MBR VS GPT | What's the Difference and Which Is Better
MBR (Master Boot Record) and GPT (GUID Partition Table) are two popular partition styles used on Windows-based computers. They determine the layout of the storage device, such as an HDD or SSD, and tell Windows how to access the data on the disk. When a disk is initialized, the partition style is decided, and each disk in use requires a partition style. Understanding the basics of MBR and GPT is necessary to decide which partitioning method to apply.
PAGE CONTENT:
- What Is MBR
- What Is GPT
- What's the Difference Between MBR and GPT
- Is GPT or MBR Better
- Does Windows 10 use GPT or MBR
- How to Check the Partition Style of a Disk
- How to Interconvert MBR and GPT
What Is MBR
The Master Boot Record (MBR) is an older disk-type that originated with IBM PC DOS 2.0 in 1983. It's named after the boot sector located at the beginning of a drive, known as the Master Boot Record. A simplified structure of an MBR disk includes this initial boot sector, followed by the rest of the disk's sectors.
MBR Sector
The first sector on both MBR and GPT disks is the MBR sector, which contains the master boot code, disk partition table, and boot signature, and describes how partitions are organized on the current storage device. If corrupted, it can be rebuilt.
Partitions
To use a disk for data storage, you need to divide it into chunks called partitions, which can be categorized as primary or extended partitions on a Master Boot Record (MBR) disk. Primary partitions are used for installing the operating system and making active for booting the computer, while the remaining space is called an extended partition, which can be used to create multiple logical drives.
The disk partition table is 64 bytes in total, and each partition's information is 16 bytes, allowing for up to four primary partitions. To have more than four partitions, one primary partition can be designated as an extended partition, enabling the creation of multiple logical drives within it.
An MBR disk has a significant limitation, as it can only utilize up to 2TiB (approximately 2.2TB) of a disk's total capacity, making it unsuitable for larger storage devices.
What Is GPT
The GUID Partition Table (GPT) is a more modern and flexible partitioning scheme compared to the older Master Boot Record (MBR) standard. Introduced as part of the UEFI initiative, GPT offers better compatibility with modern hardware and is the newer standard.
Protective MBR
The first sector on a GPT disk also serves as the Master Boot Record (MBR) but unlike an MBR disk, its protective MBR prevents tools that only support MBR disks from mistakenly recognizing and overwriting the GPT disk.
Primary GPT Header
The second sector on a GPT disk contains the primary GUID partition table header, which defines the partition entries and their CRC32 checksum for data integrity verification. If data corruption is detected, the CRC will attempt to recover the data using backups stored at the end of the disk.
Partition Entries
The third to thirty-fourth sectors of a GPT disk are used for partition entries, allowing for theoretically unlimited partitions. However, the actual number is limited by the operating system, such as Windows, which can only handle 128 partitions due to the 128-byte partition entry size. This contrasts with MBR disks, which have a much lower partition limit.
Partitions
A GPT disk can have multiple primary partitions without the need for an extended partition or logical partitions, as there are no limits on the number of primary partitions that can be created.
Backup Partition Entries/Primary GPT Header
GPT disks automatically back up the primary GPT header and partition entries on the last sectors of the disk, making them safer and more reliable than MBR disks. If the GPT header or partition table becomes corrupted, these backups can be used to restore data.
What's the Difference Between MBR and GPT
The structure of MBR and GPT disks differs, leading to variations in other aspects. Specifically, MBR disks and GPT disks differ in their supported boot modes and compatible operating systems, largely due to their distinct structures and techniques.
Boot Mode
The majority of computers run Windows using either the BIOS-MBR method or the UEFI-GPT method, indicating that MBR disks are limited to legacy BIOS mode, while GPT disks support UEFI mode.
BIOS and UEFI are low-level software that starts when you power on your PC. BIOS is the traditional approach, while UEFI is the newer alternative.
The Boot Process of BIOS:
- Powers on
- Power-on self-test (POST)
- Loads BIOS
- Identifies the boot device
- BIOS detects the code stored in the MBR sector
- The Master Boot Record (MBR) loads code from the boot sector of the active partition, which then initializes the operating system.
- The boot sector loads and runs the bootloader
The Boot Process of UEFI:
- Powers on
- The boot manager in UEFI checks the boot configuration
- The boot manager loads into memory and executes the OS loader or OS kernel, which then takes control of the system and begins the boot process.
The Advantages of UEFI-GPT over BIOS-MBR
The limits of the BIOS-The MBR method promotes the appearance of the UEFI-GPT method, which has several benefits. Unlike the MBR method, UEFI allows for booting from drives larger than 2TiB, eliminating size limitations. Additionally, UEFI provides a faster boot process compared to BIOS, making it a more efficient option. This makes UEFI a more desirable choice for modern systems.
- Better compatibility with big hard drives (larger than 2TiB)
- The support of more than four primary partitions
- Faster boot time
- Better graphics and mouse cursor support in the interface
Supported OS
GPT disks and MBR disks also differ in the operating systems they support. GPT is a newer partition scheme, which may be incompatible with older operating systems, except for 32-bit Windows XP and Windows Server 2003 editions, which can read and write GPT disks but require UEFI-based PCs to boot from them. In contrast, almost all Windows editions can read and write MBR disks, and can boot from them as long as the motherboard is either BIOS or UEFI with BIOS mode.
Is GPT or MBR Better
The traditional partition table, MBR, has limitations, while GPT offers more flexibility, allowing for larger disk sizes and more partitions, but also requires more complex configuration.
The Advantages of GPT over MBR
- Supports hard drives larger than 2TiB
- Allows to create theoretically unlimited partitions
- A device contains a cyclic redundancy check to check the integrity of its data.
- The backup of the primary GPT header and partition entries, also known as the secondary GPT header, serves as a safeguard to protect data on the disk. It contains a duplicate of the primary GPT header and partition entries, ensuring that even if the primary is damaged or corrupted, the secondary can take over and maintain the integrity of the data.
The Advantages of MBR over GPT
MBR disks are compatible with most Windows editions, particularly older versions, due to their historical use.
To determine whether GPT or MBR is better, consider your needs and hardware. If you want faster boot times, use GPT on your system disk. If your computer is BIOS-based, use MBR for the system disk.
Does Windows 10 use GPT or MBR
Windows 10 can be installed on both MBR and GPT disks, depending on the computer's firmware. If it's BIOS, it's MBR, if it's UEFI, it's GPT, and if it's UEFI with BIOS-compatibility, it's either one. Trying to install on the wrong type will give an error prompt.
How to Check the Partition Style of a Disk
To check the partitioning scheme of a hard drive under Windows Disk Management, open the Disk Management tool, right-click on the hard drive, select "Properties," and look for the "Partition style" or "Partition scheme" field. Alternatively, run the command "wmic diskdrive get partitionstyle" in the Command Prompt.
Step 1. Right-click "This PC" and choose "Manage".
Step 2. Go to "Disk Management".
Step 3. Right-click the disk you want to check and choose "Properties".
Step 4. Go to the "Volumes" tab and you will see the partition style under the disk information.
How to Interconvert MBR and GPT
To convert a disk from MBR to GPT or vice versa, you can do so freely with a data disk, but be cautious when converting the system disk, ensuring your computer has the appropriate firmware (BIOS for MBR and UEFI for GPT) to avoid boot issues. This allows you to utilize larger storage capacities or change partition styles without compromising boot functionality. This process is typically done using disk management tools within the operating system. The specific steps and tools may vary depending on the operating system and disk management software being used. It is recommended to back up any important data before making such changes. The conversion process itself is relatively straightforward and can be completed in a few steps, but the preparation and consideration of potential consequences are crucial.
To change a Master Boot Record (MBR) to a GUID Partition Table (GPT) or vice versa without erasing data, you can use Qiling Partition Master, a partition tool that facilitates this conversion process.
The Bottom Line
Understanding the MBR and GPT partitioning schemes can help you make informed decisions when initializing a disk or choosing a computer. The MBR scheme, which uses a single partition table, has limitations such as a maximum of four primary partitions and a limited number of sectors. In contrast, the GPT scheme uses a more modern and flexible approach with a partition table that can handle up to 128 partitions and is not limited by sector count. This knowledge can guide your decisions when working with partitions, ensuring you choose the best option for your needs.
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