Use of Electromagnets in Hard Drives

Hard drives store data using electromagnets. Unlike a permanent magnet the power of an electromagnet can be adjusted with differences in the electrical current that runs through it. The hard drive has rapidly rotating stiff disks with magnetic workings that can store small binary pieces of information called bits. When the magnet is on it stores information that stays stored or magnetized even when the power is turned off. A small magnetic device called a read-write head moves back and forth over the disk to record or save data. The read-write device is moved by an activator. Platters move thousands of revolutions per minute and they can be read by read-write devices on either side. There can be multiple platters in a computer.