The boot process on a Mac is a magical process, all you see is a grey screen with the magic happening in the background. Did you know that very are various keys which you can use to change how you Mac boots and access certain settings. They are not for every day use, mostly troubleshooting. They are worth knowing if anything goes wrong.
There are a variety of keys which you can use. These have been found by searching the Internet on Apple’s website as well as other peoples sites. I have not tested every single command because I haven’t had time. Although I would take them in good faith.
During boot if you press:
C You start from a bootable CD such as your install DVD in the drive.
D Perform an Apple Hard ware test if you have your install DVD in the drive.
N Boot from a network compatible server. Only useful if you have the server.
T Start up in Target Disk mode. You can usually connect to another Mac through Firewire and do lots of funky things. Gone out of fashion and not used as much.
Option Start up using the Start Up Manager. Here you can pick which drive you want to boot from. Known to people who use BootCamp. You can also boot from a CD which is the same as press C.
Option then N Similar to the item above, except you get given the choice of booting from a network disk.
Option + N Boot from the first network boot image.
Command + V Boot up in Verbose mode, where you see lots of text whizzing by which is not a lot of use to you. I have written about this command here. It will also show Verbose output on shut down.
Command + S Single User Mode. This is where you can run a lot of high level tasks as a single user. Probably not for newbies. You could probably break your computer very quickly in Single User mode. More about it here.
Shift Start up in safe mode. Very useful if you have a problem and need an environment where you don’t want unnecessary things loaded. A good bet if you get Kernel panics during boot.
Option + Command + P + R Reset NVRAM. Although you will probably never need to reset this RAM it contents some useful stuff that can become corrupted. If you are having really bad problems this may be a good lead to follow. More information on Apple’s website.
Hold Eject or F12 or Mouse Eject anything that is in the disk drive. One to follow on from yesterdays topic.
I think that is just about it. I couldn’t find any more that worked with Mac OS X. If you have any more please leave a comment below. Its useful to have a list in case you ever need to use them.