Fifth Generation Computer - History

History

In the late 1960s and early 1970s, there was much talk about "generations" of computer hardware — usually "three generations".

1. First generation: Vacuum tubes. Mid-1940s. IBM pioneered the arrangement of vacuum tubes in pluggable modules. The IBM 650 was a first-generation computer.
2. Second generation: Transistors. 1956. The era of miniaturization begins. Transistors are much smaller than vacuum tubes, draw less power, and generate less heat. Discrete transistors are soldered to circuit boards, with interconnections accomplished by stencil-screened conductive patterns on the reverse side. The IBM 7090 was a second-generation computer.
3. Third generation: Integrated circuits (silicon chips containing multiple transistors). 1964. A pioneering example is the ACPX module used in the IBM 360/91, which, by stacking layers of silicon over a ceramic substrate, accommodated over 20 transistors per chip; the chips could be packed together onto a circuit board to achieve unheard-of logic densities. The IBM 360/91 was a hybrid second- and third-generation computer.

Omitted from this taxonomy is the "zeroth-generation" computer based on metal gears (such as the IBM 4077) or mechanical relays (such as the Mark I), and the post-third-generation computers based on Very Large Scale Integrated (VLSI) circuits.

There was also a parallel set of generations for software:

1. First generation: Machine language.
2. Second generation: Assembly language.
3. Third generation: Structured programming languages such as C, COBOL and FORTRAN.
4. Fourth generation: Domain-specific languages such as SQL (for database access) and TeX (for text formatting)