Keyboard Boot Disable

[Rick C. Petty]

On Tue, Apr 25, 2006 at 06:27:53PM -0400, Lucas Holt wrote:
> I worked with someone once that said they blew out the ps/2 port on  
> the motherboard.  As an alternative, maybe you could consider a kvm  
> switch?

Maybe on an ancient motherboard??  Most motherboards have
overvoltage/overcurrent protection circuitry.  A PS/2 port is just a
glorified serial port:  5v signals vs. +/- 7.5v.

The only problem I've ever had with hot-swapping PS/2 is tricking the OS to
reinitialize the device.  FreeBSD seems to handle this better than most.
Smart KVMs work much better because they keep the virtual device connected,
and they keep keyboard initialization state so they can reinitialize the
keyboard when it's plugged in again.  Even dumb KVMs seem to handle
hot-swapping better; likely the onboard logic behaves better than the
onboard keyboard controllers.

USB works much better because it guarantees power & ground connection is
established before the data pins.  Many KVMs buffer the keyboard I/O so it
can wait until power & ground are established before trying to send/recv
data.  I've never blown out a PS/2 port or device, and I hot swap much more
than I should...

-- Rick C. Petty