The original Unix systems did not have consoles. Instead, people logged in and ran programs through terminals that were connected to the computer's serial ports. It is quite similar to using a modem and some terminal software to dial into a remote system to do text-only work.
Today's PCs have consoles capable of high quality graphics,
but the ability to establish a login session on a serial port
still exists in nearly every Unix-style operating system
today; FreeBSD is no exception. By using a terminal attached
to a unused serial port, you can log in and run any text
program that you would normally run on the console or in an
xterm window in the X Window System.
For the business user, you can attach many terminals to a FreeBSD system and place them on your employees' desktops. For a home user, a spare computer such as an older IBM PC or a Macintosh can be a terminal wired into a more powerful computer running FreeBSD. You can turn what might otherwise be a single-user computer into a powerful multiple user system.
For FreeBSD, there are three kinds of terminals:
The remaining subsections describe each kind.
Dumb terminals are specialized pieces of hardware that let you connect to computers over serial lines. They are called ``dumb'' because they have only enough computational power to display, send, and receive text. You cannot run any programs on them. It is the computer to which you connect them that has all the power to run text editors, compilers, email, games, and so forth.
There are hundreds of kinds of dumb terminals made by many manufacturers, including Digital Equipment Corporation's VT-100 and Wyse's WY-75. Just about any kind will work with FreeBSD. Some high-end terminals can even display graphics, but only certain software packages can take advantage of these advanced features.
Dumb terminals are popular in work environments where workers do not need access to graphic applications such as those provided by the X Window System.
If a dumb terminal has just enough ability to display, send, and receive text, then certainly any spare personal computer can be a dumb terminal. All you need is the proper cable and some terminal emulation software to run on the computer.
Such a configuration is popular in homes. For example, if your spouse is busy working on your FreeBSD system's console, you can do some text-only work at the same time from a less powerful personal computer hooked up as a terminal to the FreeBSD system.
X terminals are the most sophisticated kind of terminal available. Instead of connecting to a serial port, they usually connect to a network like Ethernet. Instead of being relegated to text-only applications, they can display any X application.
We introduce X terminals just for the sake of completeness. However, this chapter does not cover setup, configuration, or use of X terminals.