Definition
Keypunch refers to the process of manually entering data by punching holes into 80-column computer cards using a device known as a keypunch machine. These holes were arranged in specific patterns according to the Hollerith code—a system developed by Herman Hollerith in the late 19th century. The punched cards could then be read by early computers, facilitating data input and processing.
Examples
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Early Census Data Entry: One of the earliest and most famous uses of the keypunch method was for processing the 1890 U.S. Census data. Operators used keypunch machines to input demographic information into punched cards, which were then read and tabulated by mechanical tabulating machines.
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Business Data Processing: Throughout the mid-20th century, businesses frequently used keypunch machines to input data into mainframes for accounting, inventory management, and various other data processing tasks.
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Academic Research: Universities and research institutions utilized punched cards for compiling and analyzing large datasets in scientific research, often using the cards to program early computers like the IBM 1401.
Frequently Asked Questions
Q1: How did keypunch machines work?
- A keypunch machine had a keyboard similar to a typewriter. When keys were pressed, corresponding holes were punched into pre-printed 80-column cards based on the Hollerith code.
Q2: What replaced keypunch technology?
- Keypunch technology was largely replaced by electronic keyboards and magnetic storage media in the late 20th century, which allowed for faster, more accurate, and more flexible data input.
Q3: Are punched cards still used today?
- While largely obsolete, punched cards and keypunch technology can still be found in some legacy systems and specialized applications. However, they are primarily of interest now as historical artifacts and for educational purposes.
Related Terms
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Punched Card: A piece of stiff paper that contains digital data represented by the presence or absence of holes in predefined positions. Punched cards were commonly used for data storage and processing in early computers.
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Hollerith Code: A coding system developed by Herman Hollerith for storing data that uses punched cards. Each row in the card represented a character or an instruction based on where the holes were punched.
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Tabulating Machine: An early data processing machine that reads punched cards to tabulate or process data.
Online References
Suggested Books for Further Studies
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“Pulse: How Nature Is Inspiring the Technology of the Future” by Robert Frenay - This book explores the evolution of early computing including punched card technology.
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“IBM: The Rise and Fall and Reinvention of a Global Icon” by James W. Cortada - Offers insights into IBM’s role in the development and popularization of punched cards.
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“The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital Revolution” by Walter Isaacson - Provides historical context including the significance of punched cards in the computing revolution.
Fundamentals of Keypunch: Computer History Basics Quiz
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