By 1955, the world powers, the United States and the Soviet Union, were working hard to control space. In 1957, the Soviet Union successfully launched a Spanish satellite into space. That is why the United States is particularly concerned. Therefore, ARPANet (Advamced Research Project Agency) was formed to develop space technology; Decisions were made to try to implement communications and military plans. At that time, personal computers were just a dream for the future. In 1969, ARPANet was implemented by connecting four major computers from four universities, experimenting with various computer connectivity technologies. Ray Tomlinson, a computer scientist at the University of Cambridge, Massachusetts, has linked electronic mail (email) to computer-to-computer communication. He used the e-mail symbol @ (at) when using e-mail. In the first room, the connection started with a LAN (Local Area Network). City after city; The...