KVM switch with FreeBSD-8.2

Polytropon freebsd at edvax.de
Sun Sep 11 23:43:58 UTC 2011

On Sun, 11 Sep 2011 15:10:48 -0600 (MDT), Warren Block wrote:
> On Sun, 11 Sep 2011, Daniel Feenberg wrote:
> > If you are asking, "Is there a FreeBSD command to cause the KVM switch to 
> > move to the next system?" then the answer is "I don't know and it would amaze 
> > me if there were."
> There's often a key sequence to advance to the next port or a specific 
> port.

That can _sometimes_ be a problem when the KVM switch
doesn't properly detect this sequence - or maybe the
user has already defined that sequence for some action
in X, so X "catches" the sequence and acts properly.

My preferred solution was to get a switch that was
_fully_ independent from keyboard in regards of its
main functionality, i. e. switching. Another advantage
of that particular one was that you could DIRECTLY
switch from system #1 to system #8 without visiting
systems #2, #3, #4, #5, #6 and #7, :-)

> > If the question is "Does the switch care what the OS is?" then the answer is, 
> > you can press the physical button on the switch to change the system 
> > connected. The OS doesn't know it doesn't have the screen and keyboard, and 
> > is in no way affected by the KVM switch, just as the KVM doesn't know or care 
> > what the OS is.
> Well... there's monitor detection by the video card.  That can cause 
> problems. 

I'm not sure in how far this sill applies to "modern" hardware.
Absence of a video card vs. present video card with no monitor
attached _could_ prevent a system from booting.

The next step, starting X which obtains display information by
querying the monitor ("through" the card), can easily be dealt
with by putting the proper settings into xorg.conf. This will
make X start even if no monitor is attached to the card.

> Also, going through the KVM can reduce video quality with VGA 
> and high resolutions.

I've seen that with some cheap cabling on analog VGA. However,
when using DVI this problem should not be present, and it's
"common practice" today to use DVI to attach digital displays
(means: flatscreens).

Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

More information about the freebsd-questions mailing list