That's what a big deal Dennis Richie was.
You pretty much can't find any major computing platform that doesn't have his significant
touch on it. Even things like the iPhone. Runs an OS that takes from his heritage and apps are coded in Objective C, a derivate of his C language.
UNIX and C are veritable cornerstones of computing. I honestly don't know if there is a bigger computing giant out there.
It's kinda sad that the fathers of modern computing are now fading away. It's something I think we're going to have to get used to (the industry is so young, that it hasn't dealt with a lot of this yet).