Terminal emulator

On Unix-like operating systems, it is common to have one or more terminal windows connected to the local machine.

Connection to the mainframe computer or terminal server is achieved via RS-232 serial links, Ethernet or other proprietary protocols.

Examples of such software for DOS were Telix or Telemate, which was published in 1988 and could emulate a DEC VT102 terminal.

[5] Through the success of Linux, especially running on data centers and cloud servers,[6] the necessity of accessing remote computers through character based terminals remains.

These in turn emulate a physical port/connection to the host computing endpoint – hardware provided by operating system APIs, or software such as rlogin, telnet or SSH, among others.

As with other text terminals, there are also special escape sequences, control characters and functions that a program can use, most easily via a library such as ncurses.

For more complex operations, the programs can use console and terminal special ioctl system calls.

Typical Linux system programs used to access the virtual consoles include: Terminal emulators may implement a local echo function, which may erroneously be named "half-duplex", or still slightly incorrectly "echoplex" (which is formally an error detection mechanism rather than an input display option).

[citation needed] In this mode, the terminal emulator only sends complete lines of input to the host system.

To implement it correctly, the Network Virtual Terminal implementation provided by the terminal emulator program must be capable of recognizing and properly dealing with "interrupt" and "abort" events that arrive in the middle of locally editing a line.

Users can make numerous changes to a page, before submitting the updated screen to the remote machine as a single action.

The word "text" is key since virtual consoles are not GUI terminals and they do not run inside a graphical interface.