Hard Disk Partitioning …

Here I want to share a basic concept regarding hard disk partitioning and its layout. A hard disk can have at most four partitions which we all refer as “Primary Partition”.

Primary 1

Primary 2

Primary 3

Primary 4

But in real we may have more than four partitions in our laptops or PCs. Then how is it possible? Here comes the concept of “Extended Partition”. You can make any one of the four partitions as an extended partition and then repartition it according to your needs. These partitions are which we refer as “Logical Partition”.



Logical 1

Logical 2

Logical 3

Logical 4

In Linux, hard disks are identified as

/dev/hda    (where a stands for the 1st hard disk)


/dev/sda     (in recent linux systems sda is used instead of hda)

Now, sda1, sda2, sda3, sda4 are reserved for four primary partitions and logical partitions start with sda5 onwards. According to above layout, partition numbering in Linux should be

     /dev/sda1               Primary
     /dev/sda2               Primary
     /dev/sda3               Extended
/dev/sda5          Logical
/dev/sda6          Logical
/dev/sda7          Logical
/dev/sda8          Logical

Note that sda4 is not used as it is reserved.


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