Some file systems (eg, old versions of Microsoft FAT systems) have smaller maximum sizes than the size that provides a disk. A small partition is necessary for the proper functioning of this ancient system of files.
You can save a backup of user data on a separate partition on the same disk, to avoid the loss of important information.
On some operating systems, you need more than one partition, such as the swap partition in Linux-based operating systems.
One of the main uses is usually given to the partitions (mainly extended) is to store all user information (read music, photos , videos, documents), so that when you reinstall an operating system format, only unit that contains it without losing the rest of the user information.
Throughout the years, there have been many partitioning systems, for nearly every existing computer architectures. Many are relatively transparent and allow convenient manipulation of disk partitions, some, however, are obsolete.
The partition tables (MBR) only support up to 2.2 TB per partition. Since they only support 4 primary partitions, the maximum allowable size for a hard drive would be 8.8 TB (the remaining capacity can not be used).
Since the IBM PC architecture is very common, partition tables will probably survive for some time. However, there is a project called Intel Extensible Firmware Initiative (EFI) with the GPT system, which theoretically supports up to 9.4 ZB.
The advantages of using extended partitions
Extended partitions were invented to overcome the limit of 4 primary partitions maximum for each hard drive and can create an unlimited number of logical drives, each with a different file system from the other.
All modern systems (Linux, any Windows NT based and even OS / 2) are able to boot from a logical drive. However, the MBR by default used by Windows and DOS is only able to continue the boot process with a primary partition.
When the MBR is used, there must be at least one primary partition that contains a boot loader (NTLDR, eg, Windows). Other boot loaders that replace the MBR, such as GRUB, do not suffer from this limitation.
Applications for editing partitions
GParted is the GNOME partition editor. This application is used to create, destroy, resize, inspect and copy partitions, file systems as well.
GParted is available on a LiveCD based on Slackware and built on the latest stable Linux kernel branch ( 2.6). The LiveCD is updated with each release of GParted. The Ubuntu LiveCD of this application includes among its profits. Also available in a LiveUSB version.
Despite its simplicity, GParted has many advanced capabilities, such as support for file system Btrfs, EXT2, ext3 and ext4, NTFS, FAT 16 and FAT 32, HFS, HFS + , ReiserFS, Reiser4, UFS, XFS, etc.
In addition to several file systems, it has the ability to detect, create, read resize or change the attributes of partitions (such as UUID , labels or flags) and support for RAID and LVM volumes.
Disk Management and DiskPart
In Windows based on NT (XP, 2003, Vista, 2008) the default OS graphical tool is the Disk Management utility and the command line diskpart program exists.
Disk Management, unlike GParted , has basic functionality, such as creation, destruction and partition resizing, support schemes MBR and GPT partitions, dynamic disks, and only native support for file systems FAT, FAT32, NTFS and ExFAT for hard drives and flash drives, also supports ISO and UDF CD and DVD (often read-only , unless it is a rewritable optical disc).
In the version for Windows 7 also recognizes files in VHD virtual disk formats, and support for RAID, and in its latest version for Windows 8 adds support for virtual hard disk format VHDX, allowing virtual disk sizes greater than 2TB.
However, diskpart is a more advanced interface for managing partitions. Supports the same capabilities as Disk Management, plus editing partition IDs (MBR ) or GUID (GPT), zooming files VHD virtual hard disk , attributes and dynamic disk mirroring.