Partitioning a Drive

By William R. Stanek

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from Chapter 7, Windows NT Administrator's Pocket Consultant.

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

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

No to the prompt that asks if you want to save the changes made to the disk configuration.

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.

from Windows NT Administrator's Pocket Consultant by William R. Stanek. Copyright © 1999 Microsoft Corporation.

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