Technology And Computer|

Article by Craig Thornburrow

The objective behind the concept of computer security actually varies quite a bit depending on the use of the computer. Computer security may include the protection of specific information from corruption or theft, for example. In general this can impose specific requirements on computers in addition to most standard system requirements. There are a number of different typical approaches that can be taken when it comes to improving computer security, including the following:

- Physically limiting the access to a computer so that computer security will not be compromised by those who are granted access to use it.

- Utilizing hardware mechanisms that can create and impose rules for specific computer programs, allowing computer security to be imposed without requiring individual programs to implement it.

- Implementing operating system or OS mechanisms that are capable of creating and imposing rules that avoid having to trust programs on the computer.

- Implementing programming strategies that allow subversion to be resisted and make computer programs more dependable.

In most cases, the computer security devices that are put into place are dependent upon the application uses the computer is created for. Different computer systems require different levels of security, as the level of privacy or protection needed is going to vary significantly. Computer systems under government control, for example, require a much higher level of security than computers used by students in a university setting. The level of required computer security, then, along with what forms of security are implemented, are going to vary significantly as well.

Implementing computer security may include creating or utilizing secure operating systems, though much of the science associated with this form of security was developed several decades ago. Security architecture is another option, and involves describing how specific security countermeasures and controls are positioned to protect the information technology. Firewalls are an example of security meant to protect computers from threats that travel via the internet or peer to peer connections. Chain of trust techniques are techniques that are used to ensure that all software on a computer is certified as authentic directly from the designers of the system. Access control is used to ensure the separation of privileges, ensuring that only specified people have the right capabilities on a computer system.

There are also cryptographic techniques which transform information into something that is meant to be indecipherable by anyone but approved persons. Information can also be secured for computer security purposes using backup files which allow important files to be protected by creating copies should they ever become corrupted or destroyed.

Essentially, the primary focus of the computer security field of information technology is to protect the integrity of computers, the data contained within them, and any information that may require restricted access. Some level of computer security is needed by anyone who owns a computer, including student computers in a university setting, computers owned and operated by the government, and even the laptop that you use to check your e-mail at night.

However advanced the technology may be and whatever precautions we may take, data loss is almost inevitable. Though Linux operating system is often improved upon its previous versions than any of its counterparts, still there are a number of reasons, for which data can be lost in a Linux operating system based computer. In a Linux computer, the fstab (/etc/fstab) and mtab (/etc/fstab) are the two most crucial directories. Without these directories, the operating system could not be able to locate neither the existing hard drive volumes nor the mounted drives on your system. For this reason, the system fails to boot and all your data in the hard drive becomes inaccessible. In such situation of data loss, you need any Linux data recovery software to recover back the lost or inaccessible data.

Facts about ‘fstab’ and ‘mtab’ directories:

• The fstab or ‘file systems table’ is a system directory within the Linux operating system. This system configuration file contains information about all the available hard drives and volumes attached to the system. The file tells, the way, hard drive volumes are initialized and integrated through the file system. Moreover, it lists the details of the file systems, which are accessed by the ‘fsck command.

• The mtab or ‘mounted file systems table’ is also part of system configuration and lists all the currently mounted file systems on your Linux system. The file retains every detail of the mounted volumes, that is whether mounted manually or automatically and is automatically updated once the mount command is triggered against any drive or volume.

Sometimes, while accessing the Linux drives or the mounted volumes you may come across error messages related to the mounted file system and all the files and directories become inaccessible. The error message that you may have encountered can be read as below:

“Cannot read table of mounted file systems”

The above error is caused due to the corruption of ‘fstab’ or ‘mtab’ directories. Thus, the file system fails to mount and the data remains inaccessible thereof.

Such situation of data loss can only be dealt by any efficient Linux data recovery utility. These applications are meant to recover the lost, deleted, formatted or inaccessible data from the Linux file system based volumes. Moreover, these helpful utilities are completely safe to use and come with detailed instructions, so that can be used without any prior knowledge.

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The LINUX operating system is very much similar to UNIX and has derived many basic design principles from it. Day by day, LINUX OS has improved upon its previous versions and indeed has incorporated a number of distinguishable features over other operating systems. In LINUX, disk drives are mounted through file system volume label and not the device path. This is a newer concept applied in LINIX in order to avoid the ambiguity in distinguishing after a disk has been removed and some other have been inserted with the same device path. However, if there is corruption to the volume label, the situation becomes more complex, keeping the data from the drive completely inaccessible and a LINUX data recovery utility is a must to recover the inaccessible data.

To be a bit more elaborative, suppose, your system disk is at /dev/sda2. The system may have mapped another disk as /dev/sda2 and hence, your fstab, where all entries of the mounted disks are there, will be messed up making your system start improperly. At times, such issues can cause huge loss of data.

These kinds of situation may fire the command fsck automatically to check the LINUX volumes each time the system boots-up. As fsck, checks for file system errors and tries to repair the same, it may take a significant amount of time. Any power surge or system crash during the process may cause serious system instability and data loss. This is an added problem that may further flash a warning message and further increase the chances that your LINUX volumes become inaccessible. The message may read as below:

“Warning: invalid flag 0×0000 of partition table 4 will be corrected by w(rite)”

The warning message tells that the disk label has been corrupted and that is why the data in the drive is inaccessible. If running Disk Utility or fsck command fails, you have to restore the data from the backup. However, if backup of your data is not available, run a reliable Linux disk recovery software to recover the data.

LINUX data recovery software are designed with powerful scanning algorithms that can recover any deleted, formatted or inaccessible data with ease irrespective of the data loss situation.

Among many names, Stellar Phoenix Linux Data Recovery is tried and appreciated by many users. The application can successfully recover your lost, formatted or inaccessible data from FAT32,FAT16,FAT12,Ext3,Ext4,Ext2 file system based LINUX volumes.

Kuldeep a techno geek is a technical writer doing research on different file system in linux like Ext2, Ext3. And Ext4. He is also interested in linux data recovery, And Ext3 recovery. He is currently working with http://www.data-recovery-linux.com/

Today, the Linux operating system has carved a niche of its own. It has got a dedicated category of users who will happily pay for it if it ever comes with a price tag. The Linux system is secure, reliable, fast, and does not require hardware/software drivers to install them on the system. Having said that, even such a robust operating system can face corruption. Corruption can occur due to various reasons such as power outages, corrupt file system, human errors, damaged operating system, etc. In such cases, you should try performing appropriate corrective measures to sort out the issue. However, if you are unable to do so then you should use a third-party Linux data recovery software to perform Linux recovery.

Consider a scenario wherein you are working on a Red Hat Linux system. Suddenly, there is a power outage and the system shuts down unexpectedly. When you try to switch on the system, you fail to do so.

Cause:
The cause of this situation is that the Linux system has corrupted because of power outage.

Resolution:
If the problem is because of having a faulty hardware like bad hard drive or memory chip, the file system check may not be sufficient to resolve this problem. This happens particularly when the file system is corrupted. In such cases, the Red Hat boot process will produce an error message and guide you into a shell so that you can perform the file system repair yourself.

When the recovery shell dismounts all the file systems to mount the root file system in a read-only mode, you can perform full checks on it. To do this, you should run the e2fsck utility on the corrupted file system that will be able to resolve all the inconsistencies. Exit the shell and restart the system. The system will function normally now.

However, if you still are unable to recover the system then you should use a third-party Linux data recovery software to do the needful. Such read-only tools are able to recover the data safely without overwriting the existing data.

Stellar Phoenix Linux Data Recovery is a Linux recovery software that enables you to recover data from the corrupted Linux systems. It is supported by various Linux distributions such as Red Hat, SUSE, Debian, Caldera, Mandrake, Sorcerer, TurboLinux, Slackware, Gentoo, etc. This Linux data recovery software is able to perform ext2 recovery, ext3 recovery, and ext4 recovery. In addition, it can recover data from FAT12, FAT16, FAT32 file systems as well. This Linux recovery software is compatible with Windows 7, Vista, Server 2003, XP, and 2000.

In Linux operating system, GPT (GParted) is a useful tool that facilitates you to create, resize, move, delete, copy and check the hard drive partitions/volumes. It also copy file system on newly created partitions. It is helpful to create space to install new operating system, copying data stored on hard drive, mirroring one volume with another and recognizing disk usage. In some cases, using this tool may become problematic. It might damaged Linux superblock and lead to critical situations of system inaccessibility and possibly data loss. At this point, you are required to opt for Linux Data Recovery to get your precious and business-critical data back.

Sometimes, when the disk resizing, copying or any other GParted process is running, few read/write errors might terminate the phenomenon. Subsequent to this serious incident, your hard drive volumes could not mount and you come across a number of error message. In such circumstances, when you run the fsck utility after rebooting the system to check integrity and consistency of file system and hard drive, conditions could remain same. Situation becomes critical on every attempt to fix this issue. Linux operating system superblock may get damaged and give you that indication through following error message:

“superblock corrupted, run with -b 32768”

Superblock is a metadata structure of Linux operating system that keeps record of all file system characteristics such as size, block size, empty and filled blocks, respective counts, location and size of Inode tables, size of block groups, disk block map and the disk usage information. When it gets damaged, you can not access data from your hard drive and Data Recovery Linux is required.

Linux file system keeps redundant copies of the superblock. You can correct the problem by using any of them. You can search and use an alternative superblock with the help of ‘mkfs -n’ command.

If the above method can not help you to sort out the issue, Linux Recovery is the way to go for successful retrieval of your valuable data. Recovery is potential through advanced third-party applications, known as Linux Recovery Software.

The tools powerful and efficient scanning mechanisms to methodically scan whole hard drive and extract all of the lost, missing or inaccessible data from it. With read-only conduct and rich graphical user interface, the software are pretty safe and easy to use.

Stellar Phoenix Linux Data Recovery is an advanced and robust application for assured recovery in all data loss situations. The software recovers data from Ext4, Ext3, Ext2, FAT32, FAT16 and FAT12 file system partitions. It works well with most major distributions of Linux including Debian, SUSE, Red Hat, Fedora and Mandriva.

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Like other computer operating systems, Linux also comprise of various components, which include Superblock. Superblock is a significant metadata of the Linux operating system, which describes file systems on the Linux hard drive. The system components have interdependency and work together to keep your system functional. However, if any of these system components or data structures gets damaged, the system may not work properly and you can not access stored data from the hard drive. This behavior leads to critical data loss situations and require Linux Data Recovery to be fixed.

Under some situations, you can not mount your Linux file system and the data stored on the Linux hard drive volumes can not be accessed. Most of the problem occurs in a dual-boot system. When you try repairing your Linux file system on the root partition, process could not complete successfully. It renders your entire system inaccessible.

When you run fsck utility on the affected Linux hard drive, without ‘L’ option, you may come across the below error message:

“Leonzwei root # xfs_repair -nLv /dev/hdc3
Phase 1 – find and verify super block…
Bad primary super block – bad magic number!!!
Attempting to find secondary super block…
Found candidate secondary super block…
error reading super block 54 – seek to offset 57982058496 failed
unable to verify super block, continuing”

The repair process is interrupted after the above error message. In such cases, you need to identify the cause of this behavior and then perform Data Recovery Linux by resolving it.

Grounds of the problem

This behavior takes place because of corruption to the Linux Superblock. File system can not mount after Superblock corruption and thus your system can not boot up. Corruption may occur due to numerous reasons, such as virus infection, improper system shutdown, user errors, and more.

Solution

You can sort out this problem by replacing the damaged Superblock with its identical copy, which is maintained by Linux operating system to prevent such problems. However, if it is not possible, hard drive formatting is the only way to go. It actually removes all the data from hard drive and causes severe data loss. At this point, you need to use Linux Recovery applications to get your mission critical data back. The applications are particularly designed to methodically scan entire hard drive and extract all lost data from it, ensure absolute Linux Data Recovery.

Stellar Phoenix Linux Data Recovery is the most advanced and effective utility to ensure perfect recovery in all data loss situations. The software works well with all major distributions of Linux operating system, including Red Hat, SUSE, Fedora, and Debian. It Recover Linux from Ext4, Ext3, Ext2, FAT32, FAT16, and FAT12 file system volumes.

Linux is an open-source operating system that has various distributions, which include Fedora Core. It is an OS, which enables you to access latest open source applications. The OS uses a disk structure similar to various other Linux distributions and may face the same problem of corruption as others do. Corruption makes it inaccessible and unbootable, causing severe data loss. In such critical situations, you are required to opt for Linux data recovery solutions to get your valuable data back.

In a practical instance of the disk structure corruption in Fedora Linux OS, you may encounter the below error message when you reboot the Fedora operating system-based computer after it freezes at startup-

“EXT-fs: dm-0: couldn’t mount because of unsupported optional features (2000200)
mount error 22 – mounting ext 3″

Subsequent to the above error message, you might get further error message that says-

“kernel panic – not syncing: Attempting to kill init.”

After this error message, Fedora operating system cannot detect and access Linux hard drive partitions when you try to perform data recovery Linux using Linux Rescue CD. When you try mounting the disk manually, it says that the disk has invalid arguments and thus it cannot be mounted.

Grounds of the problem
As stated above, this problem occurs due to corruption to the logical structure of the Linux hard drive. It may also occur if disk data structures, like Superblock and file system, are damaged. Corruption might be the outcome of virus infection, improper system shutdown, operating system malfunction, and other similar reasons.

Resolution
Use any of the below Linux recovery solutions to sort out this problem-
Boot your Linux computer using the Rescue CD and then run pvscan command for checking the logical volumes.
Run fsck -C -y /dev/hdXX command.

If none of the above Ext2 recovery methods work, you are required to format the disk and reinstall operating system. Although, formatting can fix all disk related problems, but it also cause serious data loss. In such situations, Linux File recovery software are required to retrieve lost data after formatting.