Nowadays, the hard disks sold on the market are usually more than 100GBs. Even though you have larger hard disk, but have you wonder why the maximum you could only have 4 primary partitions?

The reason is because in the first 512 bytes is reserved for the Master Boot Record (MBR). It stores the information of the partitions, but 512 bytes is only allows 4 primary partitions. So, if you have more partitions to create, then you need to create extended partition. And within the extended partition, you can have any number of logical partitions.