History of Computers

The eveolution of computers can be classified by their technologies from the oldest to newest:
1. mechanical computers
2. vacuum tube computers
3. transistor computers
4. integrated circuit computers

Mechanical Computers - B.C. to 1960's

Often the is said to be the earliest know calculating device.  The origins of the abacus are disputed, as many different cultures have been known to have used similar tools. It is known to have existed in Babylonia and in China, with invention to have taken place between 2400 BC and 300 BC.

English mathematician Charles Babbage designed a Victorian era computer called the Analytical Engine.

Analytical Engine

The Antikythera Mechanism is from ancient Greece.  These fragments were discovered off the Greek island of Antikythera.  X-ray examination shows 30 miniaturized differential gears. The device was possibly used for calculating the position of the Sun, moon, and planets.  On the right is a possible reconstruction of the device.

Antikythera Mechanism gear fragmentsReconstructed Antikythera Mechanism

French mathematician Blaise Pascal created this mechanical calculator in 1648.

In the early and mid 1900's mechanical calculators were popular like the handheld Curta.  Businesses used mechanical adding machines.

Curta Calculator  Victor Adding Machine

Vacuum Tube Computers - 1940's to 1950's

The vacuum tube (left picture) was first created in 1904 and used in radios, amplifiers, and television.  In 1942, the U.S. built the first vacuum tube computer called the ENIAC (center picture) as part of the World War 2 effort.  It was used to calculate things such as ballistic tables.  The ENIAC contained 17,468 vacuum tubes, covered 1800 square feet of floor space, weighed 30 tons, and consumbed 160 kilowatts of power.  The picture on the right shows some of the tubes in the ENIAC.

 Vacuum Tube ENIAC computer  ENIAC tubes

Transistor Computers - 1950's to 1960's

The transistor (left picture) eventually replaced the vacuum tube.  It was smaller, used less power, and less likely to fail.  One company that began building and selling transistor computers was IBM.

Different Types of Transistors and Their Working  Transistor Computer

Integrated Circuit Computers - 1960's to present

In 1959 at Texas Instruments in Dallas, the first integrated circuit was invented which allowed many transistors to be placed on a single semiconductor material (silicon).  From 1960 - 1963, almost all integrated circuits produced were for NASA and the Apollo program.

Beginning in the 1970's, integrated circuit technology was used to create the brains of computers.  These are known as microprocessors or central processing units (CPU).

The picture on the left is one of the first integrated circuits containing a few transistors.  On the right is an Intel CORE i7 CPU undere a microscope containing over 700 million transistors.

first integrated circuit  Intel i7 CPU    

Below is an Intel CORE i9 CPU packaged.  It contains 6.5 billion transistors.

Intel CORE i9 CPU