Have roommates or going to be working with your PowerBook in the library? There are several reasons why you might want to disable the startup chime that notifies you when your Mac comes to life. There are two methods to solve this situation. The easiest being holding F3 (Mute on Mac hardware) when booting as described over at MacOSXHints.com. However, this may not work under the latest version of Tiger. The most widely used solution installs and uses a preference pane in the System Preferences. You can download StartupSound.prefPane from Arcana Research. Installation is as simple as extracting and running the pkg file. Once that's done, go to System Preferences and click on Startup Sound on the bottom. You can adjust the slider as you wish.