Evolution of Computers

Sand Tables

Calculations in sand tables were performed using stones. This was one of the earliest known calculating devices.

Abacus

The Abacus was one of the first mechanical computing tools. It consisted of two parts — a lower and an upper section. The upper part had two beads, and the lower part had five beads, which were moved along rods to perform calculations such as addition and subtraction.

Napier’s Bones

Invented by John Napier, this small instrument was made up of 10 rods, each engraved with a multiplication table. It simplified the process of performing multiplication and division.

Slide Rule

The Slide Rule operated based on the principle of logarithms. The distances on the rule were proportional to the logarithms of the numbers printed on it. It was used for calculations like multiplication, division, and finding roots and powers.

Pascaline

Invented by Blaise Pascal, this device featured a complex arrangement of wheels and gears. It had windows for displaying numbers and was operated using a series of dials numbered from 0 to 9 on their circumference. It could perform basic arithmetic operations like addition and subtraction.

Stepped Reckoner

Developed by Gottfried Wilhelm Leibniz, this device extended Pascal’s design to perform multiplication, division, and even to find square roots. It was a significant step toward automatic calculation.

Punch Card System

This system was primarily used in power looms and later in computing. It operated on the principle that the presence or absence of holes represented binary digits — 1s and 0s. This concept became a foundation for early data storage and programming.

Difference Engine

Designed by Charles Babbage, this machine was built to mechanically generate mathematical tables. It automated calculations that were previously done manually.

Analytical Engine

The Analytical Engine was the first general-purpose programmable computer, also conceptualized by Charles Babbage, known as the Father of Computers. This machine could perform conditional operations — taking different actions based on whether a computed number was positive or negative. It introduced the concept of control flow in computing.

Hollerith Tabulator

Developed by Herman Hollerith, this electronic machine could read information from punched cards and process it electronically. It was used for data processing in the 1890 U.S. Census and marked a major step toward modern computing.

Automatic Sequence Controlled Calculator (ASCC)

Developed by IBM in 1944, the Automatic Sequence Controlled Calculator (ASCC), also known as Mark I at Harvard University, was an electro-mechanical calculator. It could automatically perform long sequences of arithmetic calculations and was an important precursor to electronic computers.