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• What is the behavior of a WPF 4 ControlStoryboardAction trigger?

  - by jonathan_ou

  Hi all! I have a question that's been bugging me for a while: I have a lengthy IO operation which I invoke asynchronously, and I want my UI to show a blinking text to tell the users that the data is loading. I have an IsLoading boolean property in my ViewModel, and I used a ControlStoryboardAction to kickoff the blinking animation, which is set to repeat forever. For my ControlStoryboardAction trigger, I configured a data trigger to see if IsLoading is true, and start my storyboard if true. My problem is, when my IO operation returns, and I set IsLoading back to false, the animation continues to play. I thought once the trigger condition evaluated to false, it would stop the animation? I then added a second ControlStoryboardAction to stop the animation if IsLoading evaluted to false, but this didn't have any effect. The animation continued to play after IsLoading was false. Can anyone explain to me how trigger works in ControlStoryboardAction? In normal data triggers in WPF, once the condition evaluated to false, the property would be set back to its original state. It seems triggers in WPF actions don't work the same way? Thanks in advance for your help!

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• How does bridged networking work?

  - by agz

  How does bridged networking work? I have looked through the virtualbox manuals but nothing extremely technical came up (It was just a generic gloss over of the topic) How does it assign a different ip to the virtual machine but uses the same network card? Why does this different ip (I found using ip addr under linux) not show up under the "attached devices section" of my router but I can port forward to it? How come if I connect to a password protected wifi network, it does not require me to enter my password? Is this multihoming?

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• Starting one BlackBerry screen from another.

  - by DanG

  I've recently run into a snag while putting on the finishing touches for my BlackBerry app. I'm building a login screen which, if the user is successful in logging in, goes to a data loading screen, and then to a home screen. From the home screen, you can use the app. Everything works great but one thing, I can't seamlessly move from the login screen to the loading screen, to the home screen. I can move from the login screen to the loading screen ok, because I'm doing that via a button click which is on the GUI thread, but then I have the login screen at the bottom of the stack and can't get it out using the dismiss method. Once in the loading screen, I can't push the home screen because I'm not doing it via the gui method, though I'm able to update the GUI via the following piece of code: private void checkData(){ Timer loadingTimer = new Timer(); TimerTask loadingTask = new TimerTask() { public void run() { // set the progress bar progressGaugeField.setValue(DataManager.getDataLoaded()); // for repainting the screen invalidate(); } }; loadingTimer.scheduleAtFixedRate(loadingTask, 500, 500); } Does anyone know how to solve my problem of moving seamlessly from the login screen to the loading screen to the home screen? Note: once I'm at the home screen I'd like to have it be the only screen on the stack. Thanks!

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• Which version of Windows Server 2008?

  - by dragonmantank

  One of the projects I'm working on is looking like we're going to need to migrate from CentOS 5.4 over to something else (we need to run Postgresql 8.3+, and CentOS/RHEL only support 8.1), and one of the options will be Windows Server. Since 2008 R2 is out that's what I'm looking at. I'll need to run Postgres and Tomcat and don't really require anything that Windows has like IIS (if I can run Server Core, even better!). The other kicker is it will be virtualized through VMWare ESXI 4.0 so that we have three separate boxes: development, Quality, and Production servers. From a licensing standpoint though, and I good enough with just the Web Server edition? Am I right in assuming that will be three licenses? Or should I just jump up to Enterprise so that I get 4 VM licenses?

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• Help with MySQL query - Product orders report without duplicate shipping charges

  - by Paul

  Hello, I have an issue creating a custom report for an e-commerce store running on osCommerce. The client wants the report to have the following columns: Date, Order ID, Product Class, Product Price, Product Tax, Shipping, Order Total The criteria for generating the report are Date Range and Product Class (Textbooks for example) The client wants the report to list each Textbook purchased on its own line. Orders with multiple textbooks would display a separate line for each Textbook in the order. I have it all working except for one part: the shipping amount is order-specific (based on the order total), not product-specific, and is displaying for each product. I need it to display only for the first product of each order, so it is not counted more than once. My current query is: SELECT op.date_funds_captured as 'Date', op.orders_id as 'Order ID', pc.class as 'Product Class', round(op.products_price,2) as 'Product Price', round(op.products_tax*op.products_price/100,2) as 'Product Tax', round(otship.value,2) as 'Shipping', round(ot.value,2) as 'Order Total' from orders_products op, orders_total ot, orders_total otship, productclasses pc, products p where ot.orders_id = op.orders_id and ot.class='ot_total' and op.orders_id = otship.orders_id and otship.class = 'ot_shipping' and p.products_class_id = pc.id and op.products_id = p.products_id and pc.id = 1 pc.id = 1 -- Product class = Textbook Here is an example of the current report output. You can see the problem with order 2256 showing the shipping value three times instead of once: Date Order Product Class Price Tax Shipping Total 2010-01-04 2253 Textbook 24.95 2.43 10.03 37.41 2010-01-04 2256 Textbook 34.95 0.00 18.09 240.37 2010-01-04 2256 Textbook 55.50 0.00 18.09 240.37 2010-01-04 2256 Textbook 36.95 0.00 18.09 240.37 2010-01-04 2258 Textbook 55.50 5.41 12.17 124.24 Please help!!! Thanks, Paul

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• handling long running large transactions with perl dbi

  - by 1stdayonthejob

  I've got a large transaction comprising of getting lots of data from database A, do some manipulations with this data, then inserting the manipulated data into database B. I've only got permissions to select in database A but I can create tables and insert/update etc in database B. The manipulation and insertion part is written in perl and already in use for loading data into database B from other data sources, so all that's required is to get the necessary data from database A and using it to initialize the perl classes. How can I go about doing this so I can easily track back and pick up from where the error happened if any error occurs during the manipulation or insertion procedures (database disconnection, problems with class initialization because of invalid values, hard disk failure etc...)? Doing the transaction in one go doesn't seem like a good option because the amount data from database A means it would take at least a day or 2 for data manipulation and insertion into database B. The data from database A can be grouped into around 1000 groups using unique keys, with each key containing 1000s of rows each. One way I thought I could do is to write a script that does commits per group, meaning I've got to track which group has already been inserted into database B. The only way I can think of to track the progress of which groups have been processed or not is either in a log file or in a table in database B. A second way I thought could work is to dump all the necessary fields needed for loading the classes for manipulation and insertion into a flatfile, read the file to initialize the classes and insert into database B. This also means that I got to do some logging, but should narrow it down to the exact row in the flatfile if any error occurs. The script will look something like this: use strict; use warnings; use DBI; #connect to database A my $dbh = DBI->connect('dbi:oracle:my_db', $user, $password, { RaiseError => 1, AutoCommit => 0 }); #statement to get data based on group unique key my $sth = $dbh->prepare($my_sql); my @groups; #I have a list of this already open my $fh, '>>', 'my_logfile' or die "can't open logfile $!"; eval { foreach my $g (@groups){ #subroutine to check if group has already been processed, either from log file or from database table next if is_processed($g); $sth->execute($g); my $data = $sth->fetchall_arrayref; #manipulate $data, then use it to load perl classes for insertion into database B #. #. #. } print $fh "$g\n"; }; if ($@){ $dbh->rollback; die "something wrong...rollback"; } So if any errors do occur, I can just run this script again and it should skip the groups or rows that have been processed and continue. Both these methods is just variations on the same theme, and both require going back to where I've been tracking my progress (in table or file), skip the ones that've been commited to database B and process the remaining data. I'm sure there's a better way of doing this but am struggling to think of other solutions. Is there another way of handling large transactions between databases that require data manipulation between getting data out from one and inserting into another? The process doesn't need to be all in Perl, as long as I can reuse the perl classes for manipulating and inserting the data into the database.

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• VMWare Server 2 Install is Failing w/ Error 25032: "failed to customize windows logon process"

  - by Justin Searls

  VMWare Server 2 install question here.* Straightforward question that would probably require a VMWare expert to pull apart, given that Google has been totally worthless on this. On a patched Windows XP machine, any attempt to install VMWare Server 2.0.1 results in failure, just prior to completion (progress bar is full but I can tell network adapter stuff hasn't been fired yet and most of the services haven't been instaled). The error: Error 25032. Failed to customize Windows logon process (). Please contact your administrator. Upon dismissing the error, you're treated to: Warning 25033. Failed to remove Windows logon customization (VMGINA.DLL). Please contact your administrator. Clicking "OK" rolls back your installation. Killing the installer and hoping that it somehow leaves a working install behind was also unproductive. *I hope install troubleshooting isn't outside the purview of serverfault, I'm typically an SO user.

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• Windows 7 / Windows Vista won't connect to 802.1x RADIUS Server

  - by Calvin Froedge

  I've deployed Radius and have no problems connecting with TTLS, PEAP, or MD5 using linux, mac, and windows xp. For Windows 7 and Vista, I'm never prompted with the dialog box to enter username & password after configuring 802.1x support on the client. Steps taken: Enabled Wired Autoconfig in services.msc Set to use PEAP Set to require user authentication When I enable the network connection it says "Trying to authenticate" then fails with no error log / message given. The radius server gives no indication that there was ever a request (no Access-Reject - the client simply never tries to authenticate). On the windows 7 client, I can see that the DHCP server does not assign an IP to the client when 802.1x is enabled on the client (though it does when it isn't). How can I debug this further? Has anyone else run into a similar situation? My radius server is freeradius on Ubuntu 11.10.

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• Can i upgrade Photoshop CS6 to Adobe Creative Suite 6 at a discounted price?

  - by indifferentDrum

  I've had a look around on the official Adobe Shop website, but I couldn't find a clear answer for this.. I am a freelance developer and I have recently purchased Adobe Photoshop CS6 through the Adobe.com (small/medium business site, volume licensing). However, after downloading and installing it a couple of days ago, I realised that I may require the complete 'Adobe Creative Suite 6' instead. Does anyone out there know if this it is possible to upgrade your purchase, and not just the specific product you've bought previously? I guess I'm looking for something along the lines of 'Complete My Album', but for Adobe software, so that I don't end up with two copies of Photoshop. Thanks :)

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• How to assign hotkeys in OSX-snow-leopard

  - by 2816

  I am trying to assign a hotkey to open a folder in snow leopard. For example, in windows i could simply press the Windows+E to open the My Computer folder (or manually assign whatever folder i wanted to open). Is there a way to get this same behavior in OSX? I want to be able to launch applications, and open folder with my own keyboard mappings. For launching applications I use automator, create a service that receives no input to 'launch application' (from the utilities library). Then i can assign a keyboard shortcut to this service. Now i can launch applications with keyboard shortcuts. I still dont know how to open a folder. I know this can be done using quicksilver - but am looking for an organic approach that does not require any additional installs.

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• ARMv6 FIQ, acknowledge interrupt

  - by fastmonkeywheels

  I'm working with an i.mx35 armv6 core processor. I have Interrupt 62 configured as a FIQ with my handler installed and being called. My handler at the moment just toggles an output pin so I can test latency with a scope. With the code below, once I trigger the FIQ it continues forever as fast as it can, apparently not being acknowledged. I'm triggering the FIQ by means of the Interrupt Force Register so I'm assured that the source isn't triggering it this fast. If I disable Interrupt 62 in the AVIC in my FIQ routine the interrupt only triggers once. I have read the sections on the VIC Port in the ARM1136JF-S and ARM1136J-S Technical Reference Manual and it covers proper exit procedure. I'm only having one FIQ handler so I have no need to branch. The line that I don't understand is: STR R0, [R8,#AckFinished] I'm not sure what AckFinished is supposed to be or what this command is supposed to do. My FIQ handler is below: ldr r9, IOMUX_ADDR12 ldr r8, [r9] orr r8, #0x08 @ top LED str r8,[r9] @turn on LED bic r8, #0x08 @ top LED str r8,[r9] @turn off LED subs pc, r14, #4 IOMUX_ADDR12: .word 0xFC2A4000 @remapped IOMUX addr My handler returns just fine and normal system operation resumes if I disable it after the first go, otherwise it triggers constantly and the system appears to hang. Do you think my assumption is right that the core isn't acknowledging the AVIC or could there be another cause of this FIQ triggering?

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• apache 2.4 php-fpm proxypassmatch for pretty urls

  - by tubaguy50035

  I have a URL like http://newsymfony.dev/app_dev.php/_profiler/5080653d965eb. I would like to send this script to PHP-FPM. I currently have this as my vhost: VirtualHost *:80> ServerName newsymfony.dev DocumentRoot /home/COMPANY/nwalke/www/newsymfony.dev/web/ ErrorLog /var/log/apache2/error_log LogLevel info CustomLog /var/log/apache2/access_log combined <Directory /home/COMPANY/nwalke/www/newsymfony.dev/web/> AllowOverride All Require all granted DirectoryIndex app.php </Directory> ProxyPassMatch ^/(.*\.php)$ fcgi://127.0.0.1:9003/home/COMPANY/nwalke/www/newsymfony.dev/web/$1 </VirtualHost> If I browse to app_dev.php it works just fine. But if I do app_dev.php/_profiler/5080653d965eb I get a 404 and the request never gets sent to FPM. How can I alter my ProxyPassMatch to pass anything with .php in the URL? I'm trying to do this with Symfony, but I'm pretty sure it applies to everything.

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• Vista Enterprise doesn't find logon servers in a network with 802.1x authentication

  - by jneves

  In a network with 802.1x configuration and a samba server configured in the domain, I have a radius server that delegates the authentication against the samba domain for users (using LDAP). The radius defines which VLAN the user is supposed to have access. I'm trying to put a Windows Vista Enterprise in the same network, but it attempts to logon the domain before authenticating against the network in 802.1x and it doesn't find any logon servers. In the radius logs I see the machine trying to authenticate with 'host/'. Does Vista enterprise require that I put it in a network with access to the logon server at that point? Thanks in advance, João Miguel Neves

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• Lightweight spinlocks built from GCC atomic operations?

  - by Thomas

  I'd like to minimize synchronization and write lock-free code when possible in a project of mine. When absolutely necessary I'd love to substitute light-weight spinlocks built from atomic operations for pthread and win32 mutex locks. My understanding is that these are system calls underneath and could cause a context switch (which may be unnecessary for very quick critical sections where simply spinning a few times would be preferable). The atomic operations I'm referring to are well documented here: http://gcc.gnu.org/onlinedocs/gcc-4.4.1/gcc/Atomic-Builtins.html Here is an example to illustrate what I'm talking about. Imagine a RB-tree with multiple readers and writers possible. RBTree::exists() is read-only and thread safe, RBTree::insert() would require exclusive access by a single writer (and no readers) to be safe. Some code: class IntSetTest { private: unsigned short lock; RBTree<int>* myset; public: // ... void add_number(int n) { // Aquire once locked==false (atomic) while (__sync_bool_compare_and_swap(&lock, 0, 0xffff) == false); // Perform a thread-unsafe operation on the set myset->insert(n); // Unlock (atomic) __sync_bool_compare_and_swap(&lock, 0xffff, 0); } bool check_number(int n) { // Increment once the lock is below 0xffff u16 savedlock = lock; while (savedlock == 0xffff || __sync_bool_compare_and_swap(&lock, savedlock, savedlock+1) == false) savedlock = lock; // Perform read-only operation bool exists = tree->exists(n); // Decrement savedlock = lock; while (__sync_bool_compare_and_swap(&lock, savedlock, savedlock-1) == false) savedlock = lock; return exists; } }; (lets assume it need not be exception-safe) Is this code indeed thread-safe? Are there any pros/cons to this idea? Any advice? Is the use of spinlocks like this a bad idea if the threads are not truly concurrent? Thanks in advance. ;)

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• How to install Autoconf on OS X from source?

  - by chacham15

  I want to install autoconf, automake, m4, automake, etc. from the source. The problem is anything that I try and install i have to rely on autoconf. Therefore, I am trying to install autoconf i get configure.ac:30: require Automake 1.11, but have 1.10 I try to install automake, the bootstrap reports: configure.ac:20: error: Autoconf version 2.68 or higher is required configure.ac:20: the top level autom4te: /usr/bin/gm4 failed with exit status: 63 aclocal.tmp: error: autom4te failed with exit status: 63 Autoconf version: autoconf (GNU Autoconf) 2.61 Automake version: automake (GNU automake) 1.10 OS X Version: 10.7.2 XCode Version: 4.2.1

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• SQL View with Data from two tables

  - by Alex

  Hello! I can't seem to crack this - I have two tables (Persons and Companies), and I'm trying to create a view that: 1) shows all persons 2) also returns companies by themselves once, regardless of how many persons are related to it 3) orders by name across both tables To clarify, some sample data: (Table: Companies) Id Name 1 Banana 2 ABC Inc. 3 Microsoft 4 Bigwig (Table: Persons) Id Name RelatedCompanyId 1 Joe Smith 3 2 Justin 3 Paul Rudd 4 4 Anjolie 5 Dustin 4 The output I'm looking for is something like this: Name PersonName CompanyName RelatedCompanyId ABC Inc. NULL ABC Inc. NULL Anjolie Anjolie NULL NULL Banana NULL Banana NULL Bigwig NULL Bigwig NULL Dustin Dustin Bigwig 4 Joe Smith Joe Smith Microsoft 3 Justin Justin NULL NULL Microsoft NULL Microsoft NULL Paul Rudd Paul Rudd Bigwig 4 As you can see, the new "Name" column is ordered across both tables (the company names appear correctly in between the person names), and each company appears exactly once, regardless of how many people are related to it. Can this even be done in SQL?! P.S. I'm trying to create a view so I can use this later for easy data retrieval, fulltext indexing and make the programming side simpler by just querying the view.

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• Sudden issues reading uncompressed video using opencv

  - by JohnSavage

  I have been using a particular pipeline to process video using opencv to encode uncompressed video (fourcc = 0), and opencv python bindings to then open and work on these files. This has been working fine for me on OpenCV 2.3.1a on Ubuntu 11.10 until just a few days ago. For some reason it currently is only allowing me to read the first frame of a given file the first time I open that file. Further frames are not read, and once I touch the file once with my program, it then cannot even read the first frame. More detail: I created the uncompressed video files as follows: out_video.open(out_vid_name, 0, // FOURCC = 0 means record raw fps, Size(640, 480)) Again, these videos worked fine for me until about a week ago. Now, when I try to open one of these I get the following message (from what I think is ffmpeg): Processing video.avi Using network protocols without global network initialization. Please use avformat_network_init(), this will become mandatory later. [avi @ 0x29251e0] parser not found for codec rawvideo, packets or times may be invalid. It reads and displays the first frame fine, but then fails to read the next frame. Then, when I try to run my code on the same video, the capture still opens with the same message as above. However, it cannot even read the very first frame. Here is the code to open the capture: self.capture = cv2.VideoCapture(filename) if not self.capture.isOpened() print "Error: could not open capture" sys.exit() Again, this part is passed without any issue, but then the break happens at: success, rgb = self.capture.read() if not success: print "error: could not read frame" return False This part breaks at the second frame on the first run of the video file, and then on the first frame on subsequent runs. I really don't know where to even begin debugging this. Please help!

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• .htaccess has no effect

  - by Primož Kralj

  I am loosing hours with this (should-be) simple task. I want to restrict access to my website, which is on my server in /var/www/. I've created /etc/apache2/passwords file with httpasswd successfuly (user primoz). I've put .htaccess in /var/www/ and this is the content: AuthType Basic AuthName "RestrictedFiles" AuthBasicProvider file AuthUserFile /etc/apache2/passwords Require user primoz My website is still accessible. I also tried editing the /etc/apache2/sites-enabled/000-default - line AllowOverride None to AllowOverride All. No need to mention that it didn't make any changes. Should restricting really be this frustrating? EDIT: /etc/apache2/httpd.conf is empty by default because I run server on Debian - which uses apache2.conf instead. Here is the whole apache2.conf.

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• Amazon EC2 performance vs desktop

  - by flashnik

  I'm wondering how to compare performance of EC2 instances with standard dedicated servers and desktop. I've found only comparance of defferent clouds. I need to find a solution to perform some computations which require CPU and memory (disc IO is not used). The choice is to use: EC2 (High-CPU) or Xeon 5620/5630 with DDR3 or Core i7-960/980 with DDR3 Can anybody help, how to compare their performance? I'm not speaking about reliability of alternatives, I want to understand pros and cons from the point of just performance.

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• Apache POI Comment Excel

  - by Marquinio

  I need to add a comment to an HSSF Cell in Excel. Everything works fine the very first time but if I open the same file and run the code again it corrupts the file. I've also noticed that I need to create a Drawing object on a Sheet only once: _sheet.createDrawingPatriarch(); If the line above gets executed more than once comments will not work. So has anyone tried adding comments to Cells, closing the file, opening the file again and trying to add more comments to different cells? The below code works but if I open the file again then comments are not added, plus the file gets corrupted!!! Is there a way to get the existing Drawing object from a Sheet? Any ideas appreciated. Thanks!! _drawing = (HSSFPatriarch) _sheet.createDrawingPatriarch(); Row row = _sheet.getRow(rowIndex_); Cell cell = row.getCell(0); CreationHelper factory = _workbook.getCreationHelper(); HSSFAnchor anchor = new HSSFClientAnchor(0, 0, 0, 0, (short)4, 2, (short)6, 5); org.apache.poi.ss.usermodel.Comment comment = _drawing.createComment(anchor); RichTextString str = factory.createRichTextString("Hello, World "+rowIndex_); comment.setString(str); cell.setCellComment(comment);

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• cloud/grid computing

  - by tom smith

  Hi guys. I'm appologizing in advance to the guys who will tell me this isn't a tech/server/IT issue! But I've been beating my head around this for a couple of days now. I'm trying figure out who to talk to, or which company I can approach to try to see if there are Grid/Cloud Computing companies who have programs setup to deal with colleges. I'm dealing with a compsci course, and we're looking at a few projects that would require a great deal of computing/computational resources. But in calling different companies (HP/Rackspace/etc..) I'm either not getting through to the right depts, or to the right people, or the companies just aren't setup for this. There are plenty of companies who have discounts for desktop software/hardware, but who in the biz deals with discounts/offerings for Cloud/Grid Computing solutions?? Any thoughts/pointers would be greatly appreciated. Thanks -tom

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• process of connecting RTP with SIP via SDP & land lines

  - by TacB0sS

  Hello to everyone, I have a problem with starting a media session and to combine it with my SIP client. I've designed a recursive SIP client that reuse the same request template to send the next requests to server, according to the acceptable sequences noted in the RFC's, and examples that I read. as far as I could tell the SIP part is working fine registers to server invites, and authenticates. I didn't complete any calls to clients yet because of the content header needs to be filled up (which I didn't yet so I get a 503 from the server which is OK I guess). for a long time I didn't know where to start with the media session, and slowly learned how to use the JMF and I've constructed an object that handles RTP transmitting, now I'm standing at the cross road, on the one hand I have my SIP signaling but it needs the SDP content header to complete the invite, and on the other I have the RTP which is knows how to p2p. For me to complete my design I require your help with the following questions: Is there an easy//a simple//an implemented way to convert the Audio/Video format from the JMF into SDP media headers? or even a generator that I would input all the parameters for the content header, and it would generate a content header fast, or do I have to implement this myself? Once I've finished constructing the SDK and the SIP is up and running and I get an OK response from the server (after ringing and all), how do I start the media session? do I connect p2p according to caller details I send in the SIP invite? If 2 is correct, then how does a connection to land lines would be? does land lines knows that once they send an OK back to server they listen/start RTP session on a specific port? Or did I get everything wrong? :-/ I really appreciate any help I could I get, I looked every where for answers but they are not clear, they ignore question 2 as if it was an obvious thing, but for me it just isn't. Thank in advance, Adam Zehavi.

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• Best Linux dist for .NET developer looking to learn Groovy (and never used Linux)

  - by blade7

  Hi, I am planning to learn Groovy, but I want to do so on a Linux OS (because such an open minded approach will teach me more about IT and I have Windows Server VMs). Anyway, which Linux distro is the easiest to use and requires the least amount of knowledge on commands etc? As I am new to Linux, I want a dist. which doesn't require command-level knowledge (I am not at this level with Linux but I am with Windows Server). Which dist would be most suitable for me and has development utilities built in? Thanks

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• Need help choosing database server

  - by The Pretender

  Good day everyone. Recently I was given a task to develop an application to automate some aspects of stocks trading. While working on initial architecture, the database dilemma emerged. What I need is a fast database engine which can process huge amounts of data coming in very fast. I'm fairly experienced in general programming, but I never faced a task of developing a high-load database architecture. I developed a simple MSSQL database schema with several many-to-many relationships during one of my projects, but that's it. What I'm looking for is some advice on choosing the most suitable database engine and some pointers to various manuals or books which describe high-load database development. Specifics of the project are as follows: OS: Windows NT family (Server 2008 / 7) Primary platform: .NET with C# Database structure: one table to hold primary items and two or three tables with foreign keys to the first table to hold additional information. Database SELECT requirements: Need super-fast selection by foreign keys and by combination of foreign key and one of the columns (presumably DATETIME) Database INSERT requirements: The faster the better :) If there'll be significant performance gain, some parts can be written in C++ with managed interfaces to the rest of the system. So once again: given all that stuff I just typed, please give me some advice on what the best database for my project is. Links or references to some manuals and books on the subject are also greatly appreciated. EDIT: I'll need to insert 3-5 rows in 2 tables approximately once in 30-50 milliseconds and I'll need to do SELECT with 0-2 WHERE clauses queries with similar rate.

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• How does initializing inherited members inside base class constructor reduce the calls to…?

  - by flockofcode

  I’ve read that instead of initializing inherited members ( _c1 in our example ) inside derived constructor: class A { public int _c; } class B:A { public B(int c) { _c = c; } } we should initialize them inside base class constructor, since that way we reduce the calls to inherited members ( _c ): class A { public A(int c) { _c = c; } public int _c; } class B:A { public B(int c) : base(c) { } } If _c field is initialized inside base constructor, the order of initialization is the following: 1) First the field initializers of derived class B are called 2) Then field initializers of base class A are called (at this point _c is set to value 0) 3) B’s constructor is called, which in turn calls A’s custom constructor 4) _c field gets set to value of a parameter c ( inside A’s custom constructor ) 5) Once A’s custom constructor returns, B’s constructor executes its code. If _c field is initialized inside B's constructor, the order of initialization is the following: 1) First the field initializers of a derived class B are called 2) Then field initializers of a base class A are called(at this point _c is set to value 0) 3) B’s constructor is called, which in turn calls A’s default constructor 4) Once A’s custom constructor returns, B’s constructor sets _c field to a value of parameter c As far as I can tell, in both cases was _c called two times, so how exactly did we reduce calls to inherited member _c? thanx

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