Fortran remains one of the principal languages 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 PL22.3 but still informally called J3), laboured to produce a new, muchneeded modern version of the language, Fortran 90. Its purpose was to ‘promote portability, reliability, maintainability, and efficient execution . . . on a variety of computing systems’. That standard was published in 1991, and work began in 1993 on a minor revision, known as Fortran 95. Subsequently, and with the same purpose, a further major upgrade to the language was prepared by J3 and the international committee, WG5. That revision, which included object-oriented programming features, is now known as Fortran 2003. This was followed
by a further revision, Fortran 2008, including coarrays; and, most recently, a minor revision, Fortran 2018, including further coarray features. Once again, we have prepared a definitive informal description of the language that this latest standard defines. This continues the series of editions of this book – the two editions of Fortran 8x Explained that described the two drafts of the standard (1987 and 1989), Fortran 90 Explained that described the Fortran 90 standard (1990), two editions of Fortran 90/95 Explained that included Fortran 95 as well (1996 and 1999) and Fortran 95/2003 (2004), with its added chapters on Fortran 2003. In that endeavour, a third co-author was welcomed. Finally, the first edition of Modern Fortran Explained (2011) added further chapters on Fortran 2008.