Billionaire tech mogul Larry Ellison says he and Elon Musk are 'close friends.' Here are 8 other tech exec friendships that have thrived in the competitive world of Silicon Valley.

· Silicon Valley might be competitive, but it also appears to be a breeding ground for friendships among its famous execs.
· It makes sense: the tech world is home to some of the richest people in the world, and life can probably get a little lonely at the top. 
· Elon Musk, for example, is close friends with Google...