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l    Pen/Flash Drive: It is small in size, handy and is a detachable device from which
                       data  can  be  read,  copied  or  transferred  from one  system to  another.  It  is
                       re-writable  and weighs  less  than 25 g.  Nowadays,  pen drives are the most
                       commonly used  external  storage  and  data  transferring  devices. It has an
                       attachment slot which can be easily inserted or attached into the computer’s
                       USB (Universal Serial Bus) port.

                                            Memory Stick: Memory Stick is a detachable flash memory card device that
                                       l
                                            was launched by Sony in 1998. The data stored in memory card can be read
                                            or written with a memory stick (typically a small box that connects via USB
                                            or some other serial connection).  Memory Stick supports memory card of
                                            different storage capacities and helps in faster transfer of data.

                    UNITS OF STORAGE

                  A computer understands only binary language. All the data and information that are fed into a
                  computer are converted into its own (machine) language. Its language consists of two digits, i.e., 0
                  and 1 which are known as ‘Binary Digits’. Each digit i.e. 0 or 1 is known as a ‘Bit’. A group of four (4)
                  bits is called a ‘Nibble’. A group of eight (8) bits is called a ‘Byte’. Conventionally,  byte is also known
                  as the word length of computer. Storage of data is measured in multiples of bytes. Different units of

                  storage of data are:


                                            No. of bits/bytes                   Equal to


                                     8 Bits                          1 Byte

                                     1024 Bytes (B)                  1 Kilobyte

                                     1024 Kilobytes (KB)             1 Megabyte


                                     1024 Megabytes (MB)             1 Gigabyte

                                     1024 Gigabytes (GB)             1 Terabyte


                                     1024 Terabytes (TB)             1 Petabyte

                                     1024 Petabytes (PB)             1 Exabyte

                                     1024 Exabytes (EB)              1 Zettabyte


                                     1024 Zettabytes (ZB)            1 Yottabyte

                                     1024 Yottabytes (YB)            1 Brontobyte

                                     1024 Brontobytes (BB)           1 Geopbyte








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