Fortran has always been the principal language used in the fields of scientific, numerical, and engineering programming, and a series of revisions to the standard defining successive versions of the language has progressively enhanced its power and kept it competitive with several generations of rivals. Beginning in 1978, the technical committee responsible for the development of Fortran standards, X3J3 (now called J3), laboured to produce a new, much- needed modern version of the language, Fortran 90. Its purpose is to "promote portability, reliability, maintainability, and efficient execution... on a variety of computing systems". The standard was published in 1991, and work began in 1993 on a minor revision, known informally as Fortran 95. Now this revised