Disk partition
Also known as: partition, disk partitioning, drive partition, volume
A partition is a section of a physical drive that the operating system treats as a separate logical drive, each with its own file system. Partitioning lets one disk hold, for example, a system volume and a data volume, or two operating systems, while staying a single piece of hardware.
- A logical section of one physical drive
- Each partition has its own file system
- Partitioning splits space; it does not add it
How partitions divide a drive
A single physical disk can be split into one or more partitions, each formatted with its own file system and shown as a separate drive — like the `C:` and a recovery partition on Windows, or the system and data volumes on a Mac. The partition table records where each one lives.
Partitions let you keep the operating system, personal files, or a second OS apart so a problem in one does not touch the others. They do not add capacity — they only carve up the space the drive already has.
Partitions and free space
Because each partition has a fixed size, one can fill up while another still has room, and the system will report "disk full" for that volume even though the drive overall has space. Resizing partitions reclaims that room but is a careful operation best done with a backup first.
On Windows you manage partitions in Disk Management; on macOS, in Disk Utility, where APFS containers can also share space flexibly across volumes.