Electronic mail

electronic mail or e-mail, the electronic transmission of messages, letters, and documents. In its broadest sense electronic mail includes point-to-point services such as telegraph and facsimile (fax) systems. It is commonly thought of, however, in terms of computer-based message systems where the electronic text file that is received can be edited, replied to, excerpted, or even pasted into another electronic document that can be used or manipulated by a word processor, desktop publishing system, or other computer program. Users of such systems, called store-and-forward or mailbox systems, can broadcast messages to multiple recipients, read and discard messages, file and retrieve messages, or forward messages to other users. Extensions to e-mail allow the user to add graphics and sound to messages, and files can be attached to e-mails. Computer-based messaging can take place on a single computer, a computer network, or across gateways linking different computer networks (as through the Internet). With the increasing use of e-mail, unsolicited commercial e-mail, known as spam, has become a significant problem. E-mail, especially through attachments, has also become a means for disseminating computer viruses and other malicious programs.

Bibliography

See D. Angell and B. Heslop, The Elements of E-Mail Style: Communicate Effectively Via Electronic Mail (1994); N. A. Cox, ed., Handbook of Electronic Messaging (1998); J. Tunstall, Better, Faster Email: Getting the Most Out of Email (1999).

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See e-mail.

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Electronic mail

The asynchronous transmission of messages by using computers and data-communication networks. Historically, electronic mail (or e-mail) referred to any of a number of technologies that allowed people to send documents to one another through electronic means. It was frequently used to describe both wirephoto [the precursor of the facsimile (fax) machine] and telegraphy. Subsequently, usage of the term focused upon the narrower sense given above. See Facsimile

The use of electronic mail grew continuously until the late 1980s but never achieved widespread use outside of work groups or corporations. The limiting factor was the complicated addressing that had to be worked out before a message could be successfully transmitted.

There were two proposed methods to solve the problem of mail-system identification and routing. The Organization for International Standardization (ISO) formulated the X.400 standard, and the Internet community developed an extended use of the domain name system (DNS). Many impediments to the spread of X.400, such as high software costs and delays in standardization, caused the freely available DNS solution to become the de facto standard.

The DNS describes a worldwide distributed database in which each site maintains its own information about how to route messages to a computer within its administrative domain. A computer wishing to send a message to another asks the DNS for the routing information and uses the information returned to make the connection. This allows a person on virtually any online networking service to send mail to another person by giving only the personal identification and the e-mail system name of the recipient. See Distributed systems (computers)

From the time the usage of the term narrowed to exclude facsimile until the early 1990s, generally only coded textual information could be transferred via e-mail. The transmission of nontextual data required special preprocessing, postprocessing, and prior arrangements between the sending and receiving parties. It was very difficult to make these kinds of transfers if the sending and receiving computers were different types.

This restriction was lifted with the adoption of the MIME (Multimedia Internet Mail Enhancements) standard. It described a way of encoding an arbitrary list of media types within a normal textual message in an operating-system-independent manner. Finally, different types of systems could send executable, sound, picture, movie, and other kinds of files to each other via e-mail. See Multimedia technology

The spread of electronic mail was also hampered by its lack of security. As mail was passed from one site to another closer to its destination, system administrators at each intermediate site could read messages. Also, the source of an e-mail message may be fairly easily forged to make it either untraceable or appear to come from another person. This limited the use of e-mail to so-called friendly applications. Public-key cryptography has been applied to e-mail messaging, notably in PEM (Privacy Enhanced Mail), in response to these security concerns. See Computer security, Cryptography

Since the communications speeds required for e-mail are quite modest, messages are sometimes transmitted by wireless means. Cell phones and personal digital assistants can send and receive e-mail through Earth-satellite relay. See Internet

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(messaging)

electronic mail - (e-mail) Messages automatically passed from one computer user to another, often through computer networks and/or via modems over telephone lines. A message, especially one following the common RFC 822 standard, begins with several lines of headers, followed by a blank line, and the body of the message. Most e-mail systems now support the MIME standard which allows the message body to contain "attachments" of different kinds rather than just one block of plain ASCII text. It is conventional for the body to end with a signature. Headers give the name and electronic mail address of the sender and recipient(s), the time and date when it was sent and a subject. There are many other headers which may get added by different message handling systems during delivery. The message is "composed" by the sender, usually using a special program - a "Mail User Agent" (MUA). It is then passed to some kind of "Message Transfer Agent" (MTA) - a program which is responsible for either delivering the message locally or passing it to another MTA, often on another host. MTAs on different hosts on a network often communicate using SMTP. The message is eventually delivered to the recipient's mailbox - normally a file on his computer - from where he can read it using a mail reading program (which may or may not be the same MUA as used by the sender). Contrast snail-mail, paper-net, voice-net. The form "email" is also common, but is less suggestive of the correct pronunciation and derivation than "e-mail". The word is used as a noun for the concept ("Isn't e-mail great?", "Are you on e-mail?"), a collection of (unread) messages ("I spent all night reading my e-mail"), and as a verb meaning "to send (something in) an e-mail message" ("I'll e-mail you (my report)"). The use of "an e-mail" as a count noun for an e-mail message, and plural "e-mails", is now (2000) also well established despite the fact that "mail" is definitely a mass noun. Oddly enough, the word "emailed" is actually listed in the Oxford English Dictionary. It means "embossed (with a raised pattern) or arranged in a net work". A use from 1480 is given. The word is derived from French "emmailleure", network. Also, "email" is German for enamel. The story of the first e-mail message.