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releases:3.2.0:usersguide:serialconsoles

Serial Consoles

Introduction

With a little configuration, it's possible to use a dumb terminal connected to a minix host. Alternatively, one could connect a PC to a minix host via a null-modem cable and run a terminal emulator program on the PC to act as a dumb terminal.

Configuring the Minix Host

On the minix host edit /etc/ttytab. The tty00 and tty01 lines should be edited to look like this:

tty00           vt100           getty           "stty 9600"
tty01           vt100           getty           "stty 9600"

You may want to change the above entries to “stty 115200” to set a higher baud rate.

Then reboot the system with shutdown -r

Hardware Setup

Connect the terminal or null-modem cable to one of the serial ports on the minix host. Press enter a couple of times on the terminal and the login prompt should appear. Log in and have fun.

Using a Terminal Emulator

GNU Screen can be used as a terminal emulator on a Linux PC connected to a minix host via a null-modem cable with no setup needed.

screen /dev/ttyUSB0

In case you're wondering about ttyUSB0, it's a USB-to-serial adapter. Using /dev/ttyS0 should also work.

You may also use

cu -s 9600 -l /dev/ttyUSB0

The '-s' option sets the baud rate, so you can change this to 115200 if you prefer.

Gotchas

  • Logging in via a serial console is handled slightly differently than logging in normally with a keyboard. The user you are logging in as must have a password set. Trying to log into an account without a password will not work.
  • Serial connections are slow. If you're doing a make world or something with a lot of output that you don't care to read, you can redirect stdout to /dev/null like this:
make world 1> /dev/null
  * Don't set 'ctty 0' for serial debugging.
releases/3.2.0/usersguide/serialconsoles.txt · Last modified: 2014/11/11 08:52 (external edit)