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Secondary Memory

                 This memory is permanent in nature and is not
                 directly accessed by the CPU. It allows users                Just like a tree stores water
                 to store data that may be easily retrieved. It                 in its trunk, a computer
                                                                             stores information, like your
                 is cheaper as compared to primary memory.
                                                                               drawings and games in its
                 Secondary memory devices are also called
                                                                                     storage devices.
                 secondary storage devices. They are divided
                 in three categories: Magnetic Disks, Optical
                 Discs and Flash Drives.
                 Magnetic Disk


                 A magnetic disk is covered with a magnetic coating. You can record and erase data
                 on a magnetic disk any number of times.  The different types of magnetic disks are:

                 ✶  Hard Disk: It consists of one or more magnetic disks called
                    platters. It is permanently fixed in the CPU box. It comes
                    in a variety of sizes with storage capacities as high as 5 TB
                    (TeraByte) or even more.

                                                                                                      Hard disk
                 ✶  External Hard Disks are also available. They are the hard
                    disks that can be connected to any computer with the help of a USB port.
                 Optical Disc


                 An optical disc is an electronic data storage medium that can be written to and
                 read using a low powered laser beam.


                                                        ✶   Compact Disc (CD): The CD drive fitted in the
                                                            CPU box, reads information stored on a compact

                                                            disc (CD). CD is an external storage device. It
                                                            can hold upto 700 MB of data.  The different
                        CD                 DVD              types of CDs are CD-ROM, CD-RW and CD-R.


                 ✶   Digital Versatile or Video Disc (DVD): DVDs are now widely used to store data.
                    A DVD is similar to a CD. It’s storage capacity is 4.7 GB, much higher than a CD.

                 Flash Drive


                 The Flash Drive is a small portable data storage device.
                 ✶  Pen Drive: Pen drive is  a storage device which can store a

                    large amount of data. It is connected to a computer using a
                    USB (Universal Serial Bus) port. It can be carried in your pocket
                                                                                                       Pen drive
                    easily. Pen drive has storage capacity of upto 1 TB.


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