In section 25.1.2. Partitions: Turning One Drive Into Many, there is the following statement:
The partition table is divided into four sections or four primary partitions. A primary partition is a partition on a hard drive that can contain only one logical drive (or section). Each section can hold the information necessary to define a single partition, meaning that the partition table can define no more than four partitions.
I don't understand why there can only ever be four partitions. Is this just the way it was designed in the beginning? Can there really only ever be 4 primary partitions?