It's a lot quicker to search http://docs.sun.com/ for answers to this kind
of question. Indeed, a simple google search will find the information in
seconds.
RSC is Remote System Control. It's an always-on service processor that
allows remote management of a server. Together with LOM and ALOM it is
extremely useful when you have a number of servers to manage.
cediag analyses memory errors and tells you when a failing memory dimm
should be replaced.
http://sunsolve.sun.com/pub-cgi/show.pl?target=cediag