3.5. Extended MBR partitions
To create additional partitions, if needed, set the type to extended. An extended partition is similar to a disk drive. It has its own partition table, which points to one or more logical partitions, contained entirely within the extended partition.
The following diagram shows a disk drive with two primary partitions, and one extended partition containing two logical partitions, along with some unpartitioned free space.
그림 3.4. Disk with both two primary and an extended MBR partitions
You can have only up to four primary or three primary partitions and one extended partition. There is no fixed limit to the number of logical partitions. As a limit in Linux to access partitions, a single disk drive allows maximum 60 partitions.