Apple Titanium PowerBook G4 power management

[E. Robert Tisdale]

I installed Yellow Dog Linux 2.3 on a 667 MHz Apple Titanium PowerBook 
G4 laptop computer
but it goes to sleep soon after I "close the lid" and I can't wake it up 
again
unless I do a "hard reboot" holding down to power key until it shuts down.
I have disabled the Power Management Unit Daemon (pmud) so that,
as long as it is connected to external power, it doesn't go to sleep 
when I close the lid
but it will still go to sleep if I disconnect it from external power.

We really need to be able to close the lid when it is disconnected from 
external power
so that we can squeeze it into a small compartment on one of our 
experimental Mars rovers.