Managing File Systems and Drives

Article
02/20/2014

Archived content. No warranty is made as to technical accuracy. Content may contain URLs that were valid when originally published, but now link to sites or pages that no longer exist.

By William B. Stanek

Chapter 7 from Microsoft Windows NT Server 4.0 Administrator's Pocket Consultant, published by Microsoft Press

A hard drive is the most common storage device used on network workstations and servers. Users depend on hard drives to store their word-processing documents, spreadsheets, and other types of data. Drives are organized into file systems that users can access either locally or remotely:

Local file systems Local file systems are installed on a user's computer and don't require remote network connections to access. An example of a local file system is the C drive available on most workstations and servers. You access the C drive using the file path C:\.
Remote file systems Remote file systems, on the other hand, are accessed through a network connection to a remote resource. You can connect to a remote file system using the Map Network Drive feature of Microsoft Windows NT Explorer.

Wherever disk resources are located, it's your job as a system administrator to manage them. The tools and techniques you use to manage file systems and drives are discussed in this chapter. Chapter 8 looks at fault tolerance and drive arrays. Chapter 9 tells you how to manage files and directories.

Adding Hard Drives

Before you make a hard drive available to users, you'll need to configure it and consider the way it will be used. Windows NT makes it possible to configure hard drives in a variety of ways. The technique you choose depends primarily on the type of data you're working with and the needs of your network environment. For general user data stored on workstations, you may want to configure individual drives as stand-alone storage devices. In that case, user data is stored on a workstation's hard drive, where it can be accessed and stored locally.

Although storing data on a single drive is convenient, it isn't the most reliable way to store data. To improve reliability and performance, you may want a set of drives to work together. Windows NT supports drive sets and arrays using RAID (redundant array of inexpensive disk) technology, which is built into the operating system. RAID arrays are usually installed on Windows NT servers rather than on workstations.

Physical Drives

Whether you use individual drives or drive sets, you'll need physical drives. Physical drives are the actual hardware devices that are used to store data. The amount of data a drive can store depends on its size and whether compression is used. Typical drives have capacities of 500 megabytes to 10 gigabytes. The two drive types most commonly used on Windows NT are

SCSI (small computer systems interface)
IDE (integrated drive electronics)

The terms SCSI and IDE are designators for the interface type used by the hard drives. This interface is used to communicate with a drive controller. SCSI drives use SCSI controllers. IDE drives use IDE controllers. In general, you'll find that SCSI drives are more expensive than IDE but offer more options and are faster.

SCSI Drives

With SCSI, you can connect up to seven drives to a single controller. Each drive connected to the primary controller is given a numeric designation from 0 to 6. This designation is the drive's SCSI ID, meaning drive 0 is SCSI ID 0, drive 1 is SCSI ID 1, and so on. The drive controller itself is usually designated as SCSI ID 7. Designators for drives on secondary controllers start where the first controller leaves off. For example, if the first controller has seven drives, the first drive on the second controller would normally be SCSI ID 8.

Generally, you set a drive's SCSI ID number before you install it. This is done by using the jumpers on the back of the drive. Instead of jumpers, some drives have a push button or similar mechanism for setting the SCSI ID. If you change the ID of a SCSI device, you must power cycle the drive. This ensures that the change takes effect.

SCSI devices are connected to the controller in a daisy chain, with each device serially in a single line. The first and last device in the chain must be terminated properly. Typically, the SCSI controller terminates the first device itself, and the last device in the chain uses an actual terminator.

Tip If you're installing an additional SCSI-2 disk drive on a computer with SCSI devices, the system should already have a terminator. Simply remove the terminator from the existing drive, hook up the new drive, and then plug the terminator into the new drive to complete the chain.

Before you can use a hard drive, it must be low-level formatted. With SCSI, the manufacturer normally performs this task before shipping the drive. If you need to do a low-level format on site, you'll usually find that the manufacturer has supplied a utility for this purpose. If necessary, use this utility to format the drive.

IDE Drives

With IDE, you can connect up to two drives to a controller. Each drive connected to the primary controller is given a numeric designation from 0 to 1. The first drive has a designator of 0. The second drive has a designator of 1. Designators for drives on secondary controllers start where the first controller leaves off. For example, if the first controller has two drives, the first drive on the second controller normally would have a designator of 3.

As with SCSI drives, you should set an IDE drive's designator before you install it. If this is the first IDE drive on a controller, you must set it up as the master device. If there are two drives on a controller, one drive must be set up as a master device and the other as a slave device. Generally, if you're installing a new drive, the existing drive becomes the master device and the new drive becomes the slave device.

Note: Generally, you can't perform a low-level format of an IDE drive. The manufacturer performs this task before shipping the drive.

Preparing a Drive for Use

Once you install a drive, you'll need to configure it for use. You configure the drive by partitioning it and creating file systems in the partitions as needed. A partition is a section of a physical drive that functions as if it were a separate unit. After you create a partition, you can create a file system in the partition.

Disk Administrator

The tool you'll use to configure drives is Disk Administrator. Disk Administrator makes it easy to work with the internal and external drives on a local system. To use it, you'll need to log on to the workstation or server you want to configure. Run Disk Administrator by going to Start, selecting Programs, then Administrative Tools, and then Disk Administrator. Disk Administrator has two main dialog box windows: Disk Configuration and Volumes.

The Disk Configuration Window

The Disk Administrator window shown in Figure 7-1, on the following page, provides an overview of all the drives installed on the system. In this example, there are three disk devices installed on the system: Disk 0, a fixed drive of 8056 MB, Disk 1, a zip drive, and a CD-ROM device. Drive 0 is further broken down into sections: a primary partition, three logical drives, and a section of free space. The information provided for these drive sections can tell you the following information:

Drive letter for the section
The text label for the section (known as a volume label)
The file system type, either FAT or NTFS
The size of the drive section in megabytes

Figure 7-1: The Disk Administrator window shown here provides an overview of all the drives installed on the system.

Note: The first time you run Disk Administrator, the utility will display a dialog box telling you that the system configuration will be updated. Click OK. Windows NT is simply updating the system configuration information for your drives in Disk Administrator. You'll see the same dialog box anytime you install a new drive on the system and try to manage it with Disk Administrator.

More Detailed Drive Information

From the Disk Administrator window, you can get more detailed information on a drive section by right-clicking on it and then selecting Properties from the pop-up menu. Alternately, you can click on the drive section and then select the Properties button on the menu bar. When you do this, you'll see a dialog box much like the one shown in Figure 7-2. This is the same dialog box that you can access from Windows NT Explorer (by selecting the top-level folder for the drive and then choosing Properties from the File menu). The information provided on the General tab of the Properties dialog box tells you the following:

Drive letter for the section.
The text label for the section (known as a volume label).
The disk type. A local disk is a disk on the current computer system. A network drive is a disk located on a remote computer system that is accessible through a network connection. You may also see floppy, CD-ROM, and RAM drive types.
The file system type, either FAT or NTFS.

Figure 7-2: The General tab of the Properties dialog box provides detailed information about a drive.
The amount of free space on the disk.
The amount of used space on the disk.
The total capacity of the disk.

The Volumes Window

Within Disk Administrator, you can also access a window that depicts volumes installed on the system. Click on the Volumes button on the menu bar or select Volumes from the View menu. As you can see from Figure 7-3, on the following page, the Volumes window provides a detailed summary of all the drives on the computer. Clicking on a column label, such as Name, allows you to sort the disk information based on that column. The column labels are used as follows:

Volume The drive letter of the volume
Name The text label (volume name)
Capacity The amount of data the volume can hold
Free Space The amount of free space in megabytes
% Free The amount of free space as a percentage of total drive capacity
Format The file system type, either FAT or NTFS
Fault Tolerant Whether the drive uses Windows NT fault tolerant features, such as mirroring or striping
Volume Type The type of volume used, such as a mirror set or stripe set
Fault Tolerant Overhead The total additional drive space required as a result of the fault tolerant feature used
Status The status of the volume, such as running or failed

Note: Volume sets and fault tolerance are discussed in Chapter 8.

Figure 7-3: In Disk Administrator, click on the Volume button or select Volume from the View menu to access the Volume window and get a detailed summary of all the drives on the computer.

Understanding Drive Partitions

Windows NT uses two types of partitions: primary and extended.

Primary partitions Drive sections that can be used directly for file storage. Each physical drive can have up to four primary partitions. You make a primary partition accessible to users by creating a file system on it.
Extended partitions Unlike primary partitions, these can't be accessed directly. Instead, extended partitions can be configured with one or more logical drives that are used to store files. Being able to divide extended partitions into logical drives allows you to divide a physical drive into more than four sections.

On Windows NT, a physical drive can have up to four primary partitions and up to one extended partition. This allows you to configure drives in one of two ways:

Using one to four primary partitions
Using one to three primary partitions and one extended partition

Note: With MS-DOS, a physical drive can have only one primary partition. This partition is the boot partition. If you plan to boot a Windows NT system in MS-DOS, you should use only one primary partition and then use an extended partition to create additional logical drives.

Assigning Drive Letters

After you partition a drive, you format the partitions to assign drive letters. This is a high-level format that creates the file system structure rather than a low-level format that sets the drive up for initial use.

You're probably very familiar with the C drive used by Windows NT. Well, the C drive is simply the designator for a disk partition. If you partition a disk into multiple sections, each section can have its own drive letter. You use the drive letters to access file systems in various partitions on a physical drive. Unlike MS-DOS, which assigns drive letters automatically starting with the letter C, Windows NT lets you specify drive letters. Generally, the drive letters C through Z are available for your use.

Note: The drive letter A is usually assigned to the system's floppy drive. If the system has a second floppy drive, the letter B is assigned to it, meaning you can only use the letters C through Z. Don't forget that CD-ROMs, Zip drives, and other types of media drives need drive letters as well.

The total number of drive letters you can use at one time is 24. This means you can have 24 active volumes on a single Windows NT system. If you need additional volumes, you can create them without assigning a drive letter. These volumes won't, however, be accessible until you assign them a drive letter.

Figure 7-4 shows the primary and extended partitions for a sample system in Disk Administrator. Disk 0 has two partitions: one primary partition and one extended partition. The primary partition is designated by the drive letter C. The extended partition is divided into three logical drives, which are designated with the drive letters D, E, and F. Disk 1 is a removable Zip drive. The third disk in the example is a CD-ROM drive, which also has a letter designator.

Figure 7-4: Disk Administrator shows a system with several drives that are partitioned.

Color-Coding Partitions

To help you differentiate between primary partitions and extended partitions with logical drives, Disk Administrator color-codes the partitions. For example, primary partitions may be color-coded with a dark-blue band and logical drives in extended partitions may be color-coded with a light-blue band. The key for the color scheme is shown at the bottom of the Disk Administrator window. You can change the colors by using the Colors dialog box that is displayed when you select Colors and Patterns from the Options menu.

Note: Before you work with Disk Administrator, there are several things you should know. If you create a partition but don't format it, the partition may be labeled as Unknown or Unformatted. If you haven't assigned a portion of the disk to a partition, this section of the disk is labeled Free Space. In Figure 7-4, both disk 0 and disk 1 have free space.

Partitioning a Drive

When you install a new computer or update an existing computer, you'll often need to partition the drives on the computer. You partition drives using Disk Administrator.

Tip In the Windows NT environment, the partition known as the System partition contains the following files: NTLDR, NTDETECT.COM, BOOT.INI, and, optionally, BOOTSECT.DOS and NTBOOTDD.SYS. The partition containing the operating system and the NTOSKRNL.EXE is called the Boot Partition. This may not be intuitive to some users.

Caution: Before you make any changes to hard drives, consider the consequences. Changing partition information for drives may result in data loss, and improper configuring of partitions may even prevent system boot. To ensure that you can recover the drive information, Disk Administrator doesn't actually make changes until you commit them using the Commit Changes Now feature on the Partition menu. This feature allows you to discard unwanted changes.

Anytime you add partitions to a physical drive that contains the Windows NT operating system, you may inadvertently change the number of the partition containing the system files. This partition is known as the boot partition. If you change the partition number, Windows NT will display a prompt warning you that the number of the boot partition has changed. Because of this, you may need to edit the BOOT.INI file and update the designator for the boot partition as instructed.

Figure 7-5: Disk Administrator warns you with a Confirm notice if you try to create more than one primary partition.

Creating Primary Partitions

Each physical drive can have up to four primary partitions. A primary partition can fill an entire disk or be sized as appropriate for the workstation or server you're configuring.

You can create primary partitions in Disk Administrator. To do this, select an area marked Free Space by clicking on it and then choose Create from the Partition menu. When you attempt to create more than one primary partition on a disk, Disk Administrator displays the warning shown in Figure 7-5. This warning tells you that if you create the partition, the drive may not be compatible with MS-DOS. Generally, if you plan to use the drive with MS-DOS, you shouldn't create additional primary partitions. If you click Yes, you'll be able to create the partition.

Next, you should see the Create Primary Partition dialog box shown in Figure 7-6. This dialog box specifies the minimum and maximum size for the partition in megabytes and lets you size the partition within these limits. Size the partition using the Create Partition Of Size field and then repeat this procedure for other primary partitions you want to make.

New primary partitions are designated as New Unformatted. Once you commit the changes for the partition, these partitions are given a default drive letter and marked as Unformatted.

Figure 7-6: Size the primary partition within the minimum and maximum size limits and then click OK.

Creating Extended Partitions with Logical Drives

Each physical drive can have one extended partition. This extended partition can contain one or more logical drives, which are simply sections of the partition with their own file system. You can create extended partitions in Disk Administrator. To do this, select an area marked Free Space by clicking on it and then choose Create Extended from the Partition menu.

Note: If a drive already contains an extended partition, the Create Extended option won't be available. You'll need to delete the existing extended partition and create a new one, which will result in data loss.

Next, you should see the Create Extended Partition dialog box (which has the same options as the Create Primary Partition dialog box shown in Figure 7-6). This dialog box specifies the minimum and maximum size for the partition in megabytes and lets you size the partition within these limits. Size the partition using the Create Partition Of Size field.

New extended partitions are still designated as Free Space. However, Disk Administrator changes the pattern used within the area to help you tell the difference between free space that is unassigned and free space that is assigned to an extended partition. With unassigned free space, the background pattern has stripes going from the lower left to the upper right. With assigned free space that is part of an extended partition, the background pattern has stripes going from the upper left to the lower right.

Creating Logical Drives

After you create the partition, you need to create logical drives within the partition. You create a logical drive by selecting an area of free space within an extended partition and then choosing Create from the Partition menu. This opens the Create Logical Drive dialog box where you can size the logical drive using the Create Partition Of Size field. When you click OK, the drive is given a default letter and is marked as Unformatted. Any unassigned space in the extended partition remains marked as Free Space.

Tip Although you can size the logical drive any way you want, you may want to take a moment to consider how you'll use logical drives on the current workstation or server. Generally, you use logical drives to divide a large drive into manageable sections. With this in mind, you may want to divide a 3 GB extended partition into 3 logical drives of 1 GB each.

Formatting Partitions

New partitions are marked as unformatted. Before you can format new partitions, you need to commit the changes you've made using the Commit Changes Now option on the Partition menu. When you commit the changes, Disk Administrator creates the new partitions on the chosen drives. To discard unwanted changes, simply exit Disk Administrator and respond No to the prompt that asks if you want to save the changes made to the disk configuration.

Figure 7-7: Format a partition by specifying its file system type and volume label.

Figure 7-7: Format a partition by specifying its file system type and volume label.

After you commit the changes, you can format the new partitions. Select the partition by clicking on it, then chose Format from the Tools menu. This opens the Format dialog box shown in Figure 7-7.

Note: Formatting creates a file system in the partition. This is a high-level formatting that creates the file system structure rather than a low-level formatting that initializes a drive for use.

The fields in the Format dialog box are used as follows:

Capacity Specifies how much data the disk or partition can hold. With removable disks, such as a floppy, you can use the drop-down list to select a different capacity.
File System Specifies the file system type, either FAT or NTFS. FAT (file allocation table) is the file system type supported by MS-DOS and Microsoft Windows 3.1, Microsoft Windows 95, and Microsoft Windows 98. NTFS (Windows NT file system) is the native file system type for Windows NT. In the section of Chapter 9 titled "Windows NT File Structures," you'll learn more about NTFS and the advantages of using it with Windows NT.

Tip If you create a file system as FAT, you can later convert it to NTFS by using the Windows NT Convert utility. You can't, however, convert NTFS partitions to FAT. Often, you'll want your boot partition to be FAT and other partitions to be NTFS. With Intel x86 systems, having your system partition as FAT is often a good idea. This gives you freedom to boot the system under MS-DOS if necessary.

With RISC-based systems, you don't have the option of using NTFS. The boot partition must be FAT. For details on creating partitions, see the section of this chapter titled "Understanding Drive Partitions."
Allocation Unit Size Specifies the cluster size for the file system. This is the basic unit in which disk space is allocated. The default allocation unit size is 4 KB (4096 bytes). Microsoft recommends that you use the default allocation unit size for general use. The default allocation unit size (4 KB) is also necessary if you plan to compress the drive.

That said, there are times when you may want to change this setting. If you use lots of small files, you may want to use a smaller cluster size, such as 512 or 1024 bytes. With these settings, small files use less disk space.
Volume Label Specifies a text label for the partition. This label is the partition's volume name.
Quick Format Tells Windows NT to format without checking the partition for errors. With large partitions, this option can save you a few minutes. However, it is more prudent to check for errors, which allows Disk Administrator to mark bad sectors on the disk and lock them out.
Enable Compression Turns on compression for the disk. Built-in compression is only available for NTFS. Under NTFS, compression is transparent to users and compressed files can be accessed just like regular files. If you select this option, files and directories on this drive are compressed automatically. For more information on compressing drives, files, and directories, see the section of this chapter titled "Compressing Drives and Data."

When you're ready to proceed, click OK. Because formatting a partition destroys any existing data, Disk Administrator gives you one last chance to abort the procedure. Click Yes to start formatting the partition. Disk Administrator displays a bar graph to show the progress of the formatting. When formatting is complete, you'll see a prompt that tells you so.

Managing Existing Partitions and Drives

Disk Administrator provides many useful functions for managing existing partitions and drives. You can use these features to assign drive letters, delete partitions, set the active partition, and more. In addition, Windows NT provides other utilities to carry out common tasks such as converting a volume to NTFS or checking a drive for errors.

Assigning Drive Letters

Windows NT assigns default drive letters when you create new primary partitions and logical drives. Generally, these drive letters are assigned consecutively, but you can change the drive letter or remove the drive letter designator. For details on working with drive letters, see the section of this chapter titled "Understanding Drive Partitions."

To assign a drive letter or remove a drive letter designator, complete the following steps:

Select the drive you want to change by clicking on it in Disk Administrator.
Choose Drive Letter from the Tools menu. This opens the Assign Drive Letter dialog box shown in Figure 7-8.

Figure 7-8: To assign a drive letter, select the letter from the list box and click OK.
Assign a drive letter by choosing the Assign Drive Letter button and then selecting a letter from the list box. Remove a drive letter assignment by choosing the Do Not Assign A Drive Letter button.
Click OK after you make your selection.

Note: If you try to change the letter of a drive in use, Windows NT displays a warning. You'll need to exit programs that are using the drive and try again or allow Disk Administrator to make the change and reboot the system.

Changing or Deleting the Volume Label

The volume label is a text descriptor for a drive. Because this label is displayed when the drive is accessed in various Windows NT utilities, such as Windows NT Explorer, you can use the label to help provide information about the contents of a drive. You can change or delete a volume label using Disk Administrator or Windows NT Explorer.

Using Disk Administrator, you can change or delete a label by doing the following:

Select the partition or drive by clicking on it and then choose Properties from the Tools menu.
In the General tab of the Properties dialog box, use the Label field to enter a new label for the volume or delete the existing label.
Click OK.

Using Windows NT Explorer, you can change or delete a label by doing the following:

Select the top-level folder for the drive by clicking on it and then choose Properties from the File menu.
In the General tab of the Properties dialog box, use the Label field to enter a new label for the volume or delete the existing label.
Click OK.

Deleting Partitions and Drives

To change the configuration of an existing drive that is fully allocated, you may need to delete existing partitions and logical drives. Deleting a partition or drive removes the associated file system, and all data in the file system is lost. So before you delete a partition, you should backup any files and directories the partition contains.

You can delete a primary partition or logical drive as follows:

In Disk Administrator, select the partition or drive by clicking on it and then choose Delete from the Partition menu.
Confirm that you want to delete the partition by clicking Yes.
Commit the change by selecting Commit Changes Now from the Partition menu or by exiting Disk Administrator and choosing Yes when prompted.

To delete an extended partition, complete the following steps:

Delete all the logical drives on the partition following the steps outlined above.
You should now be able to select the extended partition area itself (designated as Free Space with a background pattern of stripes that run from the upper left to the lower right).

Converting a Volume to NTFS

Windows NT provides a utility for converting FAT volumes to NTFS. This utility, called Convert (CONVERT.EXE), is located in the %SystemRoot% folder. When you convert a volume using this tool, the file and directory structure is preserved and no data is lost. Keep in mind, however, that Windows NT doesn't provide a utility for converting NTFS to FAT. The only way to go from NTFS to FAT is to delete the partition by following the steps outlined in the previous section and then to recreate the partition as a FAT volume.

The Convert Utility

Convert is a command-line utility run at the Command prompt. If you want to convert a drive use the follow syntax:

convert drive_designator /FS:NTFS

where drive_designator is the drive letter followed by a colon. For example, if you wanted to convert the D drive to NTFS, you would use the following command:

convert D: /FS:NTFS

Before you use the Convert utility, double-check to see if the partition is being used as the active boot partition or a system partition containing the operating system. With Intel x86 systems, you can convert the active boot partition to NTFS. Doing so requires that the system gain exclusive access to this partition, which can only be obtained during startup. Thus, if you try to convert the active boot partition to NTFS, Windows NT displays a prompt asking if you want to schedule the drive to be converted the next time the system starts. If you click Yes, you can restart the system to begin the conversion process.

Figure 7-9: Before you use the Convert utility to convert a FAT file system to NTFS, you should make sure that the drive has enough free space. Don't attempt to use the drive while the conversion is in progress.

Tip Often it will take several restarts of a system to completely convert the active boot partition. Don't panic. Let the system proceed with the conversion.

RISC-Based Systems

RISC-based systems are hardware configured and do not use an active boot partition. RISC computers, however, do use a system partition that contains the necessary files for the operating system. This partition must be a FAT file system, so you shouldn't convert the system partition to NTFS on RISC-based computers.

Figure 7-9 shows the output from an actual drive conversion. Before Convert actually converts a drive to NTFS, the utility checks to see if the drive has enough free space to perform the conversion. Generally, Convert needs a block of free space that is roughly equal to 25 percent of the total space used on the drive. For example, if the drive stores 100 MB of data, Convert needs about 25 MB of free space. If there isn't enough free space, Convert aborts and tells you that you need to free up some space. On the other hand, if there is ample free space, Convert initiates the conversion. Be patient. The conversion process takes several minutes (longer for large drives). Don't access files or applications on the drive while the conversion is in progress.

Checking a Drive for Errors and Bad Sectors

The Windows NT utility for checking the integrity of a disk is Check Disk (CHKDSK.EXE). You'll find this utility in the %SystemRoot% folder. Use Check Disk to check for and optionally repair problems found on both FAT and NTFS volumes.

While Check Disk can check for and correct many types of errors, the utility primarily looks for inconsistencies in the file system and its related metadata. One of the ways Check Disk locates errors is by comparing the volume bitmap to the disk sectors assigned to files in the file system. But beyond this, Check Disk's usefulness is rather limited. For example, Check Disk can't repair corrupted data within files that appear to be structurally intact.

You can run Check Disk from the command line or within other utilities. At the Command prompt you can test the integrity of the E drive, by entering the command:

chkdsk E:

To find and repair errors that are found in the E drive, use the command:

chkdsk /f E:

Note: Check Disk can't repair volumes that are in use. If the volume is in use, Check Disk displays a prompt that asks if you want to schedule the volume to be checked the next time you restart the system. Answer Yes to the prompt to schedule this.

Two ways you can also run Check Disk interactively are by using either Windows NT Explorer or Disk Administrator.

Using Disk Administrator, you can access Check Disk by doing the following:

Select the drive by clicking on it and then choose Properties from the Tools menu.
In the Tools tab of the Properties dialog box, click on the Check Now button.

Using Windows NT Explorer, you can access Check Disk by doing the following:

Select the top-level folder for the drive by clicking on it and then choose Properties from the File menu.
In the Tools tab of the Properties dialog box, click on the Check Now button.

Figure 7-10 shows the dialog box for the interactive version of Check Disk. You can use the dialog box to check a disk for errors and then to repair them if you like.

To check for errors without repairing them, click on the Start button without selecting either of the check boxes.
To check for errors and fix them, make the appropriate selections in the check boxes to fix file system errors or to recover bad sectors, or both.

Figure 7-10: Check Disk is available by clicking the Check Now button on the Properties dialog box. Use it to check a disk for errors and repair them if you wish.

Figure 7-10: Check Disk is available by clicking the Check Now button on the Properties dialog box. Use it to check a disk for errors and repair them if you wish.

Defragmenting Disks

Anytime you add files to or remove files from a drive, the data on the drive can become fragmented. When a drive is fragmented, large files can't be written to a single continuous area on the disk. As a result, the operating system must write the file to several smaller areas on the disk, which means more time is spent reading the file from the disk. To reduce fragmentation, use a defragmenter, such as Disk Keeper—a network-aware utility for repairing and defragmenting disks on local and remote systems.

When you install a defragmenter on a system, you can access it in the Tools tab of the disk's Properties dialog box. Simply click on the Defragment Now button.

Compressing Drives and Data

When you format a drive for NTFS, Windows NT allows you to turn on the built-in compression feature. Using built-in compression, all files and directories stored on a drive are automatically compressed when they are created. Because this compression is transparent to users, compressed data can be accessed just like regular data. The difference is that you can store more information on a compressed drive than you can on an uncompressed drive.

Compressing Directories and Files

If you decide not to compress a drive, Windows NT lets you selectively compress directories and files. To compress a file or directory, select the file or directory in Windows NT Explorer. Then, in the General tab of the related property dialog box, select the Compress check box as shown in Figure 7-11, on the following page. Then click Apply or OK.

Figure 7-11: With NTFS, you can compress a file or directory by selecting the Compress check box on the General tab of the Properties window.

For an individual file, Windows NT marks the file as compressed and then compresses it. For a directory, Windows NT marks the directory as compressed and then compresses all files in it. If the directory contains subfolders, Windows NT displays the dialog box shown in Figure 7-12. This dialog box allows you to compress all the subfolders associated with the directory. Simply select the Also Compress Subfolders check box and then click OK. Once you compress a directory, any new files added to the directory are compressed automatically.

Expanding Compressed Files and Directories

If you decide later that you want to expand a compressed file or directory, simply reverse the process by completing the following steps:

Choose the file or directory in Windows NT Explorer.
In the General tab of the related Property dialog box, deselect the Compress check box.
Click Apply or OK.

With files, Windows NT removes compression and expands the file. With directories, Windows NT expands all files within the directory. If the directory contains subfolders, you'll also have the opportunity to remove compression from the subfolders. To do this, select the Also Uncompress Subfolders check box when prompted and then click OK.

Figure 7-12: . If you compress a directory that contains subfolders, Windows NT asks if you want to compress the subfolders. To do so, select the Also Compress Subfolders check box and then click OK.

Tip Windows NT also provides command-line utilities for compressing and decompressing your data. The compression utility is called Compact (COMPACT.EXE). The decompression utility is called Expand (EXPAND.EXE).

The Windows NT 4 Resource Kit has enhanced utilities for working with compressed files as well. Use Compress (COMPRESS.EXE) to compress sets of files and store them in separate directories. Use ExpndW32 to expand distribution files from the Windows NT CD-ROM.

Creating an Emergency Boot Disk

An emergency boot disk is handy when you have problems booting a system. You can create an emergency boot disk for an Intel x86 system by doing the following:

Insert a new floppy disk into your floppy drive.
Right-click on the floppy drive icon in Windows NT Explorer and then select Format from the pop-up menu.
Select the appropriate formatting options and then click Start to format the floppy.

Copy these files from the boot drive's base directory (normally C:\) to the floppy:
- BOOT.INI
- NTDETECT.COM
- NTLDR
- BOOTSECT.DOS (in dual boot systems)
- NTBOOTDD.SYS (if used on this system)

The BOOT.INI file tells the computer the location of the boot partition. You can edit this file to have the computer load an operating system from a different partition. For example, if you mirrored the boot partition and the primary mirror drive fails, you can point BOOT.INI to the boot partition on the secondary mirror drive and boot your system. The actual procedure for recovering a mirrored boot partition is covered in Chapter 8.

Creating an Emergency Repair Disk

Anytime you change the configuration of your system, Windows NT may display a message telling you to update your emergency repair disk. An emergency repair disk contains important system and registry information that can be used to recover a Windows NT system in case of boot failure. Because the problems that the emergency disk can resolve are extensive, it should be your first line of defense in recovering a system from boot failure. Creating and updating this disk often is a good idea.

Figure 7-13: Repair disks are essential for recovering the system in case of failure. Update the repair disk anytime you make system changes.

To create or update an emergency repair disk, you'll use the Repair Disk Utility (RDISK.EXE). You can start the Repair Disk Utility by typing rdisk at the Command prompt or from the Run dialog box. Figure 7-13 shows the main window for the utility. You can now

Create a new repair disk by selecting the Create Repair Disk button The Repair Disk Utility asks you to label a floppy disk "Emergency Repair Disk" and insert it into the floppy drive. When you do this, click OK to continue. The utility will format the floppy disk and then copy configuration files to the disk.

Afterward, you'll see a final prompt telling you to store the disk in a safe location. The disk contains sensitive information, such as registry data containing security and user information. You'll also find that some files have been created in the %SystemRoot%\repair folder. These files are also used to recover the system in case of failure.
Update an existing repair disk by selecting the Update Repair Info button The Repair Disk Utility tells you that the repair information last saved will be deleted. If you want to do this, click OK to continue. The utility will then copy configuration files to the disk. You'll also find that files in the %SystemRoot%\repair folder have been updated.

Recovering a Boot Failure

The Emergency Repair Disk created with the Repair Disk Utility (RDISK.EXE) can recover the system from most types of boot failures. To do this, you'll need the Windows NT Setup Disks and the Emergency Repair Disk created for this system.

Note: If the floppy drive is not configured as a boot drive, you'll need to edit the configuration settings of your system. During boot you should see a message that tells you which key you should press to enter system setup. Typically, this button is the Del key or a function key, such as F5. Once you're in the system setup, you'll need to enable boot from floppy.

To recover the system, insert the Windows NT Setup Disk A into the floppy drive and boot the system. Windows NT won't actually begin the installation process unless you tell it to. You should see an option menu that allows you to "Repair a Damaged NT Installation." Select this option, then follow the prompts.

Windows NT will attempt to repair the system using the repair data in the %SystemRoot%\repair folder and the Emergency Repair Disk (as necessary). When prompted, insert the Emergency Repair Disk. This disk will reflect the most recent system configuration settings if possible.

About the Author

William R. Stanek (https://www.nt-consulting@tvpress.com) has a master of science in information systems degree and more than a decade of hands-on experience with advanced programming and development. He is a leading network technology expert and an award-winning author. Over the years, his practical advice has helped programmers, developers, and network engineers all over the world. He is also a regular contributor to leading publications like PC Magazine, where you'll often find his work in the "PC Tech" section.

The author served in the Persian Gulf War as a combat crew member on an electronic warfare aircraft. He flew on numerous combat missions into Iraq and was awarded nine medals for his wartime service, including one of the United States of America's highest flying honors, the Air Force Distinguished Flying Cross.

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