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The main storage is divided into a number of storage locations that can be accessed by a unique number
                 or address, known as memory address. Within the CPU, there are high speed, special purpose memory
                 units called registers.
                 The control unit and the internal storage are linked together by the sets of parallel electrical conducting
                 lines called Buses. The buses that carry data are called Data Buses. To retrieve data from the memory, it is
                 necessary to identify the address of data in the main memory. The address is identified by (the memory)
                 Address Buses. The buses that carry control signals are called Control Buses.

                 Output Devices
                 Output is the information obtained after the processing of data. The user receives the result through
                 output devices. Output can be in the form of soft copy or hard copy. Soft copy refers to the digital copy
                 that lies in the storage device whereas hard copy refers to the printed contents on a paper or film. Some
                 common output devices are:

                      Printer                                   Plotter
                 l                                         l
                      Monitor                              l  Speaker
                 l
                 Printer

                 Printer is a common output device that is used for the purpose of printing documents. Printer generates
                 a hard copy of data or information.

                 Printers are of different types depending upon:
                 l    Quality of Printing: The quality of output produced by the printer can be measured in units of dpi
                      (dots per inch) which is also termed as resolution.

                 l    Speed: The speed of different types of printer varies widely. The speed of a printer is measured in
                      cps (characters per second), ppm (pages per minute) or lpm (line per minute).
                 l    Printing Mechanism: There are different types of mechanism that are applied in different types
                      of printers. Some printers print by striking the printer head on the paper, some print by forming
                      images on the paper, some print by spraying of ink, etc.

                 Based on the mechanism, printer can be broadly classified into two categories:

                      Impact Printer                       l    Non-Impact Printer
                 l

                                                               PRINTER





                                       IMPACT                                         NON-IMPACT




                         Line Printer         Character Printer           Ink-Jet Printer         Laser Printer










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