Chapter 9: Partitioning Basic Disks

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When you install a new computer or update an existing computer, you’ll often need to partition the drives on the computer. DiskPart can use the Master Boot Record (MBR) or GUID Partition Table (GPT) partition style. When you use the MBR partition style, a drive can have up to four primary partitions or three primary partitions and one extended partition. When you use the GPT partition style on Windows XP Professional or Windows Server 2003, there are two required partitions (the EFI system partition and the Microsoft Reserved partition) and one or more optional OEM or data partitions for a total of as many as 128 partitions.

Obtaining Partition Information

When you work with DiskPart, you can obtain partition information on the selected disk using the LIST PARTITION command. As shown in the following example, LIST PARTITION lists information on all partitions of the selected disk. For example, if you typed select disk 2 and then type list partition, you would see a list of partitions on disk 2, such as

Partition ###          Type              Size              Offset
-------------          -----------      ---------          -------
Partition 1            Primary            706 MB             32 KB
Partition 2            Primary            706 MB            706 MB
Partition 3            Primary            706 MB           1412 MB
Partition 4            Extended          1004 MB           2118 MB
Partition 5            Logical            502 MB           2118 MB
Partition 6            Logical            502 MB           2620 MB

Note

In the example, note the asterisk at the beginning of the entry for partition 6. This means the partition is currently selected and has focus.

As you can see, LIST PARTITION shows

• Partition ### The number of the partition. You can use select partition N to work with the partition.

• Type The layout type. Partition layouts include primary, extended, and logical.

• The total storage size of the partition.

• Offset The byte offset of the partition, which is always rounded to the nearest cylinder boundary.

Note

A cylinder is a section of a drive within a partition. A cylinder is in turn apportioned into tracks; the tracks are apportioned into sectors; and finally the sectors are made up of individual data bytes. For example, a 4 GB drive could have 525 cylinders with 255 tracks per cylinder. Each track in turn could have 63 sectors and the sectors could have 512 bytes. Here, a cylinder is about 8 MB in size, so the byte offset of the partition would always be rounded to the nearest 8 MB.

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