FORTRAN

1. FORTRAN

2. History of FORTRAN • Developed by IBM in the 1950s at their campus in south San Jose, California. • FORTRAN stands for The IBM Mathematical Formula Translating system • Older versions spell the language as "FORTRAN" in all capital letters, but the newer versions refer to the language as "Fortran."

3. History of FORTRAN • The very first generation of codes used to program computers was called machine language or machine code. • The second generation of code is called assembly language. • The third generation of code is referred to as HLL, or high level language. • The first widely used HLL was FORTRAN.

4. History of FORTRAN John W. Backus • John W. Backus is one of the most important developers of the language FORTRAN. • The only practical way of programming during that era was to write code in assembly. • In late 1953, Backus proposed to his superiors at IBM to develop a more practical alternative to assembly language. • This language would be used to program their IBM 704 mainframe computer.

5. History of FORTRAN • It was mainly developed for scientific and engineering applications. • During a 1979 interview with Think, the IBM employee magazine, Backus said "Much of my work has come from being lazy. I didn't like writing programs, and so, when I was working on the IBM 701, writing programs for computing missile trajectories, I started work on a programming system to make it easier to write programs."

6. History of FORTRAN • Developers of FORTRAN were John Backus, Sheldon F. Best, Harlan Herrick, Peter Sheridan, Roy Nutt, Robert Nelson, Irving Ziller, Rickard Goldberg, Lois Haibt, and David Sayre. • They designed the first FORTRAN compiler during 1954-1957. • The first programmer's reference manual for FORTRAN, The Fortran Automatic Coding System for the IBM 704, was published on October 15, 1956.

7. History of FORTRAN • The first FORTRAN compiler was delivered in April 1957. • This compiler was the first optimizing compiler, which means that it tuned the output of a compiler to minimize or maximize some attributes of an executable computer program. • Reduced program execution time • Reduced the memory occupied by a program • Reducing the power consumed by a program. • Customers did not want to use a high-level programming language (FORTRAN) unless its compiler could generate code that performed just as well, or better than, hand-coded assembly

8. History of FORTRAN • This new method of programming outperformed hand-coding. • It reduced the number of programming statements necessary to operate a machine by a factor of 20. • This caused it to quickly gain acceptance throughout the community. • Another reason it became popular was because it allowed programs to become portable.

9. History of FORTRAN • With each new release of FORTRAN, many new features and statements were included, which allowed for a greater range of programs to be developed. • Some new versions of FORTRAN were: • FORTRAN II • FORTRAN III • IMB 1401 FORTRAN • FORTRAN IV • FORTRAN 66 • FORTRAN 77 • ANSI Standard Fortran • Fortran 90 • Fortran 95 • Fortran 2003 • Fortran 2008.

10. History of FORTRAN • The development of Fortran began a $24 million dollar computer software industry and influenced the development of modern programming languages used today. • Fortran has been used to program video games, air traffic control systems, numerous scientific and military applications, payroll calculations, and parallel computer research. • The FORTRAN I compiler held the record for optimizing code efficiently for 20 years.

11. History of FORTRAN • John Backus received many awards and is considered to be one of the most influential people in the computer world. • IBM Fellow in 1963. • The IEEE awarded Backus the W.W. McDowell Award in 1967 for the development of FORTRAN. • National Medal of Science in 1975 • 1977 ACM Turing Award "for profound, influential, and lasting contributions to the design of practical high-level programming systems, notably through his work on FORTRAN, and for publication of formal procedures for the specification of programming languages." • National Academy of Engineering's Charles Stark Draper Prize in 1993, which is the highest national prize awarded in engineering. • Computer History Museum Fellow Award in 1997 • The Asteroid 6830 Johnbackus was named in his honor on June 1, 2007.

12. Problems With Programming Before FORTRAN • Machine code was difficult to program in • Assembly languages made it easier to program, but still required lengthy strings of commands • Programs were not portable • Programming was like “hand to hand combat with the machine” –Irving Ziller • Earlier Assembly languages needed to be learned for each new computer

13. How Fortran Fixed Problems • FORTRAN was the first high level language • FORTRAN’s commands did not require a long time to learn • It was implemented on many systems, so it could be written on one computer and transported to other systems

14. Continued… • FORTRAN’s commands were made to be closer to English than Assembly code • In fact, FORTRAN code can be read by non-programmers and understood unlike Assembly code • Because FORTRAN compiled the commands into a program written in lower level language it saved lots of time, and mimicked the process by which a human programmer uses

15. Assembly Code FORTRAN Code

16. Fortran and Mathematics • Fortran was developed during a time when computers were primarily used for scientific and mathematical research. • To assist these researches, who may not have had a background in computer programming, Fortran was developed to be easily read and tailored for imputing mathematic equations. • Equations in Fortran read much like they do in Mathematics. • For example, adding two numbers together would be written as “A+B” or multiplying two numbers together would be “A*B”.

17. Fortran and Mathematics • Fortran can handle more complex equations such as the quadratic formula. • In Fortran it would be written as: (B-SQRTF(B**2-(4AC)))/(2A) • Parenthesis are used to show operator precedence.

18. Procedural Programming • Fortran is a procedural language. • Procedural Programming is a paradigm where a program is written as a series of computations. • In Fortran, a series of computations could be written out as functions. • Functions, which are also known as subroutines, are smaller parts of a program that do a specific task. • Functions can do simple computations or even combine data or be grouped together with other functions.

19. Working with Variables • One of the original features of Fortran was the ability to work with variables. • Before Fortran, assembly code had to be rewritten any time the values changed. • Instead, Fortran allowed the original algorithm to remain intact and only the values need to be changed. • Variables allow the programmer to work with a variety of data types, the most common being integers, floating point numbers and characters.

20. Data Types • Because Fortran is a language based around mathematics, the most common types of data that are used are integers and floating point numbers. • Integers are simply whole numbers, such as 1, 2 and 3. • Floating point numbers are decimal numbers, such as 1.1, 2.2 and 3.3. • It is important to keep in mind what data type you are working with when programming functions. • For example, a function that divides one variable by another, such as 3 divided by 2. If the variables are integer data types, the value that is returned will be truncated to 1. Where as if the variables were floating point it would return the correct value of 1.5.

21. Pros • One advantage to FORTRAN is that it is old, The most well known in High-performance computing • It is easy to learn, allowing programming with basics codes. • FORTRAN is problem orientated and suited for numeric computation. • Since it was well known and used on many platform FORTRAN was very portable. • The way FORTRAN is written makes it easier to debug by isolating errors.

22. Cons • A big disadvantage for FORTRAN is that it is old • Early version of FORTRAN did not support recursion for subroutines, led to the creation of LISP • FORTRAN was before many advancements in computer science • Without the knowledge of debugging tools an advantage turns to a disadvantage. • FORTRAN since its old, it is difficult to convert to other languages.

23. NASTRAN • FEA (finite element analysis) developed by NASA for its aerospace program. • It was created in 1964 and is still in use today • The program helps detail how an object will react under pressures, indicating how it will bend or stretch. • Often used by automotive/maritime companies across the world. • The program was written with over a million lines of code and is available on many different operating systems. • NASTRAN makes use of FORTRAN’s vast mathematical capabilities

24. HEC-RAS • HEC-RAS is a program designed to make one dimensional models of water flow through rivers, streams • Stands for Hydraulic Engineering Center River Analysis Program • Developed by the US Department of Defense, Army Corp of Engineers. • Aids in the demonstration of how water would flow in certain channels or during the event of a flood • Has seen wide commercial use in areas like floodplain management as well as proving important visualizations for flood insurance studies • HEC-RAS utilizes the FORTRAN program SNET to compute the data

25. NEMO • Stands for the Nucleus for European Modeling of the Oceanturn • Takes multiple variables, like sea-ice, ocean, and biochemistry equations and its related physics into data which is then used to make a whole earth coupled with an “earth system” • These engines are where FORTRAN comes into play, by making use of its mathematic capabilities. • NEMO is used in at least 27 countries across the world

26. GAMESS • Stands for “General Atomic and Molecular Electronic Structure System” • Created by the NRSS (National Resources for Computation in Chemistry) • Made use of many pre-existing programs in FORTRAN handling quantum chemistry. • Computes many different problems relating to quantum chemistry, such as obtaining wavefunctions, and computing derivatives. • GAMESS computational program consists of over 650,000 lines of code

27. Colossal Cave Adventure • Text based adventure game designed and maintained on FORTRAN. • Created by Will Crowther, an avid “caver” and programmer. • Made by Crowther as a gift for his daughters • Has been updated many times, one edition even including pictures. • Most notable edition was created by Don Woods • Updated from 700 to over 3000 lines of code. • Game was based off of the Mammoth Cave system. • Greatly influenced the adventure game genre.