What Is - Boot Loader and Error Handling In Linux?

If you are a Linux user, then you must have used a utility, known as Boot Loader. It provides different levers of functionality and support, through its different variations. Along with the boot operations, Linux boot loader also handles errors and helps you keep your system functional. Boot loader generally handles boot and memory errors at start up. However, in some cases, the boot loader can not fix the errors, which makes your system unbootable and unusable. In such circumstances, you can not access the data stored on your Linux hard drive and eventually face data loss. In order to extract lost data from the Linux hard drive in such situations, you need to opt for linux data recovery solutions.

Two most popular boot loaders of Linux operating system are:

LILO (Linux Loader)- It comes as default boot loader of all Linux distributions. As one among the oldest boot loaders, its strong Linux community accompaniment has enabled LILO to develop over time and remain useful as an operational modern boot loader. Some novel functionalities, such as exploitation of newer BIOS (Basic Input/Output System) functions and improved user interface, make this boot loader more stable and reliable.

GNU GRUB (Grand Unified Boot Loader)- It is considered as a replacement of LILO. It is based on original GRUB program and developed by Free Software Foundation. GRUB is reference implementation of Multi boot Specification that enables you to have various operating systems on same computer and select which one to use for booting.

Both these boot loaders allow Error Handling for proper functioning of your Linux computer.

Error Handling:

It denotes anticipation, detection, and finally, resolution of the operating system or application errors. The Linux boot loaders forestall most of such errors, recover your system from them when the errors occur, without affecting the system operations.

Although, boot loader error handling is a useful process, but if the critical errors can not be handled by Linux boot loaders, your system may become unstable. Such situations may cause data loss and require data recovery linux to be fixed.

Linux Data Recovery is possible using powerful and advanced linux recovery software. They are particularly designed to thoroughly scan whole Linux hard drive and extract all lost, missing, and inaccessible data. The applications are capable of handling virtually every type of logical data loss situations and enabling safe and easy recovery.

Stellar Phoenix Linux Data Recovery software recovers lost, missing, and inaccessible data quickly and successfully. It supports all major distributions of Linux operating system, such as Red Hat, SUSE, Ubuntu, Fedora, Mandriva, and Debian. The software recovers lost Linux data from Ext4, Ext3, Ext2, FAT32, FAT16, and FAT12 file system volumes.

How to - Retrieve Deleted Files/Directories From Linux Computer?

Is your system virus infected and the virus has deleted your valuable files? Have you accidentally deleted your critical business files from Linux hard drive? If your answer is 'Yes' for any of the above questions, you have encountered a critical data loss situation that may severely affect your business as well as personal operations. In such cases, you need to perform Linux Data Recovery to get your mission-critical data back.

Recovering deleted files from other operating systems is quite easy as compared to Linux, as a number of free or paid recovery software are available for them. But how to recover lost data from Linux system?

To recover deleted files from the Linux hard drive, Linux operating system provides two in-built utilities. These tools are actually based on the file system of Linux, which you are using on your hard drive. The Linux Recovery tools are:

• Extundelete- It is a tool, which recovers deleted files from Ext4 or Ext3 file system volume of Linux operating system. Both these file systems are popular and widely used in Linux. These tool uses information stored in journal of Ex3 or Ext4 volumes to recover the file, which has been deleted from the volume. The utility recovers both the file names and contents of the file.

• Ext3undel- It is a set of scripts for helping you to retrieve deleted files from Ext3 or Ext2 file system volumes. This utility attempts to automate various difficult manual recovery jobs to help retrieve lost files from specified disk. You can recover a particular file by its file name or can recover all the files that are marked as deleted.

• E2undel- It is an interaction console utility, which recovers lost or deleted files from the Ext2 file system volume. It enables you to perform Data Recovery Linux for selected files by file name. It is quite simple to use.

Although, the above tools are helpful in recovering deleted files from Linux hard drive, they can neither handle severe disk corruption nor can guarantee recovery in all cases of data loss. In such cases, Linux Data Recovery software come to your rescue, and work in all cases of logical data loss. They are totally safe and easy to use.

What if the system goes to a long pause while Ubuntu installation?

It's a well known fact for those who regularly use Linux. But, more and more people are getting use to Linux and I think this is a much talked about problem at the time of installation What? am I really beating around the bush. Lets get to the point I am talking about the time when we install Ubuntu at the end of the installation process the system takes a long pause.

Is it really a error or this keep on happening all the time. I will say it's not a error, when ever you install Linux at the end it has a long pause, then it suddenly move on with the installation process. Most of the people think that the system is locked . They try reboot the system , which should not be done. It can lead to data loss and effect the previously created partition on the drive. Linux recovery or any other recovery software can only retrieve the data after the OS gets installed properly not before that, so please back up your data before any new installation.

Don't consider it as a problem after a certain amount of halt the system will resume its normal operations. Don't forcefully reboot the system at that time. If done so you will stop the installation process in between and won't find Ubuntu installed.

If already had lost the partition on the drive. Try and reinstall Ubuntu. But, before that run md5sum to check that it wasn't corrupt. Md5sum: is designed to check the data integrity and the authenticity. It verifies that data integrity using the Message Digest Algorithm 5.

Once made sure that every thing is fine reinstall Ubuntu and please avoid above mentioned points and enjoy.

How to Boot Linux from USB Drive?

Most of the notebook owners are always on the run, what if the Linux operating system installed gets corrupt. One can suggest for such cases Linux data recovery software are available in the market to backup your data and save your data from damage. But, will those data recovery software will help resume the work again? No, then what should be done? Today we will look how to get rid of such a problem.

For note book users a thumb drive is easy to use, we will create a bootable USB Drive by which it will be easy to boot the system any where in the world. Yes, this is possible Ubuntu 9.10 CD/DVD ISO images has necessary Linux and Windows utilities to get the system on a USB.

What you require is:

1)1 GB USB drive is required, back up of the data on the drive should be taken in advance.

2)Another computer, Ubuntu notebook remix ISO.

3)ISO image File

For desktop, Windows or a Mac PC users the configuration will totally change. These configuration will work only for notebook users.

Process:

Download the ISO for notebooks from http://www.ubuntu.com/getubuntu/download-netbook..Once downloaded, copy the file to the USB drive. The next step in the process is to run the usb-creator, Linux users are much familiar with the option, if not installed you can get it installed from the Synaptic Package Manager. You need to select “other” and locate the ISO image. Once you select the ISO image insert USB drive you want to make bootable. You will get a notification “USB drive in use”. Now just make sure that the correct device connected before you proceed to create a start up disk out of it. If in case you encounter a error like “two partition created” try selecting each of them, one of them should work. If not, restart your system and try booting from the USB again. Your disk is ready to use. Try booting your system using the thumb drive but before that you need to move to the system BIOS and put hard drive or removable drive depending on your system.

Need to care about:

The quality of the USB drive matters a lot, no matter how fast, spacious it is what matters is you don't lose the data. It's always recommended to go for branded USB dive. Even then if the data is lost the recovery is possible for branded drives, which has a low probability in non branded drives.

For notebook users like me this works as a boon. Now next time you need to boot the system you can do it in fraction of seconds.

How to scan Windows machine using Linux?

This time I am up with something unusual but very useful. Last week my Windows XP machine got infected from virus. The virus made the machine nearly unusable. I attempted to use various anti virus but with no effect. The machine became so slow it seemed that even a simple anti virus installation would take ages. I was quite annoyed way the things turn out for me.

I tried to think in non conventional manner and thought to take help from my good old friend, Linux. Yes, Linux can scan windows machine and it does it quite well. I will share the whole process that I followed to achieve it.

The first thing I did was, to take the back up of my data using the third party Windows data recovery software. It creates the image of the data for future use. Then removed the hard drive from the Windows machine. Yes, you guessed it right next thing was to attach it to the Linux machine. Then after connecting the hard drive to the Linux machine an icon appeared on the desktop. After that to ensure the drive is properly mounted double clicked on it. Once done with this, searched out for the location where the drive was mounted. In most of the cases it appears in /media so happened in this case. Started the scanning tools mounted on the drive.

This scan got caught of the viruses on my machine. If in case the scanner does not locate the infected files you might need to run a different scanner. Once done with this I unmounted the external hard drive before removing the hardware. After taking it off from the Linux machine, re-installed it to the windows machine and let it boot.

You would have never thought that your Linux machine will ever need a anti virus but, for such a situation when you are trying to scan your windows using Linux you need one.

Recover Lost Files From Ext2-Based Linux System

Are you using a Linux system and are unable to locate some of your files after a power outage? If yes, then there are chances that you may have lost these files due to any random reason. There are few methods in Linux that you can use to recover these files. If these methods do not work, then the taking the services of a professional Linux data recovery tool is called for.

Taking a practical case in which you are working on a Linux system that has ext2 file system. Suddenly, there is a power outage and the system shuts down abruptly. When the power is restored, you switch on the system, only to find that you have lost some of the files.

Cause:

• There could be the following reasons for such situation:

• The system could be virus infected that could have caused the data loss.

• There could be some bugs in the operating system version.

• It could be possible that the logical drives may be accidentally deleted.

• The partition table may have got corrupt or damaged.

Resolution:

There are few in-build tools that you can use to recover the lost files. But first of all, you should ensure that you unmount the file system from which the files have been lost. To recover the lost files, you can perform the following tools:

debugfs: This tool is very useful in bringing back the deleted files if it is already installed on your system. To do the recovery, you need to perform the following files:

Try the following command to invoke 'debugfs'

/sbin/debugfs device

where, 'device' is the file system

In the 'debugfs' prompt, enter the following command:

lsdel

The deleted files will be enlisted. From here, you can see the deleted files.

To write the data of the deleted file in a new file, enter the following command:

dump filename

Where, 'filename' is the name of the deleted file

Now, repeat this command to recover all the rest deleted files.

When done, type 'q' to exit 'debugfs' prompt.

E2undel: This tool is also used to recover deleted files, but it has better interface and provides more options while recovering the files. To recover the files, you have to provide the following command:

e2undel -d device -s path [-a] [-t]

Well, if even these tools are unable to recover the lost data then there is an urgent requirement to use a third-party ext2 recovery software to restore deleted files. With use of advanced scanning algorithms, these tools ensure that Linux recovery is safe and secure.

Is Ubuntu 10.4 is better than Ubuntu 9.10?

Yes, after pulling a hat-trick with 9.10, they are back with even better upgraded version .i.e Ubuntu 10.4. The release date is due in April 2010. But, is the newer version better than the previous one. I knew that this will be the questions in everyone's mind, so here is what I found out.

What I was concerned was about the interface, data protection, speed and data recovery options and data security will they improve on it this time or not. You won't believe I almost found every thing what I was looking for.

Lets see what makes Ubuntu 10.4 different from the older version

LTS - I also figured out that Ubuntu 10.4 comes with LTS(Long Term Support ) which is not there with all the versions of the Ubuntu This helps you at the time of new version release, you just have to upgrade the version in spite of fresh installation. You can Upgrade to this version and ride up to the next version which is12.04.

Free Download | Buy Now

Better Speed – It will offer a unbelievable 10 second boot time. They have targeted mid-range machine to archive the 10 second mark so you can imagine how fast your quad core machines will boot . Oh! I can't even imagine.

Fast Installation - They have come up with some unbelievable stuff, now you can download and install at the same time, this cuts down the installation time.



Graphical Startup – Another most interesting feature which is proposed is to offer a graphical Os selector for multi boot systems. The graphics of the Os will memories you of Mac OS X

What I didn't find was the data recovery options, we would have to depend on the third party linux data recovery software this time too. No, one applied thought about it neither did they, but still for me this is a complete OS. Is there anything else one can look for, I can't. I am kind of excited for the release of the Os, aren't you? I believe people will have to work hard to turn that down. Not only because of the added feature but the foundation and the overlaying structure will play a great part in it's success.

How can I clone a hard disk with Linux?

It’s always there in to our mind that if incase the data on the hard dive gets corrupt then, how will I recover the data? That’s the reason that we create a back up of the data. If the data is small enough we use the optical media CD/DVD for back up else if the data is huge in size what should we do? That’s the time when we require an additional hard disk to back up the data. But if we are doing this then also there are chances that we loose data.

So, what should be done in that case? In such a case disk cloning is done. Disk cloning creates a exact image of your data. Disk cloning minimizes the chance of data loss. It creates the image with exact preferences as you had in the old hard drive.

There can be two ways in which the clone can be created in Linux is by “dd” and “ddrescue” free utilities. Gddrescue is the newer and the faster way clone the hard drive we will see both the ways to create a clone of the hard drive.

Backup your important data through data recovery Linux software. Detach all the external drives, memory card and all other storage media accept the one you want to clone. Boot your computer with Live CD and memories the naming convention of the drives.

Steps For dd rescue clone
1) Determine your source and the destination drive. Source will the one from which you are cloning and the destination will be the one that you are cloning to.
2) One done with tis then you need to open the terminal window.
3) The next step will be to type the command “dd bs=4k if=/dev/SOURCE of=/dev/DESTINATION conv=noerror,sync.
4) Replace the source with your source drive and the destination with the destination drive.
5) If you want to create a clone of a single partition then provide the partition name else if you want to create a clone of the whole hard drive then its name.
6) Once all the steps are over then what you need Is the patience

Steps for gddrescue clone
1) Determine the source and the destination for the hard drive.
2) If you are using an ubuntu live CD then enable all the repositories by opening software source program which is located under system and administration on the top deskbar
3) Then click the check boxes for universe and multiverse repositories
4) Open the terminal under application and the accessories and download gddrescue by typing command sudo apt-get install gddrescue
5) Then type the following command and replace the source with source drive and do the same with destination
Command : sudo ddrescue -v /dev/SOURCE /dev/DESTINATION

Once done with this the data being cloned to another hard disk successfully. This was all for the technical people but if a person is not that much technical. In such a case Linux data recovery software can help. Most of such software has the option to create a clone of the hard drive.

What should be steps taken to protect your data from loss?

Most of us today have built our life all around the machines from which computer is the one without which almost none of us can live without. All of our important data like the mails, spreadsheets, pictures, documents etc. We all have most of the important data on the PC but, only few of us emphasize on to the data protection. We all should worry about it.

We will today see what are the steps which will help us protect data.

The most important step is to back up the data in and that too in two locations one has to be the external hard drive and the other should be remote online backup of the data. You should categorize your data on the basis what kind of data to be stored on a remote back up and what kind of data should be be stored on the hard drive if you ask me I will suggest to make the mirror image of the data on to the hard drive and the crucial data should be saved online. This will help the crucial data to be saved from corruption as well as theft.

The other way to protect your data is to get your anti virus updated every now and then which will protect your system from the malicious software that can affect adversely on the computer.

Only way in which data loss can't be prevented the data recovery is also not possible until and unless you have a back up is, because of the theft what we can do is apply some brains while using laptops as the desktops are bit more difficult to steel in comparison to the laptops, so never keep your laptop in a unsupervised place, never leave the laptop in a public place like coffee shop. All these steps can only reduce the chances that your data is protected but one can guarantee it.

Even if after taking all the precautions if you loose the data then also the data recovery is really possible it then if you are using the optical media like the CD, DVD, or might be working on any operating system like Windows , mac or Linux data recovery is possible for all. So at the end of the discussion I would like to say that prevention is better that cure if by taking some measures if the data can be protected then why use those data recovery tools.