Email:
- Email is a computer based method of sending messages from one computer user to another.
- These messages usually consist of individual pieces of text which we can send to another computer user even if the other user is not logged in (i.e. using the computer) at the time of send message.
- The message can then be read at a later time. This procedure is analogous to sending and receiving a letter.
- When mail is received on a computer system, it is usually stored in an electronic mailbox for the recipient to read later.
- Electronic mailboxes are usually special files on a computer which can be accessed using various commands.
- user normally has their individual mailbox.
Host-based mail systems
- The original email systems allowed communication only between users who logged into the same host or "mainframe". This could be hundreds or even thousands of users within an organization.
- By 1966 some systems allowed email between different organizations, so long as they ran compatible operating systems.
- Examples include BITNET, IBM PROFS, Digital Equipment Corporation ALL-IN-1 and the original Unix mail.
LAN-based mail systems
- From 1980, networked personal computers on LANs became increasingly important.
- Server-based systems similar to the earlier mainframe systems were developed. These systems initially allowed communication only between users logged into the same server infrastructure.
- Eventually these systems could also be linked between different organizations, as long as they ran the same email system and proprietary protocol.
- Examples include cc:Mail, Lantastic, WordPerfect Office, Microsoft Mail, Banyan VINES and Lotus Notes - with various vendors supplying gateway software to link these incompatible systems.
- Early interoperability among independent systems included:uucp was used as an open "glue" between differing mail systems, primarily over dialup telephones
- ARPANET which was the forerunner of today's Internet
- CSNet which used dial-up telephone access to link additional sites to the ARPANET and then Internet
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