Fortran programming language

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A programming language originally developed in the 1950s and still in use today. The name is short for "Formula Translation". It is a procedural language suited to scientific computation, so is commonly used by scientists.

The first FORTRAN compiler was developed in 1954-57 by a team lead by John W. Backus whilst he was at IBM. This compiler was the first compiler for any High level language, and was actually an optimizing compiler, because the authors were worried that no one would use the language if its performance was not comparable to assembly language.

Because of the heavy use by scientists doing numerical work the language grew in ways that encouraged compiler writers to produce compilers that generated high quality (fast) code. There are many high performance compiler vendors. Much work and research in compiler theory and design was motivated by the need to generate good code for Fortran programs.

Several revisions of the language have appeared, including the very well known FORTRAN IV, FORTRAN 77 and the more recent Fortran 90. The most recent formal standard for the language was published in 1997 and is known as Fortran 95.

Every version introduced 'modern' programming concepts, such as IF-THEN-ELSE and parallel constructs, while still attempting to maintain Fortran's 'lean' profile and high performance.

Vendors of high performance scientific computers (Burroughs, CDC, CRAY, IBM, Texas Instruments, ...) added extensions to FORTRAN to make use of special hardware features such as: instruction cache, CPU pipeline, vector arrays, etc. For example, one of IBM's FORTRAN compilers (H Extended IUP) had a level of optimization which reordered the machine code instructions to keep several internal arithmetic units busy at the same time. Another example is CFD, a special 'version' of FORTRAN designed specifically for the ILLIAC IV supercomputer, running at NASA's Ames Research Center. These extensions have all disappeared over time; the major remaining extension is OpenMP, which is a cross–platform extension for shared memory programming. One new extension, CoArray Fortran, is intended to promote parallel programming.

Spelling

The language was formerly known as FORTRAN (and older variants of it still are). Modern usage is to spell it Fortran. The published formal standards use Fortran.

Standards

(presumably there were earlier standards?)

ANSI X3.198-1992 (R1997) Title: Programming Language – Fortran – Extended

Informally known as Fortran 90.

This standard was published by ANSI and never became an International Standard (ISO).


ISO/IEC 1539-1:1997 Information technology - Programming languages - Fortran - Part 1: Base language

Informally known as Fortran 95. There are a further 2 parts to this standard. Part 1 has been formally adopted by ANSI.


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