A Hard Disk (Hard Disk Drive) is your computer's main storage device. It is where you would normally keep your operating system, programs and files.

For more detailed information please see below.

Hard Disk continued...

A computer can have more than one hard drive. These additional drives can either be internal (inside the box) or external. For adding an extra hard drive, see our guide to adding an internal hard drive. We also have a guide to external hard disk drives, which is an easy way of adding storage space to your computer.

Hard disk drives contain platters (disk like objects) that rotate at speeds of 5400 rpm and above. There is a device called an actuator, which can be likened to an arm, which moves across the platters and reads or writes the information, through the use of READ/WRITE heads.

The gap between the READ/WRITE heads and the platter is typically a lot less than the thickness of a human hair. The platters are made from an aluminium substance, these devices are a lot more reliable now than they used to be, although they can break down mechanically if you drop them!

For more information on hard disk drives, see our hard drive basics guide

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