Subject: Some notes on the system ID of sgi's
To: Mark Henderson <mch@geekmail.cc> 



I was tired last night when I emailed you that code (took me quite a
while).  here are some things I noticed that maybe of use to your
website as well.


I started with the kernel symbol first_address, and started the search,
when I found the system id (found in mulitple places, including eaddr +2
and eaddr + 30, but changing those values didn't effect anything), I
calculated the address by adding how many bytes I have read +
first_address, then looked for a symbol close to that address. 


That's when I noticed Octanes (and other platforms? I have to check this
out) have a kernel symbol sysid which points directly to the sysid
address, but for some reason I couldn't nlist the symbol (protected?).


So I used nm -xv to sort things by value, and saw is_octane_lx 4 bytes
below sys_id and used that for a reference.  I am going to look into
some other sgi arch's and see if sysid is availble on all 6.5.x
architectures (or ones I have access to), if it is, I will be able to
write another C program that will sort the symbols (like nm does) and
take whatevers below sysid (since I can't nlist it for an addr), or just
a shell script to add a #define symbol from the output of nm.  Making a
general not arch/specific system id changer for irix.


I will look into this later this week and let you know how it turns out
:)


LeRoy C. Miller III

