At 83, Betty Jean Jennings Bartik -- a devoted bridge player and grandmother of five -- had a secret past that was invisible to many who knew her.
Her grandson Alex knew her story. He stormed out of school one day when his teacher refused to believe his gray-haired granny was a computer pioneer who had calculated firing tables and ballistic trajectories during World War II.
The boy's parents had to explain to the teacher that Bartik and five other women had, indeed, legally hacked the world's first programmable computer, converting it into a stored machine and eventually helping to usher in the digital age.
"She was dumbfounded," said Bartik.
So, too, were the historians, who for a half century never acknowledged the wartime contributions of the six women who programmed the Electronic Numerical Integrator and Computer (ENIAC) and made programming easier and more accessible to those who followed.
In 1945, Bartik was one of a handful of female math majors at what was then Northwest Missouri State Teachers College. The feisty 20-year-old farm girl knew only one thing: She didn't want to teach.
As the war came to a close, the Army had run out of male mathematicians. Bartik answered a recruitment ad for women "computers" in a classified project at the Aberdeen Proving Ground operations at the University of Pennsylvania.
"I wanted to do something exciting and adventuresome," she told ABCNEWS.com. "I wanted to get to the big city and see what life was like."
Bartik went on to help program the BINAC for Northrop Aircraft Company in 1949 and design logic for UNIVAC I, the first commercial computer delivered to the U.S. Census Bureau in 1951. After that, she took time off to raise three children, but then returned in 1967 to help businesses understand the new microcomputers.
Her personal story -- a sort of Rosie the Riveter meets Bill Gates -- recalls the enormous talent women have brought to computer technology and illustrates the challenges today's women face in what's still a male-dominated field.
Many say their story is especially timely, because the already low numbers of female computer scientists are dropping, posing a new threat to the nation's global competitiveness.
For decades, Bartik and her colleagues were ignored by computing history. At the 40th anniversary of the ENIAC project at the University of Pennsylvania in 1946, the women were initially not invited -- only one was on the list as a spouse.
But now, a documentary film -- "Invisible Computers: The Story of the ENIAC Programmers" -- will chronicle their groundbreaking stories.
"The documentary isn't just about the history," said executive producer and ENIAC Programmers historian Kathy Kleiman, an Internet lawyer from Northern Virginia, who is fundraising for the project, "but how these programmers provided role models to really inspire women to believe that computer careers were within their reach."
Susan Hadary, a Maryland documentary producer, will help Kleiman produce a multimedia film that explains not only how ENIAC worked, but to give long-awaited recognition to the ENIAC women.
Kleiman, a former Wall Street programmer, has spent years recording their oral histories. Three of the women -- all in their 80s -- are still alive.
"There were few women in my college classes," said Kleiman. "Few people had exposure before college and they didn't think they could do it. I saw a block that began to trouble me."