краткий пересказ. (Internet) (E-mail) (краткий пересказ. (Internet) (E-mail).docx)

Internet

The Internet is a worldwide network of computers, connected to each other and transferring data packets to each other. Connections can differ from each other physically and in transmission rate.

The History. U.S. Government developed internet for its military purposes. The main requirement was to be reliable and connect different military computers. As solution, they used an idea to split data into packets and to build the information back by gathering the packets at the destination. In the beginning in early 1970 different universities connected to the first internet system, called ARPANET. Suddenly internet started to spread, owing to some applications, that became very useful for people, and it became general-purpose network and used to be called NSFnet. The main feature that made internet so popular is the development of World Wide Web (WWW).

Applications. Here are the main applications, which made internet so widespread: e-mail, which became very useful, and is almost the only one of the first applications, which still widely used, Netnews some days was largest computer bulletin, FTP the protocol that is still at large and used to transfer files, telnet is used until nowadays, but it transfer data in plaintext, that is very risky today. Another one application is called gopher, it is a system for organizing document into tree hierarchy. Probably the most general now is the World Wide Web, which became even new technology stream. Other protocols are WAIS, Streaming media, e-commerce, blogs, social networks and variety of wikis.

E-mail

Electronic mail is the ubiquitous application in our world; it allows sending messages to each other consisted of text and multimedia, using MIME type. As usually at the beginning, there was many different realizations, but only one survived to our days, it is smtp. Emails is now one of the main mean of communication in organizations. New functions in emails lead the way for different vulnerabilities, which are used by viruses to spread themselves in the email system. However, email is still very popular and used even in delicate systems that for example can provide routine bills.