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Charles Babbage's Difference Engine, first shown as a small model in 1822, was a mechanical calculator for producing mathematical tables without human error. His Analytical Engine, designed from the mid-1830s, went further: a machine that could be programmed with punched cards to carry out any calculation.

Charles Babbage, 1820s

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The story behind the card

Around 1821 Babbage and his friend, the astronomer John Herschel, were checking tables worked out by hand for the Astronomical Society of London and found so many errors that Babbage exclaimed, 'I wish to God these calculations had been executed by steam.' The British government funded a full-sized Difference Engine, but work stopped in 1833 and the project was abandoned in 1842 after more than £17,000 had been spent. The Analytical Engine separated a 'store', where numbers were kept, from a 'mill', where calculations were done, much like a modern computer's memory and processor. Neither machine was finished in his lifetime. In 1991 London's Science Museum completed a Difference Engine No. 2 from his drawings, and it worked.

Türkçe oku
Charles Babbage'ın Fark Makinesi, matematik tablolarını insan hatası olmadan hesaplamak için tasarlanmış mekanik bir hesap makinesiydi; küçük bir modelini 1822'de tanıttı. 1830'ların ortasından itibaren tasarladığı Analitik Makine ise çok daha ileri gidiyordu: Delikli kartlarla programlanıp her türlü hesabı yapabilecekti.

1821 dolaylarında Babbage ile dostu gökbilimci John Herschel, Londra Astronomi Derneği için elle hesaplanmış tabloları kontrol ederken o kadar çok hata buldular ki Babbage, “Tanrı aşkına, keşke bu hesaplar buharla yapılsaydı!” diye söylendi. İngiliz hükümeti tam boyutlu bir Fark Makinesi için para verdi, ama çalışmalar 1833'te durdu ve 17.000 sterlinden fazla harcandıktan sonra proje 1842'de bırakıldı. Analitik Makine'de sayıların tutulduğu “depo” (store) ile hesapların yapıldığı “değirmen” (mill) ayrı bölümlerdi; bu ayrım bugünkü bilgisayarlardaki bellek ile işlemciye çok benzer. İki makine de Babbage hayattayken tamamlanamadı. Londra'daki Bilim Müzesi 1991'de Babbage'ın çizimlerine göre bir Fark Makinesi No. 2 tamamladı ve makine çalıştı.

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