A hard disk or SSD can be divided into several pieces, like land. Each piece is a partition, and on Windows it usually appears with a letter such as C or D. Each partition has its own file system and can be formatted separately.

Why do we partition?#

  • Separating the operating system from personal data: if you reinstall Windows, only C is erased and the files on partition D stay safe.
  • Installing several operating systems side by side, such as Windows and Linux.
  • Better order in keeping and backing up files.

An example#

You split a one-terabyte disk in two: 250 gigabytes for Windows and programs, and the rest for photos and work. If Windows breaks and you reinstall it, your photos remain untouched.

Notes#

  • Partitioning does not replace backups; if the disk itself fails, all partitions are lost.
  • Resizing or deleting a partition without a backup is dangerous.
  • Two partition table styles are common: the older MBR and the newer GPT, which works with UEFI and larger disks.
  • Android phones also have partitions such as system, data and boot.

Common mistake#

Partition D is not necessarily a separate disk; it may be part of the same disk as C.