What is a Hard Disk partition?

è     When a hard disk drive is installed in a computer it must be partitioned before you can format and use it. Partitioning a drive is when you divided the total storage of a drive into different pieces. These pieces are called partitions once a partition is created it can then be formatted so that it can be used on a computer. When partition are made, you specify the total amount of storage that you would like to allocate to that partition from the total size of the drive. For example, if you have on 80GB drive, ten it would be possible to make one partition consisting of the entire 80GB of available storage. Alternatively you could make two partition consisting of a 20GB partition that will be used for the operating system and programs and a 60GB partition used for data, music and image.

Why make partitions-

Multiple file system-

When you create a partitions you tell the operating system what file system you would like that partition to be formatted in once you format a partition, and therefore assign the type of file system you want to use with it, you cannot change that file system without formatting the partition again and losing all the data contained on it. If you require different file system on your computer, weather it is for security or for a specific application you can then make multiple partitions and another to one of the other partitions.  

Partition size-

One folder operating system the maximum size of a partitions was limited. Therefore if you had more storage space on hard drive then was usable in a single partitions, you would need to create other partitions to utilize this unused space.

Multiple operating system-

Some operating system use file system that are not compatible with other operating system. If you want to use two operating system on the some computer that are not compatible in this way, you could then make two partitions, one for each operating system. Then boot loader could be used to switch between them when you start your computer.

Wasted disk space-

When a file systems store data in a partition, the longer the partition, the gather the chance of wasted space, by having Multiple partitions of smaller size, you reduce the amount of waste that file system may create.

Separate system file form users file-

Some components of an operating system require storage space to operate for example, in windows if you have no hard drive space available on the drive that windows is installed on, you will not be able to printer by creating a partition solely devoted to the operating system and then another partition dedicated to your own data and programs there is less of a chance of you using up the space on the operating system partitions with your data, and this not causing problems.