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After the success of this machine, Hollerith formed a Computing
Tabulating Recording Company to sell his machine. Later in 1924,
his company became a part of International Business Machines
Corporation, today popularly known as IBM.

Herman Hollerith

Hollerith’s Tabulating Machine

COMPUTER GENERATIONS

After these early calculating machines, the present computer took its shape in five generations.

First Generation (1940s)

There were many computers that were a part of the first generation computers.

MARK-I

In 1944, Prof. Howard Aikens built the first electro-mechanical powered computer named
Mark-I. It used punched cards and a typewriter for input and output. It was 50 feet long, 8 feet
high, weighed 5 tons and could perform operations like addition, subtraction, multiplication,

division and referring to previous results. Mark-I was much more reliable than early electronic
computers.

Mark-I
ENIAC

Electronic Numerical Integrator and Computer, was the first electronic general-purpose
digital computer, built in 1946 by John Mauchly and Presper Eckert. It contained over 18,000
vacuum tubes and was 1000 times faster than Mark-I. ENIAC consumed almost 200 kW of
power. It had no internal storage and required frequent maintenance.

Computer Timeline 23