Terminal
The term terminal has two meanings in computer science, relating to an individual computer and to a computer network.
In the context of an individual computer, a terminal is a device that enables the user to communicate with the computer. Generally, the device is a combination of a keyboard and a display screen. There are three classes of terminals with respect to their processing speed and data handling capability: intelligent terminal, smart terminal, and dumb terminal.
An intelligent terminal is a device that can process information. It has memory and a processor. In contrast, a dumb terminal has no processing capabilities. A dumb terminal can only accept data from the central processing unit of the computer to which it is linked. It is also the slowest operating of the three terminal classes. Nevertheless, a dumb terminal is adequate for most applications for which terminals are required. The third class of terminal, the smart terminal, has features that position in between the intelligent and dumb terminals. A smart terminal does have its own processor and built-in logic, which enables it to perform functions like bold and blinking characters.
In the context of networking, a terminal refers to a personal computer or a workstation that is connected to a mainframe computer. Typically, each personal computer runs what is termed terminal emulation software that makes the mainframe think each terminal is another mainframe terminal. This enables a personal computer to be part of the mainframe network. An example of such a setup is the SETI (Search for Extraterrestrial Intelligence) project. In SETI, individual's personal computers can emulate a mainframe terminal, so that many more individuals than those residing in the SETI facility can do the analysis of incoming signals from outer space. The speed of analysis is increased by such a configuration.
Another well-known example of network terminals is the Telnet. Telnet, the Network Terminal Protocol, is a two-way communication network. It was implemented so that users could communicate with computers, users could communicate with other users, and computers could communicate directly with other computers, all using the same protocol and rules. A useful feature of Telnet is the ability of a user at a terminal to gain access to an application that is not on the Telnet server. For example, if a user does not have an e-mail program, as would be the case using a dumb terminal, Telnet can be used to send e-mail messages. The user can establish a Telnet connection to the recipient. Then, using text commands from the computer to which the terminal is connected, the user can identify themselves as a sender, enter a text message and have the message delivered.
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