A typical PC has either two IDE or SCSI controllers,Linux named the IDE as "hdd" and SCSI as "s" in place of "h" and each of these controllers can have two drives connected to it.thus 4 hard drives can be connected,a primary master named as (/dev/hda),a primary slave (/dev/hdb),Secondary master(/dev/hdc),secondary slave(/dev/hdd).
The partition scheme for PC hard disks allowed only four partitions.These partitions are called primary partitions. To work around this limitation and allow more than four partitions, a new partition type was created, the extended partition,these extended partition further sub-divided into logical partiton.
Linux numbers primary or extended partitions as 1 through 4,so dev/hda may have four primary partitions, /dev/hda1, /dev/hda2, /dev/hda3, and /dev/hda4.Or it may have a single primary partition /dev/hda1 and an extended partition /dev/hda2. If logical partitions are defined, they are numbered starting at 5, so the first logical partition on /dev/hda will be /dev/hda5,Although the theoretical maximum number of partitions on an IDE drive is now limited to 15 for kernels with hotplug
below example you can see Hard disk 1 and 2 are primary partition and 3rd is extended partition which start the number 5.
No comments:
Post a Comment