BLV and Its contents

BLV stands for Boot Logical Volume (hd5). When an AIX system is powered on, system firmware will check the bootlist to find out the device from where the system has to boot up. Here bootlist is a part of system firmware. Once the boot device is found out from bootlist, system firmware will load the first 512 bytes of the boot device which will have the information about the BLV. This first 512 block is known as boot strap image. Boot strap code will locate the BLV from the boot device and the same will be loaded to the primary memory.

Below are the contents of the BLV:

1. AIX Kernel: AIX kernel is the core of AIX OS which will do the functions like process management, memory management, device management etc. There will be copy of AIX kernel under hd4 with name of the file as /unix, it will always be loaded from the BLV (hd5). This copy of the kernel will be used for rebuilding the kernel in BLV

2. Boot Commands: There will be many programs which will be called during the boot process. Those are known as boot commands. The commands bootinfo, cfgmgr etc are some examples.


3. Reduced ODM: In order to activate the rootvg, we should have many devices to be activated. Corresponding devices’ ODM files should be available in BLV.

4. rc.boot: Once the kernel is started, rc.boot scripts will be controlling the entire boot process. The same will be stored in BLV. The rc.boot scripts are rc.boot1, rc.boot2 and rc.boot3.