Learn Windows XP Professional: Using the Disk Management Tool (Page 2) Page 2

There are two different types of disk storage in Windows 2000 and Windows XP Professional: basic disks and dynamic disks.

Basic Disks

The number of partitions you can create on a basic disk depends on the disk's partition style.

On master boot record (MBR) disks, you can create up to four primary partitions, or you can create up to three primary partitions and one extended partition. Within the extended partition, you can create an unlimited number of logical drives.

NOTES FROM THE FIELD] - You used to be limited in the number of logical drives that could be created on a system by the number of remaining drive letters that were available to assign to the formatted partitions. With volume mount points this is no longer the case.

On GUID partition table (GPT) disks, you can create up to 128 primary partitions. Because GPT disks do not limit you to four partitions, you do not need to create extended partitions or logical drives.

NOTES FROM THE FIELD] - The GUID partition table (GPT) disk-partitioning scheme is a format that is used by the Extensible Firmware Interface (EFI) in Itanium-based computers. GUID partition table offers more advantages than master boot record (MBR) partitioning because it allows up to 128 partitions per disk, provides support for volumes up to 18 exabytes in size, allows primary and backup partition tables for redundancy, and supports unique disk and partition IDs.

A primary partition of a basic disk is a portion of the physical disk that functions as though it were a physically separate disk. On most Intel-based systems this partition is the one that is marked as active which allows the computer to start up. You can create up to four primary partitions (sometimes called volumes) on a single disk or three primary partitions and an extended partition with multiple logical drives.

Extended partitions allow you to create more than four individual volumes on a basic disk. Unlike primary partitions, you do not format an extended partition with a file system and then assign a drive letter to it. Instead, you create one or more logical drives within the extended partition. It's the logical drive of the extended partition that you format and assign a drive letter to. You can create an unlimited number of logical drives per disk.

NOTES FROM THE FIELD] - Volume mount points allow a volume to be mounted on an existing folder rather than at the root of a new drive letter. Establishing a volume mount point for an empty NTFS directory allows an administrator to create new volumes without requiring additional drive letters.

Some of the properties and characteristics of basic disks are outlined below.

  • Create and delete primary and extended partitions.
  • Create and delete logical drives within an extended partition.
  • Format a partition and mark it as active.
  • Establish drive letter assignments for volumes or partitions, optical storage devices and removable drives.
  • Establish disk sharing and security arrangements for volumes and partitions formatted with NTFS.
  • Convert a basic disk to dynamic.

Convert a basic disk to dynamic

In order to convert a basic disk to dynamic, you would start the Disk Management tool and right-click the basic disk you want to convert, then click Convert to Dynamic Disk.

You can upgrade a disk from basic storage to dynamic storage at any time without loss of data in much the same way that you might run the CONVERT command line utility to change a FAT or FAT32 partition to NTFS without losing any data. Along the same lines, all data on a dynamic disk will be lost when you convert it to a basic disk just as you would going from NTFS "back" to FAT or FAT32.

In order to convert a basic disk to a dynamic disk there needs to be 1 MB of free disk space for the upgrade to succeed. This 1 MB of free disk space is needed to hold the configuration data for the dynamic disk structure.

Converting basic disks to dynamic disks produces the following results:

Basic disk organization Dynamic disk organization
System partition Simple volume
Boot partition Simple volume
Primary partition Simple volume
Extended partition Simple volume for each logical drive and any remaining unallocated space
Logical drive Simple volume
Volume set Spanned volume
Stripe set Striped volume

There is a very good article on the Microsoft Web site entitled Description of Disk Groups in Windows Disk Management (Q222189). While it is based off of the Windows 2000 line of operating systems, it is still for the most part pertinent and a good read.

This article was originally published on Jun 24, 2002
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