Recover ur Data

U Can Recover ur Data

A lot of people don't known, but when we delete a file from a computer in fact it isn't really deleted. The operating system simply removes it from the file list and makes the space the file was using available for new data to be written. In other words, the operating system doesn't "zero" (i.e. doesn't clean) the space the file was using.

The operating system acts like that in order to save time. Imagine a large file that occupies lots of sectors on the hard drive. To really delete this file from the disk the operating system would have to fill with zeros (or any other value) all sectors occupied by this file. This could take a lot of time. Instead, it simply removes the file name from the directory where the file is located and marks the sectors the file used as available space.

This means that it is possible to recover a deleted file, since its data wasn't really removed from the disk. Recovery data software works by looking for sectors with data in them that are not currently used by any file listed.

This leads us to a very important security question: if you have really confidential files, that cannot be read by anyone else, deleting them from the disk simply by hitting the Del key and then removing the recycle bin contents isn't enough: they can be recovered by an advanced data recovery tool.

With disk formatting it isn't different. When we format a hard drive, the data that was there aren't deleted, making it possible to recover data with an advanced data recovery tool even after formatting your hard drive. A lot of people that have a hard disk full of confidential data think that by formatting the hard drive they are killing any chance of data recovery. This is far from being true.

When you format a disk, the operating system only "zeros" the root directory and the tables containing the list of sectors on disk that are occupied by files (this table is called FAT). Pay attention when you format a hard drive, a message "Verifying x%" is shown. The hard drive isn't being formatted; the format command is only testing the hard disk magnetical surface in order to see if there is any error and, in case if a error is found, mark the defective area as bad (the famous "bad blocks" or "bad sectors").

So, in the same way it happens when we delete files, the hard drive isn't really "zeroed" when we format it. In order to really "zero" your hard drive, use utilities like Zero Fill from Quantum (click here to download it). This utility fills all sectors from your hard drive with zeros, making it impossible to recover any data after this utility is run, what doesn't happen when you use the normal format procedure. You can also use the so-called "low-level format utilities". These programs fill all sectors with zeros as well. You must download the software accordingly to your hard drive manufacturer. In our download section you will find low level format utilities for the most common hard disk drive manufacturers.

Bad block or faulty sector is the name given to a damaged area on a hard disk. It is a physical problem, i. e., the hard disk's magnetic media is defective. When we run a disk utility such as Scandisk and Norton Disk Doctor, such faulty sectors are marked with a "B".

Several users have written us asking how to proceed to recover hard disks with bad blocks. Many note that bad blocks disappear after low level formatting the hard disks.

What really happens, however, is that current physical formatting programs do not actually physically format the disk. If this should be feasible, the hard disk would be damaged, since hard disk tracks have a signal called servo that operates as a guide for the hard disk head. If we really formatted a hard disk at low level, these servos would be erased and the hard disk head would be unable to move any longer.

Low level formatting programs are utilities for detecting bad sectors and wiping the disk (for security reasons, for instance, after concluding a confidential project), not carrying out – despite their name – low level formatting.

These programs have an interesting function, which consists of updating the disk's bad sector map. When you use this option, the program scans the disk, seeking defective sectors and updating the disk's map.

When you run a high level formatting (through the Format command), this command skips the sectors contained in this bad sector table. Accordingly, there will not be any sector marked B ("Bad Block") in the FAT, although the defective sectors remain on the disk.

Defective sectors are not removed, but merely noted in this table of bad sectors, resulting in the system ignoring them (in other words, the sectors are hidden).

If new bad sectors keep occurring after running this procedure, you should get rid of the disk, as its magnetic surface is deteriorating, for some reason.