CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [192]
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EXAM TIP The home editions of Windows XP and Windows Vista do not support dynamic disks.
Simple Volumes
A simple volume acts just like a primary partition. If you have only one dynamic disk in a system, it can have only a simple volume. It’s important to note here that a simple volume may act like a traditional primary partition, but it is very different. If you install a hard drive partitioned as a simple volume dynamic disk into any version of Windows prior to Windows 2000, you would see no usable partition.
In Disk Management, right-click any unallocated space on the dynamic disk and choose New Volume (Figure 12-52) to run the New Volume Wizard. You’ll see a series of screens that prompt you on size and file system, and then you’re finished. Figure 12-53 shows Disk Management with three simple volumes.
Figure 12-52 Selecting to open the New Volume Wizard
Spanning Volumes
You can extend the size of a simple volume to any unallocated space on a dynamic disk. You can also extend the volume to grab extra space on completely different dynamic disks, creating a spanned volume. To extend or span, simply right-click the volume you want to make bigger, and choose Extend Volume from the options (Figure 12-54). This opens the Extend Volume Wizard, which prompts you for the location of free space on a dynamic disk and the increased volume size you want to assign (Figure 12-55). If you have multiple drives, you can span the volume just as easily to one of those drives.
The capability to extend and span volumes makes dynamic disks worth their weight in gold. If you start running out of space on a volume, you can simply add another physical hard drive to the system and span the volume to the new drive. This keeps your drive letters consistent and unchanging so your programs don’t get confused, yet enables you to expand drive space when needed.
Figure 12-53 Simple volumes
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CAUTION Once you convert a drive to dynamic, you cannot revert it to a basic disk without losing all of the data on that drive. Be prepared to back up all data before you convert.
You can extend or span any simple volume on a dynamic disk, not just the “one on the end” in the Disk Management console. You simply select the volume to expand and the total volume increase you want. Figure 12-56 shows a simple 4-GB volume named Extended that has been enlarged an extra 7.91 GB in a portion of the hard drive, skipping the 2-GB section of unallocated space contiguous to it. This created an 11.91-GB volume. Windows has no problem skipping areas on a drive.
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NOTE You can extend and shrink hard drives in Windows Vista/7 without using dynamic disks. You can shrink any primary partition with available free space (though you can’t always shrink the partition by the whole amount of free space, based on the location of unmovable sectors such as the MBR), and you can expand partitions with unpartitioned space on the drive. Using dynamic disks in Vista/7 still has benefits, however, because you cannot expand a partition by using space on another drive, and the unpartitioned space has to be contiguous with the partition you’re expanding.
Figure 12-54 Selecting the Extend Volume option
Striped Volumes
If you have two or more dynamic disks in a PC, Disk Management enables you to combine them into a striped volume. A striped volume spreads out blocks of each file across multiple disks. Using two or more drives in a group called a stripe set, striping writes data first to a certain number of clusters on one drive, then on the next, and so on. It speeds up data throughput because the system has to wait a much shorter time for a drive to read or write data. The drawback of striping is that if any single drive in the stripe set fails, all data in the