Unlike Windows OS's, the Linux swap is it's own partition - WinOS's have a swap file. For more information, see this article at Microsoft's Technet. Partitioning Partitioning refers to the making or assigning of drive space and letters on a hard drive. To gain access to larger drives, though this is less of a concern as OS's no longer have hard drive addressing problems. To organize important data, applications, or for simple storage.
Data storage is easier to keep things organized and possibly invoke security measures if needed.
Some applications have to be on their own partition so that there are no conflicts with other programs. To install another OS for booting. Windows OS's can be installed on the same partition, but it's not recommended as there are sharing complications that are known to arise between OS's, as well as a re-install of one OS could mean a complete overhaul of all OSs on a computer if they are on the same partition. Before partitioning your HD you'll want to be aware of the types of partitions Types of Partitions. The Primary and Extended partitions are the main disk divisions, as the Logical partition is a subset of the Extended partition.