📘 Chapter Notes: Evolution of Computers

1. History of Computers

Computers evolved from simple counting tools (like the abacus) to modern devices.
Early machines were large, complex, and used mainly by scientists and engineers.
Over time, they became smaller, faster, more reliable, and affordable.
Today, smartphones act as powerful pocket-sized computers.

Abacus: First calculating device; beads on rods divided into “Heaven” and “Earth.”
Pascal’s Calculator (1642): Invented by Blaise Pascal; performed addition and subtraction using gears and wheels.
Leibniz’s Calculator (1671): Designed by Gottfried Wilhelm Leibniz; could perform multiplication, division, and square roots.
Other devices: Slide Rule and Napier’s Bones.

Difference Engine (1820s–30s): Designed by Charles Babbage; aimed to produce 20–30 digit results but never completed.
Analytical Engine: Babbage’s vision of a programmable, general-purpose computer.
Ada Lovelace: First computer programmer; wrote the first algorithm for the Analytical Engine.
Tabulating Machine (1890s): Invented by Herman Hollerith; used punch cards for census data. His company later became IBM.
Turing Machine (1936): Alan Turing’s theoretical model of a general-purpose computer.
Von Neumann Architecture (1951): Introduced stored-program concept; foundation of modern computers.
ENIAC (1946): First general-purpose electronic digital computer; weighed 30 tons.
UNIVAC (1951): First commercial computer; handled both numeric and text data.

First Generation (1940–56): Vacuum tubes, punched cards, magnetic drums, machine language.
Second Generation (1956–63): Transistors, punched cards/tapes, magnetic tapes, batch processing, FORTRAN & COBOL.
Third Generation (1964–71): Integrated Circuits (ICs), keyboards/monitors, magnetic disks, time-sharing, languages like C & C++.
Fourth Generation (1971–Present): Microprocessors, personal computers (IBM PC, Apple Macintosh), GUI, SQL & Python.
Fifth Generation (Present–Future): Artificial Intelligence, ULSI chips, machine learning, cloud computing, AI operating systems.
- Example: Sophia robot (2016), Jarvis AI system by Mark Zuckerberg.

Supercomputers: Fastest; used for space research, weather forecasting, nuclear testing.
- Example: NASA uses them; India’s AIRAWAT PSAI, world’s largest Frontier.
Mainframe Computers: Powerful but less than supercomputers; used by banks, insurance companies, government.
- Examples: Fujitsu ICL VME, Hitachi Z800.
Microcomputers (Personal Computers): Affordable, for single users; desktops, laptops, tablets, smartphones.
Hand-held Devices: Portable devices like iPads, PDAs, smartphones; mostly touch-based.

Pascaline principles are used in odometers and speedometers.
Punch cards were widely used for data storage in early computing.
Alan Turing is on the £50 note in England.
Seymour Cray is the “Father of Supercomputing.”
AI assistants like Alexa and Siri are everyday examples of fifth-generation technology.