Acronis power utilities User Manual

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The following real-life passage illustrations this idea: 
Jack V., a computer consultant from Brighton, bought a used notebook 
computer for $400.00 at the clearance sale of a bankrupt Internet company. 
It was clear that the hard disk drive contained data about the company. This 
data included social security numbers and salary levels of the company’s 
forty-six employees, plus pay roll records, strategic company plans, 
confidential board of directors minutes, and other internal documents. 
There have been many cases like this concerning the sales and purchase of 
used computer. 
6.1.2 
Data Deletion by Means of an Operating Systems 
There is a considerable difference between file deletion with operating 
systems (with the help of file managers) and data destruction with the help 
of specialized erasing programs. 
The point is that operating systems, such as Windows, do not materially 
delete anything from a hard disk when deleting a file: the name of the deleted 
file in the File Allocation Table (FAT) is substituted by the name which is not 
assumed as a correct one by the operating system.  The file only becomes 
invisible for a user and the cluster chain that contains file data is considered 
to be free. But the information contained within the hard disk sectors stays 
permanent. It is not very difficult for someone to recover it. 
File deletion under the Linux operating system is somewhat more reliable, 
but even in this case it is possible to obtain software tools to recover any 
important information. 
Neither  partitions deletion  on  a  disk  nor  even  disk  formatting solves this 
problem. When partitions are deleted on a hard disk the information of 
Partition table (if it is a primary partition) or File Allocation Table is deleted. 
The information contained within sectors however remains untouched and 
can be recovered with the help of software tools. 
Reliable information destruction on hard disks is possible only while using 
specially designed programs that implement specially designed erasing 
algorithms. 
48 
Chapter 6 : Disk Data Wiping