Members-only Printer-friendly version

STORAGE

Disk Devices    Back to top

Windows XP supports two storage types for disks: Basic and Dynamic disks both outlined below.

Basic disks support a maximum of 4 Primary partitions, or 3 when an Extended partition exists. An Extended partition contains one or more Logical drives. Each primary partition and each logical drive is assigned a drive letter and are referred to as basic volumes. Basic disks support several options for combining disks to increase the maximum disk space for a volume or to provide fault tolerance. Note that the following are not supported on Windows XP, but may exist in Windows NT 4 systems, which then must be converted to Dynamic disks before they can be used with Windows XP:

• Volume set
• Stripe set (RAID 0)
• Mirror set (RAID 1) - only available on servers
• Stripe set with parity (RAID 5) - only available on servers.

Dynamic disks contain volumes instead of the traditional primary/extended partitions. Dynamic volumes cannot be accessed by MS-DOS, Windows 95, Windows 98, Windows Millennium Edition (Me) or Windows NT operating systems. People often incorrectly refer to dynamic disks as being an NTFS feature, while both basic and dynamic disks can contain any combination of FAT16, FAT32, or NTFS volumes. Additionally, dynamic disks are not supported on the following hardware:

• IEEE 1394 (FireWire) disks
• USB disks
• Removable disks
• Disks in laptops

Disk configurations are named differently when using dynamic disks. The following list shows the possible configurations for dynamic disks:

• Simple volume - created from free space on a single physical disk. A simple volume is not fault-tolerant. If it is formatted with NTFS it can be extended to include unallocated space from the same disk, or another disk, to create a spanned volume.
• Spanned volume - created from free disk space from 2 to 32 combined disks. Data is written to the first disk until it is full, then it will write to the second disk, and so on. If one of the hard disks in the spanned volume fails, the entire volume set is lost and needs to be rebuild and restored from backup. Thus, a spanned volume is not fault-tolerant.
• Striped volume (RAID 0) - created from free disk space from 2 to 32 combined disks. When data is written to a striped volume set with 2 disks, the first block is written to the first disk, the second block to the second disk, and the third data block is written to the first disk, and so on, spreading the data evenly over all disks. A striped volume provides he best performance for Windows XP systems. A striped volume is not fault-tolerant and cannot be extended once it is created. If one of the hard disks in the striped volume fails, the entire volume set is lost and needs to be rebuild and restored from backup.
• Mirrored volume (RAID 1) - a fault-tolerant volume only available on servers (Windows 2000 and Windows 2003). Requires 2 disks allowing duplication of all the data on one volume to another disk to provide redundancy. If one of the disks fails, the data can still be accessed from the remaining disk. A mirrored volume cannot be extended.
• RAID 5 volume - a fault-tolerant volume only available on servers (Windows 2000 and Windows 2003) created from 3 or more physical disks. When data is written to the RAID 5 volume, it is distributed over several disks, and parity information about data blocks on one disk are stored on the other disks. In case of a disk failure, the parity information can be used to reconstruct the data from the missing disk. Because data is spread out over several disks, a RAID 5 volume offers better read performance than single or mirrored disks. But because every write requires the parity calculation, write performance can be slower. A RAID-5 volume cannot be mirrored or extended.

Disks and volumes are managed by using the Disk Management console. Right-click My Computer and select Manage to open Computer Management. Under Storage click Disk Management. The following list shows some of the common disk management tasks on Windows XP:

• Upgrading disks - A basic disk can be converted to a dynamic disk without losing any of the data. To upgrade a disk from basic to dynamic, right-click the disk (left from the partitions), and select Upgrade To Dynamic Disk. You will need to restart the computer after the upgrade.
• Reverting disks - If you want to revert a dynamic disk back to a basic disk, you first need to remove all the volumes, create a full backup, and remove all data. After that, right-click the disk and select Revert To Basic Disk.
• Extending volumes - simple and spanned volumes formatted with NTFS can be extended to included unallocated space from the same disk(s) or from a new disk, without losing any of the data. Only the new space will be formatted. The boot or system volume cannot be extended. When a simple volume is extended to include free space from another physical disk it will become a spanned volume. To extend a volume, right click the volume you want to extend, select Extend Volume and select unallocated space from a dynamic disk.
• Creating a striped volume - To create a striped volume, right-click unallocated space on a dynamic disk and select Striped Volume. Remember that you need at least two physical disks to create a stripe set.
• Adding disks - When you add a disk to a Windows XP computer you may need to use the Rescan option from the Action menu in Disk Management. If the computer cannot find or initialize the disk you may need to restart your computer. The Rescan command updates information about the hardware configuration of storage devices.
• Import Foreign Disks - When you add a dynamic disk moved from another computer, you need to import the disk. You can do this by right-clicking the disk that is marked as Foreign, and select Import Foreign Disks. When you want to import a disk that is part of a striped or spanned volume, you will need to move all the disks that were part of the volume.
• Refresh - The Refresh option, also located on the Action menu, allows you to refresh the displayed disk and volume information about drive letters, file systems, volumes, and removable media. The Action option also checks to see if previously unreadable volumes are now readable.
• Formatting - When you create a new partition or volume, or want to reformat a current volume, you can format it with either FAT, FAT32 or NTFS. In addition to selecting the file system you can enter the volume name, allocation unit size, opt to perform a quick format, and enable the file and folder compression.
• Marking a partition as active - When the computer boots it will read the MBR (Master Boot Record) from the active partition. On a Windows XP computer this should be the system partition which contains the files needed to boot Windows (NTLDR, BOOT.INI, etc).
• Remote Disk Management - In addition to local disk management, Disk Management can be used to manage disks on a remote computer running Windows 2000/XP/2003. You have to be a member of the Administrators group on the remote computer.
• Mounting volumes - When a basic or dynamic disk is formatted with NTFS it can be assigned a drive path instead of a drive letter. The disk can be mounted to an empty NTFS folder allowing it to be accessed like any ordinary folder. To mount a volume to a folder, create an empty folder on an NTFS volume, right-click the new volume and select Change Drive Letter and Paths, click Add. Select Mount in the following empty NTFS folder and enter the path to an empty folder on an NTFS volume.

Windows XP also offers a command-line tool to manage disks called Diskpart. You can use the command-line tool to perform the tasks you would normally perform in Disk Management, including creating volumes or upgrading disks to dynamic. The main advantage of this command-line tool is that it allows you to create scripts to automate tasks. Click the following link for more information about the Diskpart tool: A Description of the Diskpart Command-Line Utility.

Removable Media    Back to top

Windows XP supports a wide variety of removable storage devices such as CD-ROM/DVD-ROM and tape drives. Removable media devices are labeled Removable in Disk Management. Disk Management allows you to create a primary partition on removable media if necessary. A primary partition on removable media cannot be marked as active and cannot be removed.

The Removable Storage console allows you to manage the libraries, such as changers and jukeboxes that contain removable media. Right-click My Computer and click Manage to open Computer Management. Under Storage click Removable Storage. If you select Full in the View menu you will have several extra options, including creating Media Pools. Software utilities such as Windows Backup are used to manage the data stored on media in a media pool.

Although they are more often found in servers, a tape device can also be found in Windows XP desktop computers, typically for writing backups to tape. There are several different types of tape devices (and tapes), both external and internal. External tape devices for example, can be connected to an SCSI, USB or IEEE 1394 interface on the computer. Most USB and IEEE 1394 devices are plug and play, and do not require special software or configuration. For others you may need to install the manufacturers software. If the device is properly installed it should turn up in the Removable Storage console.

Unless you installed Windows XP using RIS or system imaging software, the computer will already have a CD or DVD drive installed. When you do add a new CD/DVD-drive, it will probably be auto-detected by Windows XP. In some cases, when you have a CD/DVD recorder for example, you may need to install additional drivers.

Windows XP introduced built-in CD recording software. This feature allows you to write data to a CD-R or CD-RW without using third-party CD recording software. To write files or folders to a CD simply drag them to the DVD/CD-R(W) drive icon or copy your files and folders and right-click the recorder and select Write these files to CD. On the Recording tab of the CD-recorder's Properties you can disable/enable CD recording, specify the temporary drive location, and select the recording speed. You cannot duplicate a CD using the built-in recording software.

In addition to setting security (Use, Control, and Modify permissions) on individual items such as libraries and media pools, you can configure a local security policy setting that prevents users from formatting and ejecting removable media. There is also a policy setting you can use to limit access to a CD-ROM or floppy drive to locally logged-on users only.