What is it?

Myth

How it works

Writing and reading to the "floppy" or the magnetic storage disk.

The 3.5 or 5.25 is a magnetic storage disk the computer can read and write to using a magnetic head located inside the floppy drive. It sends pulses of electricity through wires wrapped around the head creating a magnetic field causing the magnetic molecules to align. The alternative current sent through the wire, sends the molecules in the opposite direction. The data being written to the computer determines the alternative patterns. The patterns are also known as binary 1s and 0s, On’s and off's, North or South.

When you write to a disk, MS-DOS and other operating systems use the "File Allocation Table" (FAT). The computer writes to the disk and determines where a file is stored by telling the "Sector" or "Cluster" in which it is located. When reading from a disk the head reads the FAT to tell what to look up on the disk. The disk goes to the sector or cluster of the file and tells the disk to send pulses to the read write heads which translates it into binary.

When a disk is formatted, it is divided into parts (see images). One part is a pie shaped division called a grid. Another division is called tracks, resembling a sports track, that are created in a circular patern around the entire disk area. The areas created by the intersections of the grids and the tracks are called sectors. Two or more sectors make up a cluster. Each cluster contains about 256 bits. If the size of a file is 256 bits or less then the computer will use a whole cluster to store the file data.

Unformatted	A Sector	A Track	A Cluster

5.25 Inch Floppy Disk are not commonly found anymore. They are used by older computers 3.5 Inch Floppy Disk are the most commonly used disk. It is encased in a hard plastic square case that cannot be opened. Information is magnetically recorded onto this thin flexible round disk.

Floppy Capacity:

Floppies can be found in two storage capacities. They are high density disks and double-density disks. They must be formatted before they can be used to store information. By formatting the disk, it is then divided into tracks and sectors which organizes the disk for information storage and retrieval from the computer. Most disks now come formatted. If not, they need to go through a format process on your computer. Be sure and format them according to the labeled capacity of the disk.

• Double-Density Disks (720K capacity) store the least amount of information. They are still used, but not as common as the high density disks. It is referred to with the letters DD on the label. With only one hole at the top of the disk, it can store 720K of information.

• High-Density Disks (1.44K capacity) store the most information. Having two holes at the top of the disk, it can store 1.44 MB of information. It usually has the letters HD written on it. This is the most commonly used floppy disk.