Introduction

1. Laptop hard drives utilize electromagnetic energy and parts engineered to micro-fine accuracy to store gigabytes of data and remember it with near instant speed. As computer science has advanced by leaps and bounds in recent years, technology involved making a hard drive work is almost same as it was when storage medium was first utilized in late 1950s. What has modified is how much data can be stored and how quickly it can be retrieved.

Physical Structure of a Hard Drive

2. A hard drive is a set of platters covered with a magnetic iron alloy about three-millionths of an inch thick. The platters are stacked on a central spindle, with a tiny arm holding a two-sided read-write head between every platter. Information that can be stored on hard drive is decided by number of platters and particular alloy covering. A solid-state circuit board controls actions of hard drive like rotation speed and place of heads. The device is held in an almost airtight container that is strong sufficient to keep drive from damage.

As hard drive utilizes electromagnetic energy traveling at speed of light, manipulating or reading data occurs about immediately. The speed of hard drive is only restricted by how fast mechanical parts can move. In many hard drives platters spin at speeds around 15,000 rpm.

Data Storage and Retrieval

3. A laptop PC saves data on a hard drive platter by manipulating magnetic alloy on its surface. Before any information is saved, microscopic iron particles are in a disorganized state. Through interaction of software and hardware, the hard disk controller moves the read-write head into position, where it hovers so close to platter that a smoke element cannot pass between them. This head is an electromagnet, with coils of wire wrapped around a horseshoe-shaped part of metal. When current flows through wire, a magnetic field is made, arranging iron elements into rows radiating out from center of platter. Two radial rows make basic storage unit of PC a bit. The direction of current through electromagnetic head decides which pole of iron elements in rows faces each other and so whether two rows represents a "1" or "0" binary digit.

The procedure is reversed when heads are asked to read in data stored on drive. The head passes through magnetic field produced by iron elements, which causes an electrical current to flow through wires wrapped around horseshoe. The processor changes direction of current from north to south or from south to north into a binary digit. The binary digits are arranged into clusters in a pie-shaped region of platter known as a sector. PC operates data by tracking what bit is placed in which cluster in a sector, much like a document is placed in a file folder in a filing cabinet.