What is basic disk?

The disk, which uses Partition Table to manage its partition, is called to Basic Disk. One Basic Disk contains both primary partitions and extended partition, and many logical partitions are contained in extended partition. Click Start Menu -> Run and enter "diskmgmt.msc" please, and then the following graph can let us more clear realize the relationship about Basic Disk, Primary Partition, Logical Partition and Extended Partition.

We can see the Disk 0 is a Basic Disk, which contain the three partitions (E: G: and H:), in which, E: is the primary partition, but that G: and H: are the logical partition are contained in extended partition.

On Basic Disk, at most can have 4 the primary partition, and usually the best is 3. Windows do not allow create any partitions if you set up 4 primary partitions on basic disk, the graph is as follows:

The above graph show 4 the primary partition (K: L: N: and O:) on the Disk 2, but this disk have a free space with 79.97GB too. However, now we can not create any partitions on the Disk 2, because the "New Partition…" is a disabled state.

In 3 primary partitions situation, you can create an extended partition, and also you can set up any logical partitions in extended partition.

From the above graph to know, the Disk 2 contains three primary partitions and an extended partition with 80.98GB. Now, any logical partitions can be created in the extended partition. The menu item "New Logical Drive…" will help you fulfill the setting up of logical partitions.

Of course, you can only create logical partitions on basic disk, and do not create primary partition. All Windows support Basic Disk; Moreover, Basic Disk is supported by DOS and Linux, so basic disk is a prevalent way of the disk usage.