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Unit 2: RedHat Linux Basics

2.6 the Linux console notes

The console for a PC Linux system is normally the computer monitor in text mode. It emulates
a terminal of type “Linux” and the escape sequences it uses are in the man page: console_codes.
There is no way (unless you want to spend weeks rewriting the kernel code) to get it to emulate
anything else. Setting the TERM environment variable to any type of terminal other than “Linux”
will not result in emulating that other terminal. It will only result in a corrupted interface since
you have falsely declared (via the TERM variable) that your “terminal” is of a type different from
what it actually is. See Don’t Use TERM For Emulation.

Note In some cases, the console for a Linux PC is a text-terminal. One may recompile
Linux to make a terminal receive most of the messages which normally go to the console.
See Make a Serial Terminal the Console.

The “Linux” emulation of the monitor is flexible and has features which go well beyond those
of the vt102 terminal which it was intended to emulate. These include the ability to use custom
fonts and easily re-map the keyboard. These extra features reside in the console driver software
(including the keyboard driver). The console driver only works for the monitor and will not
work for a real terminal even if it’s being used for the console. Thus the “console driver” is really
a “monitor driver”. In the early days of Linux one couldn’t use a real terminal as the console so
“monitor” and “console” were once always the same thing.
The stty commands work for the monitor-console just like it was a real terminal. They are handled
by the same terminal driver that is used for real terminals. Bytes headed for the screen first go
thru the terminal (tty) driver and then thru the console driver. For the monitor some of the stty
commands don’t do anything (such as setting the baud rate). You may set the monitor baud
rate to any allowed value (such as a slow 300 speed) but the actual speed of putting text on the
monitor screen will not actually change. The file /etc/ioctl.save stores stty settings for use only
when the console is in single user mode (but you are normally in multiuser-user mode). This is
explained (a little) in the init man page.

Many commands exist to utilize the added features provided by the console-monitor driver. Real
terminals, which use neither scan codes nor VGA cards, unfortunately can’t use these features.
To find out more about the console see the Keyboard-and-Console-HOWTO. Also see the various
man pages about the console (type “man -k console”). Unfortunately, much of this documentation
is outdated.

2.7 emulation software

Emulators often don’t work quite right so before purchasing software you should try to throughly
check out what you will get.

make a Linux pc a terminal

Unless you want to emulate the standard vt100 (or close to it) or a Wyse 60, there doesn’t seem
to be much free terminal emulation software available for Linux. The free programs minicom
and seyon (only for X Window) can emulate a vt100 (or close to it). Seyon can also emulate a
Tektronix 4014 terminal.
Minicom may be used to emulate a directly connected terminal by simply starting minicom (after
configuring it for the serial port used). Of course, you don’t dial out and when you want to quit
(after you logout from the other PC) you use minicom’s q command to quit without reset since
there is no modem to reset. When minicom starts, it automatically sends out a modem init string

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