Evolution of Computers – Necessity is the mother of invention. The saying holds true for computers too. Researchers invented computers because of man's search for fast and accurate calculating devices. Blaise Pascal invented the first mechanical adding machine in 1642. Later, in the year 1671, Baron Gottfried Wilhelm von Leibniz of Germany invented the first calculator for multiplication. Keyboard machines originated in the United States around 1880 and we use them even today. Around the same period, Herman Hollerith came up with the concept of punched cards that computers used extensively as an input medium even in the late 1970s. Evolution of Computers Business machines and calculators made their appearance in Europe and America towards the end of the nineteenth century.
Evolution of Computers
Charles Babbage, a nineteenth century. Professor at Cambridge University is considered the father of modem digital programmable computers. He had employed a group of clerks for preparing mathematical and statistical tables. Babbage had to spend several hours checking these tables because even utmost care and precautions Could not eliminate human errors. Soon he became dissatisfied and exasperated with this type of monotonous job. As a result, he started thinking about building a machine that could compute tables guaranteed to be error-free. In this process, Babbage designed a “Difference Engine” in the year 1822 that could produce reliable tables. Evolution of Computers
In 1842, Babbage came out with his new idea of a completely automatic Analytical Engine for performing basic arithmetic functions for any mathematical problem at an average speed of 60 additions per minute. Unfortunately, he was unable to produce a working model of this machine. Because the precision engineering required to manufacture the machine was not available during that period. However, his efforts established a number of principles that are fundamental to the design of any digital programmable computer. Evolution of Computers
A major drawback of the early automatic calculating machines was that their programs were wired on boards that made it difficult to change programs. In the 1940s, Dr. John Von Neumann introduced the “stored program” concept that helped in overcoming hard-wired program problem. The basic idea behind this concept is that a sequence of instructions and data can be stored in the memory of a computer for automatically directing the flow of operations. This `feature considerably influenced the development of modern digital computers because of the ease with which different programs can be loaded and executed on a single computer. Due to this feature, we often refer to modern digital computers as stored program digital computers. Evolution of Computers
Generations of Computer
First (1942 – 1955)
- Key Hardware Technologies:- Vacuum tubes; electromagnetic relay memory; punched card secondary storage
- Key Software Technologies:- Machine and assembly languages; stored program concept; mostly scientific applications
- Key Characteristics:- Bulky in Size, highly unreliable, limited commercial use, commercial production difficult and costly, difficult to use
Second (1955 – 1964)
- Key Hardware Technologies:- Transistors, magnetic core memory, magnetic tapes, and disks secondary storage
- Key Software Technologies:- Batch operating system, high-level programming language, scientific and commercial applications
- Key Characteristics:- Faster, smaller, more reliable and easier to program than the previous generation system, commercial production was still difficult and costly.
Third (1964 – 1975)
- Key Hardware Technologies:- ICs with SSI and MSI technologies, larger magnetic core memory, larger capacity magnetic disks and tapes secondary storage, mini computers.
- Key Software Technologies:- Timesharing operating system, standardization of high- level programming language, unbundling of software from hardware
- Key Characteristics:- Faster, smaller, more reliable, easier and cheaper to produce commercial and interactive online applications
Fourth (1964 – 1989)
- Key Hardware Technologies:- ICs with ULSI technology, microprocessors, Semiconductor memory, larger capacity hard disk as in-built secondary storage, Magnetic tapes. Floppy disks as portable storage media, personal computer, the spread of high-speed computer network
- Key Software Technologies:- Operating System for PCs, GUI, multiple windows on a single terminal screen, multiprocessor operating system and concurrent programming language, UNIX operating system, C and C++ programming language, PC – based application, network-based applications, object-oriented software design.
- Key Characteristics:- Small, affordable, reliable, and easy to use PCs, more powerful and reliable mainframe system, general purpose machine, easier to produce commercially
Fifth (1989 – Present)
- Key Hardware Technologies:- ICs with ULSI technology, multicore processor chips, larger capacity main memory, larger capacity hard disk, optical disks as portable read-only storage media, notebook computers, powerful desktop PCs and workstation, very powerful mainframes, supercomputer based on Parallel Processing, the internet.
- Key Software Technologies:- World Wide Web, multimedia application, internet-based application, microkernel, multithreading, and multicore operating system, JAVA programming language, MPI and PVM libraries for Parallel Programming
- Key Characteristics:- Portable Computer, more powerful, cheaper, reliable, and easier to use a desktop machine, very powerful mainframe, very high uptime due to hot-pluggable components, general purpose machines, easier to produce commercially.
