Friday, July 16, 2010

Computer Hard Disk Data Recovery

First of all, if you're just browsing to find out what hard disk data recovery is and what it might do for you, the fact is that the very best and cheapest form of data recovery is that of restoring from a verified backup – if you're not backup up your documents, etc, then stop here, get yourself a backup system that backs up to a different physical device and set it up to run automatically. Do it now – it's that important!

There are a number of reasons for needing hard drive data recovery, but the basic options are

  1. To copy files/data that are in use and thus can't be normally copied to a second disk for some reason. Solutions here typically involve booting an alternative operating system, e.g. via a 'Live CD' or USB drive.

  2. To recover files that are unavailable due to a software action, which could be a file-system failure or a partition failure, or simply files which were deleted mistakenly. Solutions here include recreating the MBR, the partition table or the file system. Depending upon your computer knowledge and knowledge of what caused the problem, you may be able to recover some or all of the lost data, although it's worth considering the cost of your own time vs the cost of a commercial recovery service.

  3. To recover files that are unavailable due to a hardware failure. Unless you've been physically changing the data and/or power cables to a drive and reconnected it incorrectly, this particular failure shows up when the drive starts making clicking, grinding or whirring sounds – if this happens, shut it down immediately and unplug the drive. At this point you need to consider the cost of replacing/recreating the data – if it's all backed up, just junk the drive, otherwise you'll need to be looking at choosing a hard drive data recovery service to try and get back the information.


'In use' files

This refers to the way in which operating systems keep certain files open as they update them, which means that they can't reliably be copied while the system is running. The solution to this sort of problem is to boot the system from a second operating system that is able to run without needing to write to the files wanting to be copied. This is typically done via a boot CD or USB, known as a 'Live CD' or 'Live USB' which allows the user to run a limited set of operations without needing to install anything to the local hard drive, while still being able to read the local hard drive and write to other volumes in order to make copies of the previously unavailable files.


These traditionally involved task-specific Unix distributions, which still have their place, but for straight-forward access, these have been supplemented by standard Linux distributions that have 'live' versions, such as Knoppix and Ubuntu.

Software failure recovery

These sort of failures can be due to issues such as errors during installing new disk partitions or new operating systems, in which case you should have a good idea as to the general cause, through problems with viruses or trojans or even problems due to power outages. The main thing to be aware of is that it's very easy to make things worse, particularly if you're not sure as to the cause, so before attempting a fix yourself, consider if you can afford to loose the data completely.


If you do want to continue, a good start is normally to investigate via one of the Live CD/Live USB distributions mentioned in the previous section, but sure not to make things worse!


Hardware failure recovery

If there has been some form of physical damage to a hard disk, it's rare that there's going to be anything that can be done by normal users. The most that can be said is that if your hard disk has started making any worrying noises (ticking, clicking or whirring) and it's still working, copy any files you want off it as a matter of extreme urgency while if the sound's more of a grinding, then shut it down immediately!


Techniques that may be used to recover data after physical damage often involve opening up the drive itself. In order to ensure that no additional damage is caused, this should only be done in a 'clean-room' environment, which is not going to be available to most end-users, even before consideration is given to access to any of the replacement hardware that might be needed in the attempt to retrieve the missing data. As a result, it's normally best to try and minimize the damage before calling in a commercial data recovery services to make an attempt.


Data security best practices

A few tips to try and ensure that you don't need the data recovery sections...

  • Ensure that any data you don't want to loose is regularly backed up via an automated procedure.
  • Ensure that there's more than a single backup – a problem may not be immediately detected.
  • Check that the backups are recoverable.
  • Ensure systems are backed up before updating them.
  • Ensure that systems and drives have a suitable air flow, i.e. the ventilation isn't obstructed.
  • Don't move systems or drives while switched on.

Posted by Data Recovery Services at 5:26 AM
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