A NIF isn't the same thing as a BIF. NIFs where introduced in R13B03 and are in short, user-code written in C. BIFs on the other hand are built-ins implemented

A NIF isn't the same thing as a BIF. NIFs where introduced in R13B03 and are in short, user-code written in C. BIFs on the other hand are built-ins implemented in a completely different manner.