Generations of Computers

Generations of Computers

Computers developed after the first electronics computer ENIAC are classified into five generations. This generation is based on the technology used in architectural development of computers. It also includes computational ( processing) techniques, input-output devices and programming languages used.

The generations of computers are broadly classified into two types :

1.      Non – electronics generation.

2.      Electronic generation.

Let us discuss each one of them briefly.

Non – Electronic generation.

These are referred to as the Zero Generation  computers. They were developed before the semiconductor revolution took place in 1946 . They were made up of wooden or mechanical components.

Examples : Abacus, Napier’s bone, Differential Engine etc.

Electronic Generation

Computer  developed after 1946 are categorized into five generations. Since they are mainly built with electronic circuitry, they are called the electronic generation computers.

First Generation Computers

These were developed during  1946-59, and were built with Vacuum tubes. Their speed was  10^-3 sec. They used limited primary memory and used magnetic drums as secondary storage devices. They used punched card and magnetic tape to input and output operations. The machine language programming was adapted in these machines. They were batch processing systems and were used for both scientific and business based applications.

Examples : ENIAC, UNIVAC-I, EDSAC, EDVAC etc.

Second Generation Computers

These were developed during  1957-64 and were built with diodes and transistor. Their speed was 10^-6 sec. They had more primary memory and proved higher reliability. High level programming languages like FORTRAN, Pascal, ALGOL etc, were used in these machines. The concept of multi-proramming , time-sharing and real-time processing were also introduced.

Example: BURROUGHS 5000, IBM 1401, GE635, CDC 164, HONEYWELL 400, etc.

Third Generation Computers

These were developed during 1965-70 and were built with Integrated Circuits (ICs). There ware  10-100 transistors in a single silicon chip. Their speed was 10^-9 sec( nano second). They used semiconductor memory. They had higher reliability and reduced size. The concept of operating system , multi-programming, parallel processing were introduced. They were used in weather forecasting, airline reservation, banking services.

Examples:  IBM System/360, UNIVAC 1108/9000, CDC-6000, NCR 395, CYBER-175,etc.

Fourth Generation Computers

These were developed during 1970-90 and were built with Large Scale Integration(LSI), 100-1000 transistors in a single chip and Very Large Scale Integration(VLSI), 1000 to millions of transistors per chip. They have a huge storage capacity and their processing  speed is from  10^-9 -10^-12  sec. The concept of networking was introduced.

Example:- IBM 3033, HP-3000(minicomputer), PDP-11, CYBER-205, all modern PCs.

Fifth Generation Computer

The development of super computers was the key motivation of the fifth generation computers. Super computers were developed with Super Large Scale Integration (SLSI), i.e million of transistors were used in a single IC chip. These are knowledge processing systems. The C concept kike Artificial Intelligence and distributed processing were incorporated. They are RISC ( Reduced Instructions Set Computing) based machines. CD-ROM (Compact Disk Read Only Memory), WORM( Write Once Read Many Times) are introduced.

Examples: CRAY machines(Japan), PARAM -1000(India) are considered to be fifth generation computers.