USB console or other alternatives

Lowell Gilbert freebsd-questions-local at
Thu Apr 26 20:24:25 UTC 2007

Doug Lee <dgl at> writes:

> On Thu, Apr 26, 2007 at 11:14:26AM -0400, Lowell Gilbert wrote:
>> Doug Lee <dgl at> writes:
>> > Can modern hardware and a modern FreeBSD version provide console
>> > access before the kernel loads via USB or via anything other than an
>> > actual on-board or PCI serial port?
>> I am not sure, but I would expect that you would need BIOS support for
>> something like that.  Personally, I would stick with serial ports as
>> long as possible, because they are much more simple than any
>> alternatives.  
> More simple once found at least. :-)

More simple electrically, I was thinking.

>> What do you hook up to that serial port, anyway?
> A desktop Windows machine with a serial port, until said machine
> suddenly ceased to function entirely.  Now it would be a laptop
> with a USB-to-serial adapter except the one I bought also seems
> unwilling to function.  I tend to run short of PCMCIA slots for
> such things on my laptop, my one-and-only PCMCIA slot being occupied
> pretty permanently by an EVDO card.

So the problem is a lack of serial ports on your laptop "terminal",
not on the FreeBSD machine?  That sounds easier to work around than
the other way around.

There are some other possibilities, but I don't think they will work
as early in the boot process.  I *think* you can use a USB serial port
as a console, but the loader doesn't seem to understand it.  There's
also dcons(4), but that needs firewire, and I don't know if that knows
how to talk to anything on a Windows machine.

Good luck; sorry I can't be more help.

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