Before using a disk, it is essential to partition it, Since Windows 8, when you insert a new disk in your computer, you have two choices of partition type : MBR or GPT.
What do GPT and MBR do?
MBR (Master Boot Record) and GPT (GUID Partition Table) are two different ways to store partitioning information on a disk. For example, we find information about where the score begins and where it ends. This way, your system knows which sectors belong to which partitions and which partitions are bootable. This is why it is necessary to choose between MBR or GPT before creating partitions on a disk.
MBR (Master Boot Record) :
In short, the standard MBR is out of date. yes a little since its introduction with IBM PC DOS 2.0 in 1983.
It’s called Master Boot Record because the MBR is a boot sector located at the beginning of a drive. This sector contains a boot loader for the installed operating system as well as information about logical partitions. The Bios loads the MBR. These are the first 512 bytes of the disk. From the information in the MBR, it determines the location of the boot loader.
If the boot disk has multiple partitions, the BIOS reads the MBR of the disk and then the VBR (Volume Boot Record) of the partition. From this information, he can determine the location of the boot loader and launch it.
The MBR works with drives up to 2TB. It can not handle disks larger than 2TB. The MBR supports up to four primary partitions. Therefore, if you want more, you must transform one of your main partitions into an “extended partition” and create logical partitions.
GPT (GUID Partition Table) :
This is a new disk partitioning standard that allows to gradually replace the old MBR. It is associated with UEFI, which replaces the BIOS. This is called a GUID partition table because each partition on your hard disk has a unique identifier (GUID = unique global identifier).
This new technologie does not have the limitations as MBR has. The disks can be much, much bigger and the size limits will depend on the operating system and its file system. GPT allows almost an unlimited number of partitions, and the limit here will be your operating system. For example, Windows allows up to 128 partitions on a GPT disk, and you do not have to create an extended partition.
On an MBR disk, partitioning and boot data is stored in one place. If this data is damaged, you have problems. In contrast, GPT stores multiple copies of this data on disk. It is therefore much more robust and can recover if the data is corrupted.
GPT also stores Cyclic Redundancy Check (CRC) values to verify that its data is intact. If the data is corrupted, GPT may notice the problem and attempt to recover the corrupted data from another location on the disk. The MBR had no way of knowing if its data was corrupt. You would only see a problem when the boot process failed or the partitions on your drive disappeared.
Windows can only boot from GPT on UEFI computers running 64-bit versions of Windows 8.1, 8, 7, Vista, and the corresponding server versions. On a 32-bit BIOS version, you will not be able to boot from a GPT disk, but you can use it as a data disk.