Diff — Fran Bilas

**Fran Bilas** — born **Frances Elizabeth Bilas** (2 March 1922 – 18 July 2012), later **Spence** — was an American mathematician and one of the six original programmers of ENIAC.

## Life

Bilas earned a mathematics degree from **Chestnut Hill College** in 1942 and went straight into the Army's human-computer corps computing firing tables in Philadelphia — bored by it, like everyone, until the 1945 call went out for volunteers for a classified machine. She later completed a master's in mathematics at Temple University.

## ENIAC and after

On ENIAC, Bilas created the machine's **first sort routine** and its **first program-check mechanisms** — the beginnings of what we'd now call validation and automated testing. When a program failed, her checks were how you found out *where*. She was also one of the two who operated ENIAC through its celebrated public demonstration for the press in **February 1946**.

She married an Army engineer in 1947 — which ended her federal computing work — and moved on to programming for **Mauchly's company** on BINAC and [[UNIVAC_I|UNIVAC]]-era projects, then lived the next several decades largely out of the field's spotlight. She died in 2012 at ninety.

## Legacy

- Inducted into the **Women in Technology International Hall of Fame** (1997) with the other five.

- The "program check" idea she pioneered — the machine catching its own errors — is now so fundamental it is invisible, which is exactly the measure of a foundational invention.

## See also

- [[The first programmers]]

- [[History of Programming]]

[[Category:History]]

[[Category:People]]