What is a Hard Drive and How it Works

Posted by Tushar Bedekar

What is a Hard Drive:-

Inside a hard rive
Almost all desktop computers as well as laptops have a hard drive inside them, but do you really know what they are? Many people when they hear the word hard drive, think that it refers to the computer as a whole. In reality, though, the hard drive is just one of many different pieces that comprise a computer. The hard drive is one of the most important parts of your computer because it is used as a long-term storage space for your data. What that means, is regardless of whether or not the computer is on, or you lose power, the data will still stay stored on this hard drive keeping it safe. 
A hard drive is an integral part of your computer as your operating system and all your data are typically stored there. In the majority of the situations, if you did not have a working hard drive, or the hard drive malfunctions, you would not be able to boot your computer into the operating system and would get an error. 

How hard drives work:

The very interesting thing is that every one wants to know that how the Hard Drive works and how the data gets stored permanently for a long time even if the power is off.

A hard drive consists of the following:

    hard drive
  • Magnetic platters - Platters are the round plates in the image above. Each platter holds a certain amount of information, so a drive with a lot of storage will have more platters than one with less storage. When information is stored and retrieved from the platters it is done so in concentric circles, called tracks, which are further broken down into segments called sectors.
  • Arm - The arm is the piece sticking out over the platters. The arms will contain read and write heads which are used to read and store the magnetic information onto the platters. Each platter will have its own arm which is used to read and write data off of it.
  • Motor - The motor is used to spin the platters from 4,500 to 15,000 rotations per minute (RPM). The faster the RPM of a drive, the better performance you will achieve from it.
When a the computer wants to retrieve data off of the hard drive, the motor will spin up the platters and the arm will move itself to the appropriate position above the platter where the data is stored. The heads on the arm will detect the magnetic bits on the platters and convert them into the appropriate data that can be used by the computer.Actually these magnetic Bits are also refers to as a magnetic domains which gets align themselves according to the binary zeroes and ones. 
Conversely, when data is sent to the drive, the heads will this time, send magnetic pulses at the platters changing the magnetic properties of the platter, and thus storing your information.
It is important to note, that since the data stored on your hard drive is magnetic, that why the people are supposed to warn that don`t take the magnet near the Hard drive because it may affect the magnetic Data Stored on the Hard Drive. 

Hard Drive Interfaces:-

Hard Drive
A hard drive connects to your computer through a specific type of interface. The interface on your hard drive must match the corresponding interface on your motherboard. If you purchase a new hard drive that has a interface which doesn't matches with the interface of the Mother Board Installed on your Computer, then it will not work in your computer. Basically there are three interfaces that have become the standard for connecting your hard to your computer. Some information about each of these interfaces are below.
  • IDE or ATA - This is currently the most common interface used but is quickly becoming overcome by the newer SATA interface. Hard drives using this type of interface have speeds up to 100 Mbps.
  • SATA - A newer interface that uses less bulky cables and has speeds starting at 150 Mbps for SATA and 300 Mbps for SATA II. Almost all computer manufacturers have started using SATA drives.
  • SCSI - This type of interface is typically used in a business environment for servers. Hard Drives designed for a SCSI interface tend to have a faster RPM which therefore provides better performance.


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