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Margaret Hamilton led the MIT team that wrote the flight software for Apollo's onboard computers. When the computer overloaded during Apollo 11's descent to the Moon, the software dropped lower-priority tasks and kept the critical landing work running.

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In the last minutes before landing, the Apollo Guidance Computer flashed 1201 and 1202 alarms, meaning it had more work than it could finish in time. Much of the extra load came from the rendezvous radar, used for meeting the command module in lunar orbit, which was sending a stream of unneeded signals that ate up computing time. The software, built by Hamilton's team with other MIT engineers, ran tasks by priority: when overloaded, it restarted, dropped the least important jobs and carried on with navigation and engine control instead of freezing. Mission Control judged the alarms safe and told the crew to continue. A famous photograph shows Hamilton beside a stack of printed Apollo program listings as tall as she was.

Türkçe oku
Margaret Hamilton, Apollo uzay araçlarındaki bilgisayarların uçuş yazılımını yazan MIT ekibini yönetti. Apollo 11 Ay'a alçalırken bilgisayar aşırı yüklenince yazılım öncelikli olmayan işleri bıraktı ve inişin kritik işlerini sürdürdü.

İnişten önceki son dakikalarda Apollo güdüm bilgisayarı 1201 ve 1202 alarmları verdi; bu, bilgisayarın zamanında bitirebileceğinden fazla iş yüklendiği anlamına geliyordu. Fazladan yükün büyük kısmı, Ay yörüngesinde ana gemiyle buluşmak için kullanılan buluşma radarından geliyordu: radar, hesaplama zamanını tüketen gereksiz sinyaller gönderiyordu. Hamilton'ın ekibinin MIT'deki öteki mühendislerle birlikte yazdığı yazılım, işleri önceliğe göre yürütüyordu: aşırı yüklenince kendini yeniden başlattı, en önemsiz işleri bıraktı ve donup kalmak yerine yön bulma ve motor denetimi işlerini sürdürdü. Görev Kontrol alarmların tehlikeli olmadığına karar verdi ve mürettebata devam etmesini söyledi. Ünlü bir fotoğrafta Hamilton, kendi boyunda bir yığın basılı Apollo program listesinin yanında durur.

Sources and further reading

Background reading: Margaret Hamilton (software engineer)
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