# installboot /usr/platform/'uname -i'/lib/fs/ufs/bootblk \ /dev/rdsk/c0t3d0s0
The system firmware loads the primary bootstrap (the boot block) program into memory and runs it. The boot block is a UFS file system reader. It loads the secondary boot program (/platform/'uname -i'/ufsboot) into memory.
ufsboot loads kernel/unix, then /kernel/unix uses ufsboot to load modules from the kernel directory hierarchy until it is able to mount the root file system.
During these operations, the boot block and ufsboot use the drivers provided by the firmware; neither ufsboot nor the boot block contains any driver code. The ufsboot code does not have to change to incorporate a new SBus card with a new disk type since ufsboot uses the SBus card PROM driver.
When booting over the network, the boot program performs as it did for a diskless boot in the SunOS release 4 software. However, the boot program is now called inetboot and the client vfstab file entries are different. See System Administration Guide, Volume I for information on diskless booting.