Booting off read-only filesystems

[Dean Takemori]

Hello,

What subdirectories off of / must be mounted read-write, and which can 
be mounted
read-only in order for a generic Yellowdog system to be bootable and 
usable?

Obviously, with things like /usr and /lib read-only, one cannot upgrade 
the installed
software, and if /etc is read-only, one can't reconfigure most packages 
either, and if
/home is read-only then user files cannot be changed/saved.

Clearly, /tmp and /proc need to be read-write.  /var also (though I 
think most things
will work so long as /var/cache, /var/lock, /var/log, /var/run, 
/var/spool and /var/tmp
are writable).

What about the rest?

-dean takemori