John Warner Backus (December 3, 1924 – March 17, 2007) was an American

computer scientist A computer scientist is a scientist who specializes in the academic study of computer science. Computer scientists typically work on the theoretical side of computation. Although computer scientists can also focus their work and research on ...

. He led the team that invented and implemented FORTRAN, the first widely used

high-level programming language A high-level programming language is a programming language with strong Abstraction (computer science), abstraction from the details of the computer. In contrast to low-level programming languages, it may use natural language ''elements'', be ea ...

, and was the inventor of the

Backus–Naur form In computer science, Backus–Naur form (BNF, pronounced ), also known as Backus normal form, is a notation system for defining the Syntax (programming languages), syntax of Programming language, programming languages and other Formal language, for ...

(BNF), a widely used notation to define

syntax In linguistics, syntax ( ) is the study of how words and morphemes combine to form larger units such as phrases and sentences. Central concerns of syntax include word order, grammatical relations, hierarchical sentence structure (constituenc ...

es of

formal language In logic, mathematics, computer science, and linguistics, a formal language is a set of strings whose symbols are taken from a set called "alphabet". The alphabet of a formal language consists of symbols that concatenate into strings (also c ...

s. He later did research into the

function-level programming In computer science, function-level programming refers to one of the two contrasting programming paradigms identified by John Backus in his work on programs as mathematical objects, the other being value-level programming. In his 1977 Turin ...

paradigm, presenting his findings in his influential 1977 Turing Award lecture "Can Programming Be Liberated from the von Neumann Style?" The

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE ...

awarded Backus the W. W. McDowell Award in 1967 for the development of FORTRAN. He received the

National Medal of Science The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral science, behavior ...

in 1975 and the 1977

Turing Award The ACM A. M. Turing Award is an annual prize given by the Association for Computing Machinery (ACM) for contributions of lasting and major technical importance to computer science. It is generally recognized as the highest distinction in the fi ...

"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". John Backus retired in 1991. He died at his home in

Ashland, Oregon Ashland is a city in Jackson County, Oregon, United States. It lies along Interstate 5 in Oregon, Interstate 5 approximately 16 miles (26 km) north of the California border and near the south end of the Rogue Valley. The city's population w ...

on March 17, 2007.

Early life

Backus was born in

Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...

and grew up in nearby

Wilmington, Delaware Wilmington is the List of municipalities in Delaware, most populous city in the U.S. state of Delaware. The city was built on the site of Fort Christina, the first Swedish colonization of the Americas, Swedish settlement in North America. It lie ...

. He studied at The Hill School in Pottstown, Pennsylvania, but he was apparently not a diligent student. He entered college at the

University of Virginia The University of Virginia (UVA) is a Public university#United States, public research university in Charlottesville, Virginia, United States. It was founded in 1819 by Thomas Jefferson and contains his The Lawn, Academical Village, a World H ...

to study

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

, but struggled with his classes there, and he was expelled after less than a year for poor attendance. He was subsequently conscripted into the U.S. Army during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, and eventually came to hold the rank of corporal, being put in command of an anti-aircraft battery stationed at Fort Stewart,

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

. After receiving high scores on a military aptitude test, the Army sent him to study engineering at the

University of Pittsburgh The University of Pittsburgh (Pitt) is a Commonwealth System of Higher Education, state-related research university in Pittsburgh, Pennsylvania, United States. The university is composed of seventeen undergraduate and graduate schools and colle ...

. He later transferred to a pre-medical program at

Haverford College Haverford College ( ) is a private university, private Liberal arts colleges in the United States, liberal arts college in Haverford, Pennsylvania, United States. It was founded as a men's college in 1833 by members of the Religious Society of Fr ...

. During an internship at a hospital, he was diagnosed with a cranial bone tumor, which was successfully removed, and a plate was installed in his head. He then moved to the Flower and Fifth Avenue Medical School for medical school, but found it uninteresting and dropped out after nine months. He soon underwent a second operation to replace the metal plate in his head with one of his own design, and received an honorable medical discharge from the U.S. Army in 1946.

Fortran

After moving to

New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...

he trained initially as a

radio Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...

technician and became interested in mathematics. He graduated from

Columbia University Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...

with a bachelor's degree in 1949 and a master's degree in 1950, both in mathematics, and joined

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

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 The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. 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 The IBM 701 Electronic Data Processing Machine, known as the Defense Calculator while in development, was IBM’s first commercial scientific computer and its first series production mainframe computer, which was announced to the public on May 2 ...

computer. Programming was very difficult at this time, and in 1954 Backus assembled a team to define and develop Fortran for the

IBM 704 The IBM 704 is the model name of a large digital computer, digital mainframe computer introduced by IBM in 1954. Designed by John Backus and Gene Amdahl, it was the first mass-produced computer with hardware for floating-point arithmetic. The I ...

computer. Fortran was the first high-level programming language to be put to broad use. This widely used language made computers practical and accessible machines for scientists and others without requiring them to have deep knowledge of the machinery.

Backus–Naur form

Backus served on the international committees that developed ALGOL 58 and the very influential

ALGOL 60 ALGOL 60 (short for ''Algorithmic Language 1960'') is a member of the ALGOL family of computer programming languages. It followed on from ALGOL 58 which had introduced code blocks and the begin and end pairs for delimiting them, representing a ...

, which quickly became the ''de facto'' worldwide standard for publishing

algorithm In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...

s. Backus developed the

(BNF), published in the

UNESCO The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...

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. A few deviations from this approach were tried (notably in

Lisp Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized Polish notation#Explanation, prefix notation. Originally specified in the late 1950s, ...

and APL), but by the 1970s, Backus–Naur context-free specifications for computer languages had become quite standard, following the development of automated compiler generators such as

yacc Yacc (Yet Another Compiler-Compiler) is a computer program for the Unix operating system developed by Stephen C. Johnson. It is a lookahead left-to-right rightmost derivation (LALR) parser generator, generating a LALR parser (the part of a co ...

. This contribution helped Backus win the

in 1977.

Function-level programming

Backus later worked on a function-level programming language known as FP, which was described in his

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 computer science, functional programming is a programming paradigm where programs are constructed by Function application, applying and Function composition (computer science), composing Function (computer science), functions. It is a declarat ...

in general. When Backus publicized the function-level style of programming, his message was mostly misunderstood as being the same as traditional functional programming style languages. FP was strongly inspired by Kenneth E. Iverson's APL, even using a non-standard

character set Character encoding is the process of assigning numbers to graphical characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical values that make up a c ...

. An FP interpreter was distributed with the 4.2BSD

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

operating system, but there were relatively few implementations of the language, most of which were used for educational purposes. 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 stopped when the project was finished. Only a few papers documenting it remain, and the source code of the compiler described in them was not made public. FL was at odds with functional programming languages being developed in the 1980s, most of which were based on the

lambda calculus In mathematical logic, the lambda calculus (also written as ''λ''-calculus) is a formal system for expressing computability, computation based on function Abstraction (computer science), abstraction and function application, application using var ...

and

static typing In computer programming, a type system is a logical system comprising a set of rules that assigns a property called a ''type'' (for example, integer, floating point, string) to every '' term'' (a word, phrase, or other set of symbols). Usu ...

systems instead of, as in APL, the concatenation of primitive operations. Many of the language's ideas have now been implemented in versions of the J programming language, Iverson's successor to APL.

Awards and honors

*Named an IBM Fellow (1963) * W. W. McDowell Award (1967) *

(1975) *

(1977) *Fellow of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (The Academy) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and other ...

(1985) *Doctor

honoris causa An honorary degree is an academic degree for which a university (or other degree-awarding institution) has waived all of the usual requirements. It is also known by the Latin phrases ''honoris causa'' ("for the sake of the honour") or ''ad hono ...

Université Henri-Poincaré (1989) * Draper Prize (1993) * Computer History Museum Fellow Award "for his development of FORTRAN, contributions to computer systems theory and software project management." (1997) *

Asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

6830 Johnbackus named in his honor (June 1, 2007)

References

External links

Biography at School of Mathematics and Statistics University of St Andrews, Scotland

The FL project
(Postscript file) *

Hall of Fellows

Computer History Museum The Computer History Museum (CHM) is a computer museum in Mountain View, California. The museum presents stories and artifacts of Silicon Valley and the Information Age, and explores the Digital Revolution, computing revolution and its impact ...

*
Memorial delivered at the 2007 Conference on Programming Language Design and Implementation
{{DEFAULTSORT:Backus, John 1924 births 2007 deaths 20th-century American mathematicians 21st-century American mathematicians United States Army personnel of World War II Draper Prize winners Columbia University School of General Studies alumni Columbia University alumni Fellows of the American Academy of Arts and Sciences Fortran IBM Fellows Members of the United States National Academy of Sciences National Medal of Science laureates IBM Research computer scientists People from Ashland, Oregon Mathematicians from Philadelphia People from Wilmington, Delaware Programming language designers Programming language researchers United States Army non-commissioned officers Turing Award laureates University of Virginia alumni The Hill School alumni Scientists from Delaware Scientists from Oregon