求redhat6.2 /etc/init/rcS.conf 文件解释！

wushubo

请问redhat6.2中/etc/init/rcS.conf文件中的：
# rcS - runlevel compatibility
#
# This task runs the old sysv-rc startup scripts.

start on startup

stop on runlevel

task

# Note: there can be no previous runlevel here, if we have one it's bad
# information (we enter rc1 not rcS for maintenance).  Run /etc/rc.d/rc
# without information so that it defaults to previous=N runlevel=S.

没有注释的和被注释的都是什么意思啊？