Cover of Code by Charles Petzold - Business and Economics Book

From "Code"

Author: Charles Petzold
Publisher: Microsoft Press
Year: 2000
Category: Computers

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Chapter 18: From Abaci to Chips
Key Insight 1 from this chapter

Evolution of Early Calculation Tools

Key Insight

Humanity has consistently sought easier ways to perform mathematical calculations, often conceiving problems beyond simple manual solution despite an innate numerical ability. Early tools for tracking commodities included number systems and physical aids like pebbles or grain kernels, which led to European counting boards and the familiar frame-and-bead abacus. Although commonly associated with Asian cultures, the abacus seems to have been introduced to China by traders around 1200 CE, demonstrating a long-standing need for computational assistance.

The inherent difficulty of operations like multiplication and division spurred further innovation. John Napier (1550–1617) addressed this by inventing logarithms, simplifying multiplication to the addition of logarithms, which could then be reversed using tables. The construction of these tables occupied great minds for centuries and inspired gadgets such as the slide rule. Originating from Edmund Gunter's logarithmic scale and refined by William Oughtred, the slide rule was a prominent tool until its obsolescence in 1976, supplanted by handheld calculators. Napier also devised 'Napier's Bones,' strips inscribed with numbers for multiplication, laying groundwork for early mechanical aids.

The first somewhat automated version of Napier's Bones was built by Wilhelm Schickard around 1620. Other early mechanical calculators by mathematicians Blaise Pascal (1623–1662) and Gottfried Wilhelm von Leibniz (1646–1716) relied on interlocking wheels, gears, and levers. A central challenge in these adding machines was the 'carry bit'; if not successfully managed, the machine was incomplete. For example, Pascal's design prohibited direct subtraction, requiring the nines' complement method. Successful, usable mechanical calculators only became widely available in the late nineteenth century. The automated Jacquard loom (circa 1801), using punched metal cards to control fabric patterns, demonstrated a programmable mechanical process that later influenced computing.

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