Where to seek in the file */ }; typedef struct thread_arg_s thread_arg; /** * 'arg' is of type thread_arg. * Checks if the specified file blocks are * duplicates. */ void *check_block_dup(void *arg); /** * Checks if two files are duplicates */ int check_dup(const char *name_f1, const char *name_f2); /** * Returns a valid pointer to a file. * If the file (given by the path/name 'fname') cannot be opened * in 'mode', the program is interrupted an error message is shown. **/ FILE *safe_fopen(const char *name, const char *mode); #endif dupf.c #include <errno.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include "dupf.h" FILE *safe_fopen(const char *fname, const char *mode) { FILE *f = NULL; f = fopen(fname, mode); if (f == NULL) { char emsg[255]; sprintf(emsg, "FOPEN() %s\t", fname); perror(emsg); exit(-1); } return (f); } void *check_block_dup(void *arg) { const char *name_f1 = NULL, *name_f2 = NULL; /* File names */ FILE *f1 = NULL, *f2 = NULL; /* Streams */ int cursor = 0; /* Reading cursor */ char buff_f1[BLOCK_SIZE], buff_f2[BLOCK_SIZE]; /* Character buffers */ int rchars_1, rchars_2; /* Readed characters */ /* Initializing variables from 'arg' */ name_f1 = ((thread_arg*)arg)->name_f1; name_f2 = ((thread_arg*)arg)->name_f2; cursor = ((thread_arg*)arg)->cursor; /* Opening files */ f1 = safe_fopen(name_f1, "r"); f2 = safe_fopen(name_f2, "r"); /* Setup cursor in files */ fseek(f1, cursor, SEEK_SET); fseek(f2, cursor, SEEK_SET); /* Initialize buffers */ rchars_1 = fread(buff_f1, 1, BLOCK_SIZE, f1); rchars_2 = fread(buff_f2, 1, BLOCK_SIZE, f2); if (rchars_1 != rchars_2) { /* fread failed to read the same portion. * program cannot continue */ perror("ERROR WHEN READING BLOCK"); exit(-1); } while (rchars_1-->0) { if (buff_f1[rchars_1] != buff_f2[rchars_1]) { /* Different characters */ fclose(f1); fclose(f2); pthread_exit("notdup"); } } /* Close streams */ fclose(f1); fclose(f2); pthread_exit("dup"); } int check_dup(const char *name_f1, const char *name_f2) { int num_blocks = 0; /* Number of 'blocks' to check */ int num_tsp = 0; /* Number of threads spawns */ int tsp_iter = 0; /* Iterator for threads spawns */ pthread_t *tsp_threads = NULL; thread_arg *tsp_threads_args = NULL; int tsp_threads_iter = 0; int thread_c_res = 0; /* Thread creation result */ int thread_j_res = 0; /* Thread join res */ int loop_res = 0; /* Function result */ int cursor; struct stat buf_f1; struct stat buf_f2; if (name_f1 == NULL || name_f2 == NULL) { /* Invalid input parameters */ perror("INVALID FNAMES\t"); return (-1); } if (stat(name_f1, &buf_f1) != 0 || stat(name_f2, &buf_f2) != 0) { /* Stat fails */ char emsg[255]; sprintf(emsg, "STAT() ERROR: %s %s\t", name_f1, name_f2); perror(emsg); return (-1); } if (buf_f1.st_size != buf_f2.st_size) { /* File have different sizes */ return (1); } /* Files have the same size, function exec. is continued */ num_blocks = (buf_f1.st_size / BLOCK_SIZE) + 1; num_tsp = (num_blocks / NUM_THREADS) + 1; cursor = 0; for (tsp_iter = 0; tsp_iter < num_tsp; tsp_iter++) { loop_res = 0; /* Create threads array for this spawn */ tsp_threads = malloc(NUM_THREADS * sizeof(*tsp_threads)); if (tsp_threads == NULL) { perror("TSP_THREADS ALLOC FAILURE\t"); return (-1); } /* Create arguments for every thread in the current spawn */ tsp_threads_args = malloc(NUM_THREADS * sizeof(*tsp_threads_args)); if (tsp_threads_args == NULL) { perror("TSP THREADS ARGS ALLOCA FAILURE\t"); return (-1); } /* Initialize arguments and create threads */ for (tsp_threads_iter = 0; tsp_threads_iter < NUM_THREADS; tsp_threads_iter++) { if (cursor >= buf_f1.st_size) { break; } tsp_threads_args[tsp_threads_iter].name_f1 = name_f1; tsp_threads_args[tsp_threads_iter].name_f2 = name_f2; tsp_threads_args[tsp_threads_iter].cursor = cursor; thread_c_res = pthread_create( &tsp_threads[tsp_threads_iter], NULL, check_block_dup, (void*)&tsp_threads_args[tsp_threads_iter]); if (thread_c_res != 0) { perror("THREAD CREATION FAILURE"); return (-1); } cursor+=BLOCK_SIZE; } /* Join last threads and get their status */ while (tsp_threads_iter-->0) { void *thread_res = NULL; thread_j_res = pthread_join(tsp_threads[tsp_threads_iter], &thread_res); if (thread_j_res != 0) { perror("THREAD JOIN FAILURE"); return (-1); } if (strcmp((char*)thread_res, "notdup")==0) { loop_res++; /* Closing other threads and exiting by condition * from loop. */ while (tsp_threads_iter-->0) { pthread_cancel(tsp_threads[tsp_threads_iter]); } } } free(tsp_threads); free(tsp_threads_args); if (loop_res > 0) { break; } } return (loop_res > 0) ? 1 : 0; } The function works fine (at least for what I've tested). Still, some guys from #C (freenode) suggested that the solution is overly complicated, and it may perform poorly because of parallel reading on hddisk. What I want to know: Is the threaded approach flawed by default ? Is fseek() so slow ? Is there a way to somehow map the files to memory and then compare them ?

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  • Why should you choose Oracle WebLogic 12c instead of JBoss EAP 6?

    - by Ricardo Ferreira
    In this post, I will cover some technical differences between Oracle WebLogic 12c and JBoss EAP 6, which was released a couple days ago from Red Hat. This article claims to help you in the evaluation of key points that you should consider when choosing for an Java EE application server. In the following sections, I will present to you some important aspects that most customers ask us when they are seriously evaluating for an middleware infrastructure, specially if you are considering JBoss for some reason. I would suggest that you keep the following question in mind while you are reading the points: "Why should I choose JBoss instead of WebLogic?" 1) Multi Datacenter Deployment and Clustering - D/R ("Disaster & Recovery") architecture support is embedded on the WebLogic Server 12c product. JBoss EAP 6 on the other hand has no direct D/R support included, Red Hat relies on third-part tools with higher prices. When you consider a middleware solution to host your business critical application, you should worry with every architectural aspect that are related with the solution. Fail-over support is one little aspect of a truly reliable solution. If you do not worry about D/R, your solution will not be reliable. Having said that, with Red Hat and JBoss EAP 6, you have this extra cost that will increase considerably the total cost of ownership of the solution. As we commonly hear from analysts, open-source are not so cheaper when you start seeing the big picture. - WebLogic Server 12c supports advanced LAN clustering, detection of death servers and have a common alert framework. JBoss EAP 6 on the other hand has limited LAN clustering support with no server death detection. They do not generate any alerts when servers goes down (only if you buy JBoss ON which is a separated technology, but until now does not support JBoss EAP 6) and manual intervention are required when servers goes down. In most cases, admin people must rely on "kill -9", "tail -f someFile.log" and "ps ax | grep java" commands to manage failures and clustering anomalies. - WebLogic Server 12c supports the concept of Node Manager, which is a separated process that runs on the physical | virtual servers that allows extend the administration of the cluster to WebLogic managed servers that are often distributed across multiple machines and geographic locations. JBoss EAP 6 on the other hand has no equivalent technology. Whole server instances must be managed individually. - WebLogic Server 12c Node Manager supports Coherence to boost performance when managing servers. JBoss EAP 6 on the other hand has no similar technology. There is no way to coordinate JBoss and infiniband instances provided by JBoss using high throughput and low latency protocols like InfiniBand. The Node Manager feature also allows another very important feature that JBoss EAP lacks: secure the administration. When using WebLogic Node Manager, all the administration tasks are sent to the managed servers in a secure tunel protected by a certificate, which means that the transport layer that separates the WebLogic administration console from the managed servers are secured by SSL. - WebLogic Server 12c are now integrated with OTD ("Oracle Traffic Director") which is a web server technology derived from the former Sun iPlanet Web Server. This software complements the web server support offered by OHS ("Oracle HTTP Server"). Using OTD, WebLogic instances are load-balanced by a high powerful software that knows how to handle SDP ("Socket Direct Protocol") over InfiniBand, which boost performance when used with engineered systems technologies like Oracle Exalogic Elastic Cloud. JBoss EAP 6 on the other hand only offers support to Apache Web Server with custom modules created to deal with JBoss clusters, but only across standard TCP/IP networks.  2) Application and Runtime Diagnostics - WebLogic Server 12c have diagnostics capabilities embedded on the server called WLDF ("WebLogic Diagnostic Framework") so there is no need to rely on third-part tools. JBoss EAP 6 on the other hand has no diagnostics capabilities. Their only diagnostics tool is the log generated by the application server. Admin people are encouraged to analyse thousands of log lines to find out what is going on. - WebLogic Server 12c complement WLDF with JRockit MC ("Mission Control"), which provides to administrators and developers a complete insight about the JVM performance, behavior and possible bottlenecks. WebLogic Server 12c also have an classloader analysis tool embedded, and even a log analyzer tool that enables administrators and developers to view logs of multiple servers at the same time. JBoss EAP 6 on the other hand relies on third-part tools to do something similar. Again, only log searching are offered to find out whats going on. - WebLogic Server 12c offers end-to-end traceability and monitoring available through Oracle EM ("Enterprise Manager"), including monitoring of business transactions that flows through web servers, ESBs, application servers and database servers, all of this with high deep JVM analysis and diagnostics. JBoss EAP 6 on the other hand, even using JBoss ON ("Operations Network"), which is a separated technology, does not support those features. Red Hat relies on third-part tools to provide direct Oracle database traceability across JVMs. One of those tools are Oracle EM for non-Oracle middleware that manage JBoss, Tomcat, Websphere and IIS transparently. - WebLogic Server 12c with their JRockit support offers a tool called JRockit Flight Recorder, which can give developers a complete visibility of a certain period of application production monitoring with zero extra overhead. This automatic recording allows you to deep analyse threads latency, memory leaks, thread contention, resource utilization, stack overflow damages and GC ("Garbage Collection") cycles, to observe in real time stop-the-world phenomenons, generational, reference count and parallel collects and mutator threads analysis. JBoss EAP 6 don't even dream to support something similar, even because they don't have their own JVM. 3) Application Server Administration - WebLogic Server 12c offers a complete administration console complemented with scripting and macro-like recording capabilities. A single WebLogic console can managed up to hundreds of WebLogic servers belonging to the same domain. JBoss EAP 6 on the other hand has a limited console and provides a XML centric administration. JBoss, after ten years, started the development of a rudimentary centralized administration that still leave a lot of administration tasks aside, so admin people and developers must touch scripts and XML configuration files for most advanced and even simple administration tasks. This lead applications to error prone and risky deployments. Even using JBoss ON, JBoss EAP are not able to offer decent administration features for admin people which must be high skilled in JBoss internal architecture and its managing capabilities. - Oracle EM is available to manage multiple domains, databases, application servers, operating systems and virtualization, with a complete end-to-end visibility. JBoss ON does not provide management capabilities across the complete architecture, only basic monitoring. Even deployment must be done aside JBoss ON which does no integrate well with others softwares than JBoss. Until now, JBoss ON does not supports JBoss EAP 6, so even their minimal support for JBoss are not available for JBoss EAP 6 leaving customers uncovered and subject to high skilled JBoss admin people. - WebLogic Server 12c has the same administration model whatever is the topology selected by the customer. JBoss EAP 6 on the other hand differentiates between two operational models: standalone-mode and domain-mode, that are not consistent with each other. Depending on the mode used, the administration skill is different. - WebLogic Server 12c has no point-of-failures processes, and it does not need to define any specialized server. Domain model in WebLogic is available for years (at least ten years or more) and is production proven. JBoss EAP 6 on the other hand needs special processes to garantee JBoss integrity, the PC ("Process-Controller") and the HC ("Host-Controller"). Different from WebLogic, the domain model in JBoss is quite new (one year at tops) of maturity, and need to mature considerably until start doing things like WebLogic domain model does. - WebLogic Server 12c supports parallel deployment model which enables some artifacts being deployed at the same time. JBoss EAP 6 on the other hand does not have any similar feature. Every deployment are done atomically in the containers. This means that if you have a huge EAR (an EAR of 120 MB of size for instance) and deploy onto JBoss EAP 6, this EAR will take some minutes in order to starting accept thread requests. The same EAR deployed onto WebLogic Server 12c will reduce the deployment time at least in 2X compared to JBoss. 4) Support and Upgrades - WebLogic Server 12c has patch management available. JBoss EAP 6 on the other hand has no patch management available, each JBoss EAP instance should be patched manually. To achieve such feature, you need to buy a separated technology called JBoss ON ("Operations Network") that manage this type of stuff. But until now, JBoss ON does not support JBoss EAP 6 so, in practice, JBoss EAP 6 does not have this feature. - WebLogic Server 12c supports previuous WebLogic domains without any reconfiguration since its kernel is robust and mature since its creation in 1995. JBoss EAP 6 on the other hand has a proven lack of supportability between JBoss AS 4, 5, 6 and 7. Different kernels and messaging engines were implemented in JBoss stack in the last five years reveling their incapacity to create a well architected and proven middleware technology. - WebLogic Server 12c has patch prescription based on customer configuration. JBoss EAP 6 on the other hand has no such capability. People need to create ticket supports and have their installations revised by Red Hat support guys to gain some patch prescription from them. - Oracle WebLogic Server independent of the version has 8 years of support of new patches and has lifetime release of existing patches beyond that. JBoss EAP 6 on the other hand provides patches for a specific application server version up to 5 years after the release date. JBoss EAP 4 and previous versions had only 4 years. A good question that Red Hat will argue to answer is: "what happens when you find issues after year 5"?  5) RAC ("Real Application Clusters") Support - WebLogic Server 12c ships with a specific JDBC driver to leverage Oracle RAC clustering capabilities (Fast-Application-Notification, Transaction Affinity, Fast-Connection-Failover, etc). Oracle JDBC thin driver are also available. JBoss EAP 6 on the other hand ships only the standard Oracle JDBC thin driver. Load balancing with Oracle RAC are not supported. Manual intervention in case of planned or unplanned RAC downtime are necessary. In JBoss EAP 6, situation does not reestablish automatically after downtime. - WebLogic Server 12c has a feature called Active GridLink for Oracle RAC which provides up to 3X performance on OLTP applications. This seamless integration between WebLogic and Oracle database enable more value added to critical business applications leveraging their investments in Oracle database technology and Oracle middleware. JBoss EAP 6 on the other hand has no performance gains at all, even when admin people implement some kind of connection-pooling tuning. - WebLogic Server 12c also supports transaction and web session affinity to the Oracle RAC, which provides aditional gains of performance. This is particularly interesting if you are creating a reliable solution that are distributed not only in an LAN cluster, but into a different data center. JBoss EAP 6 on the other hand has no such support. 6) Standards and Technology Support - WebLogic Server 12c is fully Java EE 6 compatible and production ready since december of 2011. JBoss EAP 6 on the other hand became fully compatible with Java EE 6 only in the community version after three months, and production ready only in a few days considering that this article was written in June of 2012. Red Hat says that they are the masters of innovation and technology proliferation, but compared with Oracle and even other proprietary vendors like IBM, they historically speaking are lazy to deliver the most newest technologies and standards adherence. - Oracle is the steward of Java, driving innovation into the platform from commercial and open-source vendors. Red Hat on the other hand does not have its own JVM and relies on third-part JVMs to complete their application server offer. 95% of Red Hat customers are using Oracle HotSpot as JVM, which means that without Oracle involvement, their support are limited exclusively to the application server layer and we all know that most problems are happens in the JVM layer. - WebLogic Server 12c supports natively JDK 7, which empower developers to explore the maximum of the Java platform productivity when writing code. This feature differentiate WebLogic from others application servers (except GlassFish that are also managed by Oracle) because the usage of JDK 7 introduce such remarkable productivity features like the "try-with-resources" enhancement, catching multiple exceptions with one try block, Strings in the switch statements, JVM improvements in terms of JDBC, I/O, networking, security, concurrency and of course, the most important feature of Java 7: native support for multiple non-Java languages. More features regarding JDK 7 can be found here. JBoss EAP 6 on the other hand does not support JDK 7 officially, they comment in their community version that "Java SE 7 can be used with JBoss 7" which does not gives you any guarantees of enterprise support for JDK 7. - Oracle WebLogic Server 12c supports integration with Spring framework allowing Spring applications to use WebLogic special transaction manager, exposing bean interfaces to WebLogic MBeans to take advantage of all WebLogic monitoring and administration advantages. JBoss EAP 6 on the other hand has no special integration with Spring. In fact, Red Hat offers a suspicious package called "JBoss Web Platform" that in theory supports Spring, but in practice this package does not offers any special integration. It is just a facility for Red Hat customers to have support from both JBoss and Spring technology using the same customer support. 7) Lightweight Development - Oracle WebLogic Server 12c and Oracle GlassFish are completely integrated and can share applications without any modifications. Starting with the 12c version, WebLogic now understands natively GlassFish deployment descriptors and specific configurations in order to offer you a truly and reliable migration path from a community Java EE application server to a enterprise middleware product like WebLogic. JBoss EAP 6 on the other hand has no support to natively reuse an existing (or still in development) application from JBoss AS community server. Users of JBoss suffer of critical issues during deployment time that includes: changing the libraries and dependencies of the application, patching the DTD or XSD deployment descriptors, refactoring of the application layers due classloading issues and anomalies, rebuilding of persistence, business and web layers due issues with "usage of the certified version of an certain dependency" or "frameworks that Red Hat potentially does not recommend" etc. If you have the culture or enterprise IT directive of developing Java EE applications using community middleware to in a certain future, transition to enterprise (supported by a vendor) middleware, Oracle WebLogic plus Oracle GlassFish offers you a more sustainable solution. - WebLogic Server 12c has a very light ZIP distribution (less than 165 MB). JBoss EAP 6 ZIP size is around 130 MB, together with JBoss ON you have more 100 MB resulting in a higher download footprint. This is particularly interesting if you plan to use automated setup of application server instances (for example, to rapidly setup a development or staging environment) using Maven or Hudson. - WebLogic Server 12c has a complete integration with Maven allowing developers to setup WebLogic domains with few commands. Tasks like downloading WebLogic, installation, domain creation, data sources deployment are completely integrated. JBoss EAP 6 on the other hand has a limited offer integration with those tools.  - WebLogic Server 12c has a startup mode called WLX that turns-off EJB, JMS and JCA containers leaving enabled only the web container with Java EE 6 web profile. JBoss EAP 6 on the other hand has no such feature, you need to disable manually the containers that you do not want to use. - WebLogic Server 12c supports fastswap, which enables you to change classes without redeployment. This is particularly interesting if you are developing patches for the application that is already deployed and you do not want to redeploy the entire application. This is the same behavior that most application servers offers to JSP pages, but with WebLogic Server 12c, you have the same feature for Java classes in general. JBoss EAP 6 on the other hand has no such support. Even JBoss EAP 5 does not support this until now. 8) JMS and Messaging - WebLogic Server 12c has a proven and high scalable JMS implementation since its initial release in 1995. JBoss EAP 6 on the other hand has a still immature technology called HornetQ, which was introduced in JBoss EAP 5 replacing everything that was implemented in the previous versions. Red Hat loves to introduce new technologies across JBoss versions, playing around with customers and their investments. And when they are asked about why they have changed the implementation and caused such a mess, their answer is always: "the previous implementation was inadequate and not aligned with the community strategy so we are creating a new a improved one". This Red Hat practice leads to uncomfortable investments that in a near future (sometimes less than a year) will be affected in someway. - WebLogic Server 12c has troubleshooting and monitoring features included on the WebLogic console and WLDF. JBoss EAP 6 on the other hand has no direct monitoring on the console, activity is reflected only on the logs, no debug logs available in case of JMS issues. - WebLogic Server 12c has extremely good performance and scalability. JBoss EAP 6 on the other hand has a JMS storage mechanism relying on Oracle database or MySQL. This means that if an issue in production happens and Red Hat affirms that an performance issue is happening due to database problems, they will not support you on the performance issue. They will orient you to call Oracle instead. - WebLogic Server 12c supports messaging enterprise features like SAF ("Store and Forward"), Distributed Queues/Topics and Foreign JMS providers support that leverage JMS implementations without compromise developer code making things completely transparent. JBoss EAP 6 on the other hand do not even dream to support such features. 9) Caching and Grid - Coherence, which is the leading and most mature data grid technology from Oracle, is available since early 2000 and was integrated with WebLogic in 2009. Coherence and WebLogic clusters can be both managed from WebLogic administrative console. Even Node Manager supports Coherence. JBoss on the other hand discontinued JBoss Cache, which was their caching implementation just like they did with the messaging implementation (JBossMQ) which was a issue for long term customers. JBoss EAP 6 ships InfiniSpan version 1.0 which is immature and lack a proven record of successful cases and reliability. - WebLogic Server 12c has a feature called ActiveCache which uses Coherence to, without any code changes, replicate HTTP sessions from both WebLogic and other application servers like JBoss, Tomcat, Websphere, GlassFish and even Microsoft IIS. JBoss EAP 6 on the other hand does have such support and even when they do in the future, they probably will support only their own application server. - Coherence can be used to manage both L1 and L2 cache levels, providing support to Oracle TopLink and others JPA compliant implementations, even Hibernate. JBoss EAP 6 and Infinispan on the other hand supports only Hibernate. And most important of all: Infinispan does not have any successful case of L1 or L2 caching level support using Hibernate, which lead us to reflect about its viability. 10) Performance - WebLogic Server 12c is certified with Oracle Exalogic Elastic Cloud and can run unchanged applications at this engineered system. This approach can benefit customers from Exalogic optimization's of both kernel and JVM layers to boost performance in terms of 10X for web, OLTP, JMS and grid applications. JBoss EAP 6 on the other hand has no investment on engineered systems: customers do not have the choice to deploy on a Java ultra fast system if their project becomes relevant and performance issues are detected. - WebLogic Server 12c maintains a performance gain across each new release: starting on WebLogic 5.1, the overall performance gain has been close to 4X, which close to a 20% gain release by release. JBoss on the other hand does not provide SPECJAppServer or SPECJEnterprise performance benchmarks. Their so called "performance gains" remains hidden in their customer environments, which lead us to think if it is true or not since we will never get access to those environments. - WebLogic Server 12c has industry performance benchmarks with submissions across platforms and configurations leading SPECJ. Oracle WebLogic leads SPECJAppServer performance in multiple categories, fitting all customer topologies like: dual-node, single-node, multi-node and multi-node with RAC. JBoss... again, does not provide any SPECJAppServer performance benchmarks. - WebLogic Server 12c has a feature called work manager which allows your application to embrace new performance levels based on critical resource utilization of the CPUs usage. Work managers prioritizes work and allocates threads based on an execution model that takes into account administrator-defined parameters and actual run-time performance and throughput. JBoss EAP 6 on the other hand has no compared feature and probably they never will. Not supporting such feature like work managers, JBoss EAP 6 forces admin people and specially developers to uncover performance gains in a intrusive way, rewriting the code and doing performance refactorings. 11) Professional Services Support - WebLogic Server 12c and any other technology sold by Oracle give customers the possibility of hire OCS ("Oracle Consulting Services") to manage critical scenarios, deployment assistance of new applications, high skilled consultancy of architecture, best practices and people allocation together with customer teams. All OCS services are available without any restrictions, having the customer bought software from Oracle or just starting their implementation before any acquisition. JBoss EAP 6 or Red Hat to be more specifically, only offers professional services if you buy subscriptions from them. If you are developing a new critical application for your business and need the help of Red Hat for a serious issue or architecture decision, they will probably say: "OK... I can help you but after you buy subscriptions from me". Red Hat also does not allows their professional services consultants to manage environments that uses community based software. They will probably force you to first buy a subscription, download their "enterprise" version and them, optionally hire their consultants. - Oracle provides you our university to educate your team into our technologies, including of course specialized trainings of WebLogic application server. At any time and location, you can hire Oracle to train your team so you get trustful knowledge according to your specific needs. Certifications for the products are also available if your technical people desire to differentiate themselves as professionals. Red Hat on the other hand have a limited pool of resources to train your team in their technologies. Basically they are selling training and certification for RHEL ("Red Hat Enterprise Linux") but if you demand more specialized training in JBoss middleware, they will probably connect you to some "certified" partner localized training since they are apparently discontinuing their education center, at least here in Brazil. They were not able to reproduce their success with RHEL education to their middleware division since they need first sell the subscriptions to after gives you specialized training. And again, they only offer you specialized training based on their enterprise version (EAP in the case of JBoss) which means that the courses will be a quite outdated. There are reports of developers that took official training's from Red Hat at this year (2012) and in a certain JBoss advanced course, Red Hat supposedly covered JBossMQ as the messaging subsystem, and even the printed material provided was based on JBossMQ since the training was created for JBoss EAP 4.3. 12) Encouraging Transparency without Ulterior Motives - WebLogic Server 12c like any other software from Oracle can be downloaded any time from anywhere, you should only possess an OTN ("Oracle Technology Network") credential and you can download any enterprise software how many times you want. And is not some kind of "trial" version. It is the official binaries that will be running for ever in your data center. Oracle does not encourages the usage of "specific versions" of our software. The binaries you buy from Oracle are the same binaries anyone in the world could download and use for testing and personal education. JBoss EAP 6 on the other hand are not available for download unless you buy a subscription and get access to the Red Hat enterprise repositories. If you need to test, learn or just start creating your application using Red Hat's middleware software, you should download it from the community website. You are not allowed to download the enterprise version that, according to Red Hat are more secure, reliable and robust. But no one of us want to start the development of a software with an unsecured, unreliable and not scalable middleware right? So what you do? You are "invited" by Red Hat to buy subscriptions from them to get access to the "cool" version of the software. - WebLogic Server 12c prices are publicly available in the Oracle website. If you want to know right now how much WebLogic will cost to your organization, just click here and get access to our price list. In the case of WebLogic, check out the "US Oracle Technology Commercial Price List". Oracle also encourages you to get in touch with a sales representative to discuss discounts that would make possible the investment into our technology. But you are not required to do this, only if you are interested in buying our technology or maybe you want to discuss some discount scenarios. JBoss EAP 6 on the other hand does not have its cost publicly available in Red Hat's website or in any other media, at least is not so easy to get such information. The only link you will possibly find in their website is a "Contact a Sales Representative" link. This is not a very good relationship between an customer and an vendor. This is not an example of transparency, mainly when the software are sold as open. In this situations, customers expects to see the software prices publicly available, so they can have the chance to decide, based on the existing features of the software, if the cost is fair or not. Conclusion Oracle WebLogic is the most mature, secure, reliable and scalable Java EE application server of the market, and have a proven record of success around the globe to prove it's majority. Don't lose the chance to discover today how WebLogic could fit your needs and sustain your global IT middleware strategy, no matter if your strategy are completely based on the Cloud or not.

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  • value types in the vm

    - by john.rose
    value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases.  Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both.  We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types.  These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im,         /*Complex y:*/ double y_re, double y_im) {     /*Complex z = x.minus(y):*/     double z_re = x_re - y_re, z_im = x_im - y_im;     /*return z.abs():*/     return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable {     // immutable component structure:     public final double re, im;     private Complex(double re, double im) {         this.re = re; this.im = im;     }     // interoperability methods:     public String toString() { return "Complex("+re+","+im+")"; }     public List<Double> asList() { return Arrays.asList(re, im); }     public boolean equals(Complex c) {         return re == c.re && im == c.im;     }     public boolean equals(@ValueSafe Object x) {         return x instanceof Complex && equals((Complex) x);     }     public int hashCode() {         return 31*Double.valueOf(re).hashCode()                 + Double.valueOf(im).hashCode();     }     // factory methods:     public static Complex valueOf(double re, double im) {         return new Complex(re, im);     }     public Complex changeRe(double re2) { return valueOf(re2, im); }     public Complex changeIm(double im2) { return valueOf(re, im2); }     public static Complex cast(@ValueSafe Object x) {         return x == null ? ZERO : (Complex) x;     }     // utility methods and constants:     public Complex plus(Complex c)  { return new Complex(re+c.re, im+c.im); }     public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); }     public double abs() { return Math.sqrt(re*re + im*im); }     public static final Complex PI = valueOf(Math.PI, 0.0);     public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts.  The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final.  (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations.  A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations.  No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type.  If a value-safe class is marked final, it is in fact a value type.  All other value-safe classes must be abstract.  The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex.  Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable {     // All methods listed here must get redefined.     // Definitions must be value-safe, which means     // they may depend on component values only.     List<? extends Object> asList();     int hashCode();     boolean equals(@ValueSafe Object c);     String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system.  It could appear as an element type or parameter bound, for facilities which are designed to work on value types only.  More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods.  (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.)  Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation.  In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation.  Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0);  //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe")   Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object();  // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi);  // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi);  // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi);  // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero);  // error: reference comparison on value type boolean z2 = (pi == null);  // error: reference comparison on value type boolean z3 = (pi == obj2);  // error: reference comparison on value type synchronized (pi) { }  // error: synch of value, unpredictable result synchronized (obj2) { }  // unpredictable result Complex qq = pi; qq = null;  // possible NPE; warning: “null-unsafe" qq = (Complex) obj;  // warning: “null-unsafe" qq = Complex.cast(obj);  // OK @SuppressWarnings("null-unsafe")   Complex empty = null;  // possible NPE qq = empty;  // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations.  Fields and variables of value types can be split into their unboxed components.  Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules?  Why not detect programs automagically and perform unboxing transparently?  The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced.  Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal.  In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur.  This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer.  Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules.  There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme.  Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions.  One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type.  That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances.  Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe.  Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around.  Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed.  This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods.  This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors.  The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type.  Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands.  When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not.  If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible.  Proxies must be managed carefully, and this can be expensive.  On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces.  (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.)  Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems.  They require the deepest transformations, relative to today’s JVM.  There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics.  It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form.  Such value-safe arrays would not be convertible to Object[] arrays.  Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex.  I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code.  On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly.  Likewise, there are rules for providing default access modifiers for interface members.  Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types.  Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType {  // implicitly final     public double re, im;  // implicitly public final     //implicit methods are defined elementwise from te fields:     //  toString, asList, equals(2), hashCode, valueOf, cast     //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner.  The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer.  A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point.  The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage?  Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number.  Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”).  What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple {      double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly.  The supertype is an abstract class which has suitable shared declarations.  The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it.  The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types.  (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language.  (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.)  At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists.  Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection.  That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types.  Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API.  The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components  that appear as parameters, return types, and array elements.  This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations.  A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile.  Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type.  It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack.  If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction?  Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot.  But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes.  I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value.  Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType {     protected final long header;     protected private final BigInteger digits;     public DecimalValue valueOf(int value, int scale) {         assert(scale >= 0);         return new DecimalValue(((long)value << 32) + scale, null);     }     public DecimalValue valueOf(long value, int scale) {         if (value == (int) value)             return valueOf((int)value, scale);         return new DecimalValue(-scale, new BigInteger(value));     } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case.  It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues.  (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.)  Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits.  For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types.  This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant.  An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes.  More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable,         Unsynchronizable, Interchangeable { … public class Complex implements ValueType {     // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe     … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types.  This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable.  It is likely that code which violates value-safety for wrapper types exists but is uncommon.  It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code.  The design presented above obscures that distinction.  As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations.  Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed.  For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi;  // convert to boxed myList.add(boxPi); complex z = myList.get(0);  // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM.  Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type.  Something like this which can also accommodate value type components seems worthwhile.  On the other hand, does it make sense for value types to contain short arrays?  And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure.  These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types.  In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids.  No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now.  Back to work!

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  • Node.js Adventure - Storage Services and Service Runtime

    - by Shaun
    When I described on how to host a Node.js application on Windows Azure, one of questions might be raised about how to consume the vary Windows Azure services, such as the storage, service bus, access control, etc.. Interact with windows azure services is available in Node.js through the Windows Azure Node.js SDK, which is a module available in NPM. In this post I would like to describe on how to use Windows Azure Storage (a.k.a. WAS) as well as the service runtime.   Consume Windows Azure Storage Let’s firstly have a look on how to consume WAS through Node.js. As we know in the previous post we can host Node.js application on Windows Azure Web Site (a.k.a. WAWS) as well as Windows Azure Cloud Service (a.k.a. WACS). In theory, WAWS is also built on top of WACS worker roles with some more features. Hence in this post I will only demonstrate for hosting in WACS worker role. The Node.js code can be used when consuming WAS when hosted on WAWS. But since there’s no roles in WAWS, the code for consuming service runtime mentioned in the next section cannot be used for WAWS node application. We can use the solution that I created in my last post. Alternatively we can create a new windows azure project in Visual Studio with a worker role, add the “node.exe” and “index.js” and install “express” and “node-sqlserver” modules, make all files as “Copy always”. In order to use windows azure services we need to have Windows Azure Node.js SDK, as knows as a module named “azure” which can be installed through NPM. Once we downloaded and installed, we need to include them in our worker role project and make them as “Copy always”. You can use my “Copy all always” tool mentioned in my last post to update the currently worker role project file. You can also find the source code of this tool here. The source code of Windows Azure SDK for Node.js can be found in its GitHub page. It contains two parts. One is a CLI tool which provides a cross platform command line package for Mac and Linux to manage WAWS and Windows Azure Virtual Machines (a.k.a. WAVM). The other is a library for managing and consuming vary windows azure services includes tables, blobs, queues, service bus and the service runtime. I will not cover all of them but will only demonstrate on how to use tables and service runtime information in this post. You can find the full document of this SDK here. Back to Visual Studio and open the “index.js”, let’s continue our application from the last post, which was working against Windows Azure SQL Database (a.k.a. WASD). The code should looks like this. 1: var express = require("express"); 2: var sql = require("node-sqlserver"); 3:  4: var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd={PASSWORD};Encrypt=yes;Connection Timeout=30;"; 5: var port = 80; 6:  7: var app = express(); 8:  9: app.configure(function () { 10: app.use(express.bodyParser()); 11: }); 12:  13: app.get("/", function (req, res) { 14: sql.open(connectionString, function (err, conn) { 15: if (err) { 16: console.log(err); 17: res.send(500, "Cannot open connection."); 18: } 19: else { 20: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 21: if (err) { 22: console.log(err); 23: res.send(500, "Cannot retrieve records."); 24: } 25: else { 26: res.json(results); 27: } 28: }); 29: } 30: }); 31: }); 32:  33: app.get("/text/:key/:culture", function (req, res) { 34: sql.open(connectionString, function (err, conn) { 35: if (err) { 36: console.log(err); 37: res.send(500, "Cannot open connection."); 38: } 39: else { 40: var key = req.params.key; 41: var culture = req.params.culture; 42: var command = "SELECT * FROM [Resource] WHERE [Key] = '" + key + "' AND [Culture] = '" + culture + "'"; 43: conn.queryRaw(command, function (err, results) { 44: if (err) { 45: console.log(err); 46: res.send(500, "Cannot retrieve records."); 47: } 48: else { 49: res.json(results); 50: } 51: }); 52: } 53: }); 54: }); 55:  56: app.get("/sproc/:key/:culture", function (req, res) { 57: sql.open(connectionString, function (err, conn) { 58: if (err) { 59: console.log(err); 60: res.send(500, "Cannot open connection."); 61: } 62: else { 63: var key = req.params.key; 64: var culture = req.params.culture; 65: var command = "EXEC GetItem '" + key + "', '" + culture + "'"; 66: conn.queryRaw(command, function (err, results) { 67: if (err) { 68: console.log(err); 69: res.send(500, "Cannot retrieve records."); 70: } 71: else { 72: res.json(results); 73: } 74: }); 75: } 76: }); 77: }); 78:  79: app.post("/new", function (req, res) { 80: var key = req.body.key; 81: var culture = req.body.culture; 82: var val = req.body.val; 83:  84: sql.open(connectionString, function (err, conn) { 85: if (err) { 86: console.log(err); 87: res.send(500, "Cannot open connection."); 88: } 89: else { 90: var command = "INSERT INTO [Resource] VALUES ('" + key + "', '" + culture + "', N'" + val + "')"; 91: conn.queryRaw(command, function (err, results) { 92: if (err) { 93: console.log(err); 94: res.send(500, "Cannot retrieve records."); 95: } 96: else { 97: res.send(200, "Inserted Successful"); 98: } 99: }); 100: } 101: }); 102: }); 103:  104: app.listen(port); Now let’s create a new function, copy the records from WASD to table service. 1. Delete the table named “resource”. 2. Create a new table named “resource”. These 2 steps ensures that we have an empty table. 3. Load all records from the “resource” table in WASD. 4. For each records loaded from WASD, insert them into the table one by one. 5. Prompt to user when finished. In order to use table service we need the storage account and key, which can be found from the developer portal. Just select the storage account and click the Manage Keys button. Then create two local variants in our Node.js application for the storage account name and key. Since we need to use WAS we need to import the azure module. Also I created another variant stored the table name. In order to work with table service I need to create the storage client for table service. This is very similar as the Windows Azure SDK for .NET. As the code below I created a new variant named “client” and use “createTableService”, specified my storage account name and key. 1: var azure = require("azure"); 2: var storageAccountName = "synctile"; 3: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 4: var tableName = "resource"; 5: var client = azure.createTableService(storageAccountName, storageAccountKey); Now create a new function for URL “/was/init” so that we can trigger it through browser. Then in this function we will firstly load all records from WASD. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: } 18: } 19: }); 20: } 21: }); 22: }); When we succeed loaded all records we can start to transform them into table service. First I need to recreate the table in table service. This can be done by deleting and creating the table through table client I had just created previously. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: } 27: }); 28: }); 29: } 30: } 31: }); 32: } 33: }); 34: }); As you can see, the azure SDK provide its methods in callback pattern. In fact, almost all modules in Node.js use the callback pattern. For example, when I deleted a table I invoked “deleteTable” method, provided the name of the table and a callback function which will be performed when the table had been deleted or failed. Underlying, the azure module will perform the table deletion operation in POSIX async threads pool asynchronously. And once it’s done the callback function will be performed. This is the reason we need to nest the table creation code inside the deletion function. If we perform the table creation code after the deletion code then they will be invoked in parallel. Next, for each records in WASD I created an entity and then insert into the table service. Finally I send the response to the browser. Can you find a bug in the code below? I will describe it later in this post. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: for (var i = 0; i < results.rows.length; i++) { 27: var entity = { 28: "PartitionKey": results.rows[i][1], 29: "RowKey": results.rows[i][0], 30: "Value": results.rows[i][2] 31: }; 32: client.insertEntity(tableName, entity, function (error) { 33: if (error) { 34: error["target"] = "insertEntity"; 35: res.send(500, error); 36: } 37: else { 38: console.log("entity inserted"); 39: } 40: }); 41: } 42: // send the 43: console.log("all done"); 44: res.send(200, "All done!"); 45: } 46: }); 47: }); 48: } 49: } 50: }); 51: } 52: }); 53: }); Now we can publish it to the cloud and have a try. But normally we’d better test it at the local emulator first. In Node.js SDK there are three build-in properties which provides the account name, key and host address for local storage emulator. We can use them to initialize our table service client. We also need to change the SQL connection string to let it use my local database. The code will be changed as below. 1: // windows azure sql database 2: //var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd=eszqu94XZY;Encrypt=yes;Connection Timeout=30;"; 3: // sql server 4: var connectionString = "Driver={SQL Server Native Client 11.0};Server={.};Database={Caspar};Trusted_Connection={Yes};"; 5:  6: var azure = require("azure"); 7: var storageAccountName = "synctile"; 8: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 9: var tableName = "resource"; 10: // windows azure storage 11: //var client = azure.createTableService(storageAccountName, storageAccountKey); 12: // local storage emulator 13: var client = azure.createTableService(azure.ServiceClient.DEVSTORE_STORAGE_ACCOUNT, azure.ServiceClient.DEVSTORE_STORAGE_ACCESS_KEY, azure.ServiceClient.DEVSTORE_TABLE_HOST); Now let’s run the application and navigate to “localhost:12345/was/init” as I hosted it on port 12345. We can find it transformed the data from my local database to local table service. Everything looks fine. But there is a bug in my code. If we have a look on the Node.js command window we will find that it sent response before all records had been inserted, which is not what I expected. The reason is that, as I mentioned before, Node.js perform all IO operations in non-blocking model. When we inserted the records we executed the table service insert method in parallel, and the operation of sending response was also executed in parallel, even though I wrote it at the end of my logic. The correct logic should be, when all entities had been copied to table service with no error, then I will send response to the browser, otherwise I should send error message to the browser. To do so I need to import another module named “async”, which helps us to coordinate our asynchronous code. Install the module and import it at the beginning of the code. Then we can use its “forEach” method for the asynchronous code of inserting table entities. The first argument of “forEach” is the array that will be performed. The second argument is the operation for each items in the array. And the third argument will be invoked then all items had been performed or any errors occurred. Here we can send our response to browser. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: async.forEach(results.rows, 26: // transform the records 27: function (row, callback) { 28: var entity = { 29: "PartitionKey": row[1], 30: "RowKey": row[0], 31: "Value": row[2] 32: }; 33: client.insertEntity(tableName, entity, function (error) { 34: if (error) { 35: callback(error); 36: } 37: else { 38: console.log("entity inserted."); 39: callback(null); 40: } 41: }); 42: }, 43: // send reponse 44: function (error) { 45: if (error) { 46: error["target"] = "insertEntity"; 47: res.send(500, error); 48: } 49: else { 50: console.log("all done"); 51: res.send(200, "All done!"); 52: } 53: } 54: ); 55: } 56: }); 57: }); 58: } 59: } 60: }); 61: } 62: }); 63: }); Run it locally and now we can find the response was sent after all entities had been inserted. Query entities against table service is simple as well. Just use the “queryEntity” method from the table service client and providing the partition key and row key. We can also provide a complex query criteria as well, for example the code here. In the code below I queried an entity by the partition key and row key, and return the proper localization value in response. 1: app.get("/was/:key/:culture", function (req, res) { 2: var key = req.params.key; 3: var culture = req.params.culture; 4: client.queryEntity(tableName, culture, key, function (error, entity) { 5: if (error) { 6: res.send(500, error); 7: } 8: else { 9: res.json(entity); 10: } 11: }); 12: }); And then tested it on local emulator. Finally if we want to publish this application to the cloud we should change the database connection string and storage account. For more information about how to consume blob and queue service, as well as the service bus please refer to the MSDN page.   Consume Service Runtime As I mentioned above, before we published our application to the cloud we need to change the connection string and account information in our code. But if you had played with WACS you should have known that the service runtime provides the ability to retrieve configuration settings, endpoints and local resource information at runtime. Which means we can have these values defined in CSCFG and CSDEF files and then the runtime should be able to retrieve the proper values. For example we can add some role settings though the property window of the role, specify the connection string and storage account for cloud and local. And the can also use the endpoint which defined in role environment to our Node.js application. In Node.js SDK we can get an object from “azure.RoleEnvironment”, which provides the functionalities to retrieve the configuration settings and endpoints, etc.. In the code below I defined the connection string variants and then use the SDK to retrieve and initialize the table client. 1: var connectionString = ""; 2: var storageAccountName = ""; 3: var storageAccountKey = ""; 4: var tableName = ""; 5: var client; 6:  7: azure.RoleEnvironment.getConfigurationSettings(function (error, settings) { 8: if (error) { 9: console.log("ERROR: getConfigurationSettings"); 10: console.log(JSON.stringify(error)); 11: } 12: else { 13: console.log(JSON.stringify(settings)); 14: connectionString = settings["SqlConnectionString"]; 15: storageAccountName = settings["StorageAccountName"]; 16: storageAccountKey = settings["StorageAccountKey"]; 17: tableName = settings["TableName"]; 18:  19: console.log("connectionString = %s", connectionString); 20: console.log("storageAccountName = %s", storageAccountName); 21: console.log("storageAccountKey = %s", storageAccountKey); 22: console.log("tableName = %s", tableName); 23:  24: client = azure.createTableService(storageAccountName, storageAccountKey); 25: } 26: }); In this way we don’t need to amend the code for the configurations between local and cloud environment since the service runtime will take care of it. At the end of the code we will listen the application on the port retrieved from SDK as well. 1: azure.RoleEnvironment.getCurrentRoleInstance(function (error, instance) { 2: if (error) { 3: console.log("ERROR: getCurrentRoleInstance"); 4: console.log(JSON.stringify(error)); 5: } 6: else { 7: console.log(JSON.stringify(instance)); 8: if (instance["endpoints"] && instance["endpoints"]["nodejs"]) { 9: var endpoint = instance["endpoints"]["nodejs"]; 10: app.listen(endpoint["port"]); 11: } 12: else { 13: app.listen(8080); 14: } 15: } 16: }); But if we tested the application right now we will find that it cannot retrieve any values from service runtime. This is because by default, the entry point of this role was defined to the worker role class. In windows azure environment the service runtime will open a named pipeline to the entry point instance, so that it can connect to the runtime and retrieve values. But in this case, since the entry point was worker role and the Node.js was opened inside the role, the named pipeline was established between our worker role class and service runtime, so our Node.js application cannot use it. To fix this problem we need to open the CSDEF file under the azure project, add a new element named Runtime. Then add an element named EntryPoint which specify the Node.js command line. So that the Node.js application will have the connection to service runtime, then it’s able to read the configurations. Start the Node.js at local emulator we can find it retrieved the connections, storage account for local. And if we publish our application to azure then it works with WASD and storage service through the configurations for cloud.   Summary In this post I demonstrated how to use Windows Azure SDK for Node.js to interact with storage service, especially the table service. I also demonstrated on how to use WACS service runtime, how to retrieve the configuration settings and the endpoint information. And in order to make the service runtime available to my Node.js application I need to create an entry point element in CSDEF file and set “node.exe” as the entry point. I used five posts to introduce and demonstrate on how to run a Node.js application on Windows platform, how to use Windows Azure Web Site and Windows Azure Cloud Service worker role to host our Node.js application. I also described how to work with other services provided by Windows Azure platform through Windows Azure SDK for Node.js. Node.js is a very new and young network application platform. But since it’s very simple and easy to learn and deploy, as well as, it utilizes single thread non-blocking IO model, Node.js became more and more popular on web application and web service development especially for those IO sensitive projects. And as Node.js is very good at scaling-out, it’s more useful on cloud computing platform. Use Node.js on Windows platform is new, too. The modules for SQL database and Windows Azure SDK are still under development and enhancement. It doesn’t support SQL parameter in “node-sqlserver”. It does support using storage connection string to create the storage client in “azure”. But Microsoft is working on make them easier to use, working on add more features and functionalities.   PS, you can download the source code here. You can download the source code of my “Copy all always” tool here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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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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  • LVM / Device Mapper maps wrong device

    - by DaDaDom
    Hi, I run a LVM setup on a raid1 created by mdadm. md2 is based on sda6 (major:minor 8:6) and sdb6 (8:22). md2 is partition 9:2. The VG on top of md2 has 4 LVs, var, home, usr, tmp. First the problem: While booting it seems as if the device mapper takes the wrong partition for the mapping! Immediately after boot the information is like ~# dmsetup table systemlvm-home: 0 4194304 linear 8:22 384 systemlvm-home: 4194304 16777216 linear 8:22 69206400 systemlvm-home: 20971520 8388608 linear 8:22 119538048 systemlvm-home: 29360128 6291456 linear 8:22 243270016 systemlvm-tmp: 0 2097152 linear 8:22 41943424 systemlvm-usr: 0 10485760 linear 8:22 20971904 systemlvm-var: 0 10485760 linear 8:22 10486144 systemlvm-var: 10485760 6291456 linear 8:22 4194688 systemlvm-var: 16777216 4194304 linear 8:22 44040576 systemlvm-var: 20971520 10485760 linear 8:22 31457664 systemlvm-var: 31457280 20971520 linear 8:22 48234880 systemlvm-var: 52428800 33554432 linear 8:22 85983616 systemlvm-var: 85983232 115343360 linear 8:22 127926656 ~# cat /proc/mdstat Personalities : [raid1] md2 : active (auto-read-only) raid1 sda6[0] 151798080 blocks [2/1] [U_] md0 : active raid1 sda1[0] sdb1[1] 96256 blocks [2/2] [UU] md1 : active raid1 sda2[0] sdb2[1] 2931776 blocks [2/2] [UU] I have to manually "lvchange -an" all LVs, add /dev/sdb6 back to the raid and reactivate the LVs, then all is fine. But it prevents me from automounting the partitions and obviously leads to a bunch of other problems. If everything works fine, the information is like ~$ cat /proc/mdstat Personalities : [raid1] md2 : active raid1 sdb6[1] sda6[0] 151798080 blocks [2/2] [UU] ... ~# dmsetup table systemlvm-home: 0 4194304 linear 9:2 384 systemlvm-home: 4194304 16777216 linear 9:2 69206400 systemlvm-home: 20971520 8388608 linear 9:2 119538048 systemlvm-home: 29360128 6291456 linear 9:2 243270016 systemlvm-tmp: 0 2097152 linear 9:2 41943424 systemlvm-usr: 0 10485760 linear 9:2 20971904 systemlvm-var: 0 10485760 linear 9:2 10486144 systemlvm-var: 10485760 6291456 linear 9:2 4194688 systemlvm-var: 16777216 4194304 linear 9:2 44040576 systemlvm-var: 20971520 10485760 linear 9:2 31457664 systemlvm-var: 31457280 20971520 linear 9:2 48234880 systemlvm-var: 52428800 33554432 linear 9:2 85983616 systemlvm-var: 85983232 115343360 linear 9:2 127926656 I think that LVM for some reason just "takes" /dev/sdb6 which is then missing in the raid. I tried almost all options in the lvm.conf but none seems to work. Below is some more information, like config files. Does anyone have any idea about what is going on here and how to prevent that? If you need any additional information, please let me know Thanks in advance! Dominik The information (off a "repaired" system): ~# cat /etc/debian_version 5.0.4 ~# uname -a Linux kermit 2.6.26-2-686 #1 SMP Wed Feb 10 08:59:21 UTC 2010 i686 GNU/Linux ~# lvm version LVM version: 2.02.39 (2008-06-27) Library version: 1.02.27 (2008-06-25) Driver version: 4.13.0 ~# cat /etc/mdadm/mdadm.conf DEVICE partitions ARRAY /dev/md1 level=raid1 num-devices=2 metadata=00.90 UUID=11e9dc6c:1da99f3f:b3088ca6:c6fe60e9 ARRAY /dev/md0 level=raid1 num-devices=2 metadata=00.90 UUID=92ed1e4b:897361d3:070682b3:3baa4fa1 ARRAY /dev/md2 level=raid1 num-devices=2 metadata=00.90 UUID=601d4642:39dc80d7:96e8bbac:649924ba ~# mount /dev/md1 on / type ext3 (rw,errors=remount-ro) tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) procbususb on /proc/bus/usb type usbfs (rw) udev on /dev type tmpfs (rw,mode=0755) tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620) /dev/md0 on /boot type ext3 (rw) /dev/mapper/systemlvm-usr on /usr type reiserfs (rw) /dev/mapper/systemlvm-tmp on /tmp type reiserfs (rw) /dev/mapper/systemlvm-home on /home type reiserfs (rw) /dev/mapper/systemlvm-var on /var type reiserfs (rw) ~# grep -v ^$ /etc/lvm/lvm.conf | grep -v "#" devices { dir = "/dev" scan = [ "/dev" ] preferred_names = [ ] filter = [ "a|/dev/md.*|", "r/.*/" ] cache_dir = "/etc/lvm/cache" cache_file_prefix = "" write_cache_state = 1 sysfs_scan = 1 md_component_detection = 1 ignore_suspended_devices = 0 } log { verbose = 0 syslog = 1 overwrite = 0 level = 0 indent = 1 command_names = 0 prefix = " " } backup { backup = 1 backup_dir = "/etc/lvm/backup" archive = 1 archive_dir = "/etc/lvm/archive" retain_min = 10 retain_days = 30 } shell { history_size = 100 } global { umask = 077 test = 0 units = "h" activation = 1 proc = "/proc" locking_type = 1 fallback_to_clustered_locking = 1 fallback_to_local_locking = 1 locking_dir = "/lib/init/rw" } activation { missing_stripe_filler = "/dev/ioerror" reserved_stack = 256 reserved_memory = 8192 process_priority = -18 mirror_region_size = 512 readahead = "auto" mirror_log_fault_policy = "allocate" mirror_device_fault_policy = "remove" } :~# vgscan -vvv Processing: vgscan -vvv O_DIRECT will be used Setting global/locking_type to 1 File-based locking selected. Setting global/locking_dir to /lib/init/rw Locking /lib/init/rw/P_global WB Wiping cache of LVM-capable devices /dev/block/1:0: Added to device cache /dev/block/1:1: Added to device cache /dev/block/1:10: Added to device cache /dev/block/1:11: Added to device cache /dev/block/1:12: Added to device cache /dev/block/1:13: Added to device cache /dev/block/1:14: Added to device cache /dev/block/1:15: Added to device cache /dev/block/1:2: Added to device cache /dev/block/1:3: Added to device cache /dev/block/1:4: Added to device cache /dev/block/1:5: Added to device cache /dev/block/1:6: Added to device cache /dev/block/1:7: Added to device cache /dev/block/1:8: Added to device cache /dev/block/1:9: Added to device cache /dev/block/253:0: Added to device cache /dev/block/253:1: Added to device cache /dev/block/253:2: Added to device cache /dev/block/253:3: Added to device cache /dev/block/8:0: Added to device cache /dev/block/8:1: Added to device cache /dev/block/8:16: Added to device cache /dev/block/8:17: Added to device cache /dev/block/8:18: Added to device cache /dev/block/8:19: Added to device cache /dev/block/8:2: Added to device cache /dev/block/8:21: Added to device cache /dev/block/8:22: Added to device cache /dev/block/8:3: Added to device cache /dev/block/8:5: Added to device cache /dev/block/8:6: Added to device cache /dev/block/9:0: Already in device cache /dev/block/9:1: Already in device cache /dev/block/9:2: Already in device cache /dev/bsg/0:0:0:0: Not a block device /dev/bsg/1:0:0:0: Not a block device /dev/bus/usb/001/001: Not a block device [... many more "not a block device"] /dev/core: Not a block device /dev/cpu_dma_latency: Not a block device /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895: Aliased to /dev/block/8:16 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part1: Aliased to /dev/block/8:17 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part2: Aliased to /dev/block/8:18 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part3: Aliased to /dev/block/8:19 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part5: Aliased to /dev/block/8:21 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part6: Aliased to /dev/block/8:22 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800: Aliased to /dev/block/8:0 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part1: Aliased to /dev/block/8:1 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part2: Aliased to /dev/block/8:2 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part3: Aliased to /dev/block/8:3 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part5: Aliased to /dev/block/8:5 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part6: Aliased to /dev/block/8:6 in device cache /dev/disk/by-id/dm-name-systemlvm-home: Aliased to /dev/block/253:2 in device cache /dev/disk/by-id/dm-name-systemlvm-tmp: Aliased to /dev/block/253:3 in device cache /dev/disk/by-id/dm-name-systemlvm-usr: Aliased to /dev/block/253:1 in device cache /dev/disk/by-id/dm-name-systemlvm-var: Aliased to /dev/block/253:0 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr25N7CRZpUMzR18NfS6zeSeAVnVT98LuU: Aliased to /dev/block/253:0 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr3TpFXtLjYGEwn79IdXsSCZPl8AxmqbmQ: Aliased to /dev/block/253:1 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvrc5MJ4KolevMjt85PPBrQuRTkXbx6NvTi: Aliased to /dev/block/253:3 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvrYXrfdg5OSYDVkNeiQeQksgCI849Z2hx8: Aliased to /dev/block/253:2 in device cache /dev/disk/by-id/md-uuid-11e9dc6c:1da99f3f:b3088ca6:c6fe60e9: Already in device cache /dev/disk/by-id/md-uuid-601d4642:39dc80d7:96e8bbac:649924ba: Already in device cache /dev/disk/by-id/md-uuid-92ed1e4b:897361d3:070682b3:3baa4fa1: Already in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895: Aliased to /dev/block/8:16 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part1: Aliased to /dev/block/8:17 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part2: Aliased to /dev/block/8:18 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part3: Aliased to /dev/block/8:19 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part5: Aliased to /dev/block/8:21 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part6: Aliased to /dev/block/8:22 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800: Aliased to /dev/block/8:0 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part1: Aliased to /dev/block/8:1 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part2: Aliased to /dev/block/8:2 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part3: Aliased to /dev/block/8:3 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part5: Aliased to /dev/block/8:5 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part6: Aliased to /dev/block/8:6 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0: Aliased to /dev/block/8:0 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part1: Aliased to /dev/block/8:1 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part2: Aliased to /dev/block/8:2 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part3: Aliased to /dev/block/8:3 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part5: Aliased to /dev/block/8:5 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part6: Aliased to /dev/block/8:6 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0: Aliased to /dev/block/8:16 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part1: Aliased to /dev/block/8:17 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part2: Aliased to /dev/block/8:18 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part3: Aliased to /dev/block/8:19 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part5: Aliased to /dev/block/8:21 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part6: Aliased to /dev/block/8:22 in device cache /dev/disk/by-uuid/13c1262b-e06f-40ce-b088-ce410640a6dc: Aliased to /dev/block/253:3 in device cache /dev/disk/by-uuid/379f57b0-2e03-414c-808a-f76160617336: Aliased to /dev/block/253:2 in device cache /dev/disk/by-uuid/4fb2d6d3-bd51-48d3-95ee-8e404faf243d: Already in device cache /dev/disk/by-uuid/5c6728ec-82c1-49c0-93c5-f6dbd5c0d659: Aliased to /dev/block/8:5 in device cache /dev/disk/by-uuid/a13cdfcd-2191-4185-a727-ffefaf7a382e: Aliased to /dev/block/253:1 in device cache /dev/disk/by-uuid/e0d5893d-ff88-412f-b753-9e3e9af3242d: Aliased to /dev/block/8:21 in device cache /dev/disk/by-uuid/e79c9da6-8533-4e55-93ec-208876671edc: Aliased to /dev/block/253:0 in device cache /dev/disk/by-uuid/f3f176f5-12f7-4af8-952a-c6ac43a6e332: Already in device cache /dev/dm-0: Aliased to /dev/block/253:0 in device cache (preferred name) /dev/dm-1: Aliased to /dev/block/253:1 in device cache (preferred name) /dev/dm-2: Aliased to /dev/block/253:2 in device cache (preferred name) /dev/dm-3: Aliased to /dev/block/253:3 in device cache (preferred name) /dev/fd: Symbolic link to directory /dev/full: Not a block device /dev/hpet: Not a block device /dev/initctl: Not a block device /dev/input/by-path/platform-i8042-serio-0-event-kbd: Not a block device /dev/input/event0: Not a block device /dev/input/mice: Not a block device /dev/kmem: Not a block device /dev/kmsg: Not a block device /dev/log: Not a block device /dev/loop/0: Added to device cache /dev/MAKEDEV: Not a block device /dev/mapper/control: Not a block device /dev/mapper/systemlvm-home: Aliased to /dev/dm-2 in device cache /dev/mapper/systemlvm-tmp: Aliased to /dev/dm-3 in device cache /dev/mapper/systemlvm-usr: Aliased to /dev/dm-1 in device cache /dev/mapper/systemlvm-var: Aliased to /dev/dm-0 in device cache /dev/md0: Already in device cache /dev/md1: Already in device cache /dev/md2: Already in device cache /dev/mem: Not a block device /dev/net/tun: Not a block device /dev/network_latency: Not a block device /dev/network_throughput: Not a block device /dev/null: Not a block device /dev/port: Not a block device /dev/ppp: Not a block device /dev/psaux: Not a block device /dev/ptmx: Not a block device /dev/pts/0: Not a block device /dev/ram0: Aliased to /dev/block/1:0 in device cache (preferred name) /dev/ram1: Aliased to /dev/block/1:1 in device cache (preferred name) /dev/ram10: Aliased to /dev/block/1:10 in device cache (preferred name) /dev/ram11: Aliased to /dev/block/1:11 in device cache (preferred name) /dev/ram12: Aliased to /dev/block/1:12 in device cache (preferred name) /dev/ram13: Aliased to /dev/block/1:13 in device cache (preferred name) /dev/ram14: Aliased to /dev/block/1:14 in device cache (preferred name) /dev/ram15: Aliased to /dev/block/1:15 in device cache (preferred name) /dev/ram2: Aliased to /dev/block/1:2 in device cache (preferred name) /dev/ram3: Aliased to /dev/block/1:3 in device cache (preferred name) /dev/ram4: Aliased to /dev/block/1:4 in device cache (preferred name) /dev/ram5: Aliased to /dev/block/1:5 in device cache (preferred name) /dev/ram6: Aliased to /dev/block/1:6 in device cache (preferred name) /dev/ram7: Aliased to /dev/block/1:7 in device cache (preferred name) /dev/ram8: Aliased to /dev/block/1:8 in device cache (preferred name) /dev/ram9: Aliased to /dev/block/1:9 in device cache (preferred name) /dev/random: Not a block device /dev/root: Already in device cache /dev/rtc: Not a block device /dev/rtc0: Not a block device /dev/sda: Aliased to /dev/block/8:0 in device cache (preferred name) /dev/sda1: Aliased to /dev/block/8:1 in device cache (preferred name) /dev/sda2: Aliased to /dev/block/8:2 in device cache (preferred name) /dev/sda3: Aliased to /dev/block/8:3 in device cache (preferred name) /dev/sda5: Aliased to /dev/block/8:5 in device cache (preferred name) /dev/sda6: Aliased to /dev/block/8:6 in device cache (preferred name) /dev/sdb: Aliased to /dev/block/8:16 in device cache (preferred name) /dev/sdb1: Aliased to /dev/block/8:17 in device cache (preferred name) /dev/sdb2: Aliased to /dev/block/8:18 in device cache (preferred name) /dev/sdb3: Aliased to /dev/block/8:19 in device cache (preferred name) /dev/sdb5: Aliased to /dev/block/8:21 in device cache (preferred name) /dev/sdb6: Aliased to /dev/block/8:22 in device cache (preferred name) /dev/shm/network/ifstate: Not a block device /dev/snapshot: Not a block device /dev/sndstat: stat failed: Datei oder Verzeichnis nicht gefunden /dev/stderr: Not a block device /dev/stdin: Not a block device /dev/stdout: Not a block device /dev/systemlvm/home: Aliased to /dev/dm-2 in device cache /dev/systemlvm/tmp: Aliased to /dev/dm-3 in device cache /dev/systemlvm/usr: Aliased to /dev/dm-1 in device cache /dev/systemlvm/var: Aliased to /dev/dm-0 in device cache /dev/tty: Not a block device /dev/tty0: Not a block device [... many more "not a block device"] /dev/vcsa6: Not a block device /dev/xconsole: Not a block device /dev/zero: Not a block device Wiping internal VG cache lvmcache: initialised VG #orphans_lvm1 lvmcache: initialised VG #orphans_pool lvmcache: initialised VG #orphans_lvm2 Reading all physical volumes. This may take a while... Finding all volume groups /dev/ram0: Skipping (regex) /dev/loop/0: Skipping (sysfs) /dev/sda: Skipping (regex) Opened /dev/md0 RO /dev/md0: size is 192512 sectors Closed /dev/md0 /dev/md0: size is 192512 sectors Opened /dev/md0 RW O_DIRECT /dev/md0: block size is 1024 bytes Closed /dev/md0 Using /dev/md0 Opened /dev/md0 RW O_DIRECT /dev/md0: block size is 1024 bytes /dev/md0: No label detected Closed /dev/md0 /dev/dm-0: Skipping (regex) /dev/ram1: Skipping (regex) /dev/sda1: Skipping (regex) Opened /dev/md1 RO /dev/md1: size is 5863552 sectors Closed /dev/md1 /dev/md1: size is 5863552 sectors Opened /dev/md1 RW O_DIRECT /dev/md1: block size is 4096 bytes Closed /dev/md1 Using /dev/md1 Opened /dev/md1 RW O_DIRECT /dev/md1: block size is 4096 bytes /dev/md1: No label detected Closed /dev/md1 /dev/dm-1: Skipping (regex) /dev/ram2: Skipping (regex) /dev/sda2: Skipping (regex) Opened /dev/md2 RO /dev/md2: size is 303596160 sectors Closed /dev/md2 /dev/md2: size is 303596160 sectors Opened /dev/md2 RW O_DIRECT /dev/md2: block size is 4096 bytes Closed /dev/md2 Using /dev/md2 Opened /dev/md2 RW O_DIRECT /dev/md2: block size is 4096 bytes /dev/md2: lvm2 label detected lvmcache: /dev/md2: now in VG #orphans_lvm2 (#orphans_lvm2) /dev/md2: Found metadata at 39936 size 2632 (in area at 2048 size 194560) for systemlvm (rL8Oq2-dA7o-eRYe-u1or-JA7U-fnb1-kjOyvr) lvmcache: /dev/md2: now in VG systemlvm with 1 mdas lvmcache: /dev/md2: setting systemlvm VGID to rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr lvmcache: /dev/md2: VG systemlvm: Set creation host to rescue. Closed /dev/md2 /dev/dm-2: Skipping (regex) /dev/ram3: Skipping (regex) /dev/sda3: Skipping (regex) /dev/dm-3: Skipping (regex) /dev/ram4: Skipping (regex) /dev/ram5: Skipping (regex) /dev/sda5: Skipping (regex) /dev/ram6: Skipping (regex) /dev/sda6: Skipping (regex) /dev/ram7: Skipping (regex) /dev/ram8: Skipping (regex) /dev/ram9: Skipping (regex) /dev/ram10: Skipping (regex) /dev/ram11: Skipping (regex) /dev/ram12: Skipping (regex) /dev/ram13: Skipping (regex) /dev/ram14: Skipping (regex) /dev/ram15: Skipping (regex) /dev/sdb: Skipping (regex) /dev/sdb1: Skipping (regex) /dev/sdb2: Skipping (regex) /dev/sdb3: Skipping (regex) /dev/sdb5: Skipping (regex) /dev/sdb6: Skipping (regex) Locking /lib/init/rw/V_systemlvm RB Finding volume group "systemlvm" Opened /dev/md2 RW O_DIRECT /dev/md2: block size is 4096 bytes /dev/md2: lvm2 label detected lvmcache: /dev/md2: now in VG #orphans_lvm2 (#orphans_lvm2) with 1 mdas /dev/md2: Found metadata at 39936 size 2632 (in area at 2048 size 194560) for systemlvm (rL8Oq2-dA7o-eRYe-u1or-JA7U-fnb1-kjOyvr) lvmcache: /dev/md2: now in VG systemlvm with 1 mdas lvmcache: /dev/md2: setting systemlvm VGID to rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr lvmcache: /dev/md2: VG systemlvm: Set creation host to rescue. Using cached label for /dev/md2 Read systemlvm metadata (19) from /dev/md2 at 39936 size 2632 /dev/md2 0: 0 16: home(0:0) /dev/md2 1: 16 24: var(40:0) /dev/md2 2: 40 40: var(0:0) /dev/md2 3: 80 40: usr(0:0) /dev/md2 4: 120 40: var(80:0) /dev/md2 5: 160 8: tmp(0:0) /dev/md2 6: 168 16: var(64:0) /dev/md2 7: 184 80: var(120:0) /dev/md2 8: 264 64: home(16:0) /dev/md2 9: 328 128: var(200:0) /dev/md2 10: 456 32: home(80:0) /dev/md2 11: 488 440: var(328:0) /dev/md2 12: 928 24: home(112:0) /dev/md2 13: 952 206: NULL(0:0) Found volume group "systemlvm" using metadata type lvm2 Read volume group systemlvm from /etc/lvm/backup/systemlvm Unlocking /lib/init/rw/V_systemlvm Closed /dev/md2 Unlocking /lib/init/rw/P_global ~# vgdisplay --- Volume group --- VG Name systemlvm System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 19 VG Access read/write VG Status resizable MAX LV 0 Cur LV 4 Open LV 4 Max PV 0 Cur PV 1 Act PV 1 VG Size 144,75 GB PE Size 128,00 MB Total PE 1158 Alloc PE / Size 952 / 119,00 GB Free PE / Size 206 / 25,75 GB VG UUID rL8Oq2-dA7o-eRYe-u1or-JA7U-fnb1-kjOyvr ~# pvdisplay --- Physical volume --- PV Name /dev/md2 VG Name systemlvm PV Size 144,77 GB / not usable 16,31 MB Allocatable yes PE Size (KByte) 131072 Total PE 1158 Free PE 206 Allocated PE 952 PV UUID ZSAzP5-iBvr-L7jy-wB8T-AiWz-0g3m-HLK66Y :~# lvdisplay --- Logical volume --- LV Name /dev/systemlvm/home VG Name systemlvm LV UUID YXrfdg-5OSY-DVkN-eiQe-Qksg-CI84-9Z2hx8 LV Write Access read/write LV Status available # open 2 LV Size 17,00 GB Current LE 136 Segments 4 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:2 --- Logical volume --- LV Name /dev/systemlvm/var VG Name systemlvm LV UUID 25N7CR-ZpUM-zR18-NfS6-zeSe-AVnV-T98LuU LV Write Access read/write LV Status available # open 2 LV Size 96,00 GB Current LE 768 Segments 7 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 --- Logical volume --- LV Name /dev/systemlvm/usr VG Name systemlvm LV UUID 3TpFXt-LjYG-Ewn7-9IdX-sSCZ-Pl8A-xmqbmQ LV Write Access read/write LV Status available # open 2 LV Size 5,00 GB Current LE 40 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:1 --- Logical volume --- LV Name /dev/systemlvm/tmp VG Name systemlvm LV UUID c5MJ4K-olev-Mjt8-5PPB-rQuR-TkXb-x6NvTi LV Write Access read/write LV Status available # open 2 LV Size 1,00 GB Current LE 8 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:3

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  • GooglePlayServicesNotAvailable: GooglePlayServices not available due to error 1

    - by Mathias Lin
    I'm on Galaxy S III with Android 4.0.4, Google Play installed. In my app I try to get a token from the Google Play services, as described on https://developers.google.com/android/google-play-services/authentication. Since it's all quite new (the Google pages were last updated this week), there's not much documentation to be found, especially about each specific error code. final String token = GoogleAuthUtil.getToken(this, "[email protected]", "scope"); gives me an exception: 09-30 11:24:36.075: ERROR/GoogleAuthUtil(11984): GooglePlayServices not available due to error 1 09-30 11:24:36.105: ERROR/AuthTokenCheck_(11984): Error 1 com.google.android.gms.auth.GooglePlayServicesAvailabilityException: GooglePlayServicesNotAvailable at com.google.android.gms.auth.GoogleAuthUtil.f(Unknown Source) at com.google.android.gms.auth.GoogleAuthUtil.getToken(Unknown Source) at com.google.android.gms.auth.GoogleAuthUtil.getToken(Unknown Source) at mobi.app.activity.AuthTokenCheck.getAndUseAuthTokenBlocking(AuthTokenCheck.java:148) at mobi.app.activity.AuthTokenCheck$1.doInBackground(AuthTokenCheck.java:61) at android.os.AsyncTask$2.call(AsyncTask.java:264) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) at java.util.concurrent.FutureTask.run(FutureTask.java:137) at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) at java.lang.Thread.run(Thread.java:856) https://developers.google.com/android/google-play-services/reference/com/google/android/gms/auth/package-summary tells me: GooglePlayServicesAvailabilityExceptions are special instances of UserRecoverableAuthExceptions which are thrown when the expected Google Play services app is not available for some reason. But what exactly does that mean? And how to resolve it? I've added the Google Play services extras in my SDK and the jar to my project, marked as 'exported'. I'm also wondering what the "Google Play services app" exactly is. Unfortunately it's all not very clearly described at https://developers.google.com/android/google-play-services/. The Google Play services component is delivered as an APK through the Google Play Store, so updates to Google Play services are not dependent on carrier or OEM system image updates. Newer devices will also have Google Play services as part of the device's system image, but updates are still pushed to these newer devices through the Google Play Store. Isn't "Google Play services" app the same as the "Google Play" app? Another question I have, due to lack of documentation: what is the scope parameter for? The documentation just says the following, but not defining what an 'authentication scope' exactly is: scope String representing the authentication scope.

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  • WPF Dynamic Layout with ItemsControl and Grid

    - by Jason Williams
    I am creating a WPF form. One of the requirements is that it have a sector-based layout so that a control can be explicitly placed in one of the sectors/cells. I have created a tic-tac-toe example below to convey my problem: There are two types and one base type: public class XMoveViewModel : MoveViewModel { } public class OMoveViewModel : MoveViewModel { } public class MoveViewModel { public int Row { get; set; } public int Column { get; set; } } The DataContext of the form is set to an instance of: public class MainViewModel : ViewModelBase { public MainViewModel() { Moves = new ObservableCollection<MoveViewModel>() { new XMoveViewModel() { Row = 0, Column = 0 }, new OMoveViewModel() { Row = 1, Column = 0 }, new XMoveViewModel() { Row = 1, Column = 1 }, new OMoveViewModel() { Row = 0, Column = 2 }, new XMoveViewModel() { Row = 2, Column = 2} }; } public ObservableCollection<MoveViewModel> Moves { get; set; } } And finally, the XAML looks like this: <Window.Resources> <DataTemplate DataType="{x:Type vm:XMoveViewModel}"> <Image Source="XMove.png" Grid.Row="{Binding Path=Row}" Grid.Column="{Binding Path=Column}" Stretch="None" /> </DataTemplate> <DataTemplate DataType="{x:Type vm:OMoveViewModel}"> <Image Source="OMove.png" Grid.Row="{Binding Path=Row}" Grid.Column="{Binding Path=Column}" Stretch="None" /> </DataTemplate> </Window.Resources> <Grid> <ItemsControl ItemsSource="{Binding Path=Moves}"> <ItemsControl.ItemsPanel> <ItemsPanelTemplate> <Grid ShowGridLines="True"> <Grid.RowDefinitions> <RowDefinition /> <RowDefinition /> <RowDefinition /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition /> <ColumnDefinition /> </Grid.ColumnDefinitions> </Grid> </ItemsPanelTemplate> </ItemsControl.ItemsPanel> </ItemsControl> </Grid> What was not so obvious to me when I started was that the ItemsControl element actually wraps each item in a container, so my Grid.Row and Grid.Column bindings are ignored since the images are not directly contained within the grid. Thus, all of the images are placed in the default Row and Column (0, 0). What is happening: The desired result: So, my question is this: how can I achieve the dynamic placement of my controls in a grid? I would prefer a XAML/Data Binding/MVVM-friendly solution. Thanks.

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  • OpenCV/EmguCV face recognition

    - by Meko
    Hi .I am tying to make app that detect face and recognize it. I made Face detection but I want some idea to when making recognition. I using web cam for tracking and It can recognize face.Then I am taking only part of face to an new gray image and comparing it using EigenObjectRecognizer with list of images in database.But it is not giving good result.Some times find some thing wrong,some times nothing.I want to ask that for comparing photos which additional techniques i must implement?Like Histogram equalization or resolution of faces equalization ?

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  • openning files in another browser page/tab

    - by CoffeeCode
    i have an action that return a file content. i added: Response.AddHeader("Content-Disposition", "attactment; filename:\"" + survey.File + "\""); so that the image would be opened in another tab/page, gets opened in the current tab/page. whats wrong with the header?

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  • WPF DataGrid extended "copy and paste"

    - by MadSeb
    Hi, How can I make the WPF DataGrid have some sort of improved "copy and paste" where I can select a single cell , copy using Ctrl-C , select a bunch of cells of columns and paste using Ctrl-V ??? So for example...in the image bellow ...I want to be able to copy the "Tech" word to all the highlighted cells just by a Ctrl-C on tech, a select of the cells, and a Ctrl-V ... Regards, Seb

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  • C# TextBox Autocomplete (Winforms) key events and customization?

    - by m0s
    Hi, I was wondering if it is possible to catch key events for auto-complete list. For example instead of Enter key press for auto-complete use lets say Tab key. Also is it possible to change the colors and add background image for the auto-complete pop-up list? Currently I have my own implementation which is a separate window(form) with a list-box, which works OK, but Id really like to use .net's auto-complete if it can do what I need. Thanks for attention.

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  • How to programmatically replace UIToolBar items built in IB

    - by frankodwyer
    I have a toolbar with various image buttons, created in Interface Builder. I'd like to be able to programmatically replace one of the buttons with an activity indicator when pressed, and then put back the original button but change its color from white to yellow when the activity completes. Is this possible with an IB built toolbar or must I look at building the whole toolbar programmatically and custom views?

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  • Sharepoint InputFormTextBox not working on updatepanel?

    - by James123
    I have two panels in update panel. In panel1, there is button. If I click, Panel1 will be visible =false and Panel2 will be visible=true. In Panel2, I placed SharePoint:InPutFormTextBox. It not rendering HTML toolbar and showing like below image. <SharePoint:InputFormTextBox runat="server" ID="txtSummary" ValidationGroup="CreateCase" Rows="8" Columns="80" RichText="true" RichTextMode="Compatible" AllowHyperlink="true" TextMode="MultiLine" /> http://i700.photobucket.com/albums/ww5/vsrikanth/careersummary-1.jpg

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