3.4. Operating System Version Dependency
Some computer viruses depend not only on a particular operating system, but also on an actual system version. Young virus researchers often struggle to analyze such a virus. After a few minutes of unsuccessful test infections on their research systems, they might believe that a particular virus does not work at all. Especially at the beginning of a particular computer virus era, we can see a flurry of computer viruses repeating the same mistakes that make them dependent on some flavor of Windows. For example, the W95/Boza virus does not work on non-English releases of Windows 95, such as the Hungarian release of the operating system.
This leads to the discovery that computer viruses might be used to target the computers of one particular nation more than others. For example, Russian Windows systems can be different enough from U.S. versions to become recognizable, enabling the author of a virus, intentionally or unintentionally, to target only a subset of computer users. In general, however, after a virus has been created, its author has very little or no control over exactly where his or her creation will travel.