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  • Point[] and Tri not "could not be found"

    - by Craig Dannehl
    Hi I'm trying to learn how to load a .obj file using OpenTK in windows Forms. I have seen a lot of examples out there, but I do see almost everyone uses List, and Point[]. Code example show these highlighted like there IDE know what these are; for example List<Tri> tris = new List<Tri>(); but mine just returns "The type or namespace name 'Tri' could not be found" is there an include I need to add or a using I am missing. Currently have this using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Drawing; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL;

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  • /usr/share/apport/apport-gpu-error-intel.py Error

    - by gopherballs
    I was on Ubuntu 12.10 and ran the system updates and after the re-install, the system became unstable and kept prompting me with the message "System Issue" and this as the error per Ubuntu "/usr/share/apport/apport-gpu-error-intel.py". After I tried re-starting, the issue is still appearing and the system ultimately freezes (requiring a hard reset). I tried a clean install of 12.10 and the system works fine until the newest updates are applied...it then returns to the same messages. I then tried a clean install of 12.04 LTS and just like 12.10 it works until the latest updates are applied. On 12.04, I tried to use the previous kernel - going from 3.5.0-26 to 3.5.0-23 and the issue is still there. Currently, I'm sitting on 12.04 LTS clean install without doing the updates and the system is working. Does anyone have an idea how to fix this? Thanks.

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  • Cannot open an external hard drive in Windows

    - by SeeBees
    In Windows 7, I was installing wubi ubuntu to an external hard drive when suddenly it disconnected from the PC. After I connected it back to PC, and double clicked the drive's icon, Windows didn't show the content of the disk but asked me whether I wanted to format it. The hard drive has only one partition. Its format is NTFS. I also connected the disk to Windows XP. It makes the Windows Explorer super slow and I cannot open the disk as well. I can open the disk on Ubuntu and Mac. Is it possible to restore the disk and make it run in Windows? Thanks

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  • PLEASE HELP RECOVER MY MINT14 BOOT/GRUB [closed]

    - by C2940680
    Hi I have following from [bootinfoscript][1] v0.61 [1Apr-2012]: I tried to do several time to do a boot-repair from YannUbuntu. However, I get error rebooting into my Linux Mint 14 Cinnamon. I have partitioned /boot, /, /home partitions. Could I still use /home partition if I recover files on to external USB and then reformatting the whole hard drive, repartition and use /home from USB drive which I have saved before? Also, I tried to install Qubes 2beta and then deleted the partition where it was stored. Also, also {my bad} I tried to copy the BOOT.CFG from sda6 to sda1 and sda2. All answers appreciated in advance. sda1: __________________________________________ File system: ext2 Boot sector type: - Boot sector info: Operating System: Boot files: /grub/grub.cfg sda2: __________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sda5: __________________________________________ File system: swap Boot sector type: - Boot sector info: sda6: __________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Linux Mint 14 Nadia Boot files: /boot/grub/grub.cfg /etc/fstab

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  • GRUB2 not working after installing xubuntu 14.04

    - by h3bm
    I have a vaio laptop and it used to have installed windows 8 and Xubuntu 13.04 in dual boot, everything was working fine. I decided to update my version of xubuntu 14.04 LTS mainly because the support for 13.04 is finished and LTS version have 3 years of support. What I did was to format the partition where xubuntu 13.04 was installed and install 14.04 in that formated partition. When I restarted my computer willing to start using my new system I got the following message: error: symbol 'grub_term_highlight_color' not found and I was not able to enter any OS. I tried boot-repair from live USB more than two times and it did not fix the problem. I tried to enter to my computer using super GRUB2 disk, however it does not apperar to work with UEFI active (besides super grub2 disk says it can) I only get the message "no operating system found". If I boot super grub2 disk with UEFI disabled, super grub2 disk can not detect any OS,I also tried Rescatux distro, however, as of super grub2 disk, rescatux cannot enter when UEFI is active. I tried boot-repair with the option of "restore EFI backups", after that I was able to boot on windows, but no grub menu appeared. I ran boot-repair again with no improving results Here is the last Bootinfo report I got: http://paste.ubuntu.com/7609801/ Do you have any idea of what is happening? I really appreciate your help, Best regards,

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  • How to remove unused usings from class file ?

    - by Samir R. Bhogayta
    When we create a .cs file means code file class is automatically create. That .cs file means class has default usings for namespace. using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls; We don't use all namespaces  in that class so we have to remove unused namespaces from file. We can remove  namespace manually but it takes time and need full knowledge of class library so we can use Visual Studio . Step 1:  Right Click in .cs File. Step 2:  Move on Organize usings. Step 3: Click on Remove Unused Usings. After that we have only those namespaces in the file these are using.  

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  • Need to Extend Volume

    - by Roger Galindo
    Ok Here is where I am... I have an HP Proliant with 8 Drives configured as RAID5, and C:\Drive Disk 0 and D:\ drive Disk 1. I need to add more space to Disk 0 (C:) and have 150GB available on Disk 1 (D:). I tested the Disk Mgmt on D:\ and freed up 4GB which now shows to be Unallocated. How do I add the 4GB of Unallocated to the c:\? When I click on C:\ the Menu shows "Extend Volume" as Grayed Out not Black but the D:\ Drive shows Extend Volume as selectable/black.

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  • I cannot remove/install software some dependency issue?

    - by Ryuzaki
    I'm having difficulty trying to install/uninstall applications in Ubuntu 12.04 LTS. I have this warning error that appears on my desktop in the form of a red icon with a line through it and it states: An error occurred, please run Package Manager from the right-click menu or apt-get in a terminal to see what is wrong. The error message was: 'Error: BrokenCount 0' — This usually means that your installed packages have unmet dependencies. I tried to repair automatically through ubuntu software center and I kept getting errors or it just didn't seem to work. Afterwards, I opened terminal and used sudo apt-get check command to see what the problem was and the results yielded: Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: libjack-jackd2-0 : Breaks: libjack-jackd2-0:i386 (!= 1.9.8~dfsg.1-1ubuntu1) but 1.9.8~dfsg.2-1precise1 is installed libjack-jackd2-0:i386 : Breaks: libjack-jackd2-0 (!= 1.9.8~dfsg.2-1precise1) but 1.9.8~dfsg.1-1ubuntu1 is installed E: Unmet dependencies. Try using -f. After I ran sudo apt-get -f install (in an attempt to fix the issue at hand), I encountered the following errors/code: okudaira@haru-kano:~$ sudo apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: libjack-jackd2-0 Suggested packages: jackd2 The following packages will be upgraded: libjack-jackd2-0 1 upgraded, 0 newly installed, 0 to remove and 24 not upgraded. 1 not fully installed or removed. Need to get 0 B/197 kB of archives. After this operation, 3,072 B of additional disk space will be used. Do you want to continue [Y/n]? y (Reading database ... 181702 files and directories currently installed.) Preparing to replace libjack-jackd2-0 1.9.8~dfsg.1-1ubuntu1 (using .../libjack-jackd2-0_1.9.8~dfsg.2-1precise1_amd64.deb) ... Unpacking replacement libjack-jackd2-0 ... dpkg: error processing /var/cache/apt/archives/libjack-jackd2-0_1.9.8~dfsg.2-1precise1_amd64.deb (--unpack): './usr/share/doc/libjack-jackd2-0/buildinfo.gz' is different from the same file on the system dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing: /var/cache/apt/archives/libjack-jackd2-0_1.9.8~dfsg.2-1precise1_amd64.deb localepurge: Disk space freed in /usr/share/locale: 0 KiB localepurge: Disk space freed in /usr/share/man: 0 KiB localepurge: Disk space freed in /usr/share/gnome/help: 0 KiB localepurge: Disk space freed in /usr/share/omf: 0 KiB Total disk space freed by localepurge: 0 KiB E: Sub-process /usr/bin/dpkg returned an error code (1) The real problem I'm having is interpreting what is being stated. I'm fairly new to the ubuntu experience so I'm not very well-versed with the terminology and the entire in's and out's. Can someone tell me what's wrong with my system? I can no longer install/remove any programs at all.

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  • How should I determine direction from a phone's orientation & accelerometer?

    - by Manoj Kumar
    I have an Android application which moves a ball based on the orientation of the phone. I've been using the following code to extract the data - but how do I use it to determine what direction the ball should actually travel in? public void onSensorChanged(int sensor, float[] values) { // TODO Auto-generated method stub synchronized (this) { Log.d("HIIIII :- ", "onSensorChanged: " + sensor + ", x: " + values[0] + ", y: " + values[1] + ", z: " + values[2]); if (sensor == SensorManager.SENSOR_ORIENTATION) { System.out.println("Orientation X: " + values[0]); System.out.println("Orientation Y: " + values[1]); System.out.println("Orientation Z: " + values[2]); } if (sensor == SensorManager.SENSOR_ACCELEROMETER) { System.out.println("Accel X: " + values[0]); System.out.println("Accel Y: " + values[1]); System.out.println("Accel Z: " + values[2]); } } }

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  • 12.04 indicates filesystem check on next boot, but never does one

    - by pcm
    Just installed 12.04 32 bit on my machine, with 3 drives. When I open a terminal window or ssh in remotely, I see: Welcome to Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-29-generic-pae i686)  * Documentation:  https://help.ubuntu.com/ *** /dev/sda1 will be checked for errors at next reboot *** *** /dev/sda2 will be checked for errors at next reboot *** *** /dev/sdg1 will be checked for errors at next reboot *** Last login: Fri Aug 31 08:15:41 2012 from .... However, if I reboot, I never see it doing a disk check on boot up, like I used to see with 10.10. Note, after install, I was not seeing the grub menu on boot. I made a ISO disk with BootRepair and now I get the normal grub menu. Any idea as to why the disk check is not happening on boot (I know I can boot a Live CD and then check the disk - I just want the check on boot working)?

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  • Windows 7/Ubuntu 12 dual boot deleted for Windows 8 installation. How to make grub rescue go away?

    - by dimious
    I had a Windows 7/Ubuntu 12 dual boot and I decided to clean install Windows 8 over them. The problem is that after I deleted all partitions and installed windows I was getting an "Operation system not found", however after an "enter" the system will normally boot into Windows 8. I realized that Windows did their trick and put the system (not partition anymore?!?) "tag" (Disk Management) on my media hard drive. After trying to fix the boot/mbr to be able to boot from my main drive the "Operation system not found" changed to the "grub rescue" prompt. I know that I cannot use that because I have killed the grub files. Windows can still boot as long as I choose to boot from the media drive. The question is, is there any way to move the "system", whatever it is now, to the main drive and have the PC boot from there, while making grub disappear? And if that is possible after that, can I just make the Media drive inactive or I will have to somehow remove the "system" tag?

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  • Are Windows partitions gone?

    - by Gigili
    I had Windows 7 on my laptop (factory setting), because of some performance issues, I decided to use recovery options to restore it to its factory condition but I don't know what has happened or what I have done that the whole operating system was gone after playing around with recovery options from the boot menu. I couldn't find Windows, so I installed Ubuntu 11.04 on my laptop. Last time I had Ubuntu on it, it was not really compatible with laptop's configuration and I had a bit of problems trying to do normal tasks I used to do on Windows. Now I want to make sure that Windows and its drivers are gone so that I can try to install a newer version of Ubuntu or Windows. I tried the command sudo fdisk -l And the result shown was: myaccount@myaccount-VPCS116FG:~$ sudo fdisk -l [sudo] password for myaccount: Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00025b5f Device Boot Start End Blocks Id System /dev/sda1 * 1 38409 308515840 83 Linux /dev/sda2 38409 38914 4052993 5 Extended /dev/sda5 38409 38914 4052992 82 Linux swap / Solaris Disk /dev/dm-0: 4150 MB, 4150263808 bytes 255 heads, 63 sectors/track, 504 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xa668cfe8 Disk /dev/dm-0 doesn't contain a valid partition table Is it gone? If not, what command should I try to have access to Windows partitions? Thank you.

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  • IPS Package Groups

    - by Alan_Solaris_RE
    IPS group packages consist solely of dependencies on other packages that make up a logical grouping of software. These are similar to, but not the equivalent of, Solaris 10 metaclusters. The main difference is that metaclusters are nested subsets ranging from a minimal install to nearly all packages on the media. Group packages have no such hierarchy. They can overlap other groups, or be completely disjoint sets. A group dependency is set this way in an IPS package manifest file: depend fmri=full/pkg/name type=group Current Solaris Groups Solaris currently has 4 system groups defined. These are used for different types of installation, and are included in the xml manifest files used by the various Solaris installers: Package Name Summary Description Default Installation For:  group/system/solaris-desktop Oracle Solaris Desktop Provides an Oracle Solaris desktop environment Live Media  group/system/solaris-large-server Oracle Solaris Large Server Provides an Oracle Solaris large server environment Text Installer  group/system/solaris-small-server Oracle Solaris Small Server Provides a useful command-line Oracle Solaris environment  Zones  group/system/solaris-auto-install  Oracle Solaris Automated Installer Client  Provides an Oracle Solaris Automated Installer client  Automated Installer There are also several "feature" groups such as AMP and GNU Developer Tools. These are provided for convenience, but are not used directly by any installers. Retrieving Group Package Information A listing of all current groups can be found with the command: pkg info -r group/* A listing of all the packages in a group can be obtained with: pkg contents -o fmri -H -rt depend -a type=group groupname An example: $ pkg contents -o fmri -H -rt depend -a type=group solaris-desktop archiver/gnu-tar audio/audio-utilities codec/flac codec/libtheora codec/ogg-vorbis codec/speex communication/im/pidgin etc. You can determine which package group is currently installed on your system: $ pkg list group/system/\* Output would look like: NAME (PUBLISHER) VERSION IFO group/system/solaris-desktop 0.5.11-0.175.0.0.0.0.0 i-- Note that there are not version numbers associated with a group package dependency. The package version that best fits the system will be used, based on other dependencies such as what is listed in incorporation files. Installing a Group To Install a group, simple use the group package name as you would any other package: $ pkg install solaris-small-server  If you want to exclude a package from installing, you can use the --reject flag: $ pkg install --reject audio/audio-utilities solaris-desktop Creating Your Own Group To create your own group package, you can follow the pkg(5) documentation on how to create a package, and use this action for each package that is part of your group:   depend fmri=full/pkg/name type=group

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  • Is it bad to have a very full hard drive on a high traffic database server?

    - by MikeN
    Running an Ubuntu server with MySQL for a high traffic production database server. Nothing else is running on the machine except the MySQL instance. We store daily database backups on the DB server, is there any performance hit or reason why we should keep the hard disk relatively empty? If the disk is filled up to 86%+ with the database and all of the backups, does it hurt performance at all? So would the DB server running with 86-90%+ full capacity perform less well in any way than the server running with only a 10% full disk? The total disk size on the server is over 1 TB so even 10% of the disk should be enough for basic O/S swapping and such.

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  • why client can not receive message from server (java) [migrated]

    - by user1745931
    I have just started learning java. I modified the client side code for a server/client communication program, by creating two threads for the client side, main thread for receiving user's input, and inputThread for receiving server's response. I am sure that server has sent the response to client, however, no response message is obtain at client. Here is my code. Can anyone help me to figure it out? Thanks package clientnio; import java.net.*; import java.nio.*; import java.io.*; import java.nio.channels.*; import java.util.Scanner; public class ClientNIO { public static int bufferLen = 50; public static SocketChannel client; public static ByteBuffer writeBuffer; public static ByteBuffer readBuffer; public static void main(String[] args) { writeBuffer = ByteBuffer.allocate(bufferLen); readBuffer = ByteBuffer.allocate(bufferLen); try { SocketAddress address = new InetSocketAddress("localhost",5505); System.out.println("Local address: "+ address); client=SocketChannel.open(address); client.configureBlocking(false); //readBuffer.flip(); new inputThread(readBuffer); /* String a="asdasdasdasddffasfas"; writeBuffer.put(a.getBytes()); writeBuffer.clear(); int d=client.write(writeBuffer); writeBuffer.flip(); */ while (true) { InputStream inStream = System.in; Scanner scan = new Scanner(inStream); if (scan.hasNext()==true) { String inputLine = scan.nextLine(); writeBuffer.put(inputLine.getBytes()); //writeBuffer.clear(); System.out.println(writeBuffer.remaining()); client.write(writeBuffer); System.out.println("Sending data: "+new String(writeBuffer.array())); writeBuffer.flip(); Thread.sleep(300); } } } catch(Exception e) { System.out.println(e); } } } class inputThread extends Thread { private ByteBuffer readBuffer; public inputThread(ByteBuffer readBuffer1) { System.out.println("Receiving thread starts."); this.readBuffer = readBuffer1; start(); } @Override public void run() { try { while (true) { readBuffer.flip(); int i=ClientNIO.client.read(readBuffer); if(i>0) { byte[] b=readBuffer.array(); System.out.println("Receiving data: "+new String(b)); //client.close(); //System.out.println("Connection closed."); //break; } Thread.sleep(100); } } catch (Exception e) { System.out.println(e); } } }

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  • Create windows XP's live USB using ubuntu

    - by Avnish
    My hard disk crashed.. I can run Ubuntu using a pendrive by making a live USB of Ubuntu, which I made using Windows 7. In the similar way, I want to run Windows XP too using another pen drive (without hard disk) and I want to make it from Ubuntu (12.04). The resources I have are Ubuntu's live USB, Windows XP and Windows 7 installation disk, some blank DVDs but no hard drive. I have very basic knowledge of Linux. Thanks

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  • mount remotely mybook live network drive

    - by bob
    I have a mybook live western digital 1TB hard disk connected to fritzbox 7270 router in office. When I am in the office, I can mount this drive to ubuntu since I have added to the etc/fstab file: //192.168.178.30/user /home/user/DISK cifs auto,iocharset=utf8,user=user%password 0 0 Is there a similar, easy & safe way, to do the same when I am out of the office using the static IP of the fritzbox router? I have already added tcp port forwarding in the router for ports 8080 (to 80 of the disk) and 8443 (to 443 of the disk). Thank you in advance

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  • Deployment from OVA format

    - by Manvendra Bele
    I am deploying a VM using a OVA format. The size of OVA format is 57 GB. Currently free space on my datastore is 388 GB. At the time of selecting Disk Format type if shows me in red that the disk size required is 1 TB therefore you cannot select THICK provisioning. Therefore, i selected THIN provisiong. It THIN provisioing i am showed that Estimated Disk Usage is 112 GB which is less than the free space available. But even after selecting THIN proviosing at the time of deployment it throws an error that it cannot create disk as the size of disk is larger than the maximum specified limit. My block size is of 1 MB. Pasting my exact error here: Failed to deploy OVF package:File [datastore1] IMS Tester 1/IMS Tester1_2.vmdk is larger than maximum size supported by datastore 'datastore1

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  • How to create a filesystem mountable by windows in linux?

    - by wcoenen
    I have attached an external USB disk to my debian gnu/linux system. The disk showed up as device /dev/sdc, and I prepared it like this: created a single partition with fdisk /dev/sdc (and some more commands in the interactive session that follows) formatted the partition with mkfs.msdos /dev/sdc1 If I then attach the USB disk to a Windows XP or Vista system, then no new drive becomes available. The disk and its partition show up fine in the disk managment tool under "computer management", but apparently the file system in the partition is not recognized. How do I create a FAT32 file system which can actually be used in windows? edit: I've given up on this and went with a NTFS file system created by windows. In debian lenny this can be mounted read-write but apparently it requires you to install the "ntfs-3g" package and explicitly pass the -t ntfs-3g option to the mount command.

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  • How can I successfully install Ubuntu 12.10 next to windows 7

    - by Ian
    I have an installation of Windows 7 and I would like to install Ubuntu 12.10 side by side. During the installation of Ubuntu GRUB comes up with an error and gives me the option to select which disk it should be installed to. I have always found this difficult as I am never sure which disk to select. In my case I see one with "Windows bootloader". I was guessing that was the boot disk for my system but having selected it and completing the Ubuntu installation, GRUB did not appear and Windows loaded. I had no way to get to my Ubuntu installation. I then tried another disk for GRUB after receiving the same message on a re-install of Ubuntu but it didn't work either. In stead of fumbling about I thought I would ask here. Thanks for any advice!

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  • Grub2 attempting to boot hd1 when it should boot hd0

    - by JoBu1324
    I'm attempting to perform a "normal" install on a USB3 SSD (I don't know if it is noteworthy, but I don't have a swap partition). The installation proceeds normally (I'm installing from a USB2 device I created using LiLi Boot, with a copy of Ubuntu 12.10 64bit that I downloaded directly from the source. The system I'm running Ubuntu on has had a more traditional installation of ubuntu running on it without issue (also 12.10), so I know that everything works A-OK when booting from a 7200RPM internal disk. There are a number of oddities that I've noticed so far, including graphics corruption, but the first and most pressing issue is that Grub2 refuses to recognize the correct hd. From /boot/grub/grub.cfg: if [ x$feature_default_font_path = xy ] ; then font=unicode else insmod part_msdos insmod ext2 set root='hd1,msdos1' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1 b58ee4f7-d41d-400a-b7b8-18bd1f0ae9d3 else search --no-floppy --fs-uuid --set=root b58ee4f7-d41d-400a-b7b8-18bd1f0ae9d3 fi font="/usr/share/grub/unicode.pf2" fi This is from a 100% fresh install of linux (first boot), which was installed while no hard drives were connected to the system, other than the USB2 LiLi drive. The system refuses to boot unless I change the hd1,msdos1 - hd0,msdos1 in the grub menu at boot, when it is the only disk device connected to the PC. What options are left for me to troubleshoot this issue? I've been racking my brains and taxing the internet trying to dig up something on this problem, but now I'd like to see if the Ubuntu community can rise to the challenge and help me fix this boot problem. This is the second time I've attempted this particular setup. The first time, after days of wasted time, I managed to get it to boot every other boot - i.e. every even boot it would boot into Ubuntu like it was happy; every odd boot it would boot into the BusyBox or Grub prompt. At one point it complained that it couldn't find /dev/disk/by-uuid/[the disk], which I found most perplexing, since the disk was there and booted before and after the occurrence (with intervention).

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  • Deduping your redundancies

    - by nospam(at)example.com (Joerg Moellenkamp)
    Robin Harris of Storagemojo pointed to an interesting article about about deduplication and it's impact to the resiliency of your data against data corruption on ACM Queue. The problem in short: A considerable number of filesystems store important metadata at multiple locations. For example the ZFS rootblock is copied to three locations. Other filesystems have similar provisions to protect their metadata. However you can easily proof, that the rootblock pointer in the uberblock of ZFS for example is pointing to blocks with absolutely equal content in all three locatition (with zdb -uu and zdb -r). It has to be that way, because they are protected by the same checksum. A number of devices offer block level dedup, either as an option or as part of their inner workings. However when you store three identical blocks on them and the devices does block level dedup internally, the device may just deduplicated your redundant metadata to a block stored just once that is stored on the non-voilatile storage. When this block is corrupted, you have essentially three corrupted copies. Three hit with one bullet. This is indeed an interesting problem: A device doing deduplication doesn't know if a block is important or just a datablock. This is the reason why I like deduplication like it's done in ZFS. It's an integrated part and so important parts don't get deduplicated away. A disk accessed by a block level interface doesn't know anything about the importance of a block. A metadata block is nothing different to it's inner mechanism than a normal data block because there is no way to tell that this is important and that those redundancies aren't allowed to fall prey to some clever deduplication mechanism. Robin talks about this in regard of the Sandforce disk controllers who use a kind of dedup to reduce some of the nasty effects of writing data to flash, but the problem is much broader. However this is relevant whenever you are using a device with block level deduplication. It's just the point that you have to activate it for most implementation by command, whereas certain devices do this by default or by design and you don't know about it. However I'm not perfectly sure about that ? given that storage administration and server administration are often different groups with different business objectives I would ask your storage guys if they have activated dedup without telling somebody elase on their boxes in order to speak less often with the storage sales rep. The problem is even more interesting with ZFS. You may use ditto blocks to protect important data to store multiple copies of data in the pool to increase redundancy, even when your pool just consists out of one disk or just a striped set of disk. However when your device is doing dedup internally it may remove your redundancy before it hits the nonvolatile storage. You've won nothing. Just spend your disk quota on the the LUNs in the SAN and you make your disk admin happy because of the good dedup ratio However you can just fall in this specific "deduped ditto block"trap when your pool just consists out of a single device, because ZFS writes ditto blocks on different disks, when there is more than just one disk. Yet another reason why you should spend some extra-thought when putting your zpool on a single LUN, especially when the LUN is sliced and dices out of a large heap of storage devices by a storage controller. However I have one problem with the articles and their specific mention of ZFS: You can just hit by this problem when you are using the deduplicating device for the pool. However in the specifically mentioned case of SSD this isn't the usecase. Most implementations of SSD in conjunction with ZFS are hybrid storage pools and so rotating rust disk is used as pool and SSD are used as L2ARC/sZIL. And there it simply doesn't matter: When you really have to resort to the sZIL (your system went down, it doesn't matter of one block or several blocks are corrupt, you have to fail back to the last known good transaction group the device. On the other side, when a block in L2ARC is corrupt, you simply read it from the pool and in HSP implementations this is the already mentioned rust. In conjunction with ZFS this is more interesting when using a storage array, that is capable to do dedup and where you use LUNs for your pool. However as mentioned before, on those devices it's a user made decision to do so, and so it's less probable that you deduplicating your redundancies. Other filesystems lacking acapability similar to hybrid storage pools are more "haunted" by this problem of SSD using dedup-like mechanisms internally, because those filesystem really store the data on the the SSD instead of using it just as accelerating devices. However at the end Robin is correct: It's jet another point why protecting your data by creating redundancies by dispersing it several disks (by mirror or parity RAIDs) is really important. No dedup mechanism inside a device can dedup away your redundancy when you write it to a totally different and indepenent device.

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  • "Misaligned partition" - Should I do repartition (how?)

    - by RndmUbuntuAmateur
    Tried to install Ubuntu 12.04 from USB-stick alongside the existing Win7 OS 64bit, and now I'm not sure if install was completely successful: Disk Utility tool claims that the Extended partition (which contains Ubuntu partition and Swap) is "misaligned" and recommends repartition. What should I do, and if should I do this repartition, how to do it (especially if I would like not to lose the data on Win7 partition)? Background info: A considerably new Thinkpad laptop (UEFI BIOS, if that matters). Before install there were already a "SYSTEM_DRV" partition, the main Windows partition and a Lenovo recovery partition (all NTFS). Now the table looks like this: SYSTEM_DRV (sda1), Windows (sda2), Extended (sda4) (which contains Linux (sda5; ext4) and Swap (sda6)) and Recovery (sda3). Disk Utility Tool gives a message as follows when I select Ext: "The partition is misaligned by 1024 bytes. This may result in very poor performance. Repartitioning is suggested." There were couple of problems during the install, which I describe below, in the case they happen to be relevant. Installer claimed that it recognized existing OS'es fine, so I checked the corresponding option during the install. Next, when it asked me how to allocate the disk space, the first weird thing happened: the installer give me a graphical "slide" allocate disk space for pre-existing Win7 OS and new Ubuntu... but it did not inform me which partition would be for Ubuntu and which for Windows. ..well, I decided to go with the setting installer proposed. (not sure if this is relevant, but I guess I'd better mention it anyway - the previous partition tools have been more self-explanatory...) After the install (which reported no errors), GRUB/Ubuntu refused to boot. Luckily this problem was quite straightforwardly resolved with live-Ubuntu-USB and Boot-Repair ("Recommended repair" worked just fine). After all this hassle I decided to check the partition table "just to be sure"- and the disk utility gives the warning message I described.

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  • Can't boot to Ubuntu 11.10 after installation with Windows 7

    - by Tylor
    I just installed Ubuntu 11.10 on a machine with Windows 7 already installed. I want to setup the dualboot environment. I have a block of unallocated disk space at the end of the disk (some blog post suggested to do so). Then I started installing Ubuntu 11.10 on that part of disk. I installed the boot loader to /boot partition and the installation finished successfully. However, after installation, Ubuntu 11.10 doesn't show up on boot menu. Then I searched on Internet and I used EasyBCD to add a grub2 boot to boot menu. After this, the boot entry does show up in the boot menu, however it only boot into some sort of grub console. I tried many times, and it doesn't work. It looks like the boot loader is not properly installed? I only have one 1.5TB disk and the first 800GB is NTFS partition with Windows 7. Does this work?

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