What determines the maximum number of partitions on a physical drive in a partition table?

The maximum number of partitions on a physical drive in a partition table is determined by the design of the Master Boot Record (MBR). In the MBR partitioning scheme, the first sector of a storage device contains the partition table, which can accommodate a maximum of four primary partitions. This limitation arises because the MBR structure allocates a set number of entries in the partition table.

If more than four partitions are needed, one of these primary partitions can be formatted as an extended partition. This extended partition can then contain multiple logical partitions, but the primary partition limit remains at four. Hence, the design and structure of the MBR itself govern the maximum number of partitions that can be created on a physical drive.

Other factors, such as the file system type, operating system capabilities, and logical addressing limitations, do influence the management and usability of partitions but do not directly set the maximum number as determined by the MBR's design. Each of these elements plays a role in how partitions are used or formatted, but the fundamental limitation of four primary partitions stems from the specific architecture of the Master Boot Record.