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In September 1947, operators of the Harvard Mark II computer traced a fault to a moth trapped in one of its relays. They taped the insect into the logbook with the note 'First actual case of bug being found', a joke, as engineers already called faults 'bugs'.

Harvard Mark II logbook, 1947

TechnologyHistory

The story behind the card

A relay is a switch that is opened and closed by electricity; the Mark II calculated with electromechanical relays that clicked open and shut. 'Bug' for a small fault is much older than computers: in an 1878 letter, Thomas Edison described the little faults that show up in every invention as 'Bugs'. The moth story was popularised by Grace Hopper (1906–1992), a US Navy mathematician who worked on the Harvard machines and later helped create COBOL, one of the first programming languages written in English-like words. She did not find the moth herself; the operators on duty did, and they were probably making a pun on the two meanings of the word. The logbook page, with the moth still taped to it, is kept at the Smithsonian's National Museum of American History in Washington. Finding and fixing faults in software is still called debugging.

Türkçe oku
Eylül 1947'de Harvard Mark II bilgisayarının operatörleri, bir arızanın rölelerden birine sıkışan bir güveden kaynaklandığını buldu. Güveyi kayıt defterine yapıştırıp yanına “Gerçek bir böceğin (bug) bulunduğu ilk vaka” diye not düştüler. Bu bir şakaydı, çünkü mühendisler arızalara zaten “bug”, yani böcek diyordu.
Harvard Mark II kayıt defteri, 1947

Röle, elektrikle açılıp kapanan bir anahtardır; Mark II hesaplarını tık tık açılıp kapanan elektromekanik rölelerle yapıyordu. Küçük arızalara “bug” demek bilgisayarlardan çok daha eskidir: Thomas Edison 1878'de yazdığı bir mektupta, her icatta ortaya çıkan küçük kusurlardan “bug” diye söz eder. Güve hikâyesini yaygınlaştıran kişi, Harvard'daki bu makinelerde çalışan ABD Donanması matematikçisi Grace Hopper'dır (1906–1992). Hopper daha sonra, İngilizceye yakın sözcüklerle yazılan ilk programlama dillerinden COBOL'un doğuşuna katkıda bulundu. Güveyi kendisi bulmamıştı; nöbetteki operatörler bulmuş ve büyük olasılıkla sözcüğün iki anlamıyla kelime oyunu yapmıştı. Güvenin hâlâ yapışık durduğu defter sayfası bugün Washington'daki Smithsonian Ulusal Amerikan Tarihi Müzesi'nde saklanıyor. Yazılımdaki hataları bulup düzeltmeye bugün de “debugging”, yani hata ayıklama deniyor.

Sources and further reading

Background reading: Software bug
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