The abacus is the first known calculating machine, made of beads and rods used for basic arithmetic. John Napier invented a calculating device using bone rods with printed numbers that could perform addition and subtraction. Blaise Pascal invented a calculating device using gears to represent digit positions. Later innovators like Gottfried Leibniz, Charles Babbage, and others continued developing calculating machines, leading to modern computers that now use integrated circuits, artificial intelligence and other advanced technologies.

1. Abacus is the first known calculating
machine; It is made of beads and rods.
It is used for addition, subtraction,
multiplication and division.
John Napier’s invented this device that
used the bone rods for counting
purpose where some number printed
on this rod. This rod can do
subtraction, addition etc.,

2. Blaise pascal invented this device.
This device represents the position of
digits with the help of gears in it.
Gottfried Leibniz a German
mathematician modified the pascal
calculator and developed a machine
which perform various calculation
based on multiplication and division.

3. Charles Babbage invested this
machine that include such features
which is used in today’s computer
language.
First generation use vacuum tube.
These tubes produced a lot of heat and
the installation used to fuse frequently.
They were very expensive.

4. Third generation use integrated
circuits. In its user use keyboard and
monitor which interfaced with an
operating system, punch card and
printouts.
Fifth generation use artificial
intelligence. These are very portable
and small in size. Desktop, laptop,
mobile etc.,

5. Second generation used transistors. It
stored data in magnetic disk and
magnetic tape. They are smaller in size
and produced less heat then first
generation.

6. Fourth generation use microprocessor.
They used semiconductor memory
(RAM, ROM) to store data. Monitor,
mouse, keyboard.