John Backus

principal papers
Backus-Naur form, Fortran

As projectleader with IBM John Backus developed in the early 1950's with his team: Fortran - Formula Translator. The first high level programming language. This language is most widely used in physics and engineering.

He was also responsible for the Backus-Naur Form (or BNF), a standard notation which can be used to decribe the sytanx of a computer language in a formal and unambiguous way.

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.

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).

Chronology

1942 Graduated from Hill school Pottstown

1942 Entered the University of Virginia. Joined the army

1945 Entered Flower and Fifth Avenue Medical School in New York

1949 Worked on IBM'S SSEC computer

1950-1952 Watson Lab

1954 Backus and his team publish Fortran

1959 Developng a notation called Backus-Naur Form in collaboration with Naur

1991 Retirement

Honors and awards

1976 Receives National medal of Science

1993 Receives Charles Stark Draper price for his work on Fortran