Fortran is a general-purpose, compiled imperative programming language that is especially suited to numeric computation and scientific computing. It was the first commercially available programming language and was the first widely used high level general purpose programming language to have a functional implementation, as opposed to just a design on paper. It was first developed in 1954 but its first manual appeared in 1956 by a team led by John Backus at IBM.
The name Fortran stands for FORmula TRANslating system and was designed at IBM for scientific and engineering applications. The components were very simple, and provided the programmer with low-level access to the computers innards. At first it was treated with suspicison but over time it became popular because it provided a means of porting existing code to new computers, in a hardware market that was rapidly evolving; the language eventually became known for its efficiency.
Programs for the earliest computers consisted of sequences of numerical codes. Each code represented a basic operation such as ‘fetch a number from memory location X and put it in register A’ or ‘add the number in register A to the number in register B’. This style of programming was time-consuming and error-prone. Mistakes were difficult to find. By 1950, it had become possible to write programs using mnemonics such as ADD in place of the numerical codes. An assembler converted the mnemonics into the corresponding numerical codes. This made programming a little easier, but even a simple program required dozens of operations, and it was still difficult to track down mistakes.
The idea for Fortran was born out of the need to create a programming language in which a series of calculations can be expressed in something resembling mathematical notation. A translation program (a compiler) would then convert it into the numerical codes which the computer understood. By 1956, the team published a manual which described the IBM Mathematical Formula Translating System, or FORTRAN for short.
Today, this language would be considered restrictive as it only included IF, DO, and GOTO statements, but at the time, these commands were a big step forward. Fortran’s design was the basis for many other programming languages. Fortran encompasses a lineage of versions, each of which evolved to add extensions to the language while usually retaining compatibility with prior versions. Successive versions have added support for structured programming and processing of character-based data (FORTRAN 77), array programming, modular programming and generic programming (Fortran 90), high performance Fortran (Fortran 95), object-oriented programming (Fortran 2003) and concurrent programming (Fortran 2008).
FORTRAN’s growing popularity led many computer manufacturers to implement versions of it for their own machines. Each manufacturer added its own customizations, making it impossible to guarantee that a program written for one type of machine would compile and run on a different type. Today, Fortran is still a popular language for high-performance computing and is used for programs that benchmark and rank the world’s fastest supercomputers. It is also in continuous use for over six decades in computationally intensive areas such as numerical weather prediction, finite element analysis, computational fluid dynamics, computational physics, crystallography and computational chemistry.