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• Uninstall Git completely on Ubuntu?

  - by Millisami

  I installed Git on Ubuntu Lucid (latest) manually as following. cd ~/tmp wget http://kernel.org/pub/software/scm/git/git-1.7.0.6.tar.gz tar -xzvf git-1.7.0.6.tar.gz cd git-1.7.0.6.tar.gz ./configure sudo make sudo make install Now, how can I completely uninstall it?

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• links for 2010-06-14

  - by Bob Rhubart

  White Paper: Application Portfolio Rationalization: How IT Standardization Fuels Growth Co-authors Hamidou Dia and Roy Hunter describe an Enterprise Architecture approach to application portfolio rationalization. (tags: oracle otn entarch) @soatoday: Cloud & Compliance: Write a Solid Prenup "Think of your cloud contract as a prenuptial agreement," says Oracle ACE Director Jordan Braunstein. "There must be clear recourse and commitments." (tags: soa cloud oracleace entarch) @fteter: Resilience and Relationships "Take a look at your own enterprise architecture with these ideas in mind," suggests Oracle ACE Director Floyd Teter, "and see if your outlook doesn't change." (tags: entarch complexity oracleace) @lucasjellema: Calling an EJB from a SOA Composite Application using the EJB Binding based on Java Interface Oracle ACE Director Lucas Jellema illustrates the use of one of several new capabilities in Oracle SOA Suite 11g R1 Patch Set 2 (11.1.1.3.0). (tags: soa oracleace middleware soasuite oracle)

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• Postfix multiple checks

  - by xBlue

  I want to achieve the following with Postfix: Run all emails through a black list Allow any clients sending to a list of domains Allow some clients sending to any domain This is what I have: (postfix is on 10.0.8.0 and some of the senders are 10.0.8.0 and 10.0.9.0) mynetworks_style = subnet smtpd_recipient_restrictions = check_recipient_access sqlite:/etc/postfix/access-bl.query, check_client_access hash:/etc/postfix/trusted_clients, check_recipie nt_access hash:/etc/postfix/local_domains, reject_unauth_destination, permit So, right now the black list works. File /etc/postfix/trusted_clients contains who can send anywhere (3), file /etc/postfix/local_domains contains where you can send (2). Those two are fine, they return properly. My problem is getting all three working together. Not sure if it's an ordering issue. Currently sending a test from 10.0.9.17 and I get Relay access denied. If I add: mynetworks = 10.0.8.0/24 10.0.9.0/24 then anyone can send anywhere, so #2 is not working. Postfix version is 2.10 on Ubuntu 14.04. Any ideas?

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• Optimal file system type and mount options for an rsnapshot dedicated drive

  - by Nimmy Lebby

  We have an external USB 2 drive that we are using as a backup drive for our configuration. We use rsnapshot for the backups. It uses a few standard commands for managing snapshots: rm -rf: deletes expired snapshots mv: moves older snapshots down a slot cp -al: duplicates last snapshot to new slot rsync -a --delete --numeric-ids --relative: synchronizes new snapshot As you could see by the log below, the majority of the time is spent on the rm -rf and the cp -al steps: [25/Dec/2010:14:00:02] rsnapshot hourly: started [25/Dec/2010:14:00:02] echo 21012 > /var/run/rsnapshot.pid [25/Dec/2010:14:00:02] rm -rf /mnt/extdrive/snapshots/hourly.5/ [25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.4/ /mnt/extdrive/snapshots/hourly.5/ [25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.3/ /mnt/extdrive/snapshots/hourly.4/ [25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.2/ /mnt/extdrive/snapshots/hourly.3/ [25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.1/ /mnt/extdrive/snapshots/hourly.2/ [25/Dec/2010:14:15:48] cp -al /mnt/extdrive/snapshots/hourly.0 /mnt/extdrive/snapshots/hourly.1 [25/Dec/2010:14:23:32] rsync -a --delete --numeric-ids --relative /etc /mnt/extdrive/snapshots/hourly.0/sm4/ [25/Dec/2010:14:23:52] touch /mnt/extdrive/snapshots/hourly.0/ [25/Dec/2010:14:23:52] rm -f /var/run/rsnapshot.pid [25/Dec/2010:14:23:52] rsnapshot hourly: completed successfully My questions: I'm currently using ext4 for the filesystem. Maybe this is not the best choice from those available in Red Hat. Anyone have any recommendations that would speed up the process? The partition's mount options are sync,dirsync 1 2. Is there a way to optimize this since it's solely used for rsnapshot? Of course, reasoning would be greatly appreciated.

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• Installing Midnight Commander from sources (no root privileges)

  - by ouroboros

  I tried to configure ./configure --prefix=/localfolder glib-2.26.1/ make make install but it fails at make stage. trying to configure mc-4.6.1/ and make doesn't obviously work. What are the steps I need to make in order to install midnight comander for my local user in a custom folder? Make for glib gives me these errors /usr/bin/msgfmt: found 2 fatal errors cp: cannot stat `test.mo': No such file or directory gmake[4]: *** [test.mo] Error 1 gmake[4]: Leaving directory `/remote/folder/mc/glib-2.26.1/gio/tests' gmake[3]: *** [all-recursive] Error 1 gmake[3]: Leaving directory `/remote/folder/mc/glib-2.26.1/gio' gmake[2]: *** [all] Error 2 gmake[2]: Leaving directory `/remote/folder/mc/glib-2.26.1/gio' gmake[1]: *** [all-recursive] Error 1 gmake[1]: Leaving directory `/remote/folder/mc/glib-2.26.1' gmake: *** [all] Error 2

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• Home server - HP Proliant Microserver - Software and setup - OS on USB stick?

  - by Lloyd Watkin

  I've just purchased a HP ProLiant Microserver for home use. I want to set up with web server, samba shares, the usual stuff. My question is really about system setup. It has an internal USB socket so I've attempted to install a copy of Fedora 14 onto it. I turned off X/Gnome, but it still ran like a pig. I've now put the OS on one of the internal disks (250Gb, 7200rpm), but I was wondering if there was a way to utilise the internal USB to give me better power-saving allowing the hard drives to be shut down when not in use. How would you set this server up? I'd rather not go to the extra cost of an SSD right now, but if that's the best way then so be it.

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• No NFC for the iPhone, and here's why

  - by David Dorf

  I, like many others in the retail industry, was hoping the iPhone 5 would include an NFC chip that enabled a mobile wallet.  In previous postings I've discussed the possible business case and the foreshadowing of Passbook, but it wasn't meant to be.  A few weeks ago I was considering all the rumors, and it suddenly occurred to me that it wasn't in Apple's best interest to support an NFC chip.  Yes they have patents in this area, but perhaps they are more defensive than indicating new development. Steve Jobs wanted to always win, but more importantly he didn't want others to win at his expense.  It drove him nuts that Windows was more successful than MacOS, and clearly he was bothered by Samsung and other handset manufacturers copying the iPhone.  But he was most angry at Google for their stewardship of Android. If the iPhone 5 had an NFC chip, who would benefit most?  Google Wallet is far and away the leader in NFC-based payments via mobile phones in the US.  Even without Steve at the helm, Apple isn't going to do anything to help Google.  Plus Apple doesn't like to do things in an open way -- then they lose control.  For example, you don't see iPhones with expandable memory, replaceable batteries, or USB connectors.  Adding a standards-based NFC chip just isn't in their nature. So I don't think Apple is holding back on the NFC chip for the 5S or 6.  It just isn't going to happen unless they can figure out how to prevent others from benefiting from it. All the other handset manufacturers will use NFC as a differentiator, which may be enough to keep Google and Isis afloat, and of course Square and PayPal aren't betting on NFC anyway.  This isn't the end of alternative payments, its just a major speed bump.

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• Why does the Java VM process eat up more RAM then specified in -Xmx parameter?

  - by evilpenguin

  I have multiple servers running CentOS 5.4 and only one application running on Java VM. I've configured the Java VM with the following arguments: java -Xmx4500M -server -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:NewSize=1024m -Djava.net.preferIPv4Stack=true -Dcom.sun.management.jmxremote=true The machines I'm running the VM on has 6 GB RAM and no other applications running. After a while, the java process starts to hit the swap space really hard, I get this info out of the top command: 7658 root 25 0 11.7g 3.9g 4796 S 39.4 67.3 543:54.17 java On the other hand, if I connect via JConsole, it reports the Java VM has 2.6 GB used, 4.6 GB commited and 4.6 Gb max. java -version returns: java version "1.6.0_17" Java(TM) SE Runtime Environment (build 1.6.0_17-b04) Java HotSpot(TM) 64-Bit Server VM (build 14.3-b01, mixed mode) Why is the Java VM expanding so much past it's allocated heap size? And where does that memory go, if it's not reported in JConsole?

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• How to recover broken MJPEG AVI file after a camera crash

  - by Jam K

  I was recording a video when my KODAK EASYSHARE M531 Digital Camera fell to the ground and turned off. When i turned it on nothing happened to the camera but the video file is somehow broken. Obviously the camera did not have time to convert and close it properly. $file myvid.avi myvid.AVI: data where it should be: another_vid.AVI: RIFF (little-endian) data, AVI, 640 x 480, ~30 fps, video: Motion JPEG, audio: uLaw (stereo, 12000 Hz)` I would like to fix my video which I believe needs to be converted to AVI. Any idea? VLC does not play the file and returns: could not determine type of stream

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• How to set up an FTP user on UBUNTU 9 server using vsftpd utility?

  - by Pavel

  Hi guys. I'm kinda new to this so bear with me. I've set up a server and now I need to create ftp user for it. I'm doing this by typing: useradd pavel passwd pavel And then I'm running iptables -I INPUT 1 -p tcp --dport 21 -j ACCEPT iptables-save > /etc/iptables.rules in order to open ftp ports and lastly, I'm changing the usermod by: usermod -s /bin/sh pavel So now tell me - what I'm doing wrong here? I just want to connect using FTP protocol. Please help...

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• How to copy directories using debugfs?

  - by STM

  The debugfs manpage gives the impression that the command 'rdump . .' will recursively copy all files found on the specified filesystem from the debugfs cwd to the native filesystem's cwd. Instead I seem to receive a syntax error, and no copy is initiated? These are the commands I run: cd /path/to/transfer/destination debugfs /dev/sda1 -R rdump . . My task is to copy the entire contents of a clean yet unmountable USB storage device to its host machine's HD. The host machine does not support the inode size used by the USB device's filesystem (256) and its software is not upgradeable, so my intention was to use debugfs to transfer the files. If anyone has any other suggestions for this task I'd be grateful.

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• Apache 2 Fails to Start After Upgrade with No Errors

  - by Mark Davidson

  Hi all Hoping someone can help me with a server issue. Recently we upgraded to the latest apache on 2 boxes within are organisation. One being the master box the other being for failover. The upgrade went fine on the master box but on the failover box apache fails to start with no errors, being output or logged. Both boxes have the exact same configuration so found this a bit strange. I've reinstalled apache and have been through checking the configs and did not find any obvious errors. Eventally I ran a syntax check on each config file being included and found that one of the files apparently has syntax errors. Invalid command 'Order', perhaps misspelled or defined by a module not included in the server configuration Invalid command 'php_value', perhaps misspelled or defined by a module not included in the server configuration Invalid command 'GeoIPEnable', perhaps misspelled or defined by a module not included in the server configuration I've trippled checked all the modules are enabled but it still fails. I've googled the subject of these errors loads but have been unable to fine a solution. I was wondering if anyone had encountered such a problem before and could point me towards a solution. Thanks for your help in advance. P.s: Apache related versions on server. ii apache2 2.2.3-4+etch10 Next generation, scalable, extendable web se ii apache2-mpm-prefork 2.2.3-4+etch10 Traditional model for Apache HTTPD 2.1 ii apache2-utils 2.2.3-4+etch10 utility programs for webservers ii apache2.2-common 2.2.3-4+etch10 Next generation, scalable, extendable web se ii libapache2-mod-geoip 1.1.8-2 GeoIP support for apache2 ii libapache2-mod-php5 5.2.0+dfsg-8+etch15 server-side, HTML-embedded scripting languag

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• Postfix + procmail - delivery fails because "can't create user output file" - on CentOS 6.2

  - by jshin47

  I verified that my postfix installation / relaying setup worked. Now I am having trouble with procmail. I have it wired to postfix with the following command: mailbox_command = /usr/bin/procmail -f -a "$USER" I have nothing in my procmail config but the following: LOGFILE=/var/procmailrc/log And I send an email to a recipient that previously worked (before I attached procmail). Now it fails with error: Apr 6 14:07:05 localhost postfix/qmgr[15194]: D0C3DFF6E1: from=<[email protected]>, size=938, nrcpt=1 (queue active) Apr 6 14:07:05 localhost postfix/local[1953]: D0C3DFF6E1: to=<[email protected]>, orig_to=<postmaster>, relay=local, delay=0.05, delays=0.02/0.01/0/0.02, dsn=5.2.0, status=bounced (can't create user output file. Command output: procmail: Couldn't create "/var/spool/mail/nobody" procmail: Couldn't read "//root" ) Apr 6 14:07:05 localhost postfix/bounce[1955]: warning: D0C3DFF6E1: undeliverable postmaster notification discarded Apr 6 14:07:05 localhost postfix/qmgr[15194]: D0C3DFF6E1: removed It seems like there is some sort of permissions issue but I do not know what the problem is, nor do I understand how I would go about diagnosing it further. The logfile that I specified is empty, by the way. How can I make procmail+postfix work?

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• Amavisd start error

  - by Kristian

  I can't start amavis. It gives an error: Starting amavisd: Error in config file "/etc/amavis/conf.d/05-domain_id": Insecure directory in $ENV{PATH} while running with -T switch at /etc/amavis/conf.d/05-domain_id line 7. On line 7 is: chomp($mydomain = `head -n 1 /etc/mailname`); This problem occured after restaring my computer. I don't know much about amavis, so any help is appreciated. Regards, Kristian

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• how to hear mic sound over speakers- ubuntu karmic

  - by ashishsony

  Hi, I want to hear the sound that goes into the notebook's mic from the notebook's speaker itself. I am on ubuntu 9.10 Any help is much appreciated. Thanks.

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• Help creating image from LVM

  - by jackhab

  I need to duplicate CentOS hard drive image for multiple stations. The HD has the following layout: Disk /dev/sdb: 250GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 107MB 107MB primary ext3 boot 2 107MB 250GB 250GB primary lvm I saved /dev/sdb1 to file with fsarchiver but for sdb2 I get: /fsarchiver savefs an2.fsa /dev/sdb2 oper_save.c#1006,filesystem_mount_partition(): can't detect and mount filesystem of partition [/dev/sdb2], cannot continue. removed an2.fsa Although fsarchiver probe simple correctly detects sdb2 as LVM2_member. Is fsarchiver correct tool for this job? What's wrong? I'm on Ubuntu 9.1 with fsarchiver 0.6.8 and lvm tools installed. Thanks.

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• Help creating image from LVM

  - by jackhab

  I need to duplicate CentOS hard drive image for multiple stations. The HD has the following layout: Disk /dev/sdb: 250GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 107MB 107MB primary ext3 boot 2 107MB 250GB 250GB primary lvm I saved /dev/sdb1 to file with fsarchiver but for sdb2 I get: /fsarchiver savefs an2.fsa /dev/sdb2 oper_save.c#1006,filesystem_mount_partition(): can't detect and mount filesystem of partition [/dev/sdb2], cannot continue. removed an2.fsa Although fsarchiver probe simple correctly detects sdb2 as LVM2_member. Is fsarchiver correct tool for this job? What's wrong? I'm on Ubuntu 9.1 with fsarchiver 0.6.8 and lvm tools installed. Thanks.

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• How to configure multiple virtual hosts for multiple users on Linux/Apache2.2

  - by authentictech

  I want to set up a virtual hosting server on Linux/Apache2.2 that allows multiple users to set up multiple website domains as would be appropriate for commercial shared hosting. I have seen examples (from my then perspective as a shared hosting customer) that allow users to store their web files in their user home directory with directories to correspond to the virtual host domain, e.g.: /home/user1/www/example1.com /home/user2/www/example2.com instead of using /var/www Questions: How would you configure this in your Apache configuration files? (Don't worry about DNS) Is this the best way to manage multiple virtual hosts? Are there others? What safety or security issues do you think I should be aware of in doing this? Many thanks, folks. Edit: If you want to only answer question 1, please feel free, as that is the most urgent to me at this moment and I would consider that an answer to the question. I have done it for myself since posting, but I am not confident that it's the best solution and I would like to know how an experienced sysadmin would do it. Thanks.

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• Tuxedo Load Balancing

  - by Todd Little

  A question I often receive is how does Tuxedo perform load balancing.  This is often asked by customers that see an imbalance in the number of requests handled by servers offering a specific service. First of all let me say that Tuxedo really does load or request optimization instead of load balancing.  What I mean by that is that Tuxedo doesn't attempt to ensure that all servers offering a specific service get the same number of requests, but instead attempts to ensure that requests are processed in the least amount of time.   Simple round robin "load balancing" can be employed to ensure that all servers for a particular service are given the same number of requests.  But the question I ask is, "to what benefit"?  Instead Tuxedo scans the queues (which may or may not correspond to servers based upon SSSQ - Single Server Single Queue or MSSQ - Multiple Server Single Queue) to determine on which queue a request should be placed.  The scan is always performed in the same order and during the scan if a queue is empty the request is immediately placed on that queue and request routing is done.  However, should all the queues be busy, meaning that requests are currently being processed, Tuxedo chooses the queue with the least amount of "work" queued to it where work is the sum of all the requests queued weighted by their "load" value as defined in the UBBCONFIG file.  What this means is that under light loads, only the first few queues (servers) process all the requests as an empty queue is often found before reaching the end of the scan.  Thus the first few servers in the queue handle most of the requests.  While this sounds non-optimal, in fact it capitalizes on the underlying operating systems and hardware behavior to produce the best possible performance.  Round Robin scheduling would spread the requests across all the available servers and thus require all of them to be in memory, and likely not share much in the way of hardware or memory caches.  Tuxedo's system maximizes the various caches and thus optimizes overall performance.  Hopefully this makes sense and now explains why you may see a few servers handling most of the requests.  Under heavy load, meaning enough load to keep all servers that can handle a request busy, you should see a relatively equal number of requests processed.  Next post I'll try and cover how this applies to servers in a clustered (MP) environment because the load balancing there is a little more complicated. Regards,Todd LittleOracle Tuxedo Chief Architect

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• Creating Custom validation rule and register it

  - by FormsEleven

  What is Validation Rule? A validation rule is a piece of code that performs some check ensuring that data meets given constraints.In an enterprise application development environment, often it might require developers to have validation be performed based on some logic at several places across projects. Instead of redundant validation creation, a custom validation rule provides a library with a validation rules that can be registered and used across applications.A custom Validation is encapsulated in a reusable component so that you do not have to write it every time when you need to do input validation. Here is how we can easily implement a custom validation that checks for name of an employee to be "KING" For creating a custom Validation , 1.         Create Generic Application Workspace "CustomValidator" with the project "Model" 2.         Create an BC4J based on emp table. 3.         Create a custom validation rule.In EmpNamerule class, update the validateValue(..) method as follows:  public boolean validateValue(Object value) { EntityImpl emp = (EntityImpl)value; if(emp.getAttribute("Ename").toString().equals("KING")){ return false; } return true; } Create ADF Library: Next step would be to create ADF library. Create ADF library with name lets say testADFLibrary1.jarRegister ADF Library Next step is to register the ADF library , so that its available across the applications. Invoke the menu "Tools -> Preferences"Select the option "Business Components -> Registered Rules" from left paneClick on button "Pick Library". The dialog "Select Library" comes up with  the user library addedAdd new library' that points to the above jarCheck the checkbox "Register" and set the name for the rule Sample UsageHere is how we can easily implement a validation rule that restrict the name of the employee not to be "KING".Create new Application with BC4J based on EMP table.Create new validation under Business rule tab for Ename & select the above custom validation rule.Run the AppModule tester.

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• Open mysql only to localhost and a particular address

  - by Rodrigo Asensio

  My config: ubuntu server 9 and msyql 5 my.cnf = bind-address = 0.0.0.0 my iptables script = iptables -A INPUT -i eth0 -s 99.88.77.66 -p tcp --destination-port 3306 -j ACCEPT I can connect from any place to mysql, not only that IP. I made a iptables-save , /etc/init.d/netwokring restart... but I still can connect from any IP, any clue ?

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• Apache2 BufferedLogs On - anybody using it ?

  - by Qiqi

  Greetings, I am wondering, whether anybody is using BufferedLogs On with Apache2 and found any issues ? Feature is marked as experimental, but for many years now, so I guess it's rather pretty stable. I am running some servers with constrained disk IO capacity at the moment, so I turned it on hoping that even a small benefit could help in the long run ;-) I do have several to several hundreds requests per seconds so by my thoughts there is really no need to write to log after each request, cause honestly I don't think that my filesystem is the best handler for many unnecessary writes. (OCFS2 shared among several DomUs in the Xen)

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• Why do I see the weird backspace behaviour on my shell sometimes?

  - by Lazer

  I use bash shell and sometimes all of a sudded, my Backspace key stops working (when this happens Ctrl + Backspace still works fine) I am not sure why this happens, but it also carries over to any vim sessions that I use from the shell. To my surprise, getting a fresh shell does not help, and the problem seems to go away as abruptly as it started. This is what the typed characters look like, each Backspace keypress is shown by a ^? on the shell $ cat filem^?namr^?e Does anybody have a clue what might be happening? How can I restore the normal behaviour?

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• VLC tv card streaming

  - by Franco

  I'm trying to stream the output of my desktop's tv card to my laptop using vlc without success. I have on both pcs ArchLinux installed. I'm stuck here: $ cvlc v4l2:///dev/video0:norm=pal-nc:frequency=543250:size=640x480:channel=0:input-slave=alsa:///dev/dsp:audio=0 --sout '#transcode{vcodec=mp4v,acodec=mpga,vb=3000,ab=256,vt=800000,keyint=80,deinterlace}:standard{access=http,mux=ogg,dst=192.168.0.2:8080}' --ttl 12 VLC media player 1.1.4 The Luggage (revision exported) Blocked: call to unsetenv("DBUS_ACTIVATION_ADDRESS") Blocked: call to unsetenv("DBUS_ACTIVATION_BUS_TYPE") [0x1c9e480] inhibit interface error: Failed to connect to the D-Bus session daemon: /usr/bin/dbus-launch terminated abnormally with the following error: Autolaunch error: X11 initialization failed. [0x1c9e480] main interface error: no suitable interface module [0x1ca1500] main interface error: no suitable interface module [0x1bb3120] main libvlc error: interface "globalhotkeys,none" initialization failed [0x1c9f940] dummy interface: using the dummy interface module... [0x1ca4850] main access out: creating httpd [0x1ebb340] mux_ogg mux: Open And on my laptop: $ vlc http://192.168.0.2:8080 VLC media player 1.1.4.1 The Luggage (revision exported) Blocked: call to unsetenv("DBUS_ACTIVATION_ADDRESS") Blocked: call to unsetenv("DBUS_ACTIVATION_BUS_TYPE") Blocked: call to setlocale(6, "") Blocked: call to sigaction(17, 0xb25c7058, 0xb25c70e4) Warning: call to signal(13, 0x1) Warning: call to signal(13, 0x1) Blocked: call to setenv("ORBIT_SOCKETDIR", "/tmp/orbit-zf", 1) Warning: call to srand(1287690122) Warning: call to rand() Blocked: call to setlocale(6, "") (process:17933): Gtk-WARNING **: Locale not supported by C library. Using the fallback 'C' locale. Warning: call to signal(13, 0x1) Blocked: call to setlocale(6, "") [0x8af5f04] main stream error: cannot pre fill buffer Any idea why this isn't working?

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• Difference between EJB Persist & Merge operation

  - by shantala.sankeshwar

  This article gives the difference between EJB Persist & Merge operations with scenarios.Use Case Description Users working on EJB persist & merge operations often have this question in mind " When merge can create new entity as well as modify existing entity,then why do we have 2 separate operations - persist & merge?" The reason is very simple.If we use merge operation to create new entity & if the entity exists then it does not throw any exception,but persist throws exception if the entity already exists.Merge should be used to modify the existing entity.The sql statement that gets executed on persist operation is insert statement.But in case of merge first select statement gets executed & then update sql statement gets executed.Scenario 1: Persist operation to create new Emp recordLet us suppose that we have a Java EE Web Application created with Entities from Emp table & have created session bean with data control. Drop Emp Object(Expand SessionEJBLocal->Constructors under Data Controls) as ADF Parameter form in jspx pageDrop persistEmp(Emp) as ADF CommandButton & provide #{bindings.EmpIterator.currentRow.dataProvider} as the value for emp parameter.Then run this page & provide values for Emp,click on 'persistEmp' button.New Emp record gets created.So when we execute persist operation only insert sql statement gets executed :INSERT INTO EMP (EMPNO, COMM, HIREDATE, ENAME, JOB, DEPTNO, SAL, MGR) VALUES (?, ?, ?, ?, ?, ?, ?, ?)    bind => [2, null, null, e2, null, 10, null, null]Scenario 2: Merge operation to modify existing Emp recordLet us suppose that we have a Java EE Web Application created with Entities from Emp table & have created session bean with data control.Drop empFindAll() Object as ADF form on jspx page.Drop mergeEmp(Emp) operation as commandButton & provide #{bindings.EmpIterator.currentRow.dataProvider} as the value for emp parameter.Then run this page & modify values for Emp record,click on 'mergeEmp' button.The respective Emp record gets modified.So when we execute merge operation select & update sql statements gets executed :SELECT EMPNO, COMM, HIREDATE, ENAME, JOB, DEPTNO, SAL, MGR FROM EMP WHERE (EMPNO = ?) bind => [7566]UPDATE EMP SET ENAME = ? WHERE (EMPNO = ?) bind => [KINGS, 7839]

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