#### EVOLUTION OF COMPUTER

**Evolution of computer** describes the gradual changes that computer underwent from ancient time up to date.

This gives the explanation of early devices and how they were applied.
There are roughly

**three phases** in computer evolution as :-

- Early machines
- Mechanical Era computers (1623 - 1944)
- Modern computers

**Early machines:**
**Abacus:**
- It was a computational tool used to ADD and SUBTRACT numbers.
- It was used in China and Japan for thousands of years.

**Slide Rule:**
- It was first analog device to perform MULTIPLICATION and DIVISION
- It was invented in the year 1620 by William Oughted.

**Napier's Bones:**
- Used a set of long rods which looked like bones hence the name Napier's Bones.
- It was used for MATHEMATICAL calculations including MULTIPLICATION and DIVISION.
- It was designed by Napier in the year 1600.

**Mechanical Era computers (1623 - 1944)**
**Pascal's Adding Machine:**
- It was the first mechanical adding machine using a system of gears and wheels.
- It was developed by Blaise Pascal (Pascal programming language was named after him).
- It used to ADD and SUBTRUCT numbers.

**Jacquard Loom:**
- It was developed by the French inventor to automate rug weaving on a in 1804.
- This technology eliminated jobs that had been done by humans for centuries.

**Difference Engine:**
- These were efforts of Charles Babbage who realized that time consuming mathematical tasks such as calculating the squares
of numbers which required systematic approach that could be automated. He invented 1st programming machine in 1936.

**Census Tabulation Machine:**
- 40 years later after invention of Jacquard Loom, Dr. Herman Hollerith put Jacquard's punched card concept together with
the tabulating machine.

**Modern computers:**
- In this phase, computers have big memory which leads to high speed.
- They also perform many tasks at once.
- Today computer's
**specifications** are:-
**Processor: **

Measured in Hz.
**Memory (RAM) :**

Measured in Bytes
**System Type :**

Measured in bits (16, 32, 64 or 86 bit operating system).

Since then the technology has advanced at an unimaginable ace the computer professionals have labelled every new technology development as new generation in computer.