Chapter 2 of William Stallings’ book gives a detailed account of computer evolution and performance, giving examples of each generation and some statistical data.
Computers have been around since the 1940s and, surprisingly, the way computers work have changed little over the years.
Each new generation in the evolution of computers is marked by an increase in processor speed, a decrease in computer size, an increase in memory size and increasing input and output capacity and speed.
With each new generation of computers, new components marked their arrival, however, after the third generation, there is less consensus on defining generations of computers.
The first generation of computer evolution was marked by the use of vacuum tubes. The second generation of computer evolution came about with the invention of transistors, which were an improvent on vacuum tubes as they were smaller and did not consume as much power. Integrated circuits hailed the third generation of computer evolution.