messages generated during boot process ?

how to get all the messages that are thrown on the console when the
box boots up ? is there a file where some of the messages are written.
one of them is var/adm/messages ?
but till the file system is available, that is much later into the
boot process that a file system would be available for writing to ???

also in the rc.3d directory there are some K* files ? why are K* files
in this run level (comparing to solaris rc3.d ie run level 3 has only
S* files)

back to the question, till the file system is available for writing
where to log or write the messages that are written on the console ?