[11] Deeply in debt with student loans, she joined IBM Research in Poughkeepsie, New York, as a programmer in 1957, where she taught incoming employees the basics of Fortran.

She planned to return to teaching once her student loans had been paid, but ended up staying with IBM for her entire 45-year career.

In 1959, Allen was assigned to the Harvest project for code breaking with the National Security Agency, and worked on a programming language called Alpha.

During these years, she worked with fellow researcher John Cocke to write a series of seminal papers on optimizing compilers, helping to improve the efficiency of machine code translated from high-level languages.

[13] After retiring, she remained active in programs that encourage women and girls to seek careers in science and computing.

[14] Her A. M. Turing Award citation reads: Fran Allen's work has had an enormous impact on compiler research and practice.

Both alone and in joint work with John Cocke, she introduced many of the abstractions, algorithms, and implementations that laid the groundwork for automatic program optimization technology.

This paper introduced the use of graph-theoretic structures to encode program content in order to automatically and efficiently derive relationships and identify opportunities for optimization.

Allen developed and implemented her methods as part of compilers for the IBM STRETCH-HARVEST and the experimental Advanced Computing System.

[29] A list of her select publications includes:[4][6] In 1972, Allen married New York University computer science professor and collaborator Jacob T.