Allen joined IBM's T.J. Watson Research Center, with her first assignment being to teach the newly released FORTRAN language to research staff.
On July 15, 1957, Frances Allen joined IBM's Thomas J. Watson Research Center, initially planning to work there only temporarily to pay off student loans from her graduate studies in mathematics at the University of Michigan. Instead, the position launched a 45-year career that would transform computer science.
Her very first assignment was to teach IBM's research staff the newly developed FORTRAN programming language — one of the first high-level programming languages, which had just been released that year. FORTRAN represented a revolutionary shift from hand-coded machine instructions to human-readable code that could be automatically translated ('compiled') into machine language, and Allen quickly became immersed in the compiler technology needed to make this translation efficient.
This early exposure to compiler design set the trajectory for Allen's entire career. She moved from teaching the language to actively researching how to optimize the code compilers produced, laying groundwork for what would become the field of compiler optimization. Her work at IBM would eventually touch nearly every major computing initiative the company undertook, including code-breaking work for the National Security Agency, the Stretch-Harvest project, and the ambitious PTRAN project on automatic parallelization.
This moment marks the beginning of a career that would make Allen one of the most influential computer scientists of the 20th century, and eventually the first woman honored with computing's highest award.