The Apple iPod can be converted into a portable storage device should the need arise. An iPod can even be used as a boot disk to start up a Macintosh computer. Depending on how the iPod was formatted, the file system format can be compatible with a Macintosh computer or a Windows computer (HFS+ and FAT32, respectively). It is possible to change the file system format on an iPod from HFS+ to FAT32 and back, but generally speaking the iPod\’s preferred file system format will be the same as the computer to which the iPod was initially connected to.
For PC users, an iPod can be mounted as a separate disk image, allowing files to be transferred between PCs with ease. Only media files can be copied using an iPod. Macintosh users can configure their iPods to act as portable data storage devices from their iTunes control panel. Mac users can only synchronize their iPods with iTunes one way: from iTunes to iPod. Windows and Mac users can transfer music files between computers by using the iPod as a portable disk image; essentially turning an iPod into a temporary USB flash drive. After the file transfer is completed, the iPod can be reconverted back into its normal capacity as a music player.