Storage

MBR vs. GPT. What’s the Difference?

mbr vs gpt


On Windows-based systems, MBR and GPT are two prevalent partitioning methods. They are specifications for the configuration of storage devices such as hard disc drives (HDDs) and solid-state drives (SSDs).

The partition style determines how Windows accesses the data on the present drive and is selected during the disk’s setup. As a result, each disc must have its own partition style. It would help if you first had a fundamental grasp of MBR vs. GPT before deciding which partitioning technique to use.

The comparisons between an MBR vs. GPT partition are self-evident. However, there is a plethora of background material available to assist you in understanding each sort of partition and why you should use one over the other.

When you initially launch a drive in Windows, you may be prompted whether to use MBR vs. GPT. Many PC users are unsure which to select because Windows does not give further information about them. But don’t be concerned.

Here, we’ll go over the differences between MBR vs. GPT in detail to help you make an informed decision.

What is MBR?

Master Boot Record (MBR) is an older disc type that was initially released in 1983 with IBM PC DOS 2.0. It’s termed after the MBR boot sector, which is found at the very start of a disc, the first sector. An MBR disk’s structure is seen here in simplified form.

mbr structure
Image Source: IONOS

The MBR sector is the first sector on both an MBR and a GPT disc. It contains the master program code (440bytes), the disc signature (4 bytes), the disc partition table with four entries (DPT, 64bytes), and the MBR signature (2bytes), which marks the end of the MBR sector, and in total takes up 512bytes.

This sector contains information on how the partitions on the present storage device are arranged. As a result, if it becomes corrupted, you won’t be able to use the disc until the MBR is rebuilt.

You must divide a disc into partitions in order to use it for data storage. On an MBR disc, partitions are divided into two types:

  1. Primary partitions: Primary partitions are those on which the operating system may be installed and made active so that the machine can boot from them. The space remaining on a disc after primary partitions are removed referred to as an extended partition.
  2. Extended partitions: Unlike a primary partition, an extended partition is a solid storage unit with a drive letter and file system. To make the most of the space, you can only use the expanded partition to construct several logical drives.

Even though the disc partition table is 64 bytes in the count and each partition’s data is 16 bytes, you can only create four primary partitions. Suppose you want more than four partitions on the disc. In that case, you may construct logical partitions by making one of the primary partitions an extended partition.

Note: the expanded partition allows you to construct numerous logical drives within.

Main Drawback: The most obvious drawback of an MBR disc is that it can only handle discs up to 2TiB. That implies that if your disc is more extensive than 2TiB and you utilize the MBR partition type, you can only use up to 2TiB of it.

What is GPT?

In comparison to MBR, which was initially presented as part of the UEFI project, GPT, or GUID Partition Table, is a newer standard. It provides more flexibility and compatibility with contemporary hardware than the MBR partitioning technique.

gpt structure

Here we will explain all the components shown in the picture above:

  1. The Protective MBR sector is the first sector on a GPT drive. The protected MBR on a GPT disc, unlike the one on an MBR disc, aims to avoid tools that only support MBR discs from misrecognizing and overwriting GPT drives.
  2. The primary GPT partition table header is stored in the second sector of a GPT disc. It specifies the size and location of the partition entries that make up the partition table and the cyclic redundancy check (CRC32) checksum needed to ensure the GPT header’s validity. When CRC identifies data corruption, it attempts to restore the information using backups saved at the disk’s end.
  3. The partition entries are located from the third to the thirty-fourth sectors (a total of 32 sectors). On a GPT disc, you can theoretically create an endless number of partitions. The operating system, on the other hand, will limit the number of partitions you may create. For example, each partition entry in Windows is 128 bytes long, allowing you to build a maximum of 128 partitions. This is what sets a GTP disc apart from an MBR disc.
  4. There are no extended partitions or logical partitions on a GPT disc since the number of main partitions is unlimited.
  5. GPT drives automatically back up the primary GPT header and partition entries on the disk’s final sectors. As a result, GPT discs are more secure and dependable than MBR discs. These backups will be helpful in restoring data if the GPT header or partition table is damaged.

MBR vs. GPT Partitions. What is the Difference?

There are many differences between MBR and GPT partitions, but we’ll go through the most important ones here.

To begin with, MBR partition tables have a maximum capacity of just around 2 terabytes. With MBR, you can utilize a disc with more than 2 terabytes, but only the first 2 terabytes will be used. The remaining space on the drive will be thrown away.

GPT partition tables, on the other hand, have a maximum capacity of 9.7 zettabytes. You’re unlikely to run out of space very soon, as 1 zettabyte is around 1 billion terabytes.

The maximum number of partitions in an MBR partition table is four. One of those partitions, however, may be set up as an extended partition, which is a partition that can be divided into 23 further partitions. As a result, the exact maximum number of partitions in an MBR partition table is 26.

GPT partition tables support up to 128 different partitions, which is plenty for most practical uses.

MBR is generally associated with older Legacy BIOS systems, whereas GPT is associated with modern UEFI systems. You can understand the difference between UEFI vs. BIOS. This implies that MBR partitions are more compatible with software and hardware while GPT is catching up.

Conclusion

You should now have a working knowledge of the MBR vs. GPT partitioning methods. You might be able to make a better selection the next time you need to start a drive or choose a computer if you keep this knowledge in mind.

Understanding the differences between MBR and GPT partitions is like peeling an onion, but perhaps you made it through without crying.

Before you tinker with your partitions, make sure you have a backup. Make two copies of everything to avoid issues later.

About author

A finance major with a passion for all things tech, Uneeb loves to write about everything from hardware to games (his favorite genre being FPS). When not writing, he can be seen in his natural habitat reading, studying investments, or watching Formula 1.
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