Within the operating system, disks and directories are locations where data is stored and organized. The file system used by the operating system determines additional factors that affect storage such as partition size, cluster size, and security features.

Disk Structure
A hard disk is divided into specific areas called partitions. Partitions are formatted so that they can store information. The Disk Management utility displays information and performs services such as partitioning and formatting disks in Windows. Figure 1 shows the Disk Management utility used in Windows XP.

There are several types of partitions on a hard drive:

• Primary partition – This is usually the first partition. A primary partition cannot be subdivided into smaller sections. There can be up to four partitions per hard drive.
• Active partition – This partition is used by the operating system to boot the computer. Only one primary partition can be marked active.
• Extended partition – This partition normally uses the remaining free space on a hard drive or takes the place of a primary partition. There can be only one extended partition per hard drive, and it can be subdivided into smaller sections called logical drives.

NOTE: At any given time, you can only designate one partition as the active partition. The operating system uses the active partition to boot up the system. The active partition must be a primary partition.

In most cases, the C: drive is the active partition and contains the boot and system files. Some users create additional partitions to organize files or to be able to dual-boot the computer.

There are several ways to access the Disk Management utility in Windows XP:

• Select Start > right-click My Computer > Manage.
• Select Disk Management.
• Select Start > Settings > Control Panel > Administrative Tools > Computer Management.
• Select Disk Management.

There are several ways to access the Disk Management utility in Windows Vista:

• Select Start > right-click My Computer > Manage.
• Select Disk Management.
• Select Start > Settings > Control Panel > Administrative Tools > Computer Management > Continue.
• Select Disk Management.

In Windows, letters are used to name the drives. A Windows computer can have up to  26 physical and logical drives because there are 26 letters in the English alphabet. Drives A and B are reserved for floppy disk drives, and drive C is reserved for the primary, active partition. Therefore, the maximum number of additional drives is 23.

With the NTFS file system, a drive can be mapped to an empty folder on a volume and is referred to as a mounted drive. Mounted drives are assigned drive paths instead of letters and are displayed as a drive icon in Windows Explorer. Use a mounted drive to configure more than 26 drives on your computer or when you need additional storage space on a volume.

To mount a volume in Windows:

1. Select Start > Control Panel > Administrative Tools > Computer Management.

2. Click Disk Management in the left pane.

3. Right-click the partition or volume to be mounted.

4. Click Change Drive Letter and Paths.

5. Click Add.

6. Click Mount in the following empty NTFS folder.

7. Create an empty folder, type the path to an empty folder, or browse to an empty folder on an NTFS volume and click OK.

8. Close Computer Management.

Drive Status
The Disk Management utility displays the status of each disk, as shown in Figure 2. The hard drives in the computer will display one of the following conditions:

• Foreign – A dynamic disk that has been moved to a computer from another computer running Windows 2000 or Windows XP

• Healthy – A volume that is functioning properly

• Initializing – A basic disk that is being converted into a dynamic disk

• Missing – A dynamic disk that is corrupted, turned off, or disconnected

• Not Initialized – A disk that does not contain a valid signature

• Online – A basic or dynamic disk that is accessible and shows no problems

• Online (Errors) – I/O errors that are detected on a dynamic disk

• Offline – A dynamic disk that is corrupted or unavailable

• Unreadable – A basic or dynamic disk that has experienced hardware failure, corruption, or I/O errors

Other drive status indicators might be displayed when using drives other than hard drives:

• Audio CD – An audio CD that is in the optical drive

• No Media – An optical or removable drive that is empty

File System
Partitions are formatted with a file system. The three file systems available in Windows XP are FAT (FAT16), FAT32, and NTFS. FAT32 and NTFS are compared in Figure 3. NTFS has greater stability and security features.

For example, Windows does not display the file extension, but this practice can cause security problems. Virus writers are able to distribute executable files disguised as a non-executable file. To avoid this security breach, you should always show file extensions by doing the following:

Select Start > Control Panel > Folder Options > View, and uncheck the Hide extensions for known file types check box, as shown in Figure 4.

NOTE: Saving files to the root directory of the C: drive can cause organizational problems with data. It is a best practice to store data in folders created on the C: drive.

Lab Create a Partition in Windows XP Create a FAT32 formatted partition on a disk, convert the partition to NTFS, and identify the differences between the FAT32 format and the NTFS format.   Optional Lab Create a Partition in Windows Vista Create a FAT32 formatted partition on a disk, convert the partition to NTFS, and identify the differences between the FAT32 format and the NTFS format.