How can not win xp create more than four primary partitions

[Xptreak]

My Question is why we can not able to create more than 4 primary partitions in windows XP

 

[treefrog07]

If you read up on HDD partitions, you will find that having more than 3 on an HDD can cause problems in any operating system. XP prefers not having more than 2 primary partitions on an HDD. I don't know why, just what I have read.