A hard disk is a storage device that contains one or more inflexible, circular platters that use magnetic particles to store data, instructions, and information. The system unit on most desktop and notebook computers contains at least one hard disk. The entire device is enclosed in an airtight, sealed case to protect it from contamination. A hard disk that is mounted inside the system unit sometimes is called a fixed disk because it is not portable
Characteristics
Characteristics of a hard disk include capacity, platters, read/write heads, cylinders, sectors and tracks, revolutions per minute, transfer rate, and access time.
Recording
Traditionally, hard disks stored data using longitudinal recording, which aligned the magnetic particles horizontally around the surface of the disk. With perpendicular recording, by contrast, hard disks align the magnetic particles vertically, or perpendicular to the disk’s surface, making much greater storage capacities possible. Experts estimate that hard disks using perpendicular recording provide storage capacities about 10 times greater than disks that use longitudinal recording.
How a Hard Disk Works?
Step 1: The circuit board controls the movement of the head actuator and a small motor Step 2: A small motor spins the platters while the computer is running. Step 3: When software requests a disk access, the read/write heads determine the current or new location of the data. Step 4: The head actuator positions the read/write head arms over the correct location on the platters to read or write data.