## 2. What is Fortran?

Fortran is a general purpose programming language, mainly intended
for mathematical computations in e.g. engineering. Fortran is an
acronym for FORmula TRANslation, and was originally capitalized as FORTRAN.
However, following the current trend to only capitalize the first
letter in acronyms, we will call it Fortran.
Fortran was the first ever high-level programming languages.
The work on Fortran started in the 1950's at IBM and there have been
many versions since. By convention, a Fortran version is denoted by the
last two digits of the year the standard was proposed. Thus we have
- Fortran 66
- Fortran 77
- Fortran 90 (95)

The most common Fortran version today is still Fortran 77,
although Fortran 90 is growing in popularity. Fortran 95 is a
revised version of Fortran 90 which is expected to be approved by ANSI
soon (1996).
There are also several versions of Fortran aimed at parallel
computers. The most important one is High Performance Fortran (HPF),
which is a de-facto standard.
Users should be aware that most Fortran 77 compilers allow
a superset of Fortran 77, i.e. they allow non-standard extensions.
In this tutorial we will emphasize standard ANSI Fortran 77.

### Why learn Fortran?

Fortran is the dominant programming language used in engineering applications.
It is therefore important for engineering graduates to be able to read
and modify Fortran code. From time to time, so-called experts predict that
Fortran will rapidly fade in popularity and soon become extinct.
These predictions have always failed. Fortran is the most enduring
computer programming language in history. One of the main reasons Fortran
has survived and will survive is *software inertia*. Once a company has
spent many man-years and perhaps millions of dollars on a software
product, it is unlikely to try to translate the software to a different
language. Reliable software translation is a very difficult task.
### Portability

A major advantage Fortran has is that it is standardized by ANSI and ISO
(see footnotes).
Consequently, if your program is written in ANSI Fortran 77
then it will run on any computer that has a Fortran 77 compiler.
Thus, Fortran programs are portable across machine platforms.
(If you want to read some Fortran Standards Documents, click
here.)

##### Footnotes:

ANSI = American National Standards Institute

ISO = International Standards Organization

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