Booting From the PROM

Be aware of these changes when booting from PROM:

• The PROM loads bootblk from the disk. This file is similar to the previous SunOS release 4.x boot block except that it is specific to the UFS file system.

  As in the SunOS release 4.x software, you need to use installboot(1M) to install boot blocks on a partition to be used for booting.

• bootblk opens the boot device and, using the file system you specify, finds and loads ufsboot.

• The boot PROM loads the kernel, /kernel/genunix, after ufsboot is loaded into memory. SunOS release 4.x systems used /vmunix; however, in the SunOS release 5.6 software the /kernel directory contains all platform-independent kernel modules, including unix, needed to boot the system.

• The kernel, in turn, loads other drivers, such as esp, from the /kernel/drv directory. These drivers had to be built as part of the SunOS release 4.x kernel but can be dynamically loaded in SunOS release 5.6 systems when they are needed.

• The /sbin/init command generates processes to set up the system based on the directions in /etc/inittab. The next section describes the run levels that init uses.