Fortran

Fortran.

Fortran is a programming language mainly used by the scientific community. Its name is a contraction of FORmula TRANslation, and its aim is to provide a way to tell computers to calculate complicated mathematical expressions, with more ease than assembly language.

FORTRAN is one of the earliest programming languages. The original versions used punched cards to write programs with. FORTRAN's age is both a strength and a weakness. On one hand, FORTRAN has a huge number of libraries of code available. However, Fortran also has many archaic features, especially in the earlier versions.

Fortran originally included a not-so-intuitive syntax, having fixed fields (a 5-digit line number, a continuation marker, and a statement area (plus a card sequence-number area on some versions). However, newer specifications for FORTRAN , such as Fortran 90, 95, 2003 and 2008 do not require such anachronistic formatting. In addition, many compilers have additional improvements for non-standard code. This book is intended to help write code compliant with the Fortran 95 standard. Some pieces of the 2003 standard are also included. The newer standards add functionality and attempt to be fully backward compatible. Where appropriate the differences in usage between these legacy versions and the modern standard will be highlighted as there is a significant code base written in older versions, especially FORTRAN 77.

FORTRAN, in full Formula Translation,  computer-programming language created in 1957 by John Backus that shortened the process of programming and made computer programming more accessible.

The creation of FORTRAN, which debuted in 1957, marked a significant stage in the development of computer-programming languages. Previous programming was written in machine (first-generation) language or assembly (second-generation) language, which required the programmer to write instructions in binary or hexadecimal arithmetic. Frustration with the arduous nature of such programming led Backus to search for a simpler, more accessible way to communicate with computers. During the three-year development stage, Backus led an eclectic team of 10 International Business Machines (IBM) employees to create a language that combined a form of English shorthand with algebraic equations.

FORTRAN enabled the rapid writing of computer programs that ran nearly as efficiently as programs that had been laboriously hand coded in machine language. As computers were rare and extremely expensive, inefficient programs were a greater financial problem than the lengthy and painstaking development of machine-language programs. With the creation of an efficient higher-level (or natural) language, also known as a third-generation language, computer programming moved beyond a small coterie to include engineers and scientists, who were instrumental in expanding the use of computers.

By allowing the creation of natural-language programs that ran as efficiently as hand-coded ones, FORTRAN became the programming language of choice in the late 1950s. It was updated a number of times in the 1950s and 1960s in order to remain competitive with more contemporary programming languages. FORTRAN 77 was released in 1978, followed by FORTRAN 90 in 1991 and further updates in 1996 and 2004. However, fourth- and fifth-generation languages largely supplanted FORTRAN outside academic circles beginning in the 1970s.

Fortran founder:

John Backus

John Warner Backus (December 3, 1924 – March 17, 2007) was an American computer scientist. He directed the team that invented the first widely used high-level programming language (FORTRAN) and was the inventor of the Backus-Naur form (BNF), a widely used notation to define formal language syntax. He also did research in function-level programming and helped to popularize it.

The IEEE awarded Backus the W.W. McDowell Award in 1967 for the development of FORTRAN. He received the National Medal of Science in 1975, and the 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.”

Life and career

Backus was born in Philadelphia and grew up in nearby Wilmington, Delaware. He studied at the The Hill School in Pottstown, Pennsylvania, and was apparently not a diligent student. After entering the University of Virginia to study chemistry, he quit and was conscripted into the U.S. Army.He began medical training at Haverford College and, during an internship at a hospital, he was diagnosed with a cranial bone tumor, which was successfully removed; a plate was installed in his head, and he ended medical training after nine months and a subsequent operation to replace the plate with one of his own design.

After moving to New York City he trained initially as a radio technician and became interested in mathematics. He graduated from Columbia University with a master's degree in mathematics in 1949, and joined IBM in 1950. During his first three years, he worked on the Selective Sequence Electronic Calculator (SSEC); his first major project was to write a program to calculate positions of the Moon. In 1953 Backus developed the language Speedcoding, the first high-level language created for an IBM computer, to aid in software development for the IBM 701 computer.

Programming was very difficult at this time, and in 1954 Backus assembled a team to define and develop Fortran for the IBM 704 computer. Fortran was the first high-level programming language to be put to broad use.

Backus made another, critical contribution to early computer science: during the latter part of the 1950s Backus served on the international committees that developed ALGOL 58 and the very influential ALGOL 60, which quickly became the de facto worldwide standard for publishing algorithms. Backus developed the Backus-Naur Form (BNF), in theUNESCO report on ALGOL 58. It was a formal notation able to describe any context-free programming language, and was important in the development of compilers. This contribution helped Backus win the Turing Award.

Though the Backus Normal Form was discovered independently by John Backus; Pāṇini, a grammarian from India who lived sometime between 4th and 7th century BCE, presented a notation which is equivalent in its power to that of Backus and has many similar properties.

Backus later worked on a "function-level" programming language known as FP which was described in his Turing Award lecture "Can Programming be Liberated from the von Neumann Style?". Sometimes viewed as Backus's apology for creating FORTRAN, this paper did less to garner interest in the FP language than to spark research into functional programming in general. An FP interpreter was distributed with the 4.2BSD Unix operating system. FP was strongly inspired by Kenneth E. Iverson’s APL, even using a non-standard character set. Backus spent the latter part of his career developing FL (from "Function Level"), a successor to FP. FL was an internal IBM research project, and development of the language essentially stopped when the project was finished (only a few papers documenting it remain), but many of the language's innovative, arguably important ideas have now been implemented in versions of the J programming language.

Backus was named an IBM Fellow in 1963, and was awarded a degree honoris causa from the Henri Poincaré University in Nancy (France) in 1989 and a Draper Prize in 1993.^[12] He retired in 1991 and died at his home in Ashland, Oregon on March 17, 2007.

Biography

John Backus was born in Philadelphia in 1924, and grew up near there in Wilmington, Delaware. His family was wealthy, and Backus attended the prestigious Hill School in Pottstown, Pennsylvania. He was not a good student, and his years at the Hill School were marked by a series of failures.

Poor grades and attendance record notwithstanding, Backus graduated from the Hill School in 1942 and entered the University of Virginia. His father, at one time a chemist, wanted him to major in chemistry. Backus did study chemistry for awhile, and enjoyed the theoretical aspects of the science, but he disliked the lab work. By the end of his second semester, his class attendance fell to once a week, and school authorities expelled him. He joined the Army in 1942.

Backus served as a corporal in charge of an anti-aircraft crew at Fort Stewart, Georgia, but his performance on an aptitude test changed the course of his military career when the Army decided to enroll him in a pre-engineering program at the University of Pittsburgh. Another aptitude test, this time for medical skills, landed him at Haverford College, where he was to study medicine.

As part of the premed program, Backus worked at an Atlantic City hospital as part of the premed program. During that time, he was diagnosed with a brain tumor and a plate was installed in his head. In March 1945, he entered Flower and Fifth Avenue Medical School in New York, but he realized medicine wasn’t for him and he lasted only nine months.

Backus left the Army in 1946 following an additional operation to replace the plate in his head, which had never fit correctly. Not knowing what to do with his life, he took a small apartment in New York. He liked music, and wanted to buy a good hi-fi set. What he wanted didn’t exist at the time, so he enrolled at a radio technician’s school to learn how to build one.

While there, Backus helped an instructor do mathematical calculations for an amplifier curve. The work was tedious, but it uncovered an aptitude and interest in mathematics, and Backus decided to enroll at Columbia University to study math. By the spring of 1949, he was just months away from graduating with a bachelor of science degree in mathematics.
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During that spring, Backus visited the IBM Computer Center on Madison Avenue, where he toured the Selective Sequence Electronic Calculator (SSEC), one of IBM’s early electronic computers. While on the tour, Backus mentioned to the guide that he was looking for a job. She encouraged him to talk to the director of the project, and he was hired to work on the SSEC.

The SSEC was not a computer in the modern sense. It had no memory for software storage, and programs had to be entered on punched paper tape. It had thousands of electromechanical parts, making it unreliable and slow as well. Part of Backus’s job was to attend the machine, and fix it when it would stop running. Programming the SSEC was also a challenge, as there was no set way of doing it.

Backus spent three years working on the SSEC, during which time he invented a program called Speedcoding. The program was the first to include a scaling factor, which allowed both large and small numbers to be easily stored and manipulated.

In late 1953, Backus wrote a memo to his boss that outlined the design of a programming language for IBM’s new computer, the 704. This computer had a built-in scaling factor, also called a floating point, and an indexer, which significantly reduced operating time. However, the inefficient computer programs of the time would hamper the 704’s performance, and Backus wanted to design not only a better language, but one that would be easier and faster for programmers to use when working with the machine. IBM approved Backus’s proposal, and he hired a team of programmers and mathematicians to work with him.

The challenge Backus and his team faced was not designing the language, which they felt they could easily do. Instead, it was coming up with a device that would translate that language into something the machine could understand. This device, known as a translator, would eliminate the laborious hand-coding that characterized computer programming at the time. It contained an element known as a parser, which identified the various components of the program and translated them from a high-level language (one that people understand) into the binary language of the computer.

In the fall of 1954, Backus and his team felt strongly enough about their research to publish a paper, called “Preliminary Report, Specifications for the IBM Mathematical FORmula TRANslating System, FORTRAN.” Along with others from IBM, he visited customers who had ordered the 704 to present the new language and gather any feedback or comments they may have. At the time, Backus anticipated completion of the compiler in six months. Instead, it would take two years.

When completed, the compiler consisted of 25,000 lines of machine code, stored on magnetic tape. A copy of the program was provided with every IBM 704 installation, along with a 51-page manual. The first versions of the program were understandably buggy, but later versions would refine and eliminate them.

FORTRAN was designed for mathematicians and scientists, and remains the preeminent programming language in these areas today. It allows people to work with their computers without having to understand how the machines actually work, and without having to learn the machine’s assembly language. That FORTRAN is still in use 40 years after its introduction is testimony to Backus’s vision.

After FORTRAN, Backus turned his focus to other elements of computer programming. In 1959, he developed a notation called the Backus-Naur Form. It describes grammatical rules for high-level languages, and has been adapted for use in a number of languages. In the 1970s, he worked on finding better programming methods, and developed what he called a function-level language, or FP (for functional programming). Backus introduces this Functional Programming language during a lecture given on the occasion of receiving the ACM Turing award (1977), "Can Programming be liberated from the von Neumann Stype? A Functional Style and its Algebra of Programs" proposed a programming language, FP, and revived the interest in functional languages and functional programming. (2)Functional Programming. John Backus 1977