The Shocking Truth Behind Arnold Nordsieck’s Differential Analyzer

To program this electromechanical computer, you plugged in the cords in specific patterns—and with extreme caution

2 min read
Photo of the analog computer that Arnold Nordsieck built.
Photo: Mark Richards/Computer History Museum

imgPhoto: Mark Richards/Computer History Museum

In 1950, the physicist Arnold Nordsieck built himself this analog computer. Nordsieck, then at the University of Illinois, had earned his Ph.D. at the University of California, Berkeley, under Robert Oppenheimer. To make his analog computer for calculating differential equations, the inventive and budget-conscious Nordsieck relied on US $700 worth of military surplus parts, particularly synchros—specialized motors that translate the position of the shaft into an electrical signal, and vice versa.

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How Ted Hoff Invented the First Microprocessor

Hoff thought designing 12 custom chips for a calculator was crazy, so he created the Intel 4004

14 min read
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How Ted Hoff Invented the First Microprocessor
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The rays of the rising sun have barely reached the foothills of Silicon Valley, but Marcian E. (Ted) Hoff Jr. is already up to his elbows in electronic parts, digging through stacks of dusty circuit boards. This is the monthly flea market at Foothill College, and he rarely misses it.

Ted Hoff is part of electronics industry legend. While a research manager at Intel Corp., then based in Mountain View, he realized that silicon technology had advanced to the point that, with careful engineering, a complete central processor could fit on a chip. Teaming up with Stanley Mazor and Federico Faggin, he created the first commercial microprocessor, the Intel 4004.

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