Software | Operating System Software

In Linux operating system, fsck (file system check) is a command-line utility that allows you to check file system and hard drive integrity. Using this tool, you can even fix some minor errors of file system. Generally, it runs automatically during system boot when Linux detects that the file system is not in consistent state, indicating improper system shutdown like power loss or system crash. However, if you run fsck tool on physical volume, you may come across some odd error messages. The errors prevent you from accessing your data and lead to data loss. At this point, you need to use Linux Data Recovery solutions to extract lost data.

When you get such error messages, experts suggest to use the ‘pacman’ utility for upgrading your Linux kernel and reboot the system for finalizing this operation.

Pacman is an application of Linux operating system, which is used for managing other applications. This tool uses simple files in form of packages and organizes the text-based databases. This is helpful in adding, deleting, and upgrading the packages in Linux computer.

After completion of kernel up-gradation process, if you try to restart the system, system does not boot up. It may stuck on the boot screen. Despite of loading the GRUB (Grand Unified Boot Loader) and starting, the system just display “loading GRUB” message.

In such cases, if you boot the system using floppy, you may get the below error message:

“ERROR: (device hda1): XT_GETPAGE: xtree page corrupt
ERROR: (device hda1): XT_GETPAGE: xtree page corrupt”

Subsequent to above error message, if you run fsck tool, the following error occurs:

“Errors detected in Primary File/Directory Allocation Table.
File system object FF65726 linked as: /var/run/random-seed
File claims cross linked block(s).
Cannot repair FF65726.”

Cause

This problem is caused by corruption to GRUB or Linux file system. In such cases, hard drive formatting is required, which removes all the data from hard drive. To recover lost data, Data Recovery Linux is required.

You can recover lost data using Data Recovery Linux applications. These are third-party applications, which are capable of methodically scanning the entire storage media and extract lost data from it. The Linux Recovery Software have simple and self-descriptive rich graphical user interface to provide ease of use. With read-only and non-destructive conduct, the applications are safe to use.

Stellar Phoenix Linux data Recovery is the best ever made tool for quick and safe recovery of lost Linux data. It recovers data from Ext4, Ext3, Ext2, FAT32, and FAT16 file system volumes. The software works well with all major distributions of Linux operating system.

Upgrading your system with latest version of Ubuntu enables you to support the latest drivers, BIOS (Basic Input Output System), and advanced applications. While the upgradation process is simple and easy-to perform, it might result in booting problems if interrupted or performed in disorganized manner. In most of these situations, you receive a booting error message that results in inaccessibility of the data stored in your hard drive. To access the hard drive data in such scenarios, an updated data backup always helps. It allows you to restore the required data. But, if no data backup is available, then you can turn on to an advanced third-party Linux Data Recovery utility that enables you to recover your lost, missing, and deleted data.

For example, you upgrade from Ubuntu 9.04 to Ubuntu 9.10. However, when the upgradation process gets finished and you attempt to boot your system, you receive the below error message:

“error: no such device : ba123456-7890-abcd-efghijklmnop

Failed to boot default entries
Press any key to continue”

Once the above error message appears, your system becomes unbootable resulting into inaccessibility of the hard drive data. In addition, the error message pops up every time you press any key.

Cause:

The cause for the error message is improper upgradation of Ubuntu.

Resolution:

Follow the below steps to resolve the above error message:

1.Boot your computer using Ubuntu 9.10 CD.

2.Start terminal and then log on as a manager in nautilus file manager.

3.Next, go to “/boot/grub/grub.cfg” and right-click grub.cfg.

4.Select Properties and select tab permissions. Modify the permissions of “owner:root” to “read and write”
5.Right-click grub.cfg and find the below entry:

### BEGIN /etc/grub.d/10_linux ###
menuentry “Ubuntu, Linux 2.6.31-14-generic” {
recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi

et quiet=1
insmod ext2
set root=(hd0,1)
search –no-floppy –fs-uuid –set ba123456-7890-abcd-efghijklmnop
linux /boot/vmlinuz-2.6.31-14-generic root=UUID=ba123456-7890-abcd-efghijklmnop ro quiet splash
initrd /boot/initrd.img-2.6.31-14-generic

6.Change the above entry to relatively simpler one, as done below:

### BEGIN /etc/grub.d/10_linux ###
menuentry “Ubuntu, Linux 2.6.31-15-generic” {
set root=(hd0,1)
linux /boot/vmlinuz-2.6.31-15-generic root=UUID=ba123456-7890-abcd-efghijklmnop ro quiet splash
initrd /boot/initrd.img-2.6.31-15-generic
}

7.Modify the permissions of “owner:root” to “read-only” and restart your system.

If you receive the error message even after following the above steps and your data remains inaccessible, then you will need to use Linux Data Recovery software to recover your data. Such Data Recovery Linux tools perform recovery in almost all data loss cases.

Stellar Phoenix Linux Data Recovery is an effective Data Recovery Linux application that supports recovery from all Linux distributions, including Caldera, Red Hat, SUSE, Sorcerer, Debian, Mandrake, etc. It is compatible with Ext2, Ext3, Ext4, and FAT file systems.

I used to work in an organization where I had no choice but to use PVCS for version control for all projects. I still remembered how long it took to commit all changes or to check out a project from PVCS. CVS was then introduced to my team and I could see some improvement however it still had some weaknesses. For example, two people are committing changes at the same time and a change conflict occurs. In this case, some files will have been updated, while others been refused, which leaves the repository in an unstable state. CVS was however used in my team for a while until Subversion was introduced. Subversion is probably one of the best open source version control systems since it was designed to overcome the shortfalls of CVS.
CVS keeps track of individual file versions. In CVS, when you commit a set of changes, each modified file is updated separately. Subversion, by contrast, keeps track of revisions. A revision is a representation of the repository structure and contents at a given point in time. Updating the Subversion repository is a bit like updating a relational database using transactions. Either all of your changes are updated in the repository, or none are if there is a conflict. If you hate CVS, consider Subversion.

I will describe a step by step instruction to set up a Subversion system on a local machine.

1. Install Subversion server
* Install Subversion on Ubuntu:

Open a Terminal and execute the following command:
$ sudo apt-get install subversion libapache2-svn
Or using the Synaptic Package Manager:
Go to System -> Administration -> Synaptic Package Manager
Type subversion in Quick search and select subversion checkbox.
Click the Apply button on the toolbar and accept all the default

* Install Subversion on Windows:

Get Windows binaries from http://subversion.tigris.org/
Select CollabNet and download CollabNet Subversion Server and Client v1.6.6 (for Windows)
You need to create an account with CollabNet before you can download the installer file

2. Setting up a Subversion Repository:
There are 2 different storage systems for Subversion repository: Berkeley DB database and flat filesystem known as FSFS. To create a Subversion repository, you use svnadmin create command. By default, this will set up an FSFS repository at the specified location.

* $ svnadmin create /home/vietma/svn_repository/dev_repos (Linux)

* C:>svnadmin create D:svn_repositorydev_repos (Windows)

You can use –fs-type option to specify a Berkeley DB:
$ svnadmin create –fs-type bdb /home/vietma/svn_repository/dev_repos

3. Create a new Java project
You create a new Java project in your usual way. In this example, I use Maven 2
You can download Maven 2 (apache-maven-2.2.1-bin.zip) from http://maven.apache.org/download.html and extract the file in a directory of your choice on Windows OS. If you use Ubuntu, you can use the Synaptic Package Manager to install maven2 similar to subversion as described in step 1 above.
Change to a temporary folder where you can temporarily create the project.

* $ cd /home/vietma/tmp (Linux)

* $ mvn archetype:create -DgroupId=com.example.myproject -DartifactId=myproject (Linux)

* D:tmp>mvn archetype:create -DgroupId=com.example.myproject -DartifactId=myproject (Windows)

4. Initial import of the created project directory into Subversion:

* $ svn import myproject file:///home/vietma/svn_repository/dev_repos/myproject/trunk -m “Initial import of myproject” (Linux)

* D:tmp>svn import myproject file:///d:/svn_repository/dev_repos/myproject/trunk -m “Initial import of myproject” (Windows)

5. Delete the temporary project myproject from /home/vietma/tmp or D:tmp

6. Check out the clean project from Subversion.
You can use TortoiseSVN to check out the source code but I prefer to use the command line

* $ cd /home/vietma/projects (Linux)

* $ svn checkout file:///home/vietma/svn_repository/dev_repos/myproject/trunk myproject (Linux)

* D:projects>svn checkout file:///d:/svn_repository/dev_repos/myproject/trunk myproject (Windows)