Trying to get a handle on CMOS usage

ron minnich rminnich at lanl.gov
Wed Nov 5 00:23:00 CET 2003


I just found an issue with CMOS usage, and I am trying to figure out what 
tools use CMOS in which cases. 

So, can we summarize: 
- does etherboot do anything to bits in CMOS? If so, what? 

- what bits in CMOS is linuxbios V2 currently messing with?  (yeah, I
  should know this, but it turns out I don't currently; I'm still looking for 
  the place where linuxbios V2 writes to cmos nowadays)

Finally, is the CMOS really 256 bytes nowadays on something like the EPIA, 
or are we stuck at 128 still? I'm not sure at this point. 

Any and all information would be nice to have. The problem I've hit is 
that I'm storing authentication data for Plan 9 in cmos, and it appears 
that linuxbios/etherboot are storing to bytes at location 0x1f or so, 
which is bad for me. I need to find 112 bytes that will be unmolested by 
either linuxbios or etherboot.


thanks

ron




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