Disk partitioning is about making a physical or logical hard disk usable by the operating system. Each disk partition can be used like a hard disk by the operating system. A hard disk can be divided into many partitions. This is especially useful for:
- Keeping the user data independent of the operating system. There will be one partition with the operating system on it, and one with the user data. Also if there is a problem with one file system, this does usually not affect the other file systems.
- Some operating systems (those that are made like UNIX or Linux) use disk partitions for virtual memory
- Using a boot loader it is possible to run many operating systems on the same computer. This is known as multi-booting.
- Increasing security: Certain operating systems allow to limit the access to a file system (for example: read-only, do not allow executable files, do not allow system files)
Usually each partition contains exactly one file system.