why hard disk is important in a PC,s? write the two major components of it.

why hard disk is important in a PC,s? write the two major components of it.

HARD DISK:                          hard disk is the most important storage device in personal computer. it is a random access device, which... 01:33

HARD DISK:
                         hard disk is the most important storage device in personal computer. it is a random access device, which means data or information can be accessed or stored at any time and at any location on the hard disk.
hard disk is the biggest storage device in computer. its capacity is measured in gigabytes. other secondary storage devices are optional but hard disk is compulsory for a PC.
in internal structure of a hard disk, you can find the major components, disk platters and read/ write head.
1.   DISK PLATTERS:
                                    disk platter consists of circular metallic disks coated with a magnetic material on both sides of the hard disks. information or data is stored permanently on this magnetic material on the disk. the disks have smooth surfaces. when computer is turned on, these disk platters begin to rotate.
2.    READ/WRITE HEAD: 
                                           the read / write head moves along the radius of the disks for storing and retrieving the information or data on the disk.
USB FLASH DRIVE:
USB flash drive is the data storage device, which is small, light in weight, removable and rewrite-able. the drive offers more advantages over the other portable storage devices particularly the floppy disk.they are faster, hold more data and are more reliable due to their lack of moving parts. its is supported by all the recent operating system . it consists of a small circuit board and is enclosed in a metal or more often in a plastic casing. it is attached to the computer through USB port.
FLOPPY DISK:
                         the floppy disk was developed in 1987 by IBM . it has magnetic medium for storing data which is enclosed in the protective plastic casing. floppy disk have been found in the computers for several years and are still being used. the most common type which is used know a day is 3.5" floppy diskette. data is stored on the magnetic medium inside the plastic casing.