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1.3.4 Speakers/HeadPhones

        A speaker or a headphone generates sound as output. A computer typically requires specialised hardware (a sound
        card) to provide output in the form of sound.






                                                          Monitor


                                      Speaker                                Headphone
                                                      Output Devices








                                          Plotter                        Printer
                                                   Fig 1.5: Output Devices




               A 3D printer allows for making a three-dimensional solid object from a digital file.




        1.4 Memory Unit

        A computer system's memory unit (also called a storage unit) is used to store data and instructions.

        1.4.1 Units of Memory

        The data is stored and processed in a computer using binary digits, often abbreviated as bits: 0 and 1. Thus a bit is the
        basic unit of memory. Bits are grouped to form larger units of information. For example, a sequence of four bits forms
                                                                    4
        a nibble. As each bit in a nibble can be 0 or 1, four bits lead to 16 (=2 ) different nibbles: 0000, 0001, 0010, 0011, 0100,
        0101, 0110, 0111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111. Thus, a nibble can express a number between 0
                                                                                                               8
        and 15. A sequence of eight bits forms a byte. Again, as each bit in a byte can be 0 or 1, a byte can express 256 (=2 )
        different sequences. Thus, a byte is used to express a number between 0 and 255. The bytes can be further grouped
        to form bigger units of memory. Table 1.1 shows different units of memory.

                                         1 Bit              =            Binary Digit
                                         8 Bits             =              1 Byte
                                      1024 Bytes            =           1KB [Kilobyte]
                                       1024 KB              =         1MB [Megabyte]
                                       1024 MB              =          1GB [Gigabyte]
                                       1024 GB              =          1TB [Terabyte]
                                       1024 TB              =          1PB [Petabyte]
                                       1024 PB              =           1EB [Exabyte]
                                       1024 EB              =          1ZB [Zettabyte]
                                       1024 ZB              =          1YB [Yottabyte]
                                       1024 YB              =           1 Brontobyte
                                   1024 Brontobyte          =            1 Geopbyte
                                                 Table 1.1: Units of Memory
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