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Von Neumann's Memory: The Human Calculator

Abstract

John von Neumann’s speed at mental arithmetic and his memory were legendary among his colleagues. Childhood stories have him dividing eight-digit numbers in his head at six and memorizing pages of the telephone book as a party trick; Herman Goldstine recalled him reciting the opening chapter of A Tale of Two Cities from memory. Most of these stories come from friends and biographers rather than from documents, but they agree on the impression he made.

The Prodigy

John von Neumann was born in 1903 in Budapest into a wealthy Jewish banking family. The stories of his childhood, collected by Norman Macrae and others from family and friends, are of a boy who did long division of eight-digit numbers in his head and who, as a party trick, would look at a page of the telephone directory and recite the names and numbers back. How much of this is exact cannot be checked; that it was told about him by people who knew him well is the documented part.

He published his first mathematical paper, written with Michael Fekete, in 1922, at 18. In 1926 he took a doctorate in mathematics at Budapest and, the same year, a diploma in chemical engineering at the ETH in Zurich, a degree his father had insisted on as a practical fallback. In 1933 he became one of the first professors of the new Institute for Advanced Study in Princeton, alongside Albert Einstein, at 29.

Colleagues described him following a problem as it was stated and arriving at the answer before the speaker had finished. Herman Goldstine, who worked with him on the IAS computer, tested him once by asking how A Tale of Two Cities began; von Neumann recited the first chapter without pause until he was asked to stop, ten or fifteen minutes later. The mathematician Paul Halmos, who collected such stories in 1973, warned that many of them are undocumented and unverifiable.

The Architecture Named After Him

In 1944 von Neumann joined the ENIAC group at the Moore School, and in June 1945 he wrote the First Draft of a Report on the EDVAC, which described a computer that kept its program in the same memory as its data. The draft circulated under his name alone, which caused lasting resentment among J. Presper Eckert and John Mauchly, who had contributed substantially to the ideas in it. The design has been called the von Neumann architecture ever since; see Myths and Misconceptions.

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