A computer is a data and information processing machine according to a list of instructions named program. The computers that are free programmable and can process any type of data or information, are called universal computers or general computers. The actual computers aren’t just information processing machines, but devices which facilitates the communication between two or more users, in form of numbers / text / images / sound or video, or even sometimes all at once.
The oldest known mechanism seems that could function as a calculating machine which is considered to be “The Clock” from Antikythira, dating back from the year 87. b.c. and apparently used to calculate the planets movement. The technology which stood at the base of this mechanism isn’t known.
Once with the revival of mathematics and sciences from the European Renaissance, came a succession of calculating mechanical devices, based on the clock principle, for example the machine invented by Blaise Pascal. The storage and reading techniques on a perforated card, came in the 19th century. In the same century, Charles Babbage is the first to project a calculating machine completely programmable in 1837, but unfortunately his project won’t work, mainly because of the limited technology of the time.
In the first half of the 20th century, the needs for the scientific communities were satisfied by the analog computers, very specialized and increasingly sophisticated. The improvement of digital electronics – thanks to Claude Shannon in 1930 – has led to abandoning the analog computers in favor for the digital ones, which shape the problems in numbers (bits) instead of electrical or mechanical signals. It’s hard to tell which was the first digital computer; noticeable achievements were: the Atanasoff-Berry computer, the Z machines of Konrad Zuse – for example the electromechanically computer Z3, which, although very impractical, it was probably the first universal computer, then the ENIAC computer with a relatively inflexible architecture which requested cable modifications for each reprogramming, like the secret British computer, the Colossus, built on lamps and electronically programmable.
The design team of the ENIAC, recognizing its shortcomings , has developed another architecture, more flexible, which was known under the name of von Neumann architecture or “architecture with saved memory”. This stands probably at the base of every actual calculating machines. The first system which was built using von Neumann architecture was the EDSAC.
In the 1960s, the electronic tubes were replaced by transistors, more efficient, smaller, cheaper and more reliable, which took to the miniaturization and cheaper computers. Since the 1970s, the adoption of integrated circuits took to lower prices and sizes of the computers, allowing through other, to the appearance of the personal computer.
So the answer to: when was the first computer created is up to you to answer. which do you think it was the first computer.