Computer Viruses

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(a)What are computer viruses?
(b)How do they spread?
(c) What damage do computer viruses cause?

In this analysis, we shall look at computer viruses, what they are, how they spread and what damage they cause. The first question to ponder is: What are computer viruses? Many computer users would find it hard to answer that question. According to Wikipedia, a computer virus is a computer program that can replicate itself and spread from one computer to another. The term "virus" is also commonly, but erroneously used, to refer to other types of malware, including but not limited to adware and spyware programs that do not have a reproductive ability. A computer virus, according to Webster's Collegiate Dictionary, is "a computer program usually hidden within another seemingly innocuous program that produces copies of itself and inserts them into other programs or files, and that usually performs a malicious action (such as destroying data)". Two categories of viruses; macro viruses and worms, are especially common today. Computer viruses are never naturally occurring; they are always man-made. Once created and released, however, their spread is not directly under human control. The actual term "virus" was first used to denote a self-reproducing program in a short story by David Gerrold in Galaxy magazine in 1969 and later in his 1972 novel, When HARLIE Was One. In that novel, a sentient computer named HARLIE writes viral software to retrieve damaging personal information from other computers to blackmail the man who wants to turn him off. The definition of a virus has nothing to do with what terrible damage it may inflict on a computer. It is just a question of how it spreads. A virus is a program, usually a file ending in ‘exe’ that has the ability to clone itself and transmit its clones to other computers. This system of 'infection', resembling the spread of viral diseases, is why it is called a virus. Of course, unlike viral diseases computer viruses are not carried by insects or spread by coughs and sneezes. Instead, their carriers are digital. Viruses are sometimes confused with worms and Trojan horses, which are technically different. Viruses may harm a computer system's data or performance, but many are surreptitious or simply do nothing to call attention to themselves. The first academic work on the theory of computer viruses (although the term ‘computer virus’ was not used at that time) was done in 1949 by John von Neumann who held lectures at the University of Illinois about the "Theory and Organization of Complicated Automata". The work of Von Neumann was later published as the "Theory of self-reproducing automata". In his essay he described how a computer program could be designed to reproduce itself.

In 1980 Jürgen Kraus wrote his diploma thesis "Selbstreproduktion bei Programmen" (Self-reproduction of programs) at the University of Dortmund. In his work Kraus postulated that computer programs can behave in a way similar to biological viruses. In 1984 Fred Cohen from the University of Southern California wrote his paper "Computer Viruses - Theory an Experiments". It was the first paper to explicitly call a self-reproducing program a ‘virus’. One of the first computer  viruses was a boot sector virus dubbed ‘Brain’, created in 1986 by the Farooq Alvi Brothers in Lahore, Pakistan, reportedly to deter piracy of the software they had written. Traditional computer viruses emerged in the 1980s, driven by the spread of personal computers and the resultant increase in modem use, and software sharing. (Trudere 2007) | |

Computer viruses are programs written by people. A computer virus is created when a programmer creates computer code that has the capability to replicate itself, hide, watch for a certain event to occur, and deliver a destructive or prankish...
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