Bryan Cantrill's USENIX talk - Fork Yeah! The Rise and Development of illumos: https://www.youtube.com/watch?v=-zRN7XLCRhc

He gives a history of SunOS, Solaris, and OpenSolaris up to the Oracle acquisition, and then onto post acquisition and the creation of illumos. It's a brilliant talk and a must-watch for any Unix enthusiast or historian. Bryan is an incredibly engaging speaker.