Why we can create only 4 Primary Partitions in HDD?

Question: I would like to install CentOS alongside Windows 8 on my HP Laptop, but I noticed that this model has already four partitions. I would like to create one more primary partitions but unable to create. Since I am not an expert with partitions and always get confused while partitioning HDD.

Answer : Lot of users confused while partitioning HDD, but here I will explain why you can create only 4 primary partitions in Hard Drive. There is a limit on the number of primary partition on HDD because of MBR (Master Boot Record). MBR has only 64 bytes to store the partition table and one partition’s information takes 16 bytes. So as per mathematical calculation 16/6=4 , here you will find 4 primary partitions are possible in HDD.

If you have created 4 primary partitions in your HDD and still you have some free space, it will become unusable. To overcome this limit, you will need to create an Extended Partitions in your HDD in which you can create Logical Partitions. Doing like this you can create more than 4 partitions in your HDD, So next time don’t get confused while partitioning your HDD.

Remember : Extended Partitions itself is a primary partition.

I hope this article will help to understand why we can create only 4 Primary Partitions in HDD. If having any issues or questions, please feel free to mention them in the comment box below.

Thanks:)