Evolution of First and Second Generation Computers

First Generation Computers: The Vacuum Tube Era

The first generation of computers was based on vacuum tubes—electronic components similar to light bulbs. These tubes could be held in two different states, conducting or non-conducting, which allowed for the construction of digital systems based on binary logic.

Key Computers of the First Generation

• ENIAC (1947): Consisting of 18,000 valves and 7,500 resistors, it could perform decimal addition, subtraction, multiplication, and division. It filled the basement of the University of Pennsylvania, consumed 100 kW of power, and reached a processing speed of 5,000 additions per second.
• EDVAC (1949): The first computer based on the philosophy of John von Neumann, featuring programs stored in memory alongside data.
• UNIVAC (1951): Considered the first commercial computer, purchased by the U.S. Census Bureau.
• IBM 701 (1952): IBM's response to the UNIVAC and their first electronic computer, capable of 17,000 operations per second.

These systems utilized punch cards and paper tape for input and output. Programming was performed directly in machine language, which was highly complex and distant from human communication. Due to high costs and operational complexity, these machines were limited to a small group of super-companies and government agencies.

Second Generation Computers: The Transistor Revolution

The basic element of this generation was the transistor, an electronic component similar to the vacuum tube but significantly smaller with lower power consumption.

Key Computers of the Second Generation

• TRADIC (1955) by Bell Labs: The first computer built entirely with transistors. It contained nearly 800 transistors, consumed about 100 watts, and occupied only one cubic meter.
• IBM 7070 (1959): Capable of executing multiple tasks simultaneously, such as performing calculations while managing punch cards.
• IBM 1401 (1960): A budget-friendly version of the IBM 7070 designed for smaller customers.
• DEC PDP-5 (1963): A minicomputer that introduced programming via high-level languages, which were closer to human language. New programs were created to translate these instructions into machine language.

During this period, memory storage evolved with the introduction of ferrite cores, which allowed for greater capacity in less space. These computers were less complex to construct and use, leading to increased reliability and adoption, though they remained primarily accessible to large organizations.