1. In 1822, Charles Babbage conceptualized and began developing the Difference Engine, considered to be the first automatic computing machine.


2. Then after almost a decade, Charles Babbage proposed the first general mechanical computer, the Analytical Engine. The Analytical Engine contained an Arithmetic Logic Unit (ALU), basic flow control, and integrated memory concept and is the first general-purpose computer.

3. In 1946, ENIAC- Electronic Numerical Integrator and Computer was the first electronic general-purpose computer. It was the first large-scale computer to run at electronic speed without being slowed by any mechanical parts. And it was invented by J.Presper Eckert and John W. Mauchly. 

4. Douglas Engelbart invented the first computer mouse.

5. First computer with RAM - MIT introduces the Whirlwind machine, a revolutionary computer that was the first digital computer with magnetic core RAM and real-time graphics.
6. The first minicomputer - In 1960 Digital Equipment Corporation released its first of many PDP computers the PDP-1.

7. The first laptop - First Laptop was introduced in 1981 by Adom Osborne and the company “EPSON” manufactured first Laptop.

The following table categorises generations of computers and other important factors associated with the generations. 

Subject
1st
generation
2nd
generation
3rd
generation
4th
generation
5th
generation
Period
1940-1956
1956-1963
1964-1971
1971-present
present & beyond
Circuitry
Vacuum tube
Transistor
Integrated chips (IC)
Microprocessor (VLSI)
ULSI (Ultra Large Scale Integration) technology
Memory
Capacity
20 KB
128KB
1MB
Magnetic core memory, LSI and VLSI. High Capacity
ULSI
Processing
Speed
300 IPS instructions Per sec.
300 IPS
1MIPS (1 million inst. Per sec.)
Faster than 3rd generation
Very fast
Programming
Language
Machine,
Language
Assembly language & early high-level languages(FORTRAN,
COBOL, ALGOL)
C,C++
Higher level languages,C,C++,Java
All the Higher level languages,,Neural
networks,
Example
of computers
UNIVAC, EDVAC
IBM 1401, IBM 7094, CDC
3600,D UNIVAC 1108
IBM 360 series, 1900 series
Pentium series,Multimedia,
Artificial Intelligence, Robotics