boot block

bootblk

Loads ufsboot from disk

boot program

ufsboot

Loads unix from disk

vmunix

unix

Bootable kernel image 

boot.sun4c.sunos.4.1.1

inetboot

Mounts and copies unix from network

rc.boot, rc.single

/etc/rcS

Mounts /usr and checks file systems

rc.local

/etc/rc2, /etc/rc3, /etc/rc2.d, /etc/rc3.d

System configuration scripts 

config

modload, /etc/system, add_drv, rem_drv

Customizes system kernel; loads, adds, and removes modules as needed 

PROM monitor, single user, multiuser 

Run states 0 - 6, and S 

System run levels