Development of Computers

Necessity is the mother of invention. The saying holds true for computers too. Computers were invented because of man's search for fast and accurate calculating devices. Basic Pascal invented the first mechanical adding machine in 1642. Later, in the year 1671, Keyboard machines originated States around 1880 and we use them even today. Around the same period, Herman Hollerith came up with concept of punched cards that were extensively used as input medium in computers even in late 1970s. Machines and calculators made their appearance in Europe and America towards the end of the century. Charles Babbage, a nineteenth century Professor at Cambridge University, is considered the father of modern digital computers. In order to have a better idea of the evolution of computers it is worthwhile to discuss of the well-known early computers. These are as follows:

• The Mark-I Computer (1937-44). Also known as Automatic Sequence Controlled calculator, this was the first fully automatic calculating machine designed by Howard A. Aiken of Harvard University in collaboration with IBM (International Business Machines) Corporation. It was an electro-mechanical device (used both electronic and mechanical components) based on the techniques already developed for punched card machines.
• The Atanasoff-Berry Computer (1939-42). Dr. John Atanasoff developed an electronic machine to solve certain mathematical equations. The machine was called the Atanasoff-Berry Computer, or ABC, after its inventor's name and his assistant, Clifford Berry. It used 45 vacuum tubes for internal logic and capacitors for storage.
• The ENIAC (1943-46). The Electronic Numerical Integrator And Calculator (ENIAC) was the first all electronic computer. It was constructed at the Moore School of Engineering of the University of Pennsylvania, U.S.A. by a design team led by Professors J. Presper Eckert and John Mauchly. The team developed ENIAC because of military needs. It was used for many years to solve ballistic related problems. It took up wall space in a 20 x 40 square feet room and used 18,000 vacuum tubes it could add two numbers in 200 microseconds and multiply them in 2000 microseconds.
Did You Know?
Baron Gottfried Wilhelm von Leibniz of Germany invented the first calculator for multiplication.
• The EDVAC (1946-52). A major drawback of ENIAC was that its programs were wired on boards that made it difficult to change the programs. Dr. John Von Neumann later introduced the ―stored program concept that helped in overcoming this 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 the same computer. Due to this feature, we often refer to modern digital computers as stored program digital computers. The Electronic Discrete Variable Automatic Computer (EDVAC) used the stored' program concept in its design. Von Neumann also has a share of the credit for introducing the idea of storing both instructions and data in binary form (a system that uses only two digits - 0 and 1 to represent all characters), instead of decimal numbers or human readable words.
• The EDSAC (1947-49). Almost simultaneously with EDVAC of U.S.A., the Britishers developed the Electronic Delay Storage Automatic Calculator (EDSAC). The machine executed its first program in May 1949. In this machine, addition operations took 1500 microseconds and multiplication operation: took 4000 microseconds. A group of scientists headed by Professor Maurice Wilkes at the Cambridge University Mathematical Laboratory developed this machine.
• The UNIVAC I (1951). The Universal Automatic Computer (UNIVAC) was the first digital computer that was not ―one of a kind‖. Many UNIVAC machines were produced, the first of which was installed in the Census Bureau in 1951 and was used continuously for 10 years. In 1952, the International Business Machines (IBM) Corporation introduced the IBM-701 commercial computer. In rapid succession, improved models of the UNIVAC I and other 700-series machines were introduced. In 1953, IBM produced the IBM-650, and sold over 1000 of these computers.