Disk partitioning

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. It depends on what you use, but for some simple examples: Windows partitions will use FAT32 (File Allocation Table), and for the main system partition use NTFS (New Technology File System). For MacOS systems, the primary system partition uses APFS (Apple File System). For Linux, the filesystems can vary, but on average you'd have a boot partition in FAT format, and either EXT4 or BTRFS for the main system partition.