Evolution of Computers

 

Blaise Pascal invented the first mechanical adding machine in 1642.

First mechanical adding machine

Later, in the year 1671, Baron Gottfried Wilhelm von Leibniz of Germany invented the first calculator for multiplication.

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 a input medium even in late 1970s. Business machines and calculators made their appearance in Europe and America towards the end of the nineteenth century.

Charles Babbage, a nineteenth century professor at Cambridge University, is considered the Father of modern digital programmable computers. He had employed a group of clerks for preparing mathematical 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.

Difference Engine

In 1842, Babbage come out with his new idea of a completely automatic analytical Engine for performing basic arithmetic functions for many mathematical problems 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 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.  

  The term 'Computer' was first introduced in 1640 and referred to as 'one who calculates'. It was derived from the Latin word 'computare', which meant 'to calculate'. In 1897, it was known as the 'calculating machine'. Later in 1945, the term 'computer' was introduced as 'programmable digital electronic computer, which is now called a 'computer'.

When the computers were introduced, they were large and could fill an entire room. Some computers were operated using large-sized vacuum tubes. In 1833, Charles Babbage (known as the father of the computer) invented an early calculator, which was named as the 'difference engine'. Later in 1837, he introduced the first mechanical, general-purpose computer 'Analytical Engine'. Over time, computers became powerful in performance and small in size.

Analog computer -

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.[20] The first modern analog computer was a tide-predicting machine, invented by Sir William Thomson (later to become Lord Kelvin) in 1872. The differential analyser, a mechanical analog computer designed to solve differential equations by integration using wheel-and-disc mechanisms, was conceptualized in 1876 by James Thomson, the elder brother of the more famous Sir William Thomson.[16]

The art of mechanical analog computing reached its zenith with the differential analyzer, built by H. L. Hazen and Vannevar Bush at MIT starting in 1927. This built on the mechanical integrators of James Thomson and the torque amplifiers invented by H. W. Nieman. A dozen of these devices were built before their obsolescence became obvious. By the 1950s, the success of digital electronic computers had spelled the end for most analog computing machines, but analog computers remained in use during the 1950s in some specialized applications such as education (slide rule) and aircraft (control systems).

Digital computers -

By 1938, the United States Navy had developed an electromechanical analog computer small enough to use aboard a submarine. This was the Torpedo Data Computer, which used trigonometry to solve the problem of firing a torpedo at a moving target. During World War II similar devices were developed in other countries as well.

Replica of Zuse's Z3, the first fully automatic, digital (electromechanical) computer.

Early digital computers were electromechanical; electric switches drove mechanical relays to perform the calculation. These devices had a low operating speed and were eventually superseded by much faster all-electric computers, originally using vacuum tubes. The Z2, created by German engineer Konrad Zuse in 1939, was one of the earliest examples of an electromechanical relay computer.[21]

In 1941, Zuse followed his earlier machine up with the Z3, the world's first working electromechanical programmable, fully automatic digital computer.[22][23] The Z3 was built with 2000 relays, implementing a 22 bit word length that operated at a clock frequency of about 5–10 Hz.[24] Program code was supplied on punched film while data could be stored in 64 words of memory or supplied from the keyboard. It was quite similar to modern machines in some respects, pioneering numerous advances such as floating point numbers. Rather than the harder-to-implement decimal system (used in Charles Babbage's earlier design), using a binary system meant that Zuse's machines were easier to build and potentially more reliable, given the technologies available at that time.[25] The Z3 was not itself a universal computer but could be extended to be Turing