The Computer Revolution: From Room-Sized to Pocket-Sized

By Sophia Maddox | March 7, 2024

The Atlas Computer Becomes the World's Most Advanced Supercomputer

Computers are an integral part of life. People use them to communicate with people who are important to them at work and home. Many people look up information that they want to learn on a computer. Others watch movies, play games or entertain themselves using computers. From early morning to late night, people rely on computer systems to help them stay organized.

While it is hard for most people to imagine life without computers, it hasn't always been that way. Here's a look at how people developed computers and their operating programs. Along the way, meet some people who influenced their development. You'll discover how computers went from filling entire rooms to being small enough to fit in your pocket.


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Tom Kilburn and his team working at the University of Manchester with support from Ferranti Ltd built the Atlas computer, the fastest computer at the time. However, some argue that the fastest one was IBM's Stretch. The Atlas computer, which Kilburn designed to run nuclear physics calculations, used 60,000 transistors, 300,000 diodes and 40 circuit boards.

This computer, completed in 1962, was the first to have virtual memory, allowing people to use it to work on multiple projects simultaneously. The computer had a two-level storage area and would automatically move data from one level to another, which had previously been done by the operator, resulting in great time-saving. While moving more critical information into the computer's main storage area, it would also determine the least used page in the main storage area and move it to the computer's secondary storage area.

Meet the Architect Behind COBOL, Grace Hopper

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After graduating from Yale University with a Doctorate in Mathematics, Grace Hopper gave up a teaching career at Vassar College to join the U.S. Navy. She worked on developing the Mark I computer at Harvard University and wrote a 500-page operator's manual for the Automatic Sequence-Controlled Calculator. After World War II, she became a research fellow at Harvard University before joining Eckert-Mauchly Corporation and assisting with developing the universal automatic computer.

By the mid-1950s, businesses faced a problem applying computers to their companies. They were spending about $800,000 on programming costs and $500,000 on hardware to run them. A group convinced the United States Department of Defense to tackle the problem. Grace Hopper and others solved the problem by writing Common Business-Oriented Language (COBOL), allowing computers to understand words and numbers. She based COBOL on FLOW-MATIC language, which she developed first. While being modified a few times, it became the standard program all computers use.