President Obama today awards the Medal of Freedom to Margaret Hamilton, not the late actress famous for playing the Wicked Witch of the West but a pioneering computer scientist who programmed computers for the Apollo missions to the Moon and is still alive and in business at the age of 80.
One of Hamilton's most important contributions was in systematically anticipating problems including human error and developing error detection and recover code. Hank Green has a brief explanation of that in this video from June:
For more on Hamilton see this article from MIT News and this one about the famous photo showing her standing next to a giant stack of printouts containing the Apollo software. If you want to see the code itself, it's on line here.
The Medal of Freedom will also be awarded posthumously to Grace Hopper, who became a naval officer at the age of 37 during World War 2 and helped develop some of the first high-level computer languages and compilers. I met Admiral Hopper nearly 40 years ago while she was still on active duty and still somewhere have one of the "nanoseconds" she was famous for handing out, a piece of wire one light-nanosecond long. (That's a hair under 30 centimeters, or just short of a foot.) I'm rather surprised she had not already received the Medal of Freedom. She died in 1992, still employed in her post-Navy job at Digital Equipment Corporation.
In her later years Admiral Hopper was best known as a witty and entertaining public speaker. Here's her appearance on the Letterman Show shortly after she retired from active duty at the age of 79 in 1986, and you can see why people enjoyed her talks:
There's more on Hamilton and Hopper in this article.
Other honorees at today's ceremony include human rights activist Elouise Cobell (deceased), architect Frank Gehry, artist May Lin, athletes Kareem Abdul-Jabbar and Michael Jordan; educator Eduardo Padrón, entertainers Tom Hanks, Ellen DeGeneres, Robert De Niro, Robert Redford, Diana Ross, Cicely Tyson, Bruce Springsteen, and Lorne Michaels; former FCC head Newton Minow, scientist Richard Garwin, American Indian activist Elouise Cobell (deceased); sports announcer Vin Scully, and philanthropists Bill and Melinda Gates. For more see this page on the White House website.