[Beowulf] Mouse pointer disappear

Robert G. Brown rgb at phy.duke.edu
Mon Jan 29 07:13:04 PST 2007

On Sat, 27 Jan 2007, Ruhollah Moussavi Baygi  wrote:

> I have already established a Beowulf cluster with six nodes.
> Each node with cpu AMD Athlon 64-bit X2 dual core 4200+,
> motherb ASUS M2NPV-MX (chipset NVIDIA GeForce 6150 GPU, & NVIDIA nForce 430
> MCP), graphic integrated in the NVIDIA GeForce 6
> RAM 2G
> OS= FC5 64-bit
> I use one mouse/keyboard/monitor, shared by KVM box
> I prefer to work in graphical mode of Linux rather than text mode. But, my
> problem is that I cannot see mouse pointer in after Linux loading.
> If anyone knows the solution, please give me help.

Mice are funny.  Some mice have to be reset when you boot, or when X
starts up, in order to work.  If you have a KVM box it is actually
pretty easy to "freeze" the mouse.

To test whether or not this is the problem, try plugging the mouse
directly into your GUI node and booting.  The mouse should "just work".
If it does, then try putting the mouse back into the KVM chain and
booting just that node without switching the KVM box (so that the mouse
signal is sustained through the boot and startup of X11). Since the KVM
is basically nothing but an extender cable in this case, it should just

Then try switching the mouse around from system to system.  If the mouse
stops working, then you need a better KVM box, one that keeps power on
to the mouse through the switching process -- Belkin makes some
good/cheap ones, so do a few other companies.  Unpowered parallel rotary
switch boxes (which I've tried) are notorious for dropping the mouse,
and often the mouse won't come back until you send it the kind of reset
information that usually only is sent in a boot or X11 startup.

Sometimes you can get away with just adding a better mouse, as well.
Some of the newer e.g. USB mice can tolerate disconnection/reconnection
better than others.

Note that this is a very idiosyncratic problem -- some people will have
it because of their COMBINATION of hardware while others with some
overlap of that hardware will not.  You just need to find a combination
that works, probably beginning with a better KVM.

Oh, I forgot to say that if the mouse doesn't work when you first boot
straight through with no KVM in at all, either your mouse itself is
broken or you haven't correctly installed the mouse support in X.  I
don't know what the approved way of installing/configuring mice from a
tty interface is these days -- they "just work" for me pretty
consistently so I haven't had to do this for three or four revisions now
-- but somebody on list probably does.


> With best regards,
> Ruhollah Moussavi Baygi

Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu

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