Hard Disk Partition In Windows 7 ((hot)) 〈HOT ◆〉
A partition is essentially a logical division of a physical hard drive. To the operating system, a partition looks like a separate drive (e.g., Drive C:, Drive D:), even if they reside on the same physical hardware.
You can perform maintenance tasks like defragmentation on specific drives, which is faster than scanning a single massive volume. How to Partition Using Windows 7 Disk Management hard disk partition in windows 7