Setting Up Disk Drives, Partitions, and Volumes

Disk drives come in all shapes and sizes, from large and fast fixed internal devices, to externally connected FireWire drives, iPods, and even USBbased devices like the iPod shuffle, which can serve as a disk drive. Regardless of the connection method, all disk drives are formatted into software partitions called volumes. To ensure data is preserved and the file system is properly updated, mounted volumes on removable media must be ejected before the removable device is disconnected.

NOTE

All volumes in the Finder are mounted, whether they are shared network volumes or partitions on physical drives. Volumes on removable drives (FireWire disks or USB keychain drives) are unmounted using the File > Eject command in the Finder or with the Unmount button in Disk Utility. If all volumes on a physical drive are not unmounted before the drive is disconnected, if the drive is abruptly disconnected, or if there is a power outage, the disk catalog on those volumes might be damaged, which could result in data loss.

Whether a physical disk drive is formatted as one or more partitions, or whether external drives are connected, all mounted volumes appear as separate drives in the Finder, as shown here.