Booting From the PROM

Be aware of these changes when booting from the PROM:

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

  As in the SunOS release 4 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 systems used /vmunix; however, in the SunOS release 5.7 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 kernel but can be dynamically loaded in SunOS release 5.7 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.