How a Hard Drive Works

HARD DISK DRIVE
INTRODUCTION
A hard disk drive is a magnetic data storage usually found in computer systems. It is made up of spinning disks with heads that move over the disk and stores data in tracks and sectors. The head read and write data in concentric rings called tracks, which are divided into segments called sectors.
Hard disk drives usually have multiple disks, called platters, that are stacked on top of each other and spin in unison, each with two sides on which the drive stores data. Most drives have at least two or three platters resulting in four or six sides and some have up to 11 platters while spinning at 4,200, 5,400 or 7,200 RPM, although there are drives that spin faster.
In the lab, I opened up and examined a Seagate manufactured hard drive which spun at 4,500 RPM, had a 12.5mSec seek, up to 16.6mB/s transfer rate. It also had a 40 pin interface connector and a power connector.
This report is going to give a detailed description of how a hard drive operates and the coding systems used for writing data to the disk.

BODY
Tracks and Sectors A track is a single ring of data on one side of the disk. A disk track alone is too large to manage data efficiently as a single storage unit. They can store up to 100,000 bytes but this will be very inefficient for storing small files. To fix this problem, tracks are divided into several numbered divisions called sectors which represent slices of the track. A sector is normally the smallest individually-addressable unit of information stored on a hard disk, and normally holds 512 bytes of information
When a disk is formatted, the formatting program creates ID areas before and after each sector’s data that the disks controller uses for sector numbering and identifying the start and end of each sector. The sectors on a track are numbered starting with 1, unlike the heads or cylinders that are