Hitchhiker's Guide to Openbsd

amd64 and i386
To direct the boot process to use the serial port as a console, create or edit your 
/etc/boot.conf
file to 
include the line: 
set tty com0
to use the first serial port as your console. The default baud rate is 9600bps, this can be changed with a /
etc/boot.conf line using the stty option. This file is put on your boot drive, which could also be your 
install floppy, or the command can be entered at the 
boot>
prompt from the 
OpenBSD second-stage 
boot loader
for a one-time (or first time) serial console usage. 
amd64 and i386 notes:
●
OpenBSD numbers the serial ports starting at tty00, DOS/Windows labels them starting at 
COM1. So, keep in mind tty02 is COM3, not COM2. 
●
Some systems may be able to operate without a video card in the machine, but certainly not all -- 
many systems consider this an error condition. Some machines will even refuse to work easily 
without a keyboard attached. 
●
Some systems are capable of redirecting all BIOS keyboard and screen activity to a serial port 
through a configuration option, so the machine can be completely maintained through the serial 
port. Your results may vary -- when using this feature, some BIOSs may prevent the bootloader 
http://www.openbsd.org/faq/faq7.html (5 of 14)9/4/2011 10:02:08 AM

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7 - Keyboard and Display Controls
from seeing the serial port, and thus, the kernel will not be told to use it. Some BIOSs have an 
option to "Continue Console Redirection after POST" (Power On Self Test), this should be set to 
"OFF", so the boot loader and the kernel can handle their own console. Unfortunately, this 
feature is not universal. 
●
PC compatible computers are not designed to be run from a serial console, unlike some other 
platforms. Even those systems that support a serial console usually have it as a BIOS 
configuration option -- and should the configuration information get corrupted, you will find the 
system looking for a standard monitor and keyboard again. You generally must have some way to 
get a monitor and keyboard to your amd64 and i386 systems in an emergency. 
●
You will need to edit /etc/ttys as 
above
.