Hard disks are part of disk drives that store and provide quick access to large amounts of data on electromagnetically charged surfaces. They have large storage capacities, use metallic platters for storage, and are faster than floppy disks or CD-ROMs. Hard disks store programs, operating systems, and personal files, retaining data even when the computer is off. There are three types: digital versatile discs, external hard disks, and internal hard disks. However, hard disks can eventually fail and stop the computer from working, and head crashes can damage disks and cause data loss.

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Hard Disk

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Hard Disk Definition
 Hard disk is part of a unit, often called a "disk drive - hard drive
or hard disk drive”, which stores and provides relatively quick
access to large amounts of data on an electromagnetically
charged surface or set of surfaces.

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Hard Disk Features
 Large storage capacity
 Sensitive instruments
 Thick
 Cheap
 Metallic platters for storage
 Faster than floppy diskette and CD-ROM
 Store programs, operating systems, and personal files
 Data is conserving and doesn’t even we switch the computer off
 Usually fixed inside the computer so cannot get mislaid

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Hard disk types
There are three types of hard disks:
 Digital Versatile Discs
 External Hard Disks
 Internal Hard Disk

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Hard Disk Disadvantages
 Hard disks eventually fail, which stops the computer from
working.
 Regular 'head' crashes can damage the surface of the disk,
leading to loss of data in that sector. Head crash is a disaster.
 The disk is fixed inside the computer and cannot easily be
transferred to another computer.
Materials that Cause a Head Crash