As you have learned, partitions created on basic disks are fixed in size. Dynamic storage, on the other hand, allows you to add space to existing volumes by extending a volume. Let's say you have a volume on an 80GB hard drive that's dedicated for storing home movies and pictures. Originally, you made this simple volume 20GBs in size, thinking that would be plenty. But that was before the new digital camera and before your uncle asked you to convert all his 8mm tapes to digital format. Now you need to take that 20GB storage space and double it.
If you've got the unused space to do it, changing the 20GB volume to one that's 40GB in size is a snap. (Hard disk space is considered used if it has been allocated to a partition or volume.)
When you extend a volume, you take a single simple volume and add more storage area to that volume with free space from the same physical drive. Other than that, nothing else will change when accessing a volume that has been extended. The drive letter will remain unchanged; only the volume's capacity will have changed.
To extend a volume, however, the simple volume must be formatted as NTFS. Now you see why the NTFS file system is significant, and why we need to spend a couple chunks talking about file system considerations. This is precisely one of those considerations.
To extend a volume, right-click on the existing simple volume in Disk Management and choose Extend Volume (see Figure 4-14). Designate how much space you'll add to the volume and which disk the space will come from. Disk Management reflects any changes made.
Figure 4-14. Extend a simple volume.
You also cannot extend a system or boot partition, so this option will not be available on most C:\ drives.