Nearly half of all enterprises will be running mission-critical business applications on Linux in five years’ time. That’s according to survey of IT directors, VPs and CIOs carried out by Saugatuck Research, which questioned 133 businesses worldwide. The company predicts a steep rise: only 18 percent of businesses will be using Linux in business-critical roles by the end of 2007. “Linux operating systems – and open source-based software in general – have reached critical marketplace mass,” said the study’s authors, Bruce Guptill and Bill McNee of Saugatuck Research.