Linux is the UNIX like operating system that uses the Linux kernel of Monolithic type. The OS is being installed on a vast range of tablet computers, mobiles, video game consoles, mainframes, super computers etc. Even, statistics says that as, server OS, Linux accounts more than 50% of the whole global installations. Also,over the years, Linux operating system has gained fair amount of popularity among the common home users with the Fedora, Ubuntu and OpenSUSE distributions. Moreover, with the egression of smart phones, netbooks etc, which are running on embedded Linux, the operating system has been more closely used by many users. Though Linux has advanced technology and features, sometimes, some errors lead to data loss or inaccessibility and you need to look for any Linux data recovery software to recover back your valuable data.
In day to day usage of a Linux system, there can be enormous possibility of data loss situations, and you may not always successful in trouble shooting the system to gain access of your data. Hence, if you don’t have a valid backup available or failed to restore the data from the backup, Linux recovery is the answer to bring back your data.
Common data loss situations in Linux:
Error – Mount wrong fs type, bad option, bad super block on /dev/hdb2.
Error – Too many mounted file systems.
File system error.
Grub Error 12 – Invalid device requested.
Grub Error 17 – Can not mount selected partition.
There can be many such errors leading to the loss or inaccessibility of your Linux data. In such cases, if you are a technical person, then you can trouble shoot at the low-level. You can run the ‘fsck’ command to detect and fix such error. Prior to running the ‘fsck’ command, first, you need to go to the single user mode. Then, you have to unmount the file system partition, you are going to work upon, if it is not the root file system. If you don’t take enough care to unmount the file system, the ‘fsck warns you, such as- ‘The file system is mounted, do you want to continue anyway?’ Saying yes to the message, may result in the loss of your data, because, at times, ‘fsck’ writes directly to the disk.
If you need to check the root file system based partition, you have to boot the system in single user mode and run the ‘fsck’ with a ‘-b’ option so that it will run in a read-only mode. Also, the ‘-b’ option directly go to the ‘init’ and makes an emergency booting while skipping the other start-up scripts.
Sometimes, ‘fsck’ fails to run or exits without running at all. At that time, you need to force run the utility with ‘-f’ option. This is a case of severe corruption and you need to give additional information to ‘fsck’, such as the size of the alternate superblock or the address of the superblock to fetch the data and fix the error.
However, sometimes, these low-level recovery process is tedious as well as risky with respect to your valuable data. Hence, you can go for any Linux data recovery software, which can recover the data for you safely.
Stellar Phoenix Linux Data Recovery is a risk free Linux recovery utility to recover your lost, deleted, formatted or inaccessible data from ext2, ext4, ext3, FAT and NTFS file system based volumes. Moreover, with step-wise-instructions based GUI, the software can be easily used by any user without much technical knowledge.
By: Kuldeep Kulmii
About the Author:
Filed under Computers And Technology by on Nov 21st, 2010. 
Many times, you need to share documents and accessories within the local work station, which lessens individual disk space & allows access to devices, such as printers, scanners, CD/DVD drives, floppy drives etc… While working on a Linux system, if you want to share any of your documents, files or folders within the LAN or the NFS (Network File System), you need to change the ownership of the associated Linux volume.
Suppose a more complex situation, when the only way to access some of your data is through the sharing of the drive. You have certain problems with your root account and you neither able to run some applications nor access the related documents. Moreover, while trying to change the ownership of your mounted Linux hard drive volume, you are receiving a series of error messages. This is a serious situation of data inaccessibility and you need any Linux recovery utility to resolve the issue in order to regain the access to the valuable data.
The error messages that you encounter while trying to change the ownership of the drive can be read as follows:
“suse:/# chown -v ryan:ryan /mnt/hdc1
failed to change ownership of `/mnt/hdc1′ to ryan:ryan
chown: changing ownership of `/mnt/hdc1′: Operation not permitted
suse:/# chmod -v 777 /mnt/hdc1
mode of `/mnt/hdc1′ changed to 0777 (rwxrwxrwx)
suse:/# ls -l /mnt/
total 16
drwxr-xr-x 4 root root 16384 1969-12-31 17:00 hdc1
suse:/#”
cause:
Following reasons may be behind the above error message:
Incorrect setting of attributes of directory or file, which is preventing you from changing disk permissions using the command ‘chmod’.
The root directory has been damaged and hence, the operating system could not be able to read the structure of the disk.
Corruption to the file system, the superblock or the iNode.
Resolution:
In oder to resolve the issue, follow the below steps(if you have the root access):
Check your user-ID (UID).
With root access, from the terminal edit ‘/etc/fstab’ by sudo gedit /etc/fstab
Try pasting the the values, umask=0000, uid=your UID valuae, gid=your GID value in the section, save and exit.
In the terminal run: sudo umount -a
In the terminal run: sudo mount -a
If you still facing the same error, the corruption is because of the corruption of the file system/superblock/inode. In such a case, you have to format and make a fresh installation of the operating system. After formatting, you have to restore the data from the backup, failing to which you require any Linux data recovery software to recover back the data.
Stellar Phoenix Linux Data Recovery software effectively recovers all the lost, formatted or inaccessible data from any available flavor of Linux. Moreover, it comes with an interactive GUI to be used with any user without much technical knowledge.
By: Kuldeep Kulmii
About the Author:
Read more on Linux Recovery Solution for Data Inaccessibility Following Failing to Change Ownership…
Filed under Computers And Technology by on Nov 21st, 2010.
Having the ability to lookup how a kernel function works is very handy when writing your own device driver or any kernel module. Unfortunately you cannot just apt-get install kernel-manpages. Well wouldn’t that be nice! To get your kernel manual pages for a specific kernel you can download the kernel source and execute a few choice commands. Here is a short tutorial under Debian (and would probably work for most Linux distributions).
Download your kernel version, in this case I grabbed version 2.6.32.3 Untar the the document by: tar -xvf linux-2.6.32.3.tar.bz2 Now move into the new linux-2.6.32.3 directory and type make mandocs. The system might prompt you to download missing packages to build the manuals, proceed to do so. After the documents have been made type make installmandocs, this will install the manual pages into /usr/local/man/man9/. This way you can now type man copy_to_user to see how to use the specified kernel function!
So, doing a man copy_to_user you will now get the output of:
NAME
copy_to_user – Copy a block of data into user space.
SYNOPSIS
unsigned long copy_to_user (void __user * to, const void * from, unsigned long n);
ARGUMENTS
to
Destination address, in user space.
from
Source address, in kernel space.
n
Number of bytes to copy.
CONTEXT
User context only. This function may sleep.
DESCRIPTION
Copy data from kernel space to user space.
Returns number of bytes that could not be copied. On success, this will be zero.
By: Erik Schweigert
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Filed under Computers And Technology by on Nov 19th, 2010.
Whenever you are using the Linux, in whatever distribution you like the most, you have a Home folder. This is an extremely important folder for everything that you do on that machine. Due to the way that Linux segments it’s file system, it’s important to keep track of what is in this home folder. Although it sounds like basic file management and as such can sound boring or repetitive, when things go wrong being aware of where you have saved what, can make all the difference.
First of all the home folder is much like your “My Documents” that you have in Windows. Your basic files that can include pictures, music, video, documents, and downloads will be saved into this folder. For each user on the computer, you will get your own folder that holds your own personal documents. This is important as this segmentation provides you with privacy, but more importantly, your own organizational system.
There is another part of the home folder that many don’t realize. There are actually many folders within this folder that are hidden. This means that the folder starts with a period followed by the name. If you are using Gnome, hit Control+H to see these hidden items. What these are is your settings for various applications on the computer. If you have a certain application with saved states, customized choices, or whatever, it will remain this way because there are files in your hidden folder for that application that keeps those settings.
Backing up your home folder is very important because this is what you really need if you have to reinstall the system or move your settings to a new computer. When you backup, make sure that you backup all these hidden folders as well. Don’t make the mistake and forget about the hidden ones else you will lose all your customized options.
Some advanced Linux users will actually mount the home folder as a separate partition on their drive. Then when they have multiple versions of Linux or other operating systems, they can always rely on that home folder and be writing and reading from it at all times.
By: Philip Robinson
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Filed under Computers And Technology by on Nov 19th, 2010.