Zip Disk - They look like a floppy disk, but they are a little thicker. This disk also comes in a variety of colors and holds about 200 MB of data.
Floppy Disk - They are plastic square disks, usually with a silver or black sliding piece going across the top. These disks come in a variety of colors and they hold about 144 million bytes. (Bytes are characters, symbols and letters).
Smart Cards - These are the size of an ATM card. When inserted into a smart card reader, they can read and update data for you.
Micro Drive - This is a square disk that has 1 GB of space and is used with digital cameras and handheld computers.
Memory Stick - This is a rectangular shaped disk that is used mostly with digital cameras and notebook computers. They hold approximately 128 MB as well.