User Guide

ViRobot Advanced Server
106
REFERENCES
Definitions And Types Of Virus
We will see brief descriptions and types of viruses.
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Virus
Computer viruses are different from the biological viruses of living forms. A computer virus is a
cracker program that searches out other programs and infects them by embedding a copy of the
virus in the program.
This self-duplication capability explains why it is called ‘virus’. A virus may delete the user's
important files just like the organic virus may kill the healthy cells. Boot viruses, file viruses, macro
viruses, and Windows viruses are the most widely known nasty viruses according to types of
infection.
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Boot Viruses
Boot viruses infect the boot sector of a floppy disk and the boot sector or Master Boot Record
(MBR) of a hard disk. Boot viruses rely on the fact that the computer executes the program code
stored in the boot sector immediately upon start-up. Anti-CMOS and Monkey viruses are the
examples.
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File Viruses
This is a most common type of virus. It infects only files with extensions such as EXE, COM,
OVL, and SYS. You may say that Windows viruses are also file viruses that work on a different
operating system. Die_Hard virus is in its kind.