The so-called extended partitions, strictly speaking, it is not a meaningful partition, it is merely a pointer pointing to the next one partition, this pointer structure will form a one-way linked list. So that in the main boot sector in addition to the primary partition, it’s only need partition data known as the extended partition, through this extended partition can found the starting position of the next partition (in fact it is the next logical disk), from this starting position, it can found all partitions. Regardless of the system established how many logical disks, through the parameters of an extended partition can found each logical disk in the main boot sector.
Require special attention, because each partition after the primary partition is through a one-way linked list structure to achieve, therefore, if a one-way linked list occurs problem, it will result in the loss of logical disks.
