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Projector
                                       A projector  is a  display device  that  projects a  computer  screen  onto  a  flat
                                       surface: like whiteboard or wall. It is most commonly used for home theaters or
                                       in organisations for official presentations.

                 Projector


                 Computer Memory

        Computer memory holds raw data before it goes for processing and after processing it contains information which
        can either be sent to output devices or stored in secondary storage devices for future use. There are two types of
        memory in the computer— primary memory and secondary memory.

        Primary Memory

        This type of memory is necessary for a computer to work. It is also called the Internal Memory. This is the actual
        place where the data is stored before it is taken to ALU for processing. Primary memory is of two types: RAM and
        ROM.


        RAM (Random Access Memory)
        It is temporary in nature. The computer holds information in this memory and gets it
        when needed. It remembers what you tell them and can even change to remember
        new information. It is volatile in nature, which means that data will be erased when
        the computer is turned off. That’s why you always save your work! RAM is considered
        “random  access” because  any  part  of it can  be  accessed randomly  for  reading  or   Random Access Memory
        writing of the data.


                                 ROM (Read Only Memory)
                                 It is permanent in nature. It is  non-volatile which means even after turning your
                                 computer off, the contents of ROM will remain. The information is coded at the time
                                 of manufacturing  the computer. The computer  needs this information for  its basic
                                 functions.
          Read Only Memory


        Secondary Memory
        Secondary Memory provides extra storage where the data can be stored permanently for later use. It is also known
        as external memory as it can be stored anywhere. Examples of secondary memory are compact disc, hard disc,
        flash drive, etc.



        Hard Disk
        A Hard Disk  stores and provides quick access to large amounts of data  on an
        electromagnetically charged surface or set of surfaces. Hard disks are generally fitted
        inside the system unit. However, there are external hard disks also available. A hard disk
        is made-up of a collection of disks called platters stacked on a cylindrical rod. Each of
        which,  like phonograph  records, has data  recorded  electromagnetically in concentric
        circles or “tracks” on the disk. The capacity of a hard disk varies from a few Gigabytes to
        a few hundred Terabytes.
                                                                                                  Hard Disk





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