The floppy disk is a thin circular piece of mylar plastic that is coated with metal oxide. This metal oxide is also used on VCR and cassette tapes. This plastic is sandwiched between paper liners>, which are two pieces of paper that keep the mylar plastic clean. All of this is encased in an outer shell.

In a 5 1/4" floppy disk, the outer shell is a soft plastic. The read/write slot is exposed. There is a hole in the center of the disk is which the floppy drive uses to latch onto the floppy disk. As you slide the disk into the floppy drive, in the lower left-hand corner is the write protect notch.

The write protect notch, when activated, prevents your PC from writing to you floppy disk. A VCR tape has a similar device. When you punch the small tab out in the back of the tape you can no longer record on the tape. The write protect notch provides the same type of protection on the floppy disk.

In a 3 1/2" floppy disk, the outer shell is a hard plastic. The shutter which only slides open when the floppy disk is in the floppy drive protects the read/write slot. As you slide the floppy disk into the floppy drive, in the lower left-hand corner is the write protect notch.

The floppy disk is divided up into tracks, sectors, and clusters. A track is a narrow band which forms a full circle on the floppy disk. A sector is a pie-shaped wedge of the floppy disk. A cluster is 2-8 sectors in a track, and is the smallest unit of storage on a floppy disk. Cluster size is determined by the operating system.

When storing a file, the operating system breaks up the file into parts so it will fit into individual clusters. It also stores the location of the file in the FAT or table of contents of the disk.