How to change boot sequence in Mac OS X

[McGrawh]

I had installed Mac OS X on my system. The problem is that i had set an administrators password on my laptop and now i can re-collect that particular password. So, i would like to re-arrange the boot sequence and place a password on the boot sequence configuration settings. Can any body tell me that how can i change boot sequence in Mac OS X? Does any body knows about it? Kindly provide me the correct solution for the above issue. any kind of help on the above issue would be appreciated.

[Devasis]

According to my best of knowledge, you need to clear the CMOS on your system. That will allow you to supress the password on your system. After doing that, when you reboot your system it will not prompt for password option on your laptop.

[Solomon]

You need to activate BootROM firmware on your system. BootROM (which is part of the computer’s hardware) has two primary responsibilities. It will initializes the system hardware and it will automatically select an operating system to run. Once BootROM is finished and a Mac OS X partition has been selected, control passes to the BootX (PowerPC) or boot.efi (Intel) boot loader. The principal job of this boot loader is to load the kernel environment. As it does this, the boot loader draws the “booting” image on the screen.

BootX and boot.efi can be found in the /System/Library/CoreServices directory on the root partition. In addition, a copy of boot.efi can be found at /usr/standalone/i386/boot.efi. In "exotic” boot situations such as booting from a software RAID volume, a copy of the boot loader is stored on a separate HFS+ “helper” volume to get the system started. In some versions of Mac OS X, a copy of the kernel and mkext cache are also included on the helper volume. In these cases, the booter and other components on the root volume are unused.

Note:- Booting from a UFS volume is deprecated as of Mac OS X v10.5.

[MrChris-]

Here is the sequence of operations at Mac OS X startup.

1) Firstly you need to press power button on your system.
2) Then you need to run BootROM firmware on your system.
3) When BootROM (or the user) selects Mac OS X as the operating system in order to boot, control passes to the BootX booter (located in /System/Library/CoreServices).

Mac OS X uses a boot-time optimization (effectively a smart read-ahead) that monitors the pattern of incoming read requests to a block device (the boot disk), and sorts the pattern into a "playlist", which is used to cluster reads into a private cache. This "boot cache" is then used for satisfying incoming read requests, if possible. The scheme also measures the cache hit rate, and stores the request pattern into a "history list" for being adaptive in future. If the hit rate is too low, the caching is disabled. BootCache is started (via BootCacheControl) in /etc/rc, and a prefetch tag is inserted unless the system is booting in safe mode.

The loadable (sorted) read pattern is stored in /var/db/BootCache.playlist. Once this pattern is loaded, the cache comes into effect. The entire process is invisible from users.