Data loss is one of the scariest things that can happen to a person or a company that works primarily from either a personal computer or off of a server. It's also one of the most avoidable situations a person can face. Almost anyone asked will say the same thing: having a good backup is absolutely necessary for anyone who uses a computer for more than anything that browsing the internet. Backups can be done on tape drives, DVDs, flash drives, external hard drives, etc. If a person or a company does not have a good backup and a hard drive fails, it is still able to restore the data, although the process will be a bit more expensive and time consuming than having a backup to begin with.
What is involved in restoring data from a failed disk drive? Well, most often a person or a company will need to have a company that specializes in data recovery work on the drive to restore the data. This is accomplished using a variety of proprietary techniques. Different companies all have different methods of restoring hard drives, whether the issue is on the hardware side or the software side of things. There are programs available to restore drives that have failed due to software and file system errors, and there are technicians that can often fix or restore physically broken drives long enough to get the data off of the drive.
The good news is that if a failing drive is caught in the beginning stages, and is not use much between the time it starts to fail and the point of absolute failure, most of, if not all, the data can be recovered. The process may be time consuming and has the potential to be cost, but most most, if the data is important enough to need to be reclaimed, then the price is negligible compared to the value of the data.
As stated, the easiest way to avoid having to use a data recovery service is to have a good backup, but often times by the time a person realizes a backup is a good idea, it is too late. If it's too late to take preventative measures, it can be comforting to know that there are still companies out there that can help restore and recover data lost due to either a hardware or a software hard disk failure.