OS X comes with a variety of tools and utilities for managing your system (available in the /Applications/Utilities/ folder), including those for observing OS activity, network and disk activity, and also those for managing some aspects of the hardware in your system. One of the most commonly used utilities is Disk Utility, which allows you to create disk images, burn DVDs and CDs, as well as manage the partitions and formatting of your hard drives. Disk Utility comes both in the form of the Disk Utility application, but also as the “diskutil” terminal command.

Disk Utility showing hidden drive partitions.

The Disk Utility application is built to be relatively straightforward and allow you to see each device and add, resize, or remove user-accessible disk partitions as is needed for a particular drive. The diskutil command, on the other hand, is far more robust and can display and manage much more detail about a hard-drive device. For instance, if you enter the command “diskutil list” in the Terminal, the system will show you an output of each drive device along with all partitions that are on the device, which can be convenient for sizing up and checking out any hidden partitions. If you open Disk Utility, however, it will only show the user-accessible partitions and not all of those that are shown with the diskutil command.
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If you create a recovery disk using Lion Recovery Disk Assistant, Please make sure FileVault is off.

Unlike previous versions of the Mac OS, when you install OS X 10.7 Lion your system will be set up with a restore partition. This is a hidden 650MB partition that, like the previous installation DVDs for OS X, can be used to boot the system and provide tools to resintall OS X, format hard drives, and perform other maintenance and troubleshooting tasks on the system.

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