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  • Updating and deleting java (red hat / centos) (new)

    - by JochemTheSchoolKid
    I am a total noob with linux. So please explain clearly if you have a solution for me. I have an VPS and I want to update JAVA. I found a guide on the Java site which says: rpm -e < package_name I searched for the packages: [root@srv1 ~]# rpm -qa | grep java java_cup-0.10k-5.el6.x86_64 java-1.5.0-gcj-1.5.0.0-29.1.el6.x86_64 Than I tried to do the delete command [root@srv1 ~]# rpm -e java-1.5.0-gcj-1.5.0.0-29.1.el6.x86_64 error: Failed dependencies: java-gcj-compat is needed by (installed) java_cup-1:0.10k-5.el6.x86_64 java-gcj-compat >= 1.0.70 is needed by (installed) sinjdoc-0.5-9.1.el6.x86_64 What should I do now? Removing has worked thanks to the answer below Problem two! Now am I installing this package from java [root@srv1 java]# rpm -ivh jre-7u9-linux-i586.rpm Preparing... ########################################### [100%] 1:jre ########################################### [100%] Unpacking JAR files... rt.jar... Error: Could not open input file: /usr/java/jre1.7.0_09/lib/rt.pack jsse.jar... Error: Could not open input file: /usr/java/jre1.7.0_09/lib/jsse.pack charsets.jar... Error: Could not open input file: /usr/java/jre1.7.0_09/lib/charsets.pack localedata.jar... Error: Could not open input file: /usr/java/jre1.7.0_09/lib/ext/localedata.pack plugin.jar... Error: Could not open input file: /usr/java/jre1.7.0_09/lib/plugin.pack javaws.jar... Error: Could not open input file: /usr/java/jre1.7.0_09/lib/javaws.pack deploy.jar... Error: Could not open input file: /usr/java/jre1.7.0_09/lib/deploy.pack Can someone help me again with this?

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  • The real differences between Red Hat Enterprise Linux (RHEL) and CentOS

    - by w00binda
    I know that "the vast majority of changes made (by CentOS team ndr) will be made to comply with the upstream vendor's re-distribution policies concerning trademarked names or logos" But I'm looking for a way to measure the real differences between RHEL and CentOS. My goal is to demonstrate "scientifically" that is possibile to use CentOS for development and testing purpose and use RHEL in the production environment. Any suggestion? Thanks in advance.

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  • Multicast Prblem in Linux Red Hat server

    - by Uma Kant Verma
    I am facing a very strange behavior on my server. I am using a linux cluster.On fail over server my broadcast application halts after 5 minutes.But it is working fine on Primary server. My application process listening on port and send broadcast.It is working 5 mins after that it wait on socket for further packets but it didn't receive anything. Same process is working fine at Primary server. Plz help me.

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  • How to install Red Hat Enterprise Linux on Apple Macbook Pro MacBookPro4,1

    - by Todd V. Rovito
    I have a one year old Mac Book Pro that I am trying to get RHEL 5.4 installed on via bootcamp. No matter what I do I can't get the installer to boot. I have tried multiple DVD's and even verified the install works on a new Mac Book Pro. Most of the time the installer simply locks up. I usually use Linux text with all-generic-ide on the boot line. I removed the ide parameter and I just used linux text. The results I get are that a bunch of kernel messages appear then the background turns blue and a thin text box pops up saying its loading ata..... something it disappears too fast for me to read. Then the machine freezes. I pressed the alt function keys to see if I could look at the system log, here is what it says: Alt-f3 says "trying to mount CD device hda" Alt-f4 says status error: hda: lastFailedSense Hda: Failed opcode was: unknown Hda: Lost interrupt Hda: Drive not ready for command Ide-cd: command 0x3 timed out Above this junk it looks like it found the partition because it knew it was 20 GB and listed as /dev/sda3. I think it has something to do with the CD drive, is that possible? Thanks again for the support. PS I posted in the apple support forums ( Apple.com Support Discussions Boot Camp Installation and Storage) and didn't get an answer.

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  • Locale setting on a Red Hat box

    - by sasuke
    Hi all, Recently our organization got a couple of server boxes which are I guess present in some data-center in UK. The problem is that for some reason the default Locale representation in Java on that server returns en_US instead of the expected en_GB (I confirmed this by running a code on that server which simply outputs Locale.default()). I am pretty sure this has got something to do the way in which the boxes were set up. My question is: what would be the approach to fix this issue now that the OS has been installed? Is there any way I can for a given SSH session set the locale as en_GB instead of the current en_US? TIA, sasuke

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  • Red Hat Kickstart: How do I Prevent partitioning?

    - by frio
    Hey all, I'm currently working on a new virtualisation setup using Xen, and Centos for my workplace. We intend to deploy the domUs into LVM volumes. Currently, the only thing preventing this from working as smoothly as we'd like is the Kickstart script's insistence on partitioning. This is the relevant part from our current KS template (which I've been messing with): # Partitioning clearpart --all --initlabel --drives=xvda part / --size=0 --grow --ondisk=xvda --fstype=ext3 This sets up a single partition and installs to it - which would be fine, but I'd prefer if there were no partitions, and installed directly to the existing LVM (so that we could then mount the LVM from the dom0 for backup and maintenance purposes). It's possible I'm doing something wrong, and should be exporting the volume as xvda1 rather than xvda - which I'm more than happy to amend - but I'm still not sure how I'd navigate the Kickstart! I'd really appreciate any help :). Cheers in advance!

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  • Updating and deleting java (red hat / centos)

    - by JochemTheSchoolKid
    I am a total noob with linux. So please explain clearly if you have a solution for me. I have an VPS and I want to update JAVA. I found a guide on the Java site which says: rpm -e < package_name I searched for the packages: [root@srv1 ~]# rpm -qa | grep java java_cup-0.10k-5.el6.x86_64 java-1.5.0-gcj-1.5.0.0-29.1.el6.x86_64 Than I tried to do the delete command [root@srv1 ~]# rpm -e java-1.5.0-gcj-1.5.0.0-29.1.el6.x86_64 error: Failed dependencies: java-gcj-compat is needed by (installed) java_cup-1:0.10k-5.el6.x86_64 java-gcj-compat >= 1.0.70 is needed by (installed) sinjdoc-0.5-9.1.el6.x86_64 What should I do now?

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  • Linux Kernel - Red/Black Trees

    - by CodeRanger
    I'm trying to implement a red/black tree in Linux per task_struct using code from linux/rbtree.h. I can get a red/black tree inserting properly in a standalone space in the kernel such as a module but when I try to get the same code to function with the rb_root declared in either task_struct or task_struct-files_struct, I get a SEGFAULT everytime I try an insert. Here's some code: In task_struct I create a rb_root struct for my tree (not a pointer). In init_task.h, macro INIT_TASK(tsk), I set this equal to RB_ROOT. To do an insert, I use this code: rb_insert(&(current-fd_tree), &rbnode); This is where the issue occurs. My insert command is the standard insert that is documented in all RBTree documentation for the kernel: int my_insert(struct rb_root *root, struct mytype *data) { struct rb_node **new = &(root->rb_node), *parent = NULL; /* Figure out where to put new node */ while (*new) { struct mytype *this = container_of(*new, struct mytype, node); int result = strcmp(data->keystring, this->keystring); parent = *new; if (result < 0) new = &((*new)->rb_left); else if (result > 0) new = &((*new)->rb_right); else return FALSE; } /* Add new node and rebalance tree. */ rb_link_node(&data->node, parent, new); rb_insert_color(&data->node, root); return TRUE; } Is there something I'm missing? Some reason this would work fine if I made a tree root outside of task_struct? If I make rb_root inside of a module this insert works fine. But once I put the actual tree root in the task_struct or even in the task_struct-files_struct, I get a SEGFAULT. Can a root node not be added in these structs? Any tips are greatly appreciated. I've tried nearly everything I can think of.

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  • wpf error template - red box still visible on collapse of an expander

    - by Andy Clarke
    Hi, I'm doing some validation on the DataSource of TextBox that's within an Expander and have found that once a validation error has been triggered, if I collapse the Expander, the red box stays where the TextBox would have been. <Expander Header="Blah Blah Blah"> <TextBox Name="TextBox" Validation.ErrorTemplate="{DynamicResource TextBoxErrorTemplate}" Text="{Binding Path=Blah, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" /> </Expander> I've tried to get round this by binding the visibility of the Error Template to the Expander, however I think there's something wrong with the binding. <local:NotVisibleConverter x:Key="NotVisibleConverter" /> <ControlTemplate x:Key="TextBoxErrorTemplate"> <DockPanel> <Border BorderBrush="Red" BorderThickness="2" Visibility="{Binding Path=IsExpanded, Converter={StaticResource NotVisibleConverter}, RelativeSource={RelativeSource AncestorType=Expander}}" > <AdornedElementPlaceholder Name="MyAdorner" /> </Border> </DockPanel> <ControlTemplate.Triggers> <Trigger Property="Validation.HasError" Value="true"> <Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors)[0].ErrorContent}"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> I guess I've gone wrong with my binding, can someone put me back on track please? Alternatively does anyone know another solution to the ErrorTemplate still being visible on the collapse of an Expander?

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  • Segmenting and masking all shades of red from an image using opencv

    - by vrinda
    I am trying to segment all shades of red form an image using hue saturation values and use InRangeS function to create a mask which should have all red areas whitened and all others blacked(a new 1 channel image). Thwn Inpaint them to kind of obscure the segmented portions. My code is as given. However I am unable to get an output image, it doesnt segment the desired color range. Any pointers on my approach and why it isnt working. ? using namespace std; int main() { IplImage *img1=cvLoadImage("/home/techrascal/projects/test1/image2.jpeg"); //IplImage *img3; IplImage *imghsv; IplImage *img4; CvSize sz=cvGetSize(img1); imghsv=cvCreateImage(sz,IPL_DEPTH_8U,3); img4=cvCreateImage(sz,IPL_DEPTH_8U,1); int width = img1->width; int height = img1->height; int bpp = img1->nChannels; cvNamedWindow("original", 1); cvNamedWindow("hsv",1); cvNamedWindow("Blurred",1); int r,g,b; // create inpaint mask: img 4 will behave as mask cvCvtColor(img1,imghsv,CV_BGR2HSV); CvScalar hsv_min = cvScalar(0, 0, 0, 0); CvScalar hsv_max = cvScalar(255, 0, 0, 0); //cvShowImage("hsv",imghsv); cvInRangeS( imghsv, hsv_min, hsv_max, img4 ); cvInpaint(img1, img4, img1, 3,CV_INPAINT_NS ); cvShowImage("Blurred",img1); cvReleaseImage(&img1); cvReleaseImage(&imghsv); cvReleaseImage(&img4); //cvReleaseImage(&img3); char d=cvWaitKey(10000); cvDestroyAllWindows(); return 0;}

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  • How to get skin tone color pixel in iPhone?

    - by aman-gupta
    Hi In my application I m using following way to get red pixel in a image // // PixelsAccessAppDelegate.h // PixelsAccess // // Created by Fortune1 on 14/04/10. // Copyright MyCompanyName 2010. All rights reserved. // import @class clsPixelAccess; NSUInteger numberOfRedPixels; NSUInteger numberOfRedPixels1; NSUInteger numberOfRedPixels2; NSUInteger numberOfRedPixels3; NSUInteger numberOfRedPixels4; NSUInteger numberOfRedPixels5; NSUInteger numberOfRedPixels6; NSUInteger numberOfRedPixels7; NSUInteger numberOfRedPixels8; NSUInteger numberOfRedPixels9; NSUInteger numberOfRedPixels10; NSUInteger numberOfRedPixels11; NSUInteger numberOfRedPixels12; NSUInteger numberOfRedPixels13; NSUInteger numberOfRedPixels14; NSUInteger numberOfRedPixels15; NSUInteger numberOfRedPixels16; NSUInteger numberOfRedPixels17; NSUInteger numberOfRedPixels18; NSUInteger numberOfRedPixels19; NSUInteger numberOfRedPixels20; NSUInteger numberOfRedPixels21; NSUInteger numberOfRedPixels22; NSUInteger numberOfRedPixels23; NSUInteger numberOfRedPixels24; NSUInteger numberOfRedPixels25; NSUInteger numberOfRedPixels26; NSUInteger numberOfRedPixels27; NSUInteger numberOfRedPixels28; NSUInteger numberOfRedPixels29; NSUInteger numberOfRedPixels30; NSUInteger numberOfRedPixels31; @interface PixelsAccessAppDelegate : NSObject { UIWindow *window; clsPixelAccess *obj; } @property (nonatomic, retain) IBOutlet UIWindow *window; -(IBAction)processImage:(id)sender; @end //////////////////// // // PixelsAccessAppDelegate.m // PixelsAccess // // Created by Fortune1 on 14/04/10. // Copyright MyCompanyName 2010. All rights reserved. // import "PixelsAccessAppDelegate.h" import "clsPixelAccess.h" @implementation PixelsAccessAppDelegate @synthesize window; (IBAction)processImage:(id)sender { NSUInteger retVal; obj = [[clsPixelAccess alloc] init]; NSInteger imageSend =[obj processImage1:[UIImage imageNamed:@"s.jpg"]]; NSInteger iamgeCall =[obj getPixelData:retVal]; NSUInteger *numberOfRedPixels = retVal; //lblPixelCount.text = [NSString stringWithFormat: @"There are %d red pixels in the image", numberOfRedPixels]; } (void)applicationDidFinishLaunching:(UIApplication *)application { // Override point for customization after application launch [window makeKeyAndVisible]; } (void)dealloc { [window release]; [super dealloc]; } @end /////////////// // // clsPixelsAccess.h // PixelsAccess // // Created by Fortune1 on 14/04/10. // Copyright 2010 MyCompanyName. All rights reserved. // import @interface clsPixelAccess : NSObject { } -(NSInteger) processImage1: (UIImage*) image; -(NSInteger)getPixelData:(NSUInteger *)pixelCount; @end ///////// // // clsPixelsAccess.m // PixelsAccess // // Created by Fortune1 on 14/04/10. // Copyright 2010 MyCompanyName. All rights reserved. // import "clsPixelAccess.h" import "PixelsAccessAppDelegate.h" @implementation clsPixelAccess struct pixel { //unsigned char r, g, b,a; Byte r, g, b, a; int count; }; -(NSInteger)getPixelData:(NSUInteger *)pixelCount { *pixelCount =numberOfRedPixels; return 1; } // Process the image and return the number of pure red pixels in it. (NSInteger) processImage1: (UIImage*) image { // Allocate a buffer big enough to hold all the pixels struct pixel* pixels = (struct pixel*) calloc(1, image.size.width * image.size.height * sizeof(struct pixel)); if (pixels != nil) { // Create a new bitmap CGContextRef context = CGBitmapContextCreate( (void*) pixels, image.size.width, image.size.height, 8, image.size.width * 4, CGImageGetColorSpace(image.CGImage), kCGImageAlphaPremultipliedLast ); //NSLog(@"1=%d, 2=%d, 3=%d", CGImageGetBitsPerComponent(image), CGImageGetBitsPerPixel(image),CGImageGetBytesPerRow(image)); if (context != NULL) { // Draw the image in the bitmap CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, image.size.width, image.size.height), image.CGImage); NSUInteger numberOfPixels = image.size.width * image.size.height; NSMutableArray *numberOfPixelsArray = [[[NSMutableArray alloc] initWithCapacity:numberOfPixelsArray] autorelease]; NSLog( @"Pixel data %d", numberOfPixelsArray); /* NSMatrix *newMatrix = [[NSMatrix alloc] initWithFrame:NSMakeRect(138.0f, 85.0f, 0.0f, 0.0f) mode:NSRadioModeMatrix prototype:prototypeButtonCell numberOfRows: numberOfColumns:]; */ while (numberOfPixels &gt; 0) { if (pixels-&gt;r &gt; 0 &amp;&amp; pixels-&gt;r &lt;= 7) { numberOfRedPixels++; } NSLog( @"Red pixel data %d",numberOfRedPixels); if (pixels-&gt;r &gt;= 8 &amp;&amp; pixels-&gt;r &lt;= 15) { numberOfRedPixels1++; } NSLog( @"Red pixel data1 %d",numberOfRedPixels1); if (pixels-&gt;r &gt;= 16 &amp;&amp; pixels-&gt;r &lt;=23 ) { numberOfRedPixels2++; } NSLog( @"Red pixel data2 %d",numberOfRedPixels2); if (pixels-&gt;r &gt;= 24 &amp;&amp; pixels-&gt;r &lt;=31 ) { numberOfRedPixels3++; } NSLog( @"Red pixel data3 %d",numberOfRedPixels3); if (pixels-&gt;r &gt;= 32 &amp;&amp; pixels-&gt;r &lt;= 39) { numberOfRedPixels4++; } NSLog( @"Red pixel data4 %d",numberOfRedPixels4); if (pixels-&gt;r &gt;= 40 &amp;&amp; pixels-&gt;r &lt;= 47) { numberOfRedPixels5++; } NSLog( @"Red pixel data5 %d",numberOfRedPixels5); if (pixels-&gt;r &gt;= 48 &amp;&amp; pixels-&gt;r &lt;= 55) { numberOfRedPixels6++; } NSLog( @"Red pixel data6 %d",numberOfRedPixels6); if(pixels-&gt;r &gt;= 56 &amp;&amp; pixels-&gt;r &lt;= 63) { numberOfRedPixels7++; } NSLog( @"Red pixel data7 %d",numberOfRedPixels7); if (pixels-&gt;r &gt;= 64 &amp;&amp; pixels-&gt;r &lt;= 71) { numberOfRedPixels8++; } NSLog( @"Red pixel data8 %d",numberOfRedPixels8); if (pixels-&gt;r &gt;= 72 &amp;&amp; pixels-&gt;r &lt;= 79) { numberOfRedPixels9++; } NSLog( @"Red pixel data9 %d",numberOfRedPixels9); if (pixels-&gt;r &gt;= 80 &amp;&amp; pixels-&gt;r &lt;= 87) { numberOfRedPixels10++; } NSLog( @"Red pixel data10 %d",numberOfRedPixels10); if (pixels-&gt;r &gt;= 88 &amp;&amp; pixels-&gt;r &lt;= 95) { numberOfRedPixels11++; } NSLog( @"Red pixel data11 %d",numberOfRedPixels11); if (pixels-&gt;r &gt;= 96 &amp;&amp; pixels-&gt;r &lt;= 103) { numberOfRedPixels12++; } NSLog( @"Red pixel data12 %d",numberOfRedPixels12); if (pixels-&gt;r &gt;= 104 &amp;&amp; pixels-&gt;r &lt;= 111) { numberOfRedPixels13++; } NSLog( @"Red pixel data13 %d",numberOfRedPixels13); if (pixels-&gt;r &gt;= 112 &amp;&amp; pixels-&gt;r &lt;= 119) { numberOfRedPixels14++; } NSLog( @"Red pixel data14 %d",numberOfRedPixels14); if (pixels-&gt;r &gt;= 120 &amp;&amp; pixels-&gt;r &lt;= 127) { numberOfRedPixels15++; } NSLog( @"Red pixel data15 %d",numberOfRedPixels15); if (pixels-&gt;r &gt; 128 &amp;&amp; pixels-&gt;r &lt;= 135) { numberOfRedPixels16++; } NSLog( @"Red pixel data16 %d",numberOfRedPixels16); if (pixels-&gt;r &gt;= 136 &amp;&amp; pixels-&gt;r &lt;= 143) { numberOfRedPixels17++; } NSLog( @"Red pixel data17 %d",numberOfRedPixels17); if (pixels-&gt;r &gt;= 144 &amp;&amp; pixels-&gt;r &lt;=151) { numberOfRedPixels18++; } NSLog( @"Red pixel data18 %d",numberOfRedPixels18); if (pixels-&gt;r &gt;= 152 &amp;&amp; pixels-&gt;r &lt;=159 ) { numberOfRedPixels19++; } NSLog( @"Red pixel data19 %d",numberOfRedPixels19); if (pixels-&gt;r &gt;= 160 &amp;&amp; pixels-&gt;r &lt;= 167) { numberOfRedPixels20++; } NSLog( @"Red pixel data20 %d",numberOfRedPixels20); if (pixels-&gt;r &gt;= 168 &amp;&amp; pixels-&gt;r &lt;= 175) { numberOfRedPixels21++; } NSLog( @"Red pixel data21 %d",numberOfRedPixels21); if (pixels-&gt;r &gt;= 176 &amp;&amp; pixels-&gt;r &lt;= 199) { numberOfRedPixels22++; } NSLog( @"Red pixel data22 %d",numberOfRedPixels22); if(pixels-&gt;r &gt;= 184 &amp;&amp; pixels-&gt;r &lt;= 191) { numberOfRedPixels23++; } NSLog( @"Red pixel data23 %d",numberOfRedPixels23); if (pixels-&gt;r &gt;= 192 &amp;&amp; pixels-&gt;r &lt;= 199) { numberOfRedPixels24++; } NSLog( @"Red pixel data24 %d",numberOfRedPixels24); if (pixels-&gt;r &gt;= 200 &amp;&amp; pixels-&gt;r &lt;= 207) { numberOfRedPixels25++; } NSLog( @"Red pixel data25 %d",numberOfRedPixels25); if (pixels-&gt;r &gt;= 208 &amp;&amp; pixels-&gt;r &lt;= 215) { numberOfRedPixels26++; } NSLog( @"Red pixel data26 %d",numberOfRedPixels26); if (pixels-&gt;r &gt;= 216 &amp;&amp; pixels-&gt;r &lt;= 223) { numberOfRedPixels27++; } NSLog( @"Red pixel data27 %d",numberOfRedPixels27); if (pixels-&gt;r &gt;= 224 &amp;&amp; pixels-&gt;r &lt;= 231) { numberOfRedPixels28++; } NSLog( @"Red pixel data28 %d",numberOfRedPixels28); if (pixels-&gt;r &gt;= 232 &amp;&amp; pixels-&gt;r &lt;= 239) { numberOfRedPixels29++; } NSLog( @"Red pixel data29 %d",numberOfRedPixels29); if (pixels-&gt;r &gt;= 240 &amp;&amp; pixels-&gt;r &lt;= 247) { numberOfRedPixels30++; } NSLog( @"Red pixel data30 %d",numberOfRedPixels30); if (pixels-&gt;r &gt;= 248) { numberOfRedPixels31++; } NSLog( @"Red pixel data31 %d",numberOfRedPixels31); pixels++; numberOfPixels--; } CGContextRelease(context); } free(pixels); } return 1; } @end My problem is I want skin Tone Pixel how it could be possible Please help me out. Thanks in Advance

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  • IE7 Gets "Red X" when using jQuery Hover

    - by Brett
    Hi Guys, I am using a preview script via http://cssglobe.com/lab/tooltip/03/ The problem is that when I use SRC tag in this script - I get a big fat red X - in IE7 BEFORE the image is rendered. Once the image appears - all looks ok. Is there anyway to "hide" this before its loaded or something ? Love an help anyone can provide.

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  • C programming getting back into it - the red pill

    - by JavaRocky
    Can someone provide recommended reading, website resources or best practices to follow when programming with C. I am a proficient software developer with strong skills in Java and PHP. Is there standard libraries these days which people use? Like what spring is to java? And standard design patterns for managing memory or even standard libraries for that fact? I want to write solid, maintainable C programs. GO THE RED PILL! :P

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  • Background not changing to red

    - by Doug
    http://dougymak.com/jquery/# First time playing with jQuery, and kind of stuck already. I'm expecting the background to change to red on hover, but it's not for some reason. Can anyone give me a hand? Thanks!

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  • get rid of red X in IE for non-existing images

    - by hubertg
    I have a 3rd website (Confluence) which references images which are secured by a login. If the current user is logged in the image is shown if not the image url would redirect to a login form. Example When you enter this url in the browser a redirect to the login page is done. The problem now: IE shows a the dreaded red X icon for the image even though there should be just nothing (like in Firefox). Anyone knows how to get around this?

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  • Persistent (purely functional) Red-Black trees on disk performance

    - by Waneck
    I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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