[lug] apm/UPS

Peter Hutnick peter-lists at hutnick.com
Fri Aug 2 12:26:39 MDT 2002

> I'm looking at an UPS for the Linux bridge and cable modem. Obviously,
> cable modems do not have any "auto power down" feature (nor would the
> modem need it, but not totally depleting a battery's power is good for
> the life of the battery). In the case of the bridge machine, it is
> older, and does not support having the o/s power itself down, it has a
> good old-fashioned switch. However, in the case of the Linux machine, I
> can probably rewrite some of the UPS scripts for apmd, so that it starts
>  out by changing the ext3 journal speed from 5 second intervals to 1
> second intervals; and then if time goes far enough, either remount the
> drives read-only, except for /var/, or else run init 0 to halt when
> things get really close.

Have you looked into an RS-232 controlled relay?  You'd have to figure out
how to get your UPS to talk to the server (to do init 0) and the relay (to
kill power some reasonable period later), but I think it is quite doable.

Something like this http://www.qkits.com/serv/qkits/diy/pages/QK108.asp

You might also be able to pull something off with X10, such as do an init
1 then use a firecracker module to have the computer shut its own power

Good Luck!


More information about the LUG mailing list