What Is Hard Disk Drive?

Hard Disk Drive or in short, HDD, is an storage device which keeps digital data on fast revolving platters with magnetic exterior. The word ‘drive’ refers to a mechanism that is a totally independent part of the media similar to a tape drive or floppy disk drive.

Hard Disk Parts

A HDD consists of a spindle, read/write heads, motor, platters, air filter, frame, actuator and electronics. The frame supports the mechanical parts of the mechanism and is sealed with a cover. The sealed part of the mechanism is called the HAD (Hard Disk Assembly). This drive electronics usually has one or more printed circuit supported on the underneath of the HDA.

How Do Hard Disks Read/Write?

To write data, a magnetic force is exerted on the platters. The platters themselves aren’t magnetic; however, there is a layer of magnetic material on the platter. The magnetic material is arranged, and the arrangement will be read as the read-write head as data.

To enable the read-write head to access the data and read it, the platters are spun at high speeds so that the head will float at a very small height above the platters. If this distance is compromised, the head will “crash” onto the platters.

An actuator arm moves the head across the platters, and a motor drive moves the platters. These precision mechanisms are protected from dust and other undesirable influences by a sealed enclosure.