This question may have occurred to you that What is the difference between Local disk C-D-E ? generally there is no difference. but lets start with this question: What is Partition? Many drives have a pre-configured partition; But all storage devices are free as an unallocated space when they have no partitions. To set up a file system and store any file in a drive, it must be partitioned. This partition can contain all or only part of the storage space on the drive. You must first create at least one separate section with a file system. This separate partition is called a partition. You can have a partition that contains all the storage space on the drive or you can divide the available space into 20 different partitions. In both cases there must be at least one partition on the drive. After creating a partition, that partition is formatted with a file system such as the NTFS file system on Windows drives, the FAT32 file system on portable drives, the HFS + file system on Mac computer...