Every computer in the world, be it a supercomputer, desktop computer or server, contains a hard disk drive. Some mainframe supercomputers even have multiple hard disk drives to meet higher computing requirements.
Hard disk is one of the major, and normally the largest, data storage devices found in computers. It stores a number of software utilities, operating system components, media files, important documents, certificates and anything else that comes in digital format. HDDs are the essential parts of our desktop computers, and thus it is worth to have good knowledge about them.
What are these hard disks or hard drives? Why are they so important for computers? The following post sums up good information about HDDs, their functions and importance in the computing world.
Hard Disks Explained – How they actually work?
Hard Disk Drive (HDD) stores digital information in the relatively permanent form. It is a widely used data storage device in which you can store and retrieve digital data using the fast rotating discs (platters) that are coated with magnetic material. In simple words, it gives your computer an ability to store your data and hoard the things for a long time.
They were firstly introduced in 1950s, as the large disks of about 20 inches diameter with capacity to hold just few MBs. Earlier, they were called as “Winchesters” or “fixed disks”, but later they became the “Hard Disks”, in order to differentiate them from the floppy discs.
At a simplest level, hard drive can be considered as a cassette tape, because both these data storages use the same kind of magnetic recording technique. However, instead of the flexible film of floppies and tapes, the hard disk contains a solid hard platter which embraces magnetic medium.
How Information Is Stores and Retrieved From Hard Disk?
Data stored in the HDD is interpreted by hard disk controller. It tells hard disk how to move and what to do with data bytes stored in the drive. If the OS needs to write or read data, the controller first examines the FAT (File Allocation Table) to find out available areas and location of saved data.
After finding the exact locations, it signals actuator to align R/W (read/write) head and move R/W arm. Since files are spread all over the platter, R/W head should move to diverse locations in order to access the information.
The data storage is done magnetically. If computer wants to read the data from hard disk, it reads the magnetic properties of that location on platter.
Internal and External Hard Disks
While most of the hard disks are internal drives, you can also use the external HDDs in order to take data backup or expand the storage capacity of your computer. These external drives are usually fitted in the HDD case (enclosure).
In addition to providing extra protection to the hard drive, the HDD case allows you connect your PC over eSATA or USB. Some newest external HDDs are quite compact and flexible to make your data storage much easier. You can simply connect your external hard drive to any computer or laptop to transfer data to/from the hard disk.