Dennis Ritchie
loreprogramming
The creator of the C programming language and co-creator of Unix, and joint recipient with Ken Thompson of the 1983 Turing Award for the development of generic operating systems theory and the implementation of Unix.
The decision that made both last was rewriting Unix in C. Before that, an operating system was written for a machine; afterwards it could be moved to another one, and portability stopped being a research topic and became an expectation. Nearly everything since inherits from that pair: the descendants of C run the kernels and the network stacks, and the shape of Unix - a hierarchy of files, small tools composed together, processes forked from other processes - is still the mental model behind systems that have never run a line of his code.
Also known as: ritchie, dmr