虚拟终端行
=VTY
=Virtual TTY
=Virtual TeleTYpe
teletype (TTY) display:
A method of displaying characters on a monitor in which characters are generated and lent, one by one, to the video display; as the characters are received, the screen fills, line by line. When full, the screen scrolls up to accommodate the new lines of characters appearing at the bottom of the screen. Teletype display mode should be familiar to DOS users. DOS uses a teletype display for accepting commands and displaying messages
