CIH, also known  as Chernobyl or Spacefiller, is a Microsoft Windows computer virus which first emerged in 1998. It is one of the most damaging viruses, overwriting critical information on infected system drives, and more extensively, in some cases corrupting the system BIOS. The virus was produced by Chen Ing-hau who was a student at Tatung University in Taiwan. 60 million computers were believed to be infected by the virus internationally, resulting in an estimated $1 billion US dollars in commercial damages.