Today, many Mac users are aware about how to partition a hard drive using disk utility and benefits of partitioning the drive into multiple volumes. Still, there are others who don't know about both. New Mac users would find it difficult to cope up with the disk utility functions, although it is simple to use. To split a hard drive or let it be as a single hard drive: We split our large hard drive into number of others small volumes which are then mounted by OS X. To access a volume, it should be first mounted by the Mac; otherwise the volume would be inaccessible to the user. These individual volumes not only ease the saving of files & folders but also make the OS X access the information much quicker. Splitting a hard drive also facilitate creation of volumes which can be used for any kind of testing. These kinds of working conditions are best suited to those who work upon hard drives. E.g.: Testing Engineers damages the file structure of the volume and then repairs it using their new software. This way they can check the functionality of their new tool with the help of the test volume.
Installing Multiple OS on hard drive: Each volume created on Mac can be used to install an OS X, for instances, I got both Lion 10.7.3 and Mountain Lion (10.8) installed on my Mac Mini. A dedicated partition can be used to install Windows using boot camp.
Resizing Mac partitions to utilize disk space: After a Mac partition has been created it must be re-sized to completely utilize the space. Disk Utility functions allows resizing a partition either by mouse drag or by entering the definite volume size in numbers.
Is resizing partitions a risky task? No matter, you choose either disk utility or a non-Apple utility to partition a hard drive, the risk of data loss may occur on both the situations. Prior to resizing partitions, always ensure back-ups of the entire hard drive. Here, you can either copy the drives content to an external hard drive, or clone the complete drive making it bootable, else use time machine.
Resizing a large partition may be time consuming: On resizing a large partition on Mac hard drive, the disk-utility (or 3rd party software) may take hours to move blocks from a position to another. Users, often jump to negative conclusions when the tool takes hours of time to resize a large partition. But, in general it is a normal process that needs time.