Once in fdisk, you'll be greeted with a prompt that looks like this:

Command (m for help): 

Type p to display your disk's current partition configuration:

Command (m for help): p

Disk /dev/hda: 240 heads, 63 sectors, 2184 cylinders
Units = cylinders of 15120 * 512 bytes

Device Boot    Start       End    Blocks   Id  System
/dev/hda1             1        14    105808+  83  Linux
/dev/hda2            15        49    264600   82  Linux swap
/dev/hda3            50        70    158760   83  Linux
/dev/hda4            71      2184  15981840    5  Extended
/dev/hda5            71       209   1050808+  83  Linux
/dev/hda6           210       348   1050808+  83  Linux
/dev/hda7           349       626   2101648+  83  Linux
/dev/hda8           627       904   2101648+  83  Linux
/dev/hda9           905      2184   9676768+  83  Linux

Command (m for help): 

This particular disk is configured to house seven Linux filesystems (listed as "Linux") as well as a swap partition (listed as "Linux swap"). Notice the name of the corresponding partition block devices on the left side, starting with /dev/hda1 and going up to /dev/hda9. In the early days of the PC, partitioning software only allowed a maximum of four partitions (called "primary" partitions). This was too limiting, so a workaround called an extended partitioning was created. An extended partition is very similar to a primary partition, and counts towards the primary partition limit of four. However, extended partitions can hold any number of so-called logical partitions inside them, providing an effective means of working around the four partition limit.