Diagnostics
When a compiler is given a syntactically incorrect program, a good, clear error message is helpful. From the perspective of the compiler writer, it is often difficult to achieve.
The WATFIV Fortran compiler was developed at the University of Waterloo, Canada in the late 1960s. It was designed to give better error messages than IBM's Fortran compilers of the time. In addition, WATFIV was far more usable, because it combined compiling, linking and execution into one step, whereas IBM's compilers had three separate components to run.
Read more about this topic: History Of Compiler Construction