A Macintosh computer can read data from, or write data to, a wide range of storage devices and media, including:
Hard disks—high capacity magnetic media.
CD and DVD discs—high capacity, removable optical media.
Flash drives—small, relatively high capacity USB devices that are commonly used to move files from one computer to another.
RAID devices—extremely high capacity magnetic storage devices, normally used in business environments for servers or backup.
Other legacy magnetic media, including floppy disks, or diskettes, and Zip disks.
To use storage media, it must be:
Mounted—inserted, attached, or otherwise accessible to your computer.
Formatted or initialized—specially prepared for use with your computer. ...