John Backus

John Warner Backus, computer scientist: born Philadelphia 3 December 1924; programmer, IBM 1950-54, manager of programming research 1954-59, member, IBM Research 1959-63, Fellow 1963-1991; twice married (two daughters); died Ashland, Oregon 17 March 2007.

For a three-year period in 1954-57, John Backus, a mathematician in his early thirties, led the IBM Fortran project. Fortran was a new programming language that enabled programs to be written compactly in English and mathematical symbols instead of the binary-oriented machine language that computers understood.

It was not the first programming language, but its predecessors produced very inefficient programs. Fortran, however, produced programs that were as good as those written by human programmers. By enabling engineers and scientists to write their own programs, instead of employing a professional programmer, Fortran revolutionised the world of computing. Fifty years on, Fortran is still the lingua franca of scientific programming.

Backus was born in 1924 into a prosperous family in Philadelphia, the son of a stockbroker. He was raised in Wilmington, Delaware, but was sent away to a private high school, where he did not take well to academic study. In 1942 he enrolled at the University of Virginia, but was sent down for poor attendance. He was drafted into the US Army in early 1943, where aptitude tests revealed his high intelligence, and he was sent on advanced engineering and medical courses.

He enrolled in medical school, but dropped out. He left the army in 1946, and then studied mathematics at Columbia University, New York, where he at last found his métier.

At that time IBM had recently completed its first experimental electronic computer, the SSEC, and had installed it in the showroom of its New York headquarters on the corner of 57th Street and Madison Avenue, where it attracted the attention of the media and passers-by, who named it "Poppa". Backus went to see the machine, which piqued his interest, and he got himself taken on as a programmer. He spent the next year of his life calculating lunar positions, which he found a delight.

In 1952, IBM introduced its first commercial computer, the model 701. Almost no programming tools were provided with the machine, and users had to hand-craft programs, which was inordinately time-consuming and expensive. Backus designed an automatic programming system called Speedcoding but it was slow and inefficient.

In November 1953, while IBM was planning the launch of a successor machine, the model 704, Backus proposed a new automatic programming system, which he called the Formula Translator, later contracted to "Fortran". The unique feature of the proposal was that Fortran would produce programs that were at least 90 per cent as good as those written by a human programmer. His proposal was authorised and he was allocated a team of 10 people - an eclectic bunch of mathematicians-turned-programmers.

Designing a system that produced efficient programs turned out to be a major technical challenge and the project, intended to take six months, dragged on for three years before Fortran was released to users in April 1957. The system was an instant hit, and it soon accounted for a high proportion of programs written for the IBM 704. From this point on, Fortran took on a life of its own. The language was adopted by other computer manufacturers (so that their machines were software compatible with IBM's), and it was standardised by the American Standards Association. Today the International Standards Organization has a permanent Fortran working group.

After the Fortran project was completed, Backus became a member of the Algol Committee set up to design an international scientific programming language. A new language, Algol 60, was specified in the Backus-Naur Form (BNF), which Backus devised with the Danish computer scientist Peter Naur, but it never displaced Fortran for practical number-crunching.

In 1959, Backus became a staff member of IBM Research in Yorktown Heights, New York. He was made an IBM Fellow in 1960 and spent the remainder of his career with IBM Research, retiring in 1991.

Backus was awarded the National Medal of Science in 1975 and the Turing Award of the Association of Computing Machinery in 1977 - the computer- science equivalent of the Nobel Prize.

Martin Campbell-Kelly