The concept of first mechanical computer In 1822, Charles Babbage designed and developed the first mechanical computer, which was the Difference Engine. In 1822, Charles Babbage conceptualized and began developing the Difference Engine, which is considered to be the first automatic computational machine capable of approximating polynomials. Charles Babbage received some assistance with developing the Difference Engine from Ada Lovelace, considered to be the first computer programmer due to her work on the computer.

Charles Babbage began sharing with Ada his ideas about a new machine, a machine which would transcend difference engines, and which came to be very similar in architecture to todays state-of-the-art computers, although also never being built to completion (Kim & Toole, 1999). Although the analytic engine was never fully developed, the documented plans for the machines capabilities became the basis of what we understand today as computer programming and our current machines.

The differential engine was intended to produce mathematical tables, much like the logging done by the human computers mentioned above, and automate the steps needed for data computation. It lacks many features found in current computers; it is designed to perform one specialist task, and is not Turing-complete.

The analytic engine contained an ALU (Arithmetic Logic Unit), basic control of the flow, punch cards (inspired by Jacquards Loom), and integrated memory. The earliest computer to resemble modern machines was the Analytical Engine, a device invented and designed between 1833 and 1871 by British mathematician Charles Babbage. His invention was different from any of these earlier creations, and was much more sophisticated: He designed it to do just about any mathematical computation.

The first mechanical computer was considered programmable, and Charles Babbage wrote notes and sketches on the Difference Engine as well. In 1910, Henry Babbage, Charles Babbage's youngest son, was able to finish part of the first universal mechanical computer, and to do some basic calculations.

The first modern computer concept In 1938, Alan Turing first proposed the Turing machine, which became a foundation of computation and computers. In 1945, Alan Turing joined the National Physical Laboratory and began working to develop a stored-program electronic digital computer. The first stored-program computer concept was introduced in 1948, with the introduction of the SSEM (Small Scale Experimental Machine), also known as Manchester Baby or the Babe.

Between 1928 and 1931, Hazen and Vannevar Bush built the differential analyzer, which was really practical in the sense that it could be used for solving various problems, and thus, by this criteria, it can be considered to be the first computer. Although the Judge subsequently determined the ABC Computer was the first digital computer, many still believe that ENIAC was the first digital computer, as ENIAC was completely functional. The ENIAC (Electronic Numerical Integrator and Computer), also known as the Giant Brian (1945), was the first electronic, general-purpose, digital computer.

One of the earliest and best known, the Electronic Numerical Integrator and Analyzer Computer (ENIAC), was built at the University of Pennsylvania for the United States Army's ballistics calculations in WWII--and it was. The first computer to achieve Turing's completion, and one with those four essential features that characterize our computers today, was ENIAC (Electronic Numerical Integrator and Computer), which was developed covertly by the US Army, and was first commissioned to operate at the University of Pennsylvania on 10 December 1945, for use in studying the feasibility of a hydrogen bomb.

At the end of the Second World War -- during which he helped crack the Enigma codes for the Nazis encoded messages -- Turing created one of the earliest computers resembling the current ones, an automatic computing engine, that, apart from being digital, was programmable; that is, it could be used to do a lot of things just by changing a program. The machine included an arithmetic logic unit, controlled flows in the form of branching and conditional loops, and integrated memory, making it the first general-purpose computer design to be described, in todays terms, as Turing-complete. The machine did indeed make use of valves for producing its clockwaveform at 125 kHz, and for circuitry to read from and write to its magnetic-drum memory, so it was not the first fully transistorized computer.

The First Electric Programmable Computer Tommy Flowers developed the first electrically programmable computer, known as the Colossus, and it was demonstrated for the first time in 1943. Historians still debate about who built the first true computer, but the consensus is that engineers in both the United States and Britain succeeded in creating electronics machines embodying his dreams by the end of the 1940s.

As time went on, there were all sorts of specialized devices invented to help with things like collecting taxes, taking the census, etc. At first, they were purely mechanical, but early in the 20th century, they were powered by steam. The first modern computers were invented in WWII, in 1941, by a German engineer named Konrad Zuse. During the first half of the twentieth century, many of the demands of scientific computation were met by increasingly complex analogue computers, using direct mechanical or electrical models of the problem as a base for calculations. In 1938, the U.S. Navy invented the Torpedo Data Computer (TDC), arguably the first electromechanical computer.