Server Administration & Management

Why we can create only up to 4 primary partitions

Actually in basic hard disk, we can create 4 partition(either primary or extended), we can create

  • 4 primary maximum or
  • 3 primary + 1 extended or
  • 2 primary + 1 extended or
  • 1 primary + 1 extended

not more then that? why and what is the reason?

The reason is because of a limitation of the MBR (Master Boot Record- the first sector of the hard disk.) The MBR is only 512bytes of size, it is needed to store the primary boot loader, and the partition table. Typically, the area reserved for partition table is only 64 bytes. And the partition table entry for one partition is 16 bytes. So, 16×4=64. The space is over. so we cant create more than this.

July 10, 2014 Posted by | Tips & Tricks, Unix/Linux | , , , | Leave a comment