|Tip 322||Make Use of Boot-Time Options|
By holding down various key combinations before the Apple logo first appears when booting, you can do things such as boot from a CD/DVD or switch to your Microsoft Windows Boot Camp installation. Here’s a table of key combinations—you can release the key once booting is underway, and you see the boot progress indicator (the spinning circle beneath the Apple logo). Note that most of these shortcuts won’t work if you have FileVault enabled.
Switch between operating systems installed on your computer (that is, Mac or Windows) or access the rescue system. This also lets you choose to boot from an attached storage device, like a USB memory stick.
Boot into safe mode, in which your Mac starts with only strictly necessary kernel modules loaded and no start-up programs. This is ideal for repairing a damaged system that won’t boot any other way.
Boot from CD or DVD.
Network boot (usually useful only in corporate environments).
Boot in Target Disk Mode, in which case the operating system doesn’t load but the computer’s hard disk can be accessed from another computer via a FireWire connection.
Force Mac OS X to boot, even if the system can’t identify a Mac OS X hard disk (useful when things break).
Boot to recovery mode—allows you to check the disk, restore from a Time Machine backup, and reinstall OS X.
Boot to single-user mode of OS X (a command-line prompt, useful for making repairs).
Boot in verbose mode, showing boot-time messages rather than the Apple logo. This is useful for diagnosing boot problems.
Eject any inserted CD/DVD (holding the mouse button does the same thing).