How Is “Lost” Data Recovered?

How Is Data Stored in Computers?
Before we look at how data is recovered, we must have a good idea of how data is stored in computers. Of course, we all know that data is stored on hard disks, CD/DVD media, Flash disks and Magnetic Tapes. Let us now go into a little more detail on how exactly the data is stored.

There are two key elements involved in recording and accessing data. First is the data itself that is recorded on the disk surface and the second is “file system” that keeps track of which data is recorded where. It is the file system that enables us to retrieve the written data when needed.

For example, a disk surface might be divided up into “sectors” of 512 Bytes (characters) in length, with each sector having a unique ID. The file system would “allocate” sectors for each write operation. These allocated sectors would typically not be contiguous sectors. Instead, a file’s data could be scattered all over the surface of the disk. It is the file system that keeps track of on which particular sectors the data for each file is recorded.

If the file system gets damaged, the data on the disk become inaccessible. If you somehow manage to read the info on contiguous sectors in sequence, you would simply get jumbled garbage.

You need both the file system record as well as the relevant file data to read the data in a meaningful manner. That tells us of one way data could be “lost”.

It is the read/write heads above the fast rotating platters of the disk drive that records data magnetically on disk surfaces. There is a thin film of air between the head and platter surface, and in normal operation, the head does not touch the surface.
How Do Data Get Lost?
As we saw in the last section, if file system gets damaged, data could be effectively lost.

Data could also get lost in other ways. For example, the read/write head could come in contact with disk platters and this would cause damage to the magnetic media on the platter surface. Or the motor that rotates the platters, or some other mechanical component in the drive, could fail.

There is also the too common phenomenon of human errors on the part of operators and administrative staff that could result in data loss. Then there are virus and other malicious attacks, including deliberate sabotage that could destroy data on the computers.

If you stop working with the damaged drive, there would be greater chances of recovering the apparently lost data. On the other hand, continued operation of the drive, or a do-it-yourself attempt at recovering the data, could aggravate the damage making it difficult and more expensive, or even impossible, to recover the data.
How Is Lost Data Recovered?
As we saw earlier, apparently lost data is not permanently gone from the disk. A raw image would still be on the disk surface and data recovery specialists extract this image and try to reconstruct the data from it.

They repair any damage to the file system and try to make meaning out of the image so extracted. They might also replace the damaged read/write head with a matching, healthy one, or move the platter to a matching, healthy disk drive. Or replace the damaged PCB controlling the drive.

Data recovery specialists work in completely dust free environments, such as a Class 100 Clean Room, to avoid dust settling on the disk surfaces. Even microscopic particles of dust could damage the data that are densely packed on the disk.

In essence, the data recovery specialists try to preserve the image on the disk platters and use different techniques to reconstruct the data represented by the image.
Call a Data Recovery Specialist in Case of Data Loss
Data recovery is one task that you should not attempt to do yourself. You could not only aggravate the data damage but also void the manufacturer’s warranty on the drive (if you open the sealed drive). On the other hand, manufacturers authorize trained data recovery specialists to open the drives without voiding the warranty.

Reputed data recovery firms would be constantly keeping up to date with latest developments in drive technology and data storage. Because of their training and experience, these specialists would also be aware of the possible dangers involved and could take necessary precautions.

Above all, they have to facilities and specialized tools required for the task.

How Do You Prevent Data Loss or Recover “Lost” Data?

What Is Data Loss and How Does It Occur?

If you have been using a computer for some time now, you would know what data loss means. Your data becomes inaccessible, or you get a garbled (and useless) version of the original data. The data might still be there (it is usually there even after a deletion) but has somehow become unreadable.

In other cases, data could be physically wiped out, or overwritten by newer data, making the original data irrecoverable.

Every computer user would have experienced one or more of the following:

  • You delete a file, and then suddenly realize that the file you deleted was an important one for your business or work. If you realized this immediately, you would most likely be able to do a data recovery by un-deleting the file. However, if you had done much work after the original delete event, it is also most likely that you would have written other data over the contents of the deleted file. In such a case recovering the contents of the deleted file would become impossible or at least incomplete.
  • You, or the service people to whom you had entrusted your computer for maintenance, format a disk assuming that all needed files have been backed up. Later, when you search for some particular data file or program, you find that it had not been backed up. In this case, you would have to reconstruct the data or get another copy of the program.
  • Your computer operating system, or some application software, suddenly freezes and does not respond to your repeated and desperate attempt to proceed with the work. You could lose much of the work you did unless it had been saved before the freeze occurred
  • A serious power fluctuation (owing to, say, lightning) causes a hardware crash, leading to data damage or even loss. Hardware could also crash owing to mechanical failures of the components.
  • A virus or other malicious program damages your data or wipes files clean off the disk.

The kinds of events listed above are relevant both in a personal or business environment, and were mentioned to illustrate how easy it is to lose data. In businesses, things are much more complex with several computer users feeding data into a networked system as well as into their personal computers.

  • Businesses with substantial volumes of data need a systematic backup procedure to ensure that all data can be recovered in case the original data are lost. It is quite possible that such a systematic procedure had not been implemented or even developed. In such a case, valuable data might not be backed up, or even if backed up, the reliability of the backups might not be systematically checked. Without such regular checking, it is quite possible that in case of a disaster, the date cannot be restored satisfactorily.
  • A networked system adds to the complexity by making it possible for any user to cause serious damage to data stored in the system, either accidentally or maliciously, through any weakness in the control systems.
  • Businesses might use far more complex hardware and software, such as RAID servers, that adds a new dimension to the possibilities for disasters.

In short, human errors, software crashes, hardware crashes, virus or other malicious attacks, sabotage, poorly implemented backup or control procedures.

The Impact of Data Loss
Business entities depend on data to run their businesses. It is previously recorded data that tells them what is owed by each customer, how much they owe to their suppliers, which suppliers have not yet delivered against the orders, what items are in inventory, which items need to be replenished immediately and all the other info needed to take different kinds of actions that constitute a business.

If the data gets lost in full or in part, a typical business would face a serious problem. Businesses could even go bankrupt if the time or money cost of reconstructing the lost data is something that they cannot afford. Even if it does not go that far, the time involved in reconstructing the data could disrupt day to day operations, and the cost involved could come to thousands or even millions of dollars, depending on the size of the business and its data.

Needless to say, data loss is something that businesses must organize against. They do this by:

  • Carefully planning and implementing a system of backing up data so that in the event of a loss, data could be restored using the backup media
  • Regularly auditing the backup procedures and testing the backups to ensure that the system is working properly and that the data on the backup media would indeed be “restorable” if a data loss event happens

Backups could prove less than satisfactory if it is not carefully planned, strictly implemented and regularly monitored.

Recovering “Lost” Data
As we mentioned at the beginning, data is not always lost in the true sense of the word. In many cases, it would have simply become inaccessible. For example, the “file system” that keeps track of which data is where on the disk surface could become corrupted. In this case, repairing the file system would make the data accessible once again.

In other cases, some hardware procedures could reconstruct the data by deciphering the “image” that is still on the disk surfaces. However, the recovery could often turn out to be incomplete.

Trained specialists with required facilities are needed to do recovery procedures. For example, if you open a sealed hard disk drive, the microscopic particles of dust in the atmosphere could settle on the disk surface, damaging the magnetic record on it. This would make data recovery more difficult, if not impossible. Opening sealed drives would also void the manufacturer’s warranty on the drive.

Specialist data recovery organizations could open the sealed drives without voiding the warranty, because they would typically be authorized by drive manufacturers to do so. These data recovery specialists would also have facilities like Class 100 Clean Rooms to open the sealed drives and work with them.

So if a data loss happens to you, don’t try DIY, but call a specialist with experience and required facilities.

Data Recovery Software (DRS)

Data Recovery Software (DRS) can be a very useful tool for everyone, ranging from individuals who use their computer for personal use to high profile business people who have loads of important information that would be devastating to lose. Whatever your situation, having data recovery software actively installed on your computer can save much frustration and stress in the future.

Not so long ago a friend of mine lost his entire hard drive because of a power issue. On his computer he had a whole semester of his university course and about 4 years of photos. He lost them all. If he had data recovery software installed on his hard drive, it would have been a simple process to recover all the data but because he didn’t, the files could not be saved.
There are many instances where people can lose important files and that is mainly why data recovery software was created.

It can be a difficult process finding what software is the fastest and easiest to use but no one can give you a better idea than those who have used this type of software in the past. There are many free programs available and just as many paid programs. My best suggestion would be to go to the various technology forums and post a new topic asking which software works the best in both free and paid versions. If you don’t get a response try other forums even if they only have the slightest thing to do with software.

Another way to choose between purchasing either paid or free data recovery software is to ask this question to yourself: “How important is the files that I wish to back up using this software and what effects would it have if I lost these files?”. Obviously if the files are extremely important to you and there would be devastating consequences you would look closely into paid versions of the software.

Alternatively if the files you wish to back up were of minimal importance and the effects of losing them was not so bad, you would look more closely into the free versions. It is the most difficult to decide when you are stuck in-between these two extremes.

Many people over estimate the power of technology but anyone who uses a computer should have in mind that the data stored on their computer is not 100% safe. Data Recovery Software can be only a small investment if you are backing up very important data.

There are a number of different programs on the market today but by closely researching each one and looking into the specific advantages and disadvantages, the most appropriate program will become clear after a while. In conclusion, no one is forcing you to go to the trouble of playing around with this software but if you want to not be constantly assessing the risks of hard drive failure it can be a good investment.