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

computer scientist A computer scientist is a person who is trained in the academic study of computer science. Computer scientists typically work on the theoretical side of computation, as opposed to the hardware side on which computer engineers mainly focus (al ...

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

high-level programming language In computer science, 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 ...

, and was the inventor of the Backus–Naur form (BNF), a widely used notation to define

formal language In logic, mathematics, computer science, and linguistics, a formal language consists of words whose letters are taken from an alphabet and are well-formed according to a specific set of rules. The alphabet of a formal language consists of symb ...

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 ( constituency) ...

. 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 Turing A ...

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 a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...

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 and social scienc ...

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 compu ...

" 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". He retired in 1991 and died at his home in

Ashland, Oregon Ashland is a city in Jackson County, Oregon, United States. It lies along 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 was 21,360 at the 2020 cen ...

on March 17, 2007.

Early life

Backus was born in

Philadelphia Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Sinc ...

and grew up in nearby

Wilmington, Delaware Wilmington ( Lenape: ''Paxahakink /'' ''Pakehakink)'' is the largest city in the U.S. state of Delaware. The city was built on the site of Fort Christina, the first Swedish settlement in North America. It lies at the confluence of the Christina ...

. He studied at

The Hill School The Hill School (commonly known as The Hill) is a coeducational preparatory boarding school located on a campus in Pottstown, Pennsylvania, about northwest of Philadelphia. The Hill is part of the Ten Schools Admissions Organization (TSAO). ...

Pottstown, Pennsylvania Pottstown is a borough in Montgomery County, Pennsylvania. Pottstown was laid out in 1752–53 and named Pottsgrove in honor of its founder, John Potts. The old name was abandoned at the time of the incorporation as a borough in 1815. In 1888 ...

, 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. Founded in 1819 by Thomas Jefferson, the university is ranked among the top academic institutions in the United S ...

to study

chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...

, 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 The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...

during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

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

Fort Stewart Fort Stewart is a United States Army post in the U.S. state of Georgia. It lies primarily in Liberty and Bryan counties, but also extends into smaller portions of Evans, Long and Tattnall counties. The population was 11,205 at the 2000 census. Th ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

. 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 public state-related research university in Pittsburgh, Pennsylvania. The university is composed of 17 undergraduate and graduate schools and colleges at its urban Pittsburgh campus, home to the universit ...

. He later transferred to a pre-medical program at

Haverford College Haverford College ( ) is a private liberal arts college in Haverford, Pennsylvania. It was founded as a men's college in 1833 by members of the Religious Society of Friends (Quakers), began accepting non-Quakers in 1849, and became coeducational ...

. During an internship at a hospital, he was diagnosed with a cranial

bone tumor A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, thyroi ...

, 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 or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

he trained initially as a

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

technician and became interested in mathematics. He graduated from

Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...

with a bachelor's degree in 1949 and a master's degree in 1950, both in mathematics, 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 The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

. In 1953 Backus developed the language

Speedcoding Speedcoding, Speedcode or SpeedCo was the first high-level programming language created for an IBM computer. The language was developed by John W. Backus in 1953 for the IBM 701 to support computation with floating point numbers. The idea ...

, 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 The IBM 704 is a large digital mainframe computer introduced by IBM in 1954. It was the first mass-produced computer with hardware for floating-point arithmetic. The IBM 704 ''Manual of operation'' states: The type 704 Electronic Data-Pro ...

computer. Fortran was the first high-level programming language to be put to broad use.

Backus–Naur form

Backus served on the international committees that developed

ALGOL 58 ALGOL 58, originally named IAL, is one of the family of ALGOL computer programming languages. It was an early compromise design soon superseded by ALGOL 60. According to John Backus The Zurich ACM-GAMM Conference had two principal motives in pro ...

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 k ...

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

algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...

s. Backus developed the Backus–Naur form (BNF), published in the

UNESCO The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...

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 A lisp is a speech impairment in which a person misarticulates sibilants (, , , , , , , ). These misarticulations often result in unclear speech. Types * A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lisping ...

and APL—but by the 1970s, 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 Look Ahead Left-to-Right Rightmost Derivation (LALR) parser generator, generating a LALR parser (the part of a com ...

, Backus–Naur context-free specifications for computer languages had become quite standard. 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 declar ...

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 digital computers. The numerical values that ...

. An FP interpreter was distributed with the

4.2BSD The History of the Berkeley Software Distribution begins in the 1970s. 1BSD (PDP-11) The earliest distributions of Unix from Bell Labs in the 1970s included the source code to the operating system, allowing researchers at universities to modify a ...

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser 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, and ot ...

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 Lambda calculus (also written as ''λ''-calculus) is a formal system in mathematical logic for expressing computation based on function abstraction and application using variable binding and substitution. It is a universal model of computation ...

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 to every "term" (a word, phrase, or other set of symbols). Usually the terms are various constructs of a computer progra ...

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 The J programming language, developed in the early 1990s by Kenneth E. Iverson and Roger Hui, is an array programming language based primarily on APL (also by Iverson). To avoid repeating the APL special-character problem, J uses only the basic ...

, Iverson's successor to APL.

Awards and honors

*Named an

IBM Fellow An IBM Fellow is an appointed position at IBM made by IBM's CEO. Typically only four to nine (eleven in 2014) IBM Fellows are appointed each year, in May or June. Fellow is the highest honor a scientist, engineer, or programmer at IBM can achie ...

(1963) * W. W. McDowell Award (1967) *

(1975) *

(1977) *Fellow of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) 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 ...

(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 The U.S. National Academy of Engineering annually awards the Draper Prize, which is given for the advancement of engineering and the education of the public about engineering. It is one of three prizes that constitute the "Nobel Prizes of Enginee ...

(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 of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

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 museum of computer history, located in Mountain View, California. The museum presents stories and artifacts of Silicon Valley and the information age, and explores the computing revolution and its impact on ...

*
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