Bruce Roberts - The C Language, appearing in Byte Vol. 8 No. 8, August 1983, emphasis added:

Why is C so popular? The primary reason is that it allows programmers to easily transport programs from one computer or operating system to another while taking advantage of the specific features of the microprocessor in use. And C is at home with systems from 8-bit microcomputers to the Cray-1, the world's fastest computer. As a result, C has been called a "portable assembly language," but it also includes many of the advanced structured-programming features found in languages like Pascal.