October 2009 marked an important milestone in the history of computing. It was exactly 40 years since the first Multics computer system was used for information management at the Massachusetts Institute of Technology. In this edition of Blast from the Past we talk to Fernando Corbato on the early days of Multics, why it was so influential, open source and software development practices, and how cloud computing is a modern incarnation of Multics’ time-sharing philosophy.