Post Format Data Recovery: 3 Factors Affecting Its Success

by Rod Dunne on August 26, 2010

in Data Recovery

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It is a common misconception that formatting a hard disk will completely wipe the files from the drive’s memory but this simple isn’t the case. Formatted data recovery is possible because the process only removes index references to where your documents are stored on the drive. This article shows how a post format data recovery is technically possible along with the 3 factors affecting how many files will be found.

A data recovery after format is possible due to the way documents are stored and deleted. Each document you save is written to the disk memory as several data clusters located around the disk. A system file called the file allocation table (FAT) keeps an index of each document name (which you see in directory listings) and the memory addresses of its associated data clusters. Formatting a computer will clear out the list of indexes in the FAT but it leaves the clusters alone.

File recovery software can recover lost documents by scanning the drive for clusters and reforming them into the documents you will recognize.

Note: Deleted data recovery is even easier (than doing a data recovery after format) as the FAT index is not cleared so recovery software has the clusters along with the FAT index of document-to-clusters associations to piece together the documents.

Factor 1: How much the disk is used after formatting

While data clusters are left intact after formatting, they are marked as available to the operating system for writing any new files to disk.

They may not get overwritten straight away, but with ongoing use of the hard disk the pre-format clusters will begin to disappear. Extensive usage of the disk (e.g. reinstalling an OS) will accelerate the loss of your files.

Factor 2: Format data recovery software – Each tool finds different files

Each data recovery tool uses different code and processing logic to find the clusters on disk and establish which clusters go together to form a document/file you might recognize.

As a result, some post format data recovery software can be more successful than others at piecing together the fragments. One option is to try out the free trial scans of these tools to establish which can find all the documents you are seeking before making a purchase.

Suggested Post Format Data Recovery Software:

  • Remo Undelete: FAT/NTFS support, Windows 2000/XP/Vista/Server 2003; Comes with a free trial scan.

Factor 3: Formatted data recovery will be decimated by data cleansing/scrubbing

Most formatting processes work simply by clearing the FAT of document indexes. However, it is increasingly common for people to use data cleaning/scrubbing software in an effort to clear even the clusters on the hard drive.

These tools work by repeatedly writing files to the formatted drive in an effort to overwrite all the data clusters on you disk. This process is not always 100% successful but it usually results in only fragments of original documents remaining on the disk.

So, if you do find yourself needing to do a data recovery after format, then you’ll recover more lost files if the disk has not been used and try using the free scans on several tools to identify which can find the most clusters.

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