History of Computer viruses

Theories for self-replicating programs were first developed in 1949. However, it wasn't until the late 1980s that traditional computer viruses were widely seen. The first PC virus, the " Brain" virus was created in 1986 by 2 Pakistani brothers. The virus only infects the boot records of floppy disks by occupying unused space on the disk, thus rendering it useless. In addition, this latest creation was also the first "stealth" virus, as it will try to hide itself from detection. This virus evades detection by displaying the original, uninfected boot sector if a computer user tries to view the infected space on the disk.

Viruses came about due to several factors. The first factor was the spread of personal computers (PCs). Before the 1980s, home computers were non- existent. Real computers were rare and they were used exclusively by "experts." During the 1980s, personal computers began to be employed in businesses and homes because of the popularity of the IBM PC (released in 1982) and the Apple Macintosh (released in 1984). By the late 1980s, PCs were commonly used in businesses, homes and college campuses.

The use of computer "bulletin boards." is another factor attributed to the creation of viruses. People were able to dial up a bulletin board with a modem and download all types of programmes. Games, simple word processors and spreadsheets were extremely popular downloads. Therefore, this led to the evolution of the predecessor of the virus known as the Trojan Horse (A Trojan horse is a program that one usually downloads out of curiosity. However, when one runs the programme, this curiosity will turn into a nightmare, as it will erase your disk or even wipes out your system. Fortunately, Trojan horses were easily discovered, and thus, its prevention was quite successful.
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The third factor that led to the creation of viruses was the floppy disk. In the 1980s, programs were small and one could fit several programs (including the operating system and a word processor) into a floppy disk or two. As many computers of the past did not have hard disks, the machine simply loads the operating system from the floppy disk.

Therefore, viruses took advantage of these three facts to create the first self-replicating programs!