Tyan serial console - how?

Donald Becker becker at scyld.com
Thu Nov 7 14:05:56 PST 2002

On Thu, 7 Nov 2002, David Mathog wrote:
> > Ken Chase wrote:
> > I had massive problems playing with the serial console on linux at
> > anything higher than 9600. Having no flow control is good, but more
> > and more dangerous at higher bitrates.
> Can anybody explain why there no flow control is good?  The
> cables in question have all pins, so naively, I would have
> thought that hardware flow control would have been the best choice.

The usual problem is that missing or miswired pins prevent
communication.  It's considered better to have a apparently-working
system than nothing at all.

> This BIOS serial console mode really is a dreadful hack.

Ohhhh yeeaahh.  The first time I saw it I though "Neat hack.  Thank
goodness it will never be on production machines."

It gets worse: guess how IPMI 1.5 based BIOS setup over the network is
done.  Hint: the IPMI controller already has wires going to the serial

Still, however ugly internally, IPMI is big step forward for
standards-based cluster hardware management.  With the new IPMI
motherboards our next release series will be able to do the following
from the master, even before the OS is running:
    Hard power on and off
    Configure the BIOS
    Check the physical parameters (the usual temp/fans/volts/case open)
    Report critical hardware failures e.g.  memory failures during count
    Monitor the boot as the OS starts

Donald Becker				becker at scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Scyld Beowulf cluster system
Annapolis MD 21403			410-990-9993

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