Linux Community Magazine

After an unexpected shutdown, when you try to start your Linux computer, your system may refuse to boot and you might experience some error messages. The error message may sound like the followings:Your system appears to have shut down uncleanlyPress Y within 4 seconds to force file system integrity checkAs suggested in the error message, when you press Y, you may receive another error message stating:Checking root filesystem [/sbin/fsck.ext2 (1) -- /] fsck.ext2 - a / WARNING: couldn't open /etc/fstat: no such file or directoryext2fs_check_if_mount/The superblock could not read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 :No such file or directory while determining whether / is mounted.fsck.ext2: Is a directory while trying to open //etc/rc.d/rc.sysinit: li ne 415: failure: command not found.After these errors, the system does not boot and you can not access your valuable data from hard drive and thus may face the nightmare of data loss. CauseThis behavior of Linux operating system occurs due to severely corrupted root file system. Due to the same, operating system can not find the required files to boot and thus shows you the error messages. In Linux operating system, the root file system is the file system which is used to manage data on the root partition, the partition is the one on which operating system is installed. Root file system contains very important file and corruption to this will put you in need of Linux Recovery.Linux Data Recovery is the process of retrieving missing, lost or inaccessible data from Linux hard drive. It is best possible using Linux Recovery Software. These software are able to scan your hard drive, locate the lost data and then carry out Linux Recovery. Stellar Phoenix Linux Data Recovery sof tware is the best ever made and the most comprehensive Linux Recovery Software. It is powerful enough to thoroughly scan your hard drive and retrieve all of your data from it. Phoenix Linux Data Recovery is compatible with most of the Linux flavors.

CRC (Cyclic Redundancy Check) is the standard check process that different files use to detect corruption inconsistencies, if any. Using this check, Linux systems ensure that kernel image hasn't changed after it was built. If system finds any mismatch between the original and current value, it doesn't proceed further while booting and eventually the system halts. Data becomes inaccessible and to restore lost information, you need to use your recent data backup. But if it gives errors or is found as incomplete or damaged, Linux Data Recovery applications can be used for data recovery. You might encounter the following error message when trying to boot your Linux-based computer:"CRC error - System Halted"This error message occurs immediately after system prompts: 'Uncompressing Linux'. System doesn't boot up and you cannot use CTRL-ALT-DEL key to reset the system.CausePossible causes of the above issue to occur are:* Kernel image is stored on bad sectors. When Linux kernel i mage gets uncompressed, it runs a CRC check to ensure its integrity. If checksum values don't match, it gives errors, as above. * Bad hard drive* Bad hardware components like system memory or CPU cache* File system issuesSolutionYou should follow these methods in order to fix this problem:* Use Live CD to boot your system. After this, you need to copy the kernel image from the bootable disk and delete the existing kernel image. Rename the copied image to the one that boot loader recognizes. If you use LILO (LInux LOader), you should run /sbin/lilo to translate present location of copied image to disk geometry language and write to partition's boot sector.* Backup all the possible data and replace the bad hard drive* Diagnose and replace the damaged hardware components* Run fsck, if file system is dirty* If problem persists, reformat the hard drive and restore from backupDisk formatting deletes all the existing information and if you observe any issues with your backup, you c an use Linux Recovery tools. These are effective Linux Data Recovery software that restore lost information using powerful and safe scanning algorithms. Stellar Phoenix Linux Data Recovery is an optimum tool to locate and recover lost data. It supports Ext2, Ext3, and ReiserFS file systems. This Linux Recovery tool provides advanced features including Disk Imaging, RAW File Recovery, File Filer etc. The application is compatible with most of the Linux distributions, like Red Hat, SlackWare, Turbo Linux, Sorcerer, SUSE etc.

Linux boot process proceeds in steps. At first, BIOS selects the boot device and loads the boot sector. The boot manager then loads the kernel image in RAM to execute and run the setup code. Kernel initializes all the installed devices, switches the CPU from Real Mode to Protected Mode, loads the compressed kernel and performs further boot process steps. But in case if system cannot find this kernel image, it will fail to boot. In such situations, your system either hangs or displays error messages and eventually, you cannot access your data. Data backup, if present, valid and updated, can be used to restore missing information. In case backup fails, you should use Linux Recovery Software to restore.You might encounter the similar error message when trying to boot a Linux-based system: "Could Not Find Kernel image: Linux"CauseYou receive this Kernel image error due to any of the possible reasons:* Missing configuration file. This file tells the system about te location of kernel image and initrd files* Name of kernel image file has been changed* Absent required parameters, for example /boot/grub/menu.lst is missing* Boot sector is corrupted or damagedSolution You can try following steps to overcome such issues:* Enter the boot line prompt and try using such commands:root (hd0,1)kernel /vmlinuz devfs=mount root=/dev/hda2initrd /initrd.imgbootOrroot (hd0,1)chainloader +1boot* If the above measure fails and you can get into GRUB command mode, you can use tab key and auto completion feature to find the missing kernel and initrd files. If no boot menu displays, enter into rescue mode.* Reformat the drive as the last solution. To restore lost data in this way, use your recent data backup or alternatively, commercial Linux Recovery tools (if backup is invalid or absent).Linux Recovery applications are specially designed tools that scan Linux-based disks for locating and recovering lost information. Such applications provide rich interface to work w ith and safe read-only design. In addition, you get advanced options that help enhancing recovery results. Stellar Phoenix Linux Data Recovery is a complete Data Recovery Linux tool. The application supports recovery from Ext2, Ext3, ReiserFS partitions. With powerful features like RAW File Recovery, File Filter, Disk Imaging, and similar such, this Linux Recovery software proves to be an efficient tool to recover. It is compatible with most of the Linux distributions, like Red Hat, SlackWare, Turbo Linux, SUSE etc.

fstab (also referred as file system table) is an important system configuration file in Linux. Located at /etc/fstab, this file lists all available disk and disk partitions. This file is used to determine disk initialization information and is usually used by mount command. Generally, while booting if system prompts that it cannot open fstab file, it indicates that the file system is corrupt. As its result, you lose data accessibility and to restore lost information, you require using your recent data backup. To get required results, data backup should be updated and healthy. In any case where data backup violates restoration, you are recommended to scan your drive using Linux Data Recovery software. You might receive the below error message while trying to boot a Linux based system:"Checking root filesystemWARNING: couldn't open /etc/fstab: Input/output error"The error message further describes fsck results that the superblock cannot be read and is corrupt.* uperblock is the data structure that describes a Linux file system itself. It contains file system metadata like file system type, size, status and generic information about other metadata structuresCauseThe most prominent cause of the above error message to occur is file system corruption. It can occur due to unexpected shutdown, incorrect use of terminal commands, virus infection and other similar reasons.SolutionThe fstab error could be corrected by following these methods:* Boot your system using Linux Live CD* After ensuring that the affected file system is not mounted, you should run fsck* Mount the partition and check if the same issue exists * If these steps cannot resolve the existing behavior, you should format and install. You need to restore lost data using your last data backup that should be valid and recently updated to offer desired results. While no backup availability or its invalid state, use Linux Recovery applications.Linux Data Recovery software are comprehensive a pplications that are equipped with powerful data recovery technology for Linux based drives. They can scan a logically crashed drive and offer safe and efficient lost data recovery in any case.Stellar Phoenix Linux Data Recovery is an advanced recovery tool for Ext2, Ext3 and ReiserFS file systems. It efficiently recovers and restores lost data at a safe location. A read-only application that supports complete Data Recovery Linux for all Linux distributions like Sorcerer, SUSE, Mandrake, Red Hat, Turbo Linux, SlackWare etc.

Linux Root directory is the initial point, from where the system starts looking for the files stored on the hard disk. Each file and folder that you store on your Linux-based system is marked under this root directory. It is denoted by '/'. The Linux root directory further subdivides into subdirectories in hierarchical form. But you might experience frustrating experiences if this root directory gets corrupt. Besides giving certain error messages, it makes your data inaccessible. Thus it is must that you have valid copy of all the important data. But most of the times, users don't maintain or update their backup. In such situations, you should use Linux Data Recovery applications and scan your affected disk to restore lost information. All Linux directories (like /bin, /boot, /etc, /initrd, /usr, /home, /root tec.) are below this root directory, '/'. There can be several reasons that could corrupt it like unexpected shutdown, operating system errors and more. A Linux syste m shows abrupt behvior while the root directory is corrupt. Some of the typical errors that it shows while such situations are:* "No such file or directory"* System becomes unbootable * System fails to create or delete files and folders SolutionTo solve root directory corruption issues, you should try following these methods:* Try scanning your disk using fsck. You need to ensure that you run this command in single-user mode and the file system is not mounted.* If fsck fails to repair file system corruption, you should reformat the disk. This process will recreate the entire file system structure.Since formatting deletes all the data from hard disk, you need to check the status of backup. To get complete restoration results, the data backup must be completely updated and healthy. If you find that data backup cannot restore, use Data Recovery Linux tools. Linux Data Recovery software are advanced applications that use safe scanning algorithms to locate the missing informatio n. Such tools empower you easy data recovery through interactive user interface and well-documentation. You can use such utilities in each case of logical data loss. Stellar Phoenix Linux Data Recovery is a comprehensive data recovery tool for Linux-based system. It supports Data Recovery Linux for Ext2, Ext3, and ReiserFS file systems. The application provides you advanced features such as, RAW File Recovery, File Filter, Append File Header etc. It is compatible with almost all Linux distributions including Gentoo, SlackWare, Mandrake, Ubuntu, SUSE etc.