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  • why there is a lot change in the hardware support features in different linux os?

    - by TrazerWalker
    i am using lenovo b460 with 3 GB ram and 500 GB hard disk,(no graphics card). when i live boot Linux mint i was able to connect to WiFi.but when i booted up Ubuntu 11.4 i was not able to connect through WiFi.then later i installed Ubuntu 12.4 and then i got connected with WiFi, but after installing icons and themes through my unity i am not able to view the content in the terminal and the WiFi is also not connecting now even after i changed them all back. wireless connectivity

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  • Why use binary files to stack up different versions on DMSs?

    - by edgarator
    I've used both Liferay and Alfresco trying to use them as the Document Management System for an intranet. I noticed the following: They use the file system and the database to store files They use a GUID to name the file on the filesystem and that GUID is used as an Id in the database. The GUID-named file is a binary file The GUID-named binary file stores all versions for a given file The path for the file in the DMS doesn't match the one in the file system The URL makes reference to the GUID when a certain file is requested What I want to know is why is this, and what would be the best way of doing it. Like how to would you create the binary file (zip?), and what parts would you keep in the binary file and what parts would you store in the database (meta-data, path?). I'm assuming some of the benefits of doing it like this. As having the same URL for a file, regardless of its current document path. And having only one file even if the file has changed names over time.

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  • iphone: Help with AudioToolbox Leak: Stack trace/code included here...

    - by editor guy
    Part of this app is a "Scream" button that plays random screams from cast members of a TV show. I have to bang on the app quite a while to see a memory leak in Instruments, but it's there, occasionally coming up (every 45 seconds to 2 minutes.) The leak is 3.50kb when it occurs. Haven't been able to crack it for several hours. Any help appreciated. Instruments says this is the offending code line: [appSoundPlayer play]; that's linked to from line 9 of the below stack trace: 0 libSystem.B.dylib malloc 1 libSystem.B.dylib pthread_create 2 AudioToolbox CAPThread::Start() 3 AudioToolbox GenericRunLoopThread::Start() 4 AudioToolbox AudioQueueNew(bool, AudioStreamBasicDescription const*, TCACallback const&, CACallbackTarget const&, unsigned long, OpaqueAudioQueue*) 5 AudioToolbox AudioQueueNewOutput 6 AVFoundation allocAudioQueue(AVAudioPlayer, AudioPlayerImpl*) 7 AVFoundation prepareToPlayQueue(AVAudioPlayer*, AudioPlayerImpl*) 8 AVFoundation -[AVAudioPlayer prepareToPlay] 9 Scream Queens -[ScreamViewController scream:] /Users/laptop2/Desktop/ScreamQueens Versions/ScreamQueens25/Scream Queens/Classes/../ScreamViewController.m:210 10 CoreFoundation -[NSObject performSelector:withObject:withObject:] 11 UIKit -[UIApplication sendAction:to:from:forEvent:] 12 UIKit -[UIApplication sendAction:toTarget:fromSender:forEvent:] 13 UIKit -[UIControl sendAction:to:forEvent:] 14 UIKit -[UIControl(Internal) _sendActionsForEvents:withEvent:] 15 UIKit -[UIControl touchesEnded:withEvent:] 16 UIKit -[UIWindow _sendTouchesForEvent:] 17 UIKit -[UIWindow sendEvent:] 18 UIKit -[UIApplication sendEvent:] 19 UIKit _UIApplicationHandleEvent 20 GraphicsServices PurpleEventCallback 21 CoreFoundation CFRunLoopRunSpecific 22 CoreFoundation CFRunLoopRunInMode 23 GraphicsServices GSEventRunModal 24 UIKit -[UIApplication _run] 25 UIKit UIApplicationMain 26 Scream Queens main /Users/laptop2/Desktop/ScreamQueens Versions/ScreamQueens25/Scream Queens/main.m:14 27 Scream Queens start Here's .h: #import <UIKit/UIKit.h> #import <AVFoundation/AVFoundation.h> #import <MediaPlayer/MediaPlayer.h> #import <AudioToolbox/AudioToolbox.h> #import <MessageUI/MessageUI.h> #import <MessageUI/MFMailComposeViewController.h> @interface ScreamViewController : UIViewController <UIApplicationDelegate, AVAudioPlayerDelegate, MFMailComposeViewControllerDelegate> { //AudioPlayer related AVAudioPlayer *appSoundPlayer; NSURL *soundFileURL; BOOL interruptedOnPlayback; BOOL playing; //Scream button related IBOutlet UIButton *screamButton; int currentScreamIndex; NSString *currentScream; NSMutableArray *screams; NSMutableArray *personScreaming; NSMutableArray *photoArray; int currentSayingsIndex; NSString *currentButtonSaying; NSMutableArray *funnyButtonSayings; IBOutlet UILabel *funnyButtonSayingsLabel; IBOutlet UILabel *personScreamingField; IBOutlet UIImageView *personScreamingImage; //Mailing the scream related IBOutlet UILabel *mailStatusMessage; IBOutlet UIButton *shareButton; } //AudioPlayer related @property (nonatomic, retain) AVAudioPlayer *appSoundPlayer; @property (nonatomic, retain) NSURL *soundFileURL; @property (readwrite) BOOL interruptedOnPlayback; @property (readwrite) BOOL playing; //Scream button related @property (nonatomic, retain) UIButton *screamButton; @property (nonatomic, retain) NSMutableArray *screams; @property (nonatomic, retain) NSMutableArray *personScreaming; @property (nonatomic, retain) NSMutableArray *photoArray; @property (nonatomic, retain) UILabel *personScreamingField; @property (nonatomic, retain) UIImageView *personScreamingImage; @property (nonatomic, retain) NSMutableArray *funnyButtonSayings; @property (nonatomic, retain) UILabel *funnyButtonSayingsLabel; //Mailing the scream related @property (nonatomic, retain) IBOutlet UILabel *mailStatusMessage; @property (nonatomic, retain) IBOutlet UIButton *shareButton; //Scream Button - (IBAction) scream: (id) sender; //Mail the scream - (IBAction) showPicker: (id)sender; - (void)displayComposerSheet; - (void)launchMailAppOnDevice; @end Here's the top of .m: #import "ScreamViewController.h" //top of code has Audio session callback function for responding to audio route changes (from Apple's code), then my code continues... @implementation ScreamViewController @synthesize appSoundPlayer; // AVAudioPlayer object for playing the selected scream @synthesize soundFileURL; // Path to the scream @synthesize interruptedOnPlayback; // Was application interrupted during audio playback @synthesize playing; // Track playing/not playing state @synthesize screamButton; //Press this button, girls scream. @synthesize screams; //Mutable array holding strings pointing to sound files of screams. @synthesize personScreaming; //Mutable array tracking the person doing the screaming @synthesize photoArray; //Mutable array holding strings pointing to photos of screaming girls @synthesize personScreamingField; //Field updates to announce which girl is screaming. @synthesize personScreamingImage; //Updates to show image of the screamer. @synthesize funnyButtonSayings; //Mutable array holding the sayings @synthesize funnyButtonSayingsLabel; //Label that updates with the funnyButtonSayings @synthesize mailStatusMessage; //did the email go out @synthesize shareButton; //share scream via email Next line begins the block with the offending code: - (IBAction) scream: (id) sender { //Play a click sound effect SystemSoundID soundID; NSString *sfxPath = [[NSBundle mainBundle] pathForResource:@"aClick" ofType:@"caf"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:sfxPath],&soundID); AudioServicesPlaySystemSound (soundID); // Because someone may slam the scream button over and over, //must stop current sound, then begin next if ([self appSoundPlayer] != nil) { [[self appSoundPlayer] setDelegate:nil]; [[self appSoundPlayer] stop]; [self setAppSoundPlayer: nil]; } //after selecting a random index in the array (did that in View Did Load), //we move to the next scream on each click. //First check... //Are we past the end of the array? if (currentScreamIndex == [screams count]) { currentScreamIndex = 0; } //Get the string at the index in the personScreaming array currentScream = [screams objectAtIndex: currentScreamIndex]; //Get the string at the index in the personScreaming array NSString *screamer = [personScreaming objectAtIndex:currentScreamIndex]; //Log the string to the console NSLog (@"playing scream: %@", screamer); // Display the string in the personScreamingField field NSString *listScreamer = [NSString stringWithFormat:@"scream by: %@", screamer]; [personScreamingField setText:listScreamer]; // Gets the file system path to the scream to play. NSString *soundFilePath = [[NSBundle mainBundle] pathForResource: currentScream ofType: @"caf"]; // Converts the sound's file path to an NSURL object NSURL *newURL = [[NSURL alloc] initFileURLWithPath: soundFilePath]; self.soundFileURL = newURL; [newURL release]; [[AVAudioSession sharedInstance] setDelegate: self]; [[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error: nil]; // Registers the audio route change listener callback function AudioSessionAddPropertyListener ( kAudioSessionProperty_AudioRouteChange, audioRouteChangeListenerCallback, self ); // Activates the audio session. NSError *activationError = nil; [[AVAudioSession sharedInstance] setActive: YES error: &activationError]; // Instantiates the AVAudioPlayer object, initializing it with the sound AVAudioPlayer *newPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL: soundFileURL error: nil]; //Error check and continue if (newPlayer != nil) { self.appSoundPlayer = newPlayer; [newPlayer release]; [appSoundPlayer prepareToPlay]; [appSoundPlayer setVolume: 1.0]; [appSoundPlayer setDelegate:self]; //NEXT LINE IS FLAGGED BY INSTRUMENTS AS LEAKY [appSoundPlayer play]; playing = YES; //Get the string at the index in the photoArray array NSString *screamerPic = [photoArray objectAtIndex:currentScreamIndex]; //Log the string to the console NSLog (@"displaying photo: %@", screamerPic); // Display the image of the person screaming personScreamingImage.image = [UIImage imageNamed:screamerPic]; //show the share button shareButton.hidden = NO; mailStatusMessage.hidden = NO; mailStatusMessage.text = @"share!"; //Get the string at the index in the funnySayings array currentSayingsIndex = random() % [funnyButtonSayings count]; currentButtonSaying = [funnyButtonSayings objectAtIndex: currentSayingsIndex]; NSString *theSaying = [funnyButtonSayings objectAtIndex:currentSayingsIndex]; [funnyButtonSayingsLabel setText: theSaying]; currentScreamIndex++; } } Here's my dealloc: - (void)dealloc { [appSoundPlayer stop]; [appSoundPlayer release], appSoundPlayer = nil; [screamButton release], screamButton = nil; [mailStatusMessage release], mailStatusMessage = nil; [personScreamingField release], personScreamingField = nil; [personScreamingImage release], personScreamingImage = nil; [funnyButtonSayings release], funnyButtonSayings = nil; [funnyButtonSayingsLabel release], funnyButtonSayingsLabel = nil; [screams release], screams = nil; [personScreaming release], personScreaming = nil; [soundFileURL release]; [super dealloc]; } @end Thanks so much for reading this far! Any input appreciated.

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  • Choosing the right TV tuner - USB or PCI TV tuners, hardware/software, DVB? Hybrid/combo/analog?

    - by Nucleon
    Greetings, I'll start with some background information so you know what I'm trying to accomplish and then get to my question. I work at a Television station in the US and we are working on setting up an online DVR/Podcast system for all of our newscasts. So basically we would be recording every newscast in HD, encoding it to flv/h.264 for viewing in a browser on flash compatible and iphone/ipad devices, eventually migrating to WebM when it's browser compliant. This task is theoretically pretty simple as it all it involves is a TV tuner device and a program like VLC, MythTV or whatever to schedule and dump it to a file, encode it with VLC/FFMPEG and push it to the streaming server. Now to the hardware, in order to accomplish that task, should I use an internal PCI tuner or a USB 2.0 tuner? Is there a difference? The bus speeds of both are not too far apart, and is the bus speed really relevant in this case? Does it matter if the device has a hardware encoder or a software encoder? On many sites the USB was recommended for ease of set up and use, but would it overly task a processor, or is that not a concern as long as it's a decent PC (at least duo core, 6gb ram). What's the difference between the stick USB and the Box USBs? To my understanding analog is basically gone in the US, so we would want a hybrid or combo tuner correct? How do those differ from DVB? Are there any other features or concepts which I am missing which may influence the recommended product. It would be ideal if the device which could work in both Linux and a Windows environment, to my knowledge most Hauppauge are? Example 1: PCI Hauppage http://www.newegg.com/Product/Product.aspx?Item=N82E16815116033 Example 2: USB 2.0 Box http://www.newegg.com/Product/Product.aspx?Item=N82E16815116029 Example 3: USB 2.0 Stick http://www.newegg.com/Product/Product.aspx?Item=N82E16815116031 Any guidance from the Superusers would be much appreciated!

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  • Can a hardware firewall block a server accessing its OWN UNC shares?

    - by Simon
    I need to set up a UNC share for my hosted dedicated server to access a share on itself. Unfortunately TFS requires a UNC share. I am on a Windows Server 2008 Standard SP2 64bit dedicated server behind a PIX 501 firewall hosted with GoDaddy. I just cannot get the server to access itself and get this error: Windows cannot access \\SERVER\SHARE Check the spelling of the name.. etc. I've found numerous questions about this but no answer to my problem. Server 2008 Standard x64 SP2 Workgroup - not domain Windows Firewall is off Computer browser service is on I am trying to access \\MYMACHINE\TFS-BUILDS by typing in - or double clicking. Neither works. Machine has single network card Filesharing wizard says share was ok Share was showing under 'Computer management' Permissions are set to 'everyone' full control No obvious errors in eventlog Reboot didn't fix it Unfortunately I cannot try to access other shares in or out of this machine because it is a hosted dedicated server and the only machine behind a hardware firewall. The only thing left i can think of is that the hardware firewall needs to be configured. Is this possible? Does 'UNC traffic' go out of the machine and then back in again?

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  • What's the piece of hardware listening on Facebook's or Wikipedia's IP address?

    - by Igor Ostrovsky
    I am trying to understand how massive sites like Facebook or Wikipedia work, for my intellectual curiosity. I read about various techniques for building scalable sites, but I am still puzzled about one particular detail. The part that confuses me is that ultimately, the DNS will map the entire domain to a single IP address, or a handful of IP addresses in the case of round-robin DNS. For example, wikipedia.org has only one type-A DNS record. So, people from all over the world visiting Wikipedia have to send a request to the one IP address specified in DNS. What is the piece of hardware that listens on the IP address for a massive site, and how can it possibly handle all the load coming from the requests for users all over the world? Edit 1: Thanks for all the responses! Anycast seems like a feasible answer... Does anyone know of a way to check whether a particular IP address is anycast-routed, so that I could verify that this really is the trick used in practice by large sites? Edit 2: After more reading on the topic, it appears that anycast is not typically used for dynamic web content. Anycast is usually used for UDP (e.g., DNS lookups), or sometimes for static content. One interesting thing to note is that Facebook uses profile.ak.fbcdn.net to host static content like style sheets and javascript libraries. Each time I ping this name, I get a response from a different IP address. However, I can't tell whether this is anycast in action, or a completely different technique. Back to my original question: as far as I can tell, even a large site will have a single expensive piece of load-balancing hardware listening on its handful of public IP addresses.

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  • How do I lower the hardware volume? (volume too high)

    - by Zom-B
    I have a 4yo Dell laptop with Windows XP Pro (modern ones unfortunately don't have a physical volume knob), and lately I'm using my Apple earphones, because they have much better low frequency response than my $10 earphones. They also have the side effect of being much louder. To give an indication of my agony, for most tasks (movie, music, games) I have my main volume at 3 ticks: drag to 0 with the mouse and press the up key 3 times (the handle does not even raise 1 pixel) and my wave volume at 50%. I notice that when I do this, I have a lot of digital noise, because I'm using just a tiny fraction of the 16-bit space. If I drag the Wave slider down until I barely hear the audio, it becomes really distorted and noisy, indicating that this is digital volume (in the DirectSound driver or something) and not hardware volume. I experimented in Audition. When I make a tone of 1000Hz at -50db, (all windows volumes at max) the volume is just below my pain threshold. When I zoom in to see how high the sample values reach, I see that just 8 of the 16 bits are used (about -100 ~ 100). When I generate such tone at -80db (minimum I can specify) then I can still clearly hear the tone, although really noisy. When I zoom in, I see that just 3 out of 16 bits are used. I created a squarewave tone that is just 1 bit high, and I can still hear it! For most uses, this is not a big problem (audiophiles will disagree!), as I just have more noise than usual (about the same as old 8 bit hardware), but I'm also in the process of programming a hearing test program, in which case this problem is a death blow as the test subjects will even hear tones at the bottom of the theoretical range (lowering the windows volume is futile, see above) (I cannot update drivers, as Dell has discontinued XP support for my model)

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  • Zero downtime deployment (Tomcat), Nginx or HAProxy, behind hardware LB - how to "starve" old server?

    - by alexeypro
    Currently we have the following setup. Hardware Load Balancer (LB) Box A running Tomcat on 8080 (TA) Box B running Tomcat on 8080 (TB) TA and TB are running behind LB. For now it's pretty complicated and manual job to take Box A or Box B out of LB to do the zero downtime deployment. I am thinking to do something like this: Hardware Load Balancer (LB) Box A running Nginx on 8080 (NA) Box A running Tomcat on 8081 (TA1) Box A running Tomcat on 8082 (TA2) Box B running Nginx on 8080 (NB) Box B running Tomcat on 8081 (TB1) Box B running Tomcat on 8082 (TB2) Basically LB will be directing traffic between NA and NB now. On each of Nginx's we'll have TA1, TA2 and TB1, TB2 configured as upstream servers. Once one of the upstreams's healthcheck page is unresponsive (shutdown) the traffic goes to another one (HttpHealthcheckModule module on Nginx). So the deploy process is simple. Say, TA1 is active with version 0.1 of the app. Healthcheck on TA1 is OK. We start TA2 with Healthcheck on it as ERROR. So Nginx is not talking to it. We deploy app version 0.2 to TA2. Make sure it works. Now, we switch the Healthcheck on TA2 to OK, switch Healthcheck to TA1 to ERROR. Nginx will start serving TA2, and will remove TA1 out of rotation. Done! And now same with the other box. While it sounds all cool and nice, how do we "starve" the Nginx? Say we have pending connections, some users on TA1. If we just turn it off, sessions will break (we have cookie-based sessions). Not good. Any way to starve traffic to one of the upstream servers with Nginx? Thanks!

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  • How do I optimize TCP stack for HTTP server?

    - by jcisio
    I have a HTTP server that serves only two kinds of page: about 10 KB and about 16 KB (both compressed, other files are from CDN). As the latency is quite high (ping takes more than 300 ms), I want to optimize the TCP stack so that client receives the whole page ASAP. Thus, I have a double question: Which parameter do I have to change (which value of TCP window)? How to change in (a Debian box, and FYI, there is a Varnish before the HTTP server).

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  • How to get stack dump from crashing ASP.NET process?

    - by Dylan
    An unhandled exception ('System.Net.Sockets.SocketException') occurred in w3wp.exe [9740]. Just-In-Time debugging this exception failed with the following error: Debugger could not be started because no user is logged on. We're getting the above error in the Application log. Is there a way to capture a .NET stack trace that doesn't require user interactivity?

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  • 32bit to 64bit inline assembly porting

    - by Simone Margaritelli
    I have a piece of C++ code (compiled with g++ under a GNU/Linux environment) that load a function pointer (how it does that doesn't matter), pushes some arguments onto the stack with some inline assembly and then calls that function, the code is like : unsigned long stack[] = { 1, 23, 33, 43 }; /* save all the registers and the stack pointer */ unsigned long esp; asm __volatile__ ( "pusha" ); asm __volatile__ ( "mov %%esp, %0" :"=m" (esp)); for( i = 0; i < sizeof(stack); i++ ){ unsigned long val = stack[i]; asm __volatile__ ( "push %0" :: "m"(val) ); } unsigned long ret = function_pointer(); /* restore registers and stack pointer */ asm __volatile__ ( "mov %0, %%esp" :: "m" (esp) ); asm __volatile__ ( "popa" ); I'd like to add some sort of #ifdef _LP64 // 64bit inline assembly #else // 32bit version as above example #endif But i don't know inline assembly for 64bit machines, anyone could help me? Thanks

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  • Python: re-initialize a function's default value for subsequent calls to the function.

    - by Peter Stewart
    I have a function that calls itself to increment and decrement a stack. I need to call it a number of times, and I'd like it to work the same way in subsequent calls but, as expected, it doesn't re-use the default value. I've read that this is a newbie trap and I've seen suggested solutions, but I haven't been able to make any solution work. It would be nice to be able to "fun.reset" def a(x, stack = [None]): print x,' ', stack if x > 5: temp = stack.pop() if x <=5: stack.append(1) if stack == []: return a(x + 1) print a(0) print a(2) #second call print a(3) #third call I expected this to work, but it doesn't. print a(0, [None]) print a(2, [None]) #second call print a(3, [None]) #third call Can I reset the function to it's initial state? Any help would be appreciated.

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  • jQuery action being called when selector isn't met?

    - by dougoftheabaci
    I've been working on a prototype for a client's web site and I've run into a rather significant snag. You can view the prototype here. As you can see, the way it works is you can scroll a set of slides horizontally and, by clicking one, open a stack containing yet more slides. If you then click again on an image in that stack it opens up a lightbox. Clicking on another stack or the close button will close that stack (and open another, as case may be). That all works great. However you get some weird behavior if you do the following: Click to open any stack. Click to open an image's light box (this works best if you click on the image that's level with the main list). Close the light box and the stack either by clicking the close button or clicking on another stack. Click back to the first stack. Instead of reopening the stack, you get the lightbox. This confuses me as the light box should only ever be called if there is a class on the containing UL and that class is removed when the lightbox is closed. I've checked and double-checked this, it's definitely missing. Here are the respective functions: $("ul.hide a.lightbox").live("click",function(){ $("ul.show").removeClass("show").addClass("hide"); $(this).parent().parent().removeClass("hide").addClass("show"); $("ul.hide").animate({opacity: 0.2}); $("ul.show").animate({opacity: 1}); $("#next").animate({opacity: 0.2}); $("#prev").animate({opacity: 0.2}); return false; }); $("ul.show a.lightbox").live("click",function(){ $(this).fancybox().trigger("click"); return false; }); As you can see, in order for the lightbox to be called the containing UL has to have the class of show. However, if you check it with Firebug it won't. For those who are curious, the added .trigger("click"); is because the lightbox will require a double-click to launch otherwise. Any idea how I can fix this?

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  • How solve consumer/producer task using semaphores

    - by user1074896
    I have SimpleProducerConsumer class that illustrate consumer/producer problem (I am not sure that it's correct). public class SimpleProducerConsumer { private Stack<Object> stack = new Stack<Object>(); private static final int STACK_MAX_SIZE = 10; public static void main(String[] args) { SimpleProducerConsumer pc = new SimpleProducerConsumer(); new Thread(pc.new Producer(), "p1").start(); new Thread(pc.new Producer(), "p2").start(); new Thread(pc.new Consumer(), "c1").start(); new Thread(pc.new Consumer(), "c2").start(); new Thread(pc.new Consumer(), "c3").start(); } public synchronized void push(Object d) { while (stack.size() >= STACK_MAX_SIZE) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } stack.push(new Object()); System.out.println("push " + Thread.currentThread().getName() + " " + stack.size()); notify(); } public synchronized Object pop() { while (stack.size() == 0) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(50); } catch (InterruptedException e) { e.printStackTrace(); } stack.pop(); System.out.println("pop " + Thread.currentThread().getName() + " " + stack.size()); notify(); return null; } class Consumer implements Runnable { @Override public void run() { while (true) { pop(); } } } class Producer implements Runnable { @Override public void run() { while (true) { push(new Object()); } } } } I found simple realization of semaphore(here:http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html I know that there is concurrency package) How I need to change code to exchange java objects monitors to my custom semaphore. (To illustrate C/P problem using semaphores) Semaphore: class Semaphore { private int counter; public Semaphore() { this(0); } public Semaphore(int i) { if (i < 0) throw new IllegalArgumentException(i + " < 0"); counter = i; } public synchronized void release() { if (counter == 0) { notify(); } counter++; } public synchronized void acquire() throws InterruptedException { while (counter == 0) { wait(); } counter--; } }

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  • Is recursion really bad?

    - by dotneteer
    After my previous post about the stack space, it appears that there is perception from the feedback that recursion is bad and we should avoid deep recursion. After writing a compiler, I know that the modern computer and compiler are complex enough and one cannot automatically assume that a hand crafted code would out-perform the compiler optimization. The only way is to do some prototype to find out. So why recursive code may not perform as well? Compilers place frames on a stack. In additional to arguments and local variables, compiles also need to place frame and program pointers on the frame, resulting in overheads. So why hand-crafted code may not performance as well? The stack used by a compiler is a simpler data structure and can grow and shrink cleanly. To replace recursion with out own stack, our stack is allocated in the heap that is far more complicated to manage. There could be overhead as well if the compiler needs to mark objects for garbage collection. Compiler also needs to worry about the memory fragmentation. Then there is additional complexity: CPUs have registers and multiple levels of cache. Register access is a few times faster than in-CPU cache access and is a few 10s times than on-board memory access. So it is up to the OS and compiler to maximize the use of register and in-CPU cache. For my particular problem, I did an experiment to rewrite my c# version of recursive code with a loop and stack approach. So here are the outcomes of the two approaches:   Recursive call Loop and Stack Lines of code for the algorithm 17 46 Speed Baseline 3% faster Readability Clean Far more complex So at the end, I was able to achieve 3% better performance with other drawbacks. My message is never assuming your sophisticated approach would automatically work out better than a simpler approach with a modern computer and compiler. Gage carefully before committing to a more complex approach.

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  • LIVE: Oracle FY13 Partner Kickoff - Red Stack. Red Team. Engineered to Win.

    - by Kristin Rose
    Oracle’s FY13 Partner Kickoff is still in full swing and what an exciting day it has already been! Oracle executives started their mornings off at 5 a.m. to address our partners from around the world. The day began with the EMEA region, closely followed by the North America region in front of a live audience, and then on to Latin America! But hang tight because Japan and APAC are up next!If you haven’t already done so, be sure you register to watch the rest of the show. Also, join the Twitter conversation via #OPN and @OraclePartners and keep sending in those questions. Here is what the rest of the day looks like: JAPAN - 6:00pm – 7:30pm PT APAC - 8:00 pm – 9:30pm PT We also had a chance to speak with Nick Kritikos, VP of Partner Enablement and host of the PKO after show, “Partner Pulse”, to get his thoughts on the day. See what Nick had to say below: To all of our Partners, thanks for tuning in! Until next year, Good Selling,The OPN Communications Team

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  • How to "Un-Eject" a USB Flash drive -- Eject is easy (safely remove hardware), but what about Un-Eje

    - by Jian Lin
    There are times after I eject a USB Flash drive, I want to copy some more files over to the USB Flash drive. In this case, do I always need to unplug the drive and plug it back in? Is there a way to "reconnect" or "un-eject" the drive? To eject, that are two ways: 1) Right Click the drive (say H:) and choose Eject 2) Click "Safely remove hardware" from the icon tool But there seems to be no way to un-eject or reconnect a drive.

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  • List DB2 version, OS and hardware on Linux? (aws image)

    - by mestika
    Hello everybody, I'm not that familiar with Linux but I'm currently working on a aws image for an assignment and I need to display the DB2 version, the OS and the hardware. Is there a commando or program of some sort I can use for this purpose? I tried a rpm called "Bonnie" but that only writes the throughput for the system. Thanks Mestika

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  • List DB2 version, OS and hardware on Linux? (aws image)H

    - by mestika
    Hello everybody, I'm not that familiar with Linux but I'm currently working on a aws image for an assignment and I need to display the DB2 version, the OS and the hardware. Is there a commando or program of some sort I can use for this purpose? I tried a rpm called "Bonnie" but that only writes the throughput for the system. Thanks Mestika

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  • Any hardware/software routers that support Full Cone NAT?

    - by Ian Boyd
    i'm trying to get Teredo to function on my machine. Most routers, it seems, refuse to forward packets from any host other than the one i specifically connected to first. Teredo requires full Cone NAT in order to function. Does any router, hardware or software, allow full cone NAT? Is this an oversight by the designers of Teredo that nobody, in practice, can use it? i've tried m0n0wall pfsense D-Link Linksys SMC

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