Most computer users have come across the term “computer virus”. It conjures up a negative image that represents something horrific. The idea that computer viruses are always destructive is deeply ingrained in most people’s thinking.
A computer virus is a computer program that has the ability to destroy data and gain control of a computer. Its similarity with the biological virus is its ability to make a fully functional copy of itself (reproduce).
When a computer virus is executed it makes one or more copies of itself. These copies may later be executed, to create still more copies.
It is crucial to understand that not all computer programs that are destructive are classified as viruses because they do not all reproduce. Similarly not all computer viruses are destructive because reproduction, in itself, is not destructive.
What qualifies a program to be termed a virus is its destructive purpose, ability to gain control of a computer and its reproductive capability.
The very term “virus” is an emotionally charged epithet. The scientifically correct term for a computer virus is “self-reproducing automation (SRA)”.
A computer virus is written by someone with a purpose in mind. In this sense, a computer virus has the same two basic goals of a living organism: to survive and to reproduce.
Computer viruses have to be executed if they are to attain their functionality. To achieve this, the virus must attach itself to a COM, EXE or SYS file. If it attaches to any other file, it may corrupt some data, but it won’t normally get executed, and it won’t reproduce. A virus designed to attack COM files cannot attack EXE file.
We live in an interconnected world and computer viruses have the potential of spreading at phenomenal speed. Famous virus attacks have occurred in the past. The most memorable ones include the Melissa virus, I Love You virus and SQL slammer worm.
You can protect yourself from computer viruses by using an internet firewall. Windows XP with SP2 and Vista have an already built-in firewall and it is turned on by default.
You should also subscribe to industry standard antivirus software. This software should be constantly updated.
Finally never open an e-mail attachment from someone you don’t know. You should also avoid opening attachments from friends, unless you know exactly what the attachment is. The sender may be unaware that it contains a virus.