A discussion of history of computer becomes somewhat open to conflicting views because of a lack of common definition of what constitutes a computer. Computers ave gradually evolved out of very simple aids to computing like counting on fingers and abacus to increasingly sophisticated computing devices like mechanical adding machines, electrical calculators, unit record data processing machines and then programmable computers. There is no clear cut dividing line between what is simply a calculating device and what is a computer.
However some people define a computer as a computing or data processing device that contains memory which stores data to be used for computing as well as instructions on the processing operations to be performed. This enables the device to perform multiple data processing operation without external inputs. Accepting this definition of computers, the first real computer can be considered to be the Mark I computer built in 1944. It was designed and built by IBM, in collaboration with Howard Atkins for the army of U.S.A. This was a completely mechanical equipment which used punched paper tape for feeding data to the computer.
The next important step in the history of development of computer was Eniac, is an acronym for the name Electronic numerical integrator and calculator. It is the first electronic computer built between 1943 and 1945 by John Mauchly and J.Presper Eckert, again for the U.S.A. Army.
Eniac became very successfulul, which prompted other people to build computers with similar sounding names like Illiac, Jhnniac and Maniac.
The first commercially produced computer was Univac released in 1950. It was manufactured by a company started by Mauchly and Eckert. This computer used magnetic tapes for data input and output. Perhaps this computer can be said to have all the basic defining features of a computer in a well developed form. Thus all subsequent developments in computer can be said to be in the form of improving performance in terms like size of memory and computing capabilities, speed, size, and reliability. These development s have also concentrated on reducing the cost of computers. This reduction in cost is also attributable in part to explosive increase in popularity and demand for computers, leading to economy of scale.