Performing Data Recovery

There comes a time in the life of each hard-drive when it just won’t access any of the data on the drive anymore. The same applies to CDs and DVDs which, due to their fragile nature, get scratched and scraped beyond readability. As Murphy’s law would often have it, it happens exactly to the files you need when you need them. In order to preserve your data (and your sanity in case data starts mysteriously disappearing), you need to know exactly what can be done to make sure you don’t find yourself losing important files.

• Hard drives

Hard drives of today are more than well-known for their high capacity, speed and reliability. However, even their high level of quality doesn’t warrant that absolutely nothing wrong would happen. For the purpose of this article, let’s assume whatever happens to the files was not a user error (as was covered in the How to Recover Accidentally Deleted Files article) and that it is a genuine hard-drive fault.

One of the most common problems with hard-drives (and indeed all magnetic media, including floppy drives, if you’re old enough to remember them) is the existence of bad sectors. Bad sectors actually come as something natural to the hard-drive, as quite a few drives leave factories with a bad sector or two. Although that might seem detrimental to the drive’s performance from the start, every formatting automatically marks all detected bad sectors as unusable and invisible to the operating system. The real problem starts if a bad sector pops up on an existing drive or partition, as it means your data might be compromised.

The first step in recovering data off those sectors is by using whatever comes with your Windows (2000 or XP). To do that, the simplest way go to the Command Prompt (via Start → Run → cmd), and starting the CheckDisk utility by typing chkdsk <drive letter:> /f – this will instruct CheckDisk to search the specified disk drive, recover data onto known good sectors and attempt to fix the bad ones.

While chkdsk can help in some cases, it’s not an almighty tool – if the bad sector is more of a hardcore defect, chances are it’s caused by a demagnetized cluster. In cases such as these, there are two courses of action you may follow. If you’ve already secured the files off the problematic hard-drive, performing a low-level format (the tool provided by your HDD’s manufacturer on their webpage) is a step towards recovery as it instructs the hard-drive to reorganize the data paths and grooves on the drive platters. The procedure is not without risk, but has a high success rate provided the drive manufacturer’s instructions are closely followed. Following a low-level format, repartitioning the drive is neccessary to continue normal usage – this can be performed from within the Windows installation procedure.

Alternatively, you can attempt using utilities such as SpinRite or the HDD Regenerator – while they are both payware, they’re hardware-independent – they work on most, if not all, drive models, and may restore them to near-pristine quality.

Finally, if you have data that needs professional recovery, consulting a professional recovery company is your best option – provided you can foot the bill, that is, as the recovery costs may rise up to hundreds of euros or dollars. As a safety precaution, do some research into the recovery market beforehand to make sure the company you’ll hire has credibility and a good discretionary policy.

• Optical media

Optical media such as CDs and DVDs are useful everywhere, from MP3 players to your standalone DVD suites. So, naturally, once DVDs start stuttering and CDs start skipping, you have every right to get worried. There is no reason for panic, but skips, stutters, jitters and read errors (of which the most common is the I/O error) are a sign something might be wrong with the media itself.

Optical disks can fail in two ways. If the bottom of the CD (the clear plastic side) is scratched or smudged, there may be hope for repair. If the top of the CD (containing the label and recordable layer) is damaged, there is usually slim to no chance of survival – although exceptions have been known.