In either case, devices are checked in a continuous loop until a valid boot device is found for system startup. Separate default and user boot lists are also maintained for booting from the Service key position. Included in the key boot record data are the starting location of the boot image on the boot device, the length of the boot image, and instructions on where to load the boot image in memory. The boot image is read sequentially from the boot device into memory starting at the location specified in the boot record. The disk boot image consists of the kernel, a RAM file system, and base customized device information.
Control is passed to the kernel, which begins system initialization.
Process 1 executes init , which executes phase 1 of the rc.boot script. When the kernel initialization phase is completed, base device configuration begins. The Base Device Configuration Phase diagram illustrates this part of the boot process. The init process starts the rc.boot script. The boot script starts the configuration manager, which accesses phase 1 configuration rules to configure the base devices.