A Short History

Traditional computer viruses were first widely seen in the late 1980s, and they came about because of several factors. The first factor was the spread of personal computers. Prior to the 1980s, home computers were nearly non-existent. Computers were rare, and they were locked away for use by "experts." During the 1980s, computers started to spread to 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 widespread in businesses, homes, and college campuses.

The second factor was the use of computer bulletin boards. People could dial up a bulletin board with a modem and download programs of all types. Games were extremely popular, so were simple word processors, and spreadsheets. Bulletin boards then led to the precursor of the virus known as the Trojan horse. A Trojan horse is simply a computer program. The program claims to do one thing while it does another. A Trojan horse is a program that is designed to sounds interesting, but after you download and run it, the program does something really uncool like erase your hard drive. You think you got a neat game, but it wipes out your system. Trojan horses only hit a small number of people because they are discovered rather quickly and the bulletin board owner either erases the file from the system, or people send out messages warning one another.

The third factor that led to the creation of viruses was the floppy disk. In the 1980s, programs were small and you could fit the operating system, a word processor, plus several other programs and documents onto a floppy disk or two. Many computers did not have hard disks, so you would turn your machine on and it would load the operating system and everything else off of the floppy disk. It was easy to use this transportable method to pass viruses on and viruses took advantage of all three facts to create the first self-replicating programs.

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