The Hard Disk Drive (HDD):   In your system it is the “Data centre” of the PC. It is here that all your programs and data stored between the occasions that you use the computer. Your hard disk is the most important of the various types of permanent storage used in PCs (the others being the floppy disk and CD-ROMs, tapes, removable drive, etc.) The hard disk differs from the other primarily in three ways: size (usually large), speed (usually faster)) and permanence (usually fixed in the PC and not removable)

            Hard disk drives are almost an amazing as microprocessors in terms the technology they use and how much progress they have made in terms the technology they used and how much progress they have made in terms of capacity, speed, and price in the last 20 Years. The First PC Hard disk of 10 MB and a cost of over Rs. 2,500 per MB. Modern hard disk have capacity approaching 1 TB and a cost of less than one rupee per MB! At the same time, the speed of the hard disk and its interface has increased dramatically as well.    

 

Monitor:

 It is also called as Video Display Unit. It accepts programming instructions a sometimes a monitor is also referred to as a video display terminal

Floppy Disk Drive : The invention of hard disk relegated floppy disks to the secondary roles of data transfer and software installation . The floppy disk still persists, mainly because of its universality: The 3.5 inch 1.44 MB floppy is present on virtually every PC made in the last 10 years, which makes it still a useful tool. The floppy disk’s current roles is in the following areas :

   Ø  Data Transfer

   Ø  Small File Storage and Backup

   Ø  Software Installation and Drivers Updates

CD Rom or DVD Rom: CDs and DVDs are a common thing now-a-days. You get movies in CD’s, games in DVDs and books in CDs. Many technical magazines and books now come with CD and DVD packaged in them. CDs have really revolutionized portable storage, not only in entertainment in them. But also in computer use.  

 Keyboard: This is attached to a micro computer or the terminal of a mini large computer. A keyboard is similar to the keyboard of a typewriter. It contains alphabets digits special characters and some control keys, When a key pressed, an electronic signals is produced which is detected by an electronic circuit called keyboard encoder. A Keyboard encoder may be special IC or single chip microcomputer used as encoder. The function of an encoder is to detect which key has been pressed and send a binary code.

Mouse : Mice (plural for ‘Mouse’) first broke onto the public stage with the introduction of the Apple Macintosh in 1984, and since then they have helped completely redefine the way we use computers1 Every day of your computing life, you reach out for your mouse whenever you want to move your cursor or activate something. Your mouse senses your motion and your clicks and sends them to the computer so that it can respond appropriately.