A computer is an electronic device that manipulates information, or data. It has the ability to store, retrieve, and process data OR A computer is a device that accepts information (in the form of digitalized data) and manipulates it for some result based on a program, software, or sequence of instructions on how the data is to be processed.
They are used to type documents, send e-mail, play games, browse the Internet, create
presentations, event invitations, and listen to music or watch videos.
The five basic operations that a computer performs are input, storage, processing, output and control.
- Input: this is the process of entering data and programs into the computer system.Input devices accept data and instructions from the user.Following are the examples of various input devices, which are keyboard, mouse, joystick etc.
- connected to the computer for this purpose
- Control Unit (CU): The process of input, output, processing and storage is performed under the supervision of a unit called ‘Control Unit’. It decides when to start receiving data, when to stop it, where to store data, etc. It takes care of step -by-step processing of all operations in side the computer.
- Memory Unit: Computer is used to store data and instructions.
- Arithmetic Logic Unit (ALU): The major operations performed by the ALU are addition, subtraction,
multiplication, division, logic and comparison. - Output: This is the process of producing results from the data for getting useful information.
The ALU and the CU of a computer system are jointly known as the central processing unit (CPU). You may call CPU as the brain of any computer system.
The history of computers began with primitive designs in the early 19th century and went on to change the world during the 20th century. The first counting device was used by the primitive people. They used sticks, stones and bones as counting tools. As human mind and technology improved with time more computing devices were developed. Some of the popular computing devices starting with the first to recent ones are described below;
Abacus
An abacus is an ancient tool used in mathematics. It is used for counting and performing mathematical operations such as addition, subtraction, multiplication, and division. The abacus is traditionally made with a frame that holds wires or rods on which movable beads are placed. It is said that Chinese invented Abacus around 4,000 years ago.
Napier’s Bones
It was a manually-operated calculating device which was invented by John Napier (1550-1617) of Merchiston. In this calculating tool, he used 9 different ivory strips or bones marked with numbers to multiply and divide. So, the tool became known as “Napier’s Bones. It was also the first machine to use the decimal point.
Pascaline
Pascaline is also known as Arithmetic Machine or Adding Machine. It was invented between 1642 and 1644 by a French mathematician-philosopher Biaise Pascal. It is believed that it was the first mechanical and automatic calculator.
Stepped Reckoner or Leibnitz wheel
It was developed by a German mathematician-philosopher Gottfried Wilhelm Leibnitz in 1673. He improved Pascal’s invention to develop this machine. It was a digital mechanical calculator which was called the stepped reckoner as instead of gears it was made of fluted drums.
Difference Engine
In the early 1820s, it was designed by Charles Babbage who is known as “Father of Modern Computer”. It was a mechanical computer which could perform simple calculations. It was a steam driven calculating machine designed to solve tables of numbers like logarithm tables.
Analytical Engine
This calculating machine was also developed by Charles Babbage in 1830. It was a mechanical computer that used punch-cards as input. It was capable of solving any mathematical problem and storing information as a permanent memory.
Tabulating Machine
It was invented in 1890, by Herman Hollerith, an American statistician. It was a mechanical tabulator based on punch cards. It could tabulate statistics and record or sort data or information. This machine was used in the 1890 U.S. Census. Hollerith also started the Hollerith?s Tabulating Machine Company which later became International Business Machine (IBM) in 1924.
Mark I
The next major changes in the history of computer began in 1937 when Howard Aiken planned to develop a machine that could perform calculations involving large numbers. In 1944, Mark I computer was built as a partnership between IBM and Harvard. It was the first programmable digital computer.