[Beowulf] ATX on switch

Tony Travis a.travis at abdn.ac.uk
Sun Oct 4 07:09:19 PDT 2009

Tomislav Maric wrote:
> Hi Dmitri and Tony,
> thank you both very much for your answers. I'm on my way to rip out a
> switch from an old computer case so I can start the master node for the
> first time (hopefully without calling the firemen and an ambulance :) ).
> I'll setup the BIOS as you've told me: "ON after AC loss". Does that
> mean that next time it will be turned on(off) when the PS is turned on(off)?

Hello, Tomislav.

Many PC BIOS's default to PSU in the "previous state" when AC power is 
restored, but you can force the state to "on" if you want, which means 
that when the AC power is restored, the BIOS will switch the PSU back on 
automatically. This is not desirable for a server, but is fine for a 
compute node - It's safer to leave a server off after AC power loss.

> If I do this,  I can power the master with PS on switch, and use the
> switch I have for adding another node with the same setup: set it up to
> run diskless, set it's BIOS the same way, turn it off, disconnect the
> switch and use it for adding another node. Is this OK?

Or, learn to short the pins with a screwdriver like the rest of us ;-)


Dr. A.J.Travis, University of Aberdeen, Rowett Institute of Nutrition
and Health, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
tel +44(0)1224 712751, fax +44(0)1224 716687, http://www.rowett.ac.uk
mailto:a.travis at abdn.ac.uk, http://bioinformatics.rri.sari.ac.uk/~ajt

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