One of the most curious questions of those who deal with storage devices is the difference between GPT and MBR. In this article, we explain the difference between the two disk partitioning systems and remove all the question marks in your mind.
If you have tinkered and partitioned your hard disk a lot, you have often come across terms like MBR and GPT. Especially users running a Dual-Boot Mac are quite familiar with these terms.
Most users are aware that their hard drives can be partitioned. However, many of these users do not know how the operating system configures these partitions. This is where MBR (Master Boot Record) and GPT (GUID Partition Table) come into play. Although in different architectures, both structures are used for information collection and management for disk partitions.
What is Master Boot Record (MBR)?
MBR is a relatively old partitioning system used to manage partitions, but still used by many users today. Information about disk partitions organized in the storage area is also kept by this system. The MBR also contains the code for scanning partitions for the operating system.
An MBR disk can have up to four primary partitions. The fourth partition can be set as expandable to create more partitions. In this way, more subsections can be created within the fourth section. Since MBR disks use a 32-bit recording system for partitions, there is a 2TB limit for each partition.
What is GUID Partition Table (GPT)?
This system, which has the UEFI standard, is the most up-to-date system that organizes the partitions of the disk. So if you have a UEFI-based system, you should use GPT instead of MBR. Unlike MBR, GPT can theoretically create unlimited partitions. In other words, thanks to MBR, there can be a maximum of 4 primary partitions on a disk, while with GPT there is no such limit. You can divide the disk into as many partitions (E, F, G etc.) as you want.
GPT is one step ahead of MBR in terms of storage. The limit of 2TB for each partition in MBR can reach sizes such as 9.44ZB (Zettabyte) in GPT. Of course, this value is only theoretically possible. Because in Windows operating systems, the maximum capacity of each partition is fixed as 256 TB.
As you can see from the diagram above, GPT disks have two GPT Headers, one at the beginning and one at the end. One of the most important details that makes GPT more useful than MBR is this sequence. Because GPT disks store the spare header at the end, it is much easier to recover the disk if the main header is damaged. GPT disks also use CRC32 checksums to detect problems.
Another noteworthy detail in the diagram is Protective MBR, which allows BIOS-based systems to boot GPT disks with the bootloader in this area. In addition, Protective MBR prevents disk tools undefined against GPT from damaging the disk.
Operating System Support
Intel Macs use GPT on their disks as standard. It is not possible to install Mac OS X on MBR system by ordinary means. Also, many Linux kernels have GPT support. To use the GPT disk with Linux, the Grub 2 bootloader must be used.
On the Windows side, GPT disks have been supported since Windows XP. Computers with 64-bit Windows 8 (except 32-bit XP) use GPT by default, while Windows 7 and earlier have MBR by default.
