A disk is further divided by sectors. To understand what a sector is, picture the spokes on a bicycle wheel radiating from the center of the wheel to the tire. The space between one spoke and the next is like a sector on a diskette. (See the figure below.) Each track on a 1.2MB diskette has 15 sectors, and each sector holds 512 bytes.
Figure
Your computer uses the read/write heads in a disk drive to store and retrieve data on a disk. There is one head above the diskette and one below, so the drive can write to both sides of the diskette. To write to a disk, the computer spins it in the drive to a position where one of the read/write heads can access the diskette through the read/write slot. The read/write slot on a diskette exposes the diskette’s magnetic surface so the read/write head can write on the appropriate area.
Because data is stored magnetically, you can retrieve it, record over it, and erase it — just as you play, record, and erase music on a cassette tape.
Using Your Computer