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DVD (Digital Versatile Disc): A DVD is similar to a CD but with a larger storage
                                   capacity, holding up to 10 GB of data. It is commonly used for storing large files,
                                   including videos and audio.


                            Blu-ray Disc: A Blu-ray disc is an optical disc that stores large amounts of
                         data and plays high-definition videos. It holds up to 25 GB, much more
                         than a DVD, which holds about 4.7 GB. The key difference is Blu-ray's larger
                         storage capacity.
                                         Pen Drive

                                    A pen drive is a small, portable storage device that uses flash memory and has
                                    a USB connector. It easily connects to any computer or device with a USB port
                                    and can be carried in a pocket or on a keychain. Pen drives come in various
                  sizes, from a few megabytes to over 1 terabyte.
                       Memory Card: A memory card, also called a multimedia memory card, is a
                     tiny storage device, usually 1 to 1.5 inches in size. It is used in mobile phones
                     and digital cameras. A card reader is required to access the data stored on it.

                  Measuring Unit for Memory

                  The basic unit for measuring the memory of a computer is byte. A byte consists of a group of
                  eight bits, for example, 10001011, i.e., 1 byte equals 8 bits. A group of 4 bits is known as a nibble
                  (half a byte), for example, 1001 i.e., 1 nibble equals 4 bits or 10101011 is 2 nibbles equal to 1 Byte.
                  To represent huge data, we have different units to measure, as listed below:


                                                    8 bits        1 Byte
                                                    1024 Bytes    1 KiloByte(KB)
                                                    1024 KB       1 MegaByte(MB)

                                                    1024 MB       1 GigaByte(GB)
                                                    1024 GB       1 TeraByte(TB)
                                                    1024 TB       1 PetaByte(PB)

                                                    1024 PB       1 ExaByte(EB)
                                                    1024 EB       1 ZettaByte(ZB)

                  Software

                  It is a set of instructions given to a computer to perform tasks. For example, in a mobile phone,
                  the device is the hardware, and the apps installed are the software. Computer software is broadly
                  classified as system software and application software.
                  System Software

                  System  software  controls the functions of a computer,  acting  as an intermediary  between
                  hardware and user applications.





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