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Random Access Memory (RAM)

                  RAM is a temporary memory. The information stored in this
                  memory is lost when the computer is turned off. That’s why it is also
                  called volatile memory. It temporarily stores data and instructions

                  given by the user and also the results produced by the computer.
                  Types of RAM:                                                                         RAM

                  1.   Dynamic RAM (DRAM): It requires continuous power to refresh the data stored in it.
                  2.   Static RAM (SRAM): It also requires constant power to hold on to data, but unlike
                     DRAM, it does not need to be continually refreshed.

                      However, SRAM is significantly faster and uses less power than DRAM.
                                            Read Only Memory (ROM)

                                            Information stored in ROM is permanent in nature, i.e., it holds

                                            the data even if the system is switched off. It holds the startup
                                            instructions that are required to start a computer. It is also called
                    ROM
                                            non-volatile memory.

                  Secondary Memory

                  Secondary memory is permanent in nature and is not directly accessed by the CPU. It
                  allows users to store data that may be easily retrieved. It is cheaper as compared to primary
                  memory.

                  Secondary  memory devices are  also called  secondary storage devices. They are
                  categorised into three types: Magnetic disk, Optical disc and Flash drive.

                                                 Secondary Storage Devices



                         Magnetic Disk                    Optical Disc                    Flash Drive




                            Hard Disk           CD     DVD       Blu-ray Disc      Pen Drive     Memory Card
                  Magnetic Disk


                  A device, covered with a magnetic coating is called a magnetic disk. You can record and
                  erase data on a magnetic disk any number of times.

                  Hard Disk
                  The hard disk consists of one or more magnetic disks stacked
                  together. Each disk has top and bottom surfaces where data is

                  recorded using magnetic head. It is permanently fixed in the
                  system unit. The most important function of the hard disk is to
                                                                                                     Hard disk
                  store program files and data files.



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