E-mail: Electronic mail
From Network Dictionary Wiki
Electronic mail (E-Mail or Email) is a widely used network application in which messages and documents are transmitted electronically between end users over various types of networks using various network protocols.
Origins of e-mail
E-mail predates the Internet; existing e-mail systems were a crucial tool in creating the Internet. The Compatible Time-Sharing System (CTSS) was begun at MIT in 1961. It allowed multiple users to log into the 7094 from remote dial-up terminals, and to store files online on disk. This new ability encouraged users to share information in new ways. E-mail started in 1965 as a way for multiple users of a time-sharing mainframe computer to communicate. Although the exact history is murky, among the first systems to have such a facility were SDC's Q32 and MIT's CTSS.
E-mail was quickly extended to become network e-mail, allowing users to pass messages between different computers. The messages could be transferred between users on different computers by 1966, but it is possible the SAGE system had something similar some time before.
The ARPANET computer network made a large contribution to the evolution of e-mail. There is one report which indicates experimental inter-system e-mail transfers on it shortly after its creation, in 1969. Ray Tomlinson initiated the use of the @ sign to separate the names of the user and their machine in 1971. The ARPANET significantly increased the popularity of e-mail, and it became the killer app of the ARPANET.
Growing popularity
As the utility and advantages of e-mail on the ARPANET became more widely known, the popularity of e-mail increased, leading to demand from people who were not allowed access to the ARPANET. A number of protocols were developed to deliver e-mail among groups of time-sharing computers over alternative transmission systems, such as UUCP and IBM's VNET e-mail system.
Since not all computers or networks were directly inter-networked, e-mail addresses had to include the "route" of the message, that is, a path between the computer of the sender and the computer of the receivers. E-mail could be passed this way between a number of networks, including the ARPANET, BITNET, and NSFNET, as well as to hosts connected directly to other sites via UUCP.
The route was specified using so-call "bang path" addresses, specifying hops to get from some assumed-reachable location to the addressee, so called because each hop is into a form understandable by another vendor.
The CCITT developed the X.400 standard in the 1980s to allow different e-mail systems to interoperate. Roughly at the same time, the IETF developed a much simpler protocol called the Simple Mail Transfer Protocol (SMTP) which has become the de facto standard for e-mail transfer on the Internet. With the advent of widespread use of home personal computers connected to the Internet, interoperability via SMTP-based Internet e-mail has become a critical feature for all e-mail systems.
In 1969 US Air Force users were sending text messages by keypunching cards with long text messages using one card for each 80 character line and transmitting them as card decks from one computer to another. By 1979, US Air Force users were logging onto central computers k within hours. By the end of 1983 US Air Force users were using user names like alclark@vax1.mil to send e-mail between a nationwide linkup of VAX computers. By 1984 these same users were using personal computers for same.
In 1979, the US Post Office bought a computer specifically for e-mail, but wound up selling it to private industry.
In 1982 the White House adopted a prototype e-mail system from IBM called the Professional Office System, or PROFs for the National Security Council (NSC) staff. By April 1985, the system was fully operational within the NSC with home terminals for principals on the staff. By November of 1986 the rest of the White House came online, first with the PROFs system, and later (by the end of the 1980s) through a variety of systems including VAX A-1 ("All in One"), and ccmail.
In 1991, the first e-mail from space was sent from aboard the Space Shuttle Atlantis, mission STS-43, using AppleLink running on a Macintosh Portable.
Email can be better than postal mail because with email, one can still have contact with people without the risk of somebody making an appearance at his or her house that comes with the use of postal mail.