Boot Process

During Boot Process, the system will  test hardware, loads and runs the operating system, and configures devices.

To boot the operating system, a boot image is loaded  and access to / and  /usr  filesystem is required.

Cold Boot : System is started by turning on the power switch

Warm Boot: System is restarted by shutdown or  reboot command.

Events  occurs on system before it is ready for use.

1.       ROS (Read Only Storage) Kernel init phase. (Problems with the motherboard are checked. It searches   for bootlist and boot image is read into memory and system initialization starts.)

2.       Base device configuration phase.   ( All the devices are configured with cfgmgr )

3.       System Boot phase.(all the lv's are varied on ,paging is started and inittab is processed)

RS6000 uses sound  and graphics to show different phases of the boot process. As soon as you power on the system, an audio beep is produced when the processor is found to be active, the PowerPC logo is shown (or text is presented) when the system memory checking is completed, and device logos are shown for all devices that have a valid address. At the end of the device logo display, if the system ROS is not damaged, an audio beep is again produced.


To clear the boot record 
# mkboot -c  -d /dev/hdisk