I checked the situation tonight again. If I turn off the console
vt100 terminal (it is flaky and will crash is left on for too long)
then a message to the console will block until the terminal is
turned on (no problem here) but all other serial ports seem to
block (ppp stalls, bad) and the clock stops too (bad).

Are we waiting with interrupts off? I am looking at arch/dev/scn.c
and cannot see anything more than blocking on one serial port, so
clock ints should be honoured - right? I am still unsure about the
preemptability of the kernel.

--
Eyal Lebedinsky (eyal@eyal.emu.id.au) <http://samba.org/eyal/>