partitionstabeller

Partitionstabeller is a data structure on a storage device that describes how the device’s space is divided into partitions. Each partition entry contains information such as the starting and ending sector (or logical block address), the size, a partition type, and flags such as a boot indicator. The partition table enables an operating system to locate and access the file systems stored on the device and to manage how the device’s space is allocated.

Historically, the Master Boot Record (MBR) was the predominant scheme on personal computers. An MBR consists of a 512-byte sector at the beginning of the disk that contains a small boot program and a partition table with up to four primary partitions. One of these can be an extended partition, which can house additional logical partitions; this arrangement supports large disks but imposes limits on the number of partitions.

Modern systems increasingly use the GUID Partition Table (GPT), defined by the UEFI standard. GPT stores partition entries in a dedicated region near the start of the disk, and it includes a primary header and a secondary, backup header for redundancy. Each partition has a globally unique identifier (GUID), a type GUID, starting and ending LBAs, and a textual name. GPT supports many partitions and provides integrity checks via checksums, plus protective measures against damage from non‑GPT-aware tools.

Other formats, such as BSD disklabels or Apple Partition Map, remain in use in some environments or on older hardware.

Editing a partition table is potentially destructive and can lead to data loss if mishandled; common tools include fdisk, gdisk, parted, and diskutil. Proper backups and careful planning are essential when resizing, creating, or deleting partitions.