Subject: Re: serial console
To: Jeff Rizzo <>
From: Steven M. Bellovin <>
List: current-users
Date: 01/22/2005 11:53:22
In message <>, Jeff Rizzo writes:
>Chris Ross wrote:
>> On Jan 21, 2005, at 14:52, David Laight wrote:
>>> On Fri, Jan 21, 2005 at 11:51:44AM -0700, Co Thai Ngo wrote:
>>>> Hi,
>>>>  I would like to install NetBSD 2.0 by using a serial console with 
>>>> boot-com. But I don't
>>>>  know if there is any way so that I could change the baud rate when 
>>>> booting the
>>>>  computer with boot-com without rebuilding the sources. I have to 
>>>> use the dafault baud
>>>>  rate 9600 while my computer can run with the baud rate 115200. Any 
>>>> suggestion and
>>>>  comment is appreciated.
>>> For NetBSD 2.0, you should just use the normal bootxx_ffsv1 (or 
>>> equivalent
>>> for the root filesystem type).  You can set the baudrate using the
>>> -o speed=<baud rate> option to installboot (use -o console=com0 to 
>>> select
>>> a serial console).
>>   David, I think you're misunderstanding his question.  He wants to 
>> perform
>> the *install* using a serial console.  I do this all the time, but I 
>> must admit,
>> mostly on sparc's, where it's much easier.
>>   Looking at the man page for boot(8), there is of course the consdev 
>> command.
>> But, as you note, it simply allows you to specify use of a serial 
>> console, not
>> its baud rate.  I myself don't see a way to specify it.  Someone more 
>> familiar
>> with the boot code will have to speak up.
>>   If it isn't possible, it should be.  I presume it wouldn't be too 
>> hard to add this
>> to the bootloader...
>>                                          - Chris
>I think you're misunderstanding David's answer.  You can use installboot 
>to set the speed of the serial console for the bootblocks on the bootfloppy.
>Something like (not tested):
>installboot -o console=com0,speed=115200 /dev/fd0a /usr/mdec/bootxx_ffsv1
>(this really doesn't belong on current-users;  either netbsd-help or 
>port-i386 would have been more appropriate)

I read the question the same way Chris did: can you *run* sysinst 
from a serial console at a different baud rate than 9600?

		--Prof. Steven M. Bellovin,