MBR VS GPT in Depth.

MBR (Master Boot Record) and GPT (GUID Partition Table) are two different ways of storing the partitioning information on a drive. This information includes where partitions start and begin, so your operating system knows which sectors belong to each partition and which partition is bootable. This is why you have to choose MBR or GPT before creating partitions on a drive.

GPT brings with it many advantages, but MBR is still the most compatible and is still necessary in some cases. This isn’t a Windows-only standard — Mac OS X, Linux, and other operating systems can also use GPT.

MBR, short for Master Boot Record, is an old standard to manage the partitions in a hard disk that is used extensively by many people. MBR refers to a specific boot sector at the very beginning of the hard disk and it holds some information on how the partitions are organized in a hard disk.

Generally speaking, MBR is made up of three sections:

1. Executable code called the Master Boot Code, which is used to
   • Scan the partition table for active partitions.
   • Find the starting sector of the active partition.
   • Load a copy of the boot sector from the active partition into memory. 
   • Transfer control to the executable code in the boot sector. 
2. Partition table for the disk.
3. Disk Signature
   
   
   In short, MBR loads up the OS boot code or procedure from the active partition. Here is the MBR disk layout:
   
   
    
   
                                              Fig. MBR Disk Layout
   GPT stands for GUID Partition Table. It’s a new standard that’s gradually replacing MBR. It’s associated with UEFI — UEFI replaces the clunky old BIOS with something more modern, and GPT replaces the clunky old MBR partitioning system with something more modern. It’s called GUID Partition Table because every partition on your drive has a “globally unique identifier,” or GUID — a random string so long that every GPT partition on earth likely has its own unique identifier.
   GPT adopts primary and backup partition structures that are located, respectively, at the beginning and the end of the disk to provide redundancy.
   
   
   Here is the GPT disk layout below:
   
                        Fig: GPT Disk Layout
   
   
   After learning so much information about GPT VS MBR. Now let’s make a comparison for them in detail. When comparing MBR disk and GPT disk, you can clearly get four evident differences.
   
   
   ① Partition Number
   MBR: Master Boot Record contains a 64-byte partition table made up of four partition tables entries, each using 16 bytes. Therefore, MBR can accommodate four primary partitions.
   
   
   To create more partitions, the fourth partition can be changed to an extended partition to accommodate more logical drives. Microsoft supports up to 128 sub-­partitions.
   
   In summary, MBR disk supports up to four primary partitions, or three primary partitions plus an extended partition with up to 128 logical drives.
   
   GPT: The partition table header of a GPT disk defines the usable blocks on the disk, as well as the number and sizes of the partition entries that make up the partition table.
   EFI requires a minimum of 16,384 bytes reserved for partition table. That is, the partition table contains 128 partition entries of 128 bytes each, meaning that you can create up to 128 primary partitions on a GPT disk.
   
   EFI requires a minimum of 16,384 bytes reserved for partition table. That is, the partition table contains 128 partition entries of 128 bytes each, meaning that you can create up to 128 primary partitions on a GPT disk.
   

   ② Disk Size

   In addition to the vast differences in the number of partitions, MBR and GPT also differ in disk sizes.

   
   MBR limits its maximum addressable storage space to 2TB with each sector being 512 bytes. That is, even if an MBR disk has a storage space of larger than 2TB, you will find the disk space outside of 2TB to be "unallocated" in Disk Management.
   

   

   On the other hand, GIP allocates 64 bits for logical block addresses, hence allowing a maximum disk size of 264 sectors. With each sector being 512 bytes, it is equivalent to 9.44 ZB (1 ZB is 1 billion terabytes) or 8 ZiB. Summing it up, GPT disk supports up to 18EB in capacity.

   ③ MBR VS GPT in Security

   Comparing the layouts of MBR and GPT, we can see that at the beginning of the disk is a primary GUID partition table header and at the end of the disk is the backup GUID partition table header.

   It is significant to note that GPT contains a CRC32 checksum for itself and for the partition table. Its firmware, bootloader and operating system can use the checksum to diagnose the partition table. Once errors are detected on the primary GPT, it is allowed to recover the whole partition table from the backup GUID partition header.
   

   This is an outstanding advantage of GPT compared to MBR. Once the partition table is corrupted, the MBR disk is unusable. In this aspect, GPT has a higher level of security than MBR disk.
   

   ④ OS Support

   The above content mentioned MBR VS GUID Partition Table in three aspects, moreover, you also need to pay attention to the supported operating system and BIOS.
   
   Generally speaking, legacy BIOS only supports MBR, but UEFI supports MBR and GPT.
   
   When comparing MBR and GPT in OS support, note that all operating systems can be installed on the MBR disk. However, on the contrary, not all Windows systems support GUID Partition Table.
   
   
   So in Short, we believe that GPT is better for the following reasons:
   • It supports more than four primary partitions.
     - GPT allows for a nearly unlimited amount of partitions, and the limit here will be your operating system — Windows allows up to 128 partitions on a GPT drive
   • It supports storage (more than 2TB compared to MBR)
   • It is more compatible with the newer UEFI­-based systems
   •  More Security