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  • Redirect output of Python program to /dev/null

    - by STM
    I have a Python executable, written and compiled by somebody else, that I simply need to run once halfway down my own bash script. The program uses a text-based UI, therefore waits for input before proceeding, but the key operations it performs when starting are required in my bash script. A messy (and strange) procedure I know, but unfortunately I haven't got any other options. I've gotten around forcefully closing the program with a kill signal, but the program's TUI insists on outputting to wherever it's run. I've tried redirecting both stdout and stderr to /dev/null and running the program in the background by suffixing an ampersand, but simply can't get it to play ball. I believe the cause is the program spawns other processes, and the output redirection of the parent process doesn't affect them. Is there any trick I can utilise to redirect all output from child processes too?

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  • Ubuntu login takes 15 seconds, "I/O error dev fd0 sector 0"

    - by Dan
    After upgrading to Ubuntu 10.04, when I first login it takes 10+ seconds where it just sits at the gdm backgroup before taking me to gnome. By switching to a terminal window during this 10 seconds I saw the error message "I/O error /dev/fd0 sector 0" being outputted. I assume this has to do with the floppy drive... but I don't even have a floppy drive! How do I disable this device and make this error message go away (and hopefully fix the long wait)? Thanks.

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  • Webserver: Performance impact when storing session files on /dev/shm

    - by GetFree
    I have a website runing on a typical setup: Linux, Apache, PHP, MySQL. However, what's not typical about it, is that it's getting tons of traffic (400,000+ visits a day) and so, efficiency is becoming more and more important to me. I'm constantly looking for things I could optimize and, right now, my attention is focused on PHP's session files. There's a hell lot of session files constantly being read and created on the /tmp directory. So my question is: Is it a good idea to store the session files in /dev/shm (tmpfs) in order to speed things up a little bit??

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  • mount dev, proc, sys in a chroot environment?

    - by Patrick
    I'm trying to create a Linux image with custom picked packages. I followed the guide here http://www.olpcnews.com/forum/index.php?topic=4766.0 However, when I tried to install some packages, it failed to configure due to missing the proc, sys, dev directories. So, I learned from other places that I need to "mount" the host proc, ... directories to my chroot environment. Though, I saw two syntax and am not sure which one to use. In host machine: mount --bind /proc <chroot dir>/proc and another syntax (in chroot envrionment): mount -t proc none /proc Which one should I use, and what are the difference? Edit: What I'm trying to do is to hand craft the packages I'm going to use on an XO laptop, because compiling packages takes really long time on the real XO hardware, if I can build all the packages I need and just flash the image to the XO, I can save time and space.

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  • end_request: I/O error, dev sda, sector xxxxxxxxx

    - by muruga
    I have a IBM server. This server contains 3 hard disk with RAID 5. It was working fine earlier. Unfortunately this machine got the following error message. After that I have rebooted the systems. After that I am getting the following error message in kern.log and demsg kernel: [65896.678870] end_request: I/O error, dev sda, sector 17430271 kernel: [69263.783957] sd 0:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK : [69263.783957] sd 0:0:0:0: [sda] Sense Key : Hardware Error [current] kernel: [69263.783957] sd 0:0:0:0: [sda] Add. Sense: Internal target failure Whether it is kernel problem or hard disk problem or Raid problem

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  • xf86OpenConsole: Cannot open /dev/tty0 (No such file or directory)

    - by mazgalici
    root@mazgalici:~# startx X.Org X Server 1.7.6 Release Date: 2010-03-17 X Protocol Version 11, Revision 0 Build Operating System: Linux 2.6.24-28-server i686 Ubuntu Current Operating System: Linux mazgalici 2.6.18-194.26.1.el5.028stab079.2PAE #1 SMP Fri Dec 17 19:34:22 MSK 2010 i686 Kernel command line: quiet Build Date: 10 November 2010 11:25:26AM xorg-server 2:1.7.6-2ubuntu7.4 (For technical support please see ) Current version of pixman: 0.16.4 Before reporting problems, check to make sure that you have the latest version. Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. (==) Log file: "/var/log/Xorg.0.log", Time: Tue Jan 11 01:28:48 2011 (==) Using config directory: "/usr/lib/X11/xorg.conf.d" Fatal server error: xf86OpenConsole: Cannot open /dev/tty0 (No such file or directory) Please consult the The X.Org Foundation support at http://wiki.x.org for help. Please also check the log file at "/var/log/Xorg.0.log" for additional information. ddxSigGiveUp: Closing log

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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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  • How to redirect output away from /dev/null

    - by Gowtham
    I have an application that runs the a command as below: <command> >& /dev/null I have no control on this. All the o/p generated by this command goes to /dev/null. I want the output to be visible on screen or redirected to a log file. I tried to use freopen() and related functions to reopen /dev/null to another file, but could not get it working. Do you have any other ideas? Is this possible at all? Thanks for your time. PS: I am working on Linux. -Gowtham

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  • Installing SharePoint 2010 on a dev machine with an external database

    - by Dan Revell
    I've been following Microsoft's guide for installing a dev environment on Windows 7: http://msdn.microsoft.com/en-us/library/ee554869.aspx In order for it to not run like a dog I've created a SQL Server 2008 instance on our database server specifically for this dev machine. The article does mention that you might be wanting to use an external database in regard to making sure the database cumulative update is installed. It doesn't make any other mention of configuring it to use a external database. I was hoping that the configuration wizard would then prompt about which database to use but annoyingly it just set-up the configuration database locally. How do I go about installing SharePoint on a dev environment with an external database, and will I need to reformat this machine and do it all again?

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  • No device file for partition on logical volume (Linux LVM)

    - by Brian
    I created a logical volume (scandata) containing a single ext3 partition. It is the only logical volume in its volume group (case4t). Said volume group is comprised by 3 physical volumes, which are three primary partitions on a single block device (/dev/sdb). When I created it, I could mount the partition via the block device /dev/mapper/case4t-scandatap1. Since last reboot the aforementioned block device file has disappeared. It may be of note -- I'm not sure -- that my superior (a college professor) had prompted this reboot by running sudo chmod -R [his name] /usr/bin, which obliterated all suid in its path, preventing the both of us from sudo-ing. That issue has been (temporarily) rectified via this operation. Now I'll cut the chatter and get started with the terminal dumps: $ sudo pvs; sudo vgs; sudo lvs Logging initialised at Sat Jan 8 11:42:34 2011 Set umask to 0077 Scanning for physical volume names PV VG Fmt Attr PSize PFree /dev/sdb1 case4t lvm2 a- 819.32G 0 /dev/sdb2 case4t lvm2 a- 866.40G 0 /dev/sdb3 case4t lvm2 a- 47.09G 0 Wiping internal VG cache Logging initialised at Sat Jan 8 11:42:34 2011 Set umask to 0077 Finding all volume groups Finding volume group "case4t" VG #PV #LV #SN Attr VSize VFree case4t 3 1 0 wz--n- 1.69T 0 Wiping internal VG cache Logging initialised at Sat Jan 8 11:42:34 2011 Set umask to 0077 Finding all logical volumes LV VG Attr LSize Origin Snap% Move Log Copy% Convert scandata case4t -wi-a- 1.69T Wiping internal VG cache $ sudo vgchange -a y Logging initialised at Sat Jan 8 11:43:14 2011 Set umask to 0077 Finding all volume groups Finding volume group "case4t" 1 logical volume(s) in volume group "case4t" already active 1 existing logical volume(s) in volume group "case4t" monitored Found volume group "case4t" Activated logical volumes in volume group "case4t" 1 logical volume(s) in volume group "case4t" now active Wiping internal VG cache $ ls /dev | grep case4t case4t $ ls /dev/mapper case4t-scandata control $ sudo fdisk -l /dev/case4t/scandata Disk /dev/case4t/scandata: 1860.5 GB, 1860584865792 bytes 255 heads, 63 sectors/track, 226203 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x00049bf5 Device Boot Start End Blocks Id System /dev/case4t/scandata1 1 226203 1816975566 83 Linux $ sudo parted /dev/case4t/scandata print Model: Linux device-mapper (linear) (dm) Disk /dev/mapper/case4t-scandata: 1861GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 1861GB 1861GB primary ext3 $ sudo fdisk -l /dev/sdb Disk /dev/sdb: 1860.5 GB, 1860593254400 bytes 255 heads, 63 sectors/track, 226204 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x00000081 Device Boot Start End Blocks Id System /dev/sdb1 1 106955 859116006 83 Linux /dev/sdb2 113103 226204 908491815 83 Linux /dev/sdb3 106956 113102 49375777+ 83 Linux Partition table entries are not in disk order $ sudo parted /dev/sdb print Model: DELL PERC 6/i (scsi) Disk /dev/sdb: 1861GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 880GB 880GB primary reiserfs 3 880GB 930GB 50.6GB primary 2 930GB 1861GB 930GB primary I find it a bit strange that partition one above is said to be reiserfs, or if it matters -- it was previously reiserfs, but LVM recognizes it as a PV. To reiterate, neither /dev/mapper/case4t-scandatap1 (which I had used previously) nor /dev/case4t/scandata1 (as printed by fdisk) exists. And /dev/case4t/scandata (no partition number) cannot be mounted: $sudo mount -t ext3 /dev/case4t/scandata /mnt/new mount: wrong fs type, bad option, bad superblock on /dev/mapper/case4t-scandata, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so All I get on syslog is: [170059.538137] VFS: Can't find ext3 filesystem on dev dm-0. Thanks in advance for any help you can offer, Brian P.S. I am on Ubuntu GNU/Linux 2.6.28-11-server (Jaunty) (out of date, I know -- that's on the laundry list).

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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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  • Error installing RVM

    - by Dbugger
    I am following this guide, but this is the output I receive. What am the problem? dbugger@mercury:~$ \curl -sSL https://get.rvm.io | bash -s stable --rails Downloading https://github.com/wayneeseguin/rvm/archive/stable.tar.gz Upgrading the RVM installation in /home/dbugger/.rvm/ RVM PATH line found in /home/dbugger/.profile /home/dbugger/.bashrc /home/dbugger/.zshrc. RVM sourcing line found in /home/dbugger/.bash_profile /home/dbugger/.zlogin. Upgrade of RVM in /home/dbugger/.rvm/ is complete. # Enrique, # # Thank you for using RVM! # We sincerely hope that RVM helps to make your life easier and more enjoyable!!! # # ~Wayne, Michal & team. In case of problems: http://rvm.io/help and https://twitter.com/rvm_io Upgrade Notes: * No new notes to display. rvm 1.25.27 (stable) by Wayne E. Seguin <[email protected]>, Michal Papis <[email protected]> [https://rvm.io/] Searching for binary rubies, this might take some time. No binary rubies available for: ubuntu/14.04/x86_64/ruby-2.1.2. Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies. Checking requirements for ubuntu. Installing requirements for ubuntu. Updating system.......... Installing required packages: gawk, libreadline6-dev, libssl-dev, libyaml-dev, libsqlite3-dev, sqlite3.... Error running 'requirements_debian_libs_install gawk libreadline6-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3', showing last 15 lines of /home/dbugger/.rvm/log/1401804140_ruby-2.1.2/package_install_gawk_libreadline6-dev_libssl-dev_libyaml-dev_libsqlite3-dev_sqlite3.log ++ /scripts/functions/utility : __rvm_try_sudo() 405 > sudo -p '%p password required for '\''apt-get --no-install-recommends --yes install gawk libreadline6-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3'\'': ' apt-get --no-install-recommends --yes install gawk libreadline6-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3 Reading package lists... Building dependency tree... Reading state information... Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: libssl-dev : Depends: libssl1.0.0 (= 1.0.1f-1ubuntu2) but 1.0.1f-1ubuntu2.1 is to be installed E: Unable to correct problems, you have held broken packages. ++ /scripts/functions/utility : __rvm_try_sudo() 405 > return 100 ++ /scripts/functions/requirements/ubuntu : requirements_debian_libs_install() 36 > return 100 Requirements installation failed with status: 100.

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  • RAID1: can't replace faulty spare (marked again as 'faulty spare' within seconds)

    - by user212475
    I got a problem that I cannot solve: Our fileserver runs XUbuntu and 3 RAID1s. One has a problem since monday: it consists of sdb and sdc. sdb was marked as faulty by mdadm for unknown reasons. I used --remove to remove it from the RAID and then to add it by --add. All was fine, re-syncing started but never got above 0% and after a few seconds, sdb was again marked as 'faulty spare' (and therefore the RAID degraded, but clean). So I saved the first 512 byte of the old sdb to a file, bought a new HDD of same size (4TB), shut down the computer and replaced sdb physically, switched the computer back on and wrote the 512 byte back to the new drive to have the same partition info as the old drive (both are the same type, from same company). But the new drive shows the same behaviour as the old: I can add, re-syncing starts and after a few seconds its marked as 'faulty spare'. Here exactly what i did: mdadm --remove /dev/md/1 /dev/sdb maadm --detail /dev/md/1 gives me: /dev/md/1: Version : 1.2 Creation Time : Sat Jun 8 22:32:05 2013 Raid Level : raid1 Array Size : 3906887360 (3725.90 GiB 4000.65 GB) Used Dev Size : 3906887360 (3725.90 GiB 4000.65 GB) Raid Devices : 2 Total Devices : 1 Persistence : Superblock is persistent Update Time : Thu Nov 7 06:56:13 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 Name : File-Server:1 (local to host File-Server) UUID : 44ed561f:b733e946:e69820f4:aba9b223 Events : 2424 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 32 1 active sync /dev/sdc mdadm --add /dev/md/1 /dev/sdb mdadm --detail /dev/md/1 gives me: Version : 1.2 Creation Time : Sat Jun 8 22:32:05 2013 Raid Level : raid1 Array Size : 3906887360 (3725.90 GiB 4000.65 GB) Used Dev Size : 3906887360 (3725.90 GiB 4000.65 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Thu Nov 7 06:57:49 2013 State : clean, degraded, recovering Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Rebuild Status : 0% complete Name : File-Server:1 (local to host File-Server) UUID : 44ed561f:b733e946:e69820f4:aba9b223 Events : 2431 Number Major Minor RaidDevice State 2 8 16 0 faulty spare rebuilding /dev/sdb 1 8 32 1 active sync /dev/sdc and after a few seconds: /dev/md/1: Version : 1.2 Creation Time : Sat Jun 8 22:32:05 2013 Raid Level : raid1 Array Size : 3906887360 (3725.90 GiB 4000.65 GB) Used Dev Size : 3906887360 (3725.90 GiB 4000.65 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Thu Nov 7 06:57:50 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Name : File-Server:1 (local to host File-Server) UUID : 44ed561f:b733e946:e69820f4:aba9b223 Events : 2436 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 32 1 active sync /dev/sdc 2 8 16 - faulty spare /dev/sdb same behaviour if I zero the superblock (mdadm --zero-superblock /dev/sdb) before adding sdb. I do all commands as root and the system holds 3 more 4TB drives, ie the mainboard can handle them. The old harddrive was checked for errors using badblocks, but all is fine. Does anybody have any idea, what the problem is?

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