This tutorial mainly describes how to use Hasleo Backup Suite to restore the MBR system backup image to GPT disk, and also introduces some knowledge related to restoring MBR system backup image to GPT disk, as follows:
MBR: MBR is short for Master Boot Record, was first introduced in 1983 with the IBM PC DOS to define the layout of the partition table on a hard drive. MBR is located in the first sector of the disk (LBA 0 or CHS 0/0/1). MBR consists of boot code, disk signature, partition table, and end flag, and the specific structure is as follows:
| Offset | Size (bytes) | Description |
|---|---|---|
| 0x000 | 440 | Boot code (flat binary executable code) |
| 0x1B8 | 4 | Unique disk signature |
| 0x1BC | 16 | First partition table entry |
| 0x1CC | 16 | Second partition table entry |
| 0x1DC | 16 | Third partition table entry |
| 0x1EC | 16 | Fourth partition table entry |
| 0x1FE | 2 | End flag(0x55, 0xAA) |
MBR uses partition table entries to describe the partitions on the disk, the partition table entry is structured as follows:
| Offset | Size (bytes) | Description |
|---|---|---|
| 0x00 | 1 | Drive attributes (0x80: active partition) |
| 0x01 | 3 | CHS Address of partition start |
| 0x04 | 1 | Partition type |
| 0x05 | 3 | CHS address of last partition sector |
| 0x08 | 4 | LBA of partition start |
| 0x0C | 4 | Number of sectors in partition |
Since the CHS addressing method can only access disks no larger than 7.844 GB, operating systems nowadays typically use the LBA addressing method to access disks, and we see only 4 bytes of LBA in the partition table entries of the MBR, so this results in the MBR partition scheme only accessing disks up to 2 TB (2 ^ 32 x 512) in size.
GPT: GPT is short for GUID partition table, it is a part of the EFI standard that defines the layout of the partition table on a hard drive, it uses LBA addressing in place of the historical CHS addressing, mainly designed to replace the MBR partition scheme used by legacy BIOS computers. In a GPT hard disk, the location information of the partition table is stored in the GPT header, and for compatibility reasons, the first sector of the hard disk is still used as the MBR (usually called Protective MBR), and then the primary GPT header, primary partition table, partitions, backup partition table and GPT header, the specific structure is as follows:
✦ Protective MBR: There is a partition table entry with partition type 0xEE in the Protective MBR of the GPT disk, which is used to distinguish whether it is a GPT disk or a MBR disk.
✦ Primary GPT header: The primary GPT header stores information such as the unique disk GUID (used to uniquely identify a GPT disk), CRC (cyclic redundancy check) of GPT header and partition table, the number of partition table entries, and the start LBA of the partition table entries array.
✦ Partition table entry: It is used to describe a partition on the disk, including the partition GUID, start LBA and end LBA, as follows:
| Offset | Size (bytes) | Description |
|---|---|---|
| 0x00 | 16 | Partition type GUID |
| 0x10 | 16 | Unique partition GUID |
| 0x20 | 8 | First LBA |
| 0x28 | 8 | Last LBA |
| 0x30 | 8 | Attribute flags (read-only, hidden, etc.) |
| 0x38 | 72 | Partition name |
✦ Backup partition table and GPT header: They are backups of the primary partition table and GPT header, used to restore GPT if the primary partition table or GPT header is lost or corrupted.
Compare with the MBR partition scheme, the GPT partition scheme has more advantages.
| MBR | GPT | |
|---|---|---|
| Maximum disk capacity | 2 TB | 9.4 ZB (9,400,000,000 TB) |
| Maximum partition capacity | 2 TB | 9.4 ZB (9,400,000,000 TB) |
| Maximum number of partitions | 4 primary partitions and several logical partitions | Unlimited number of primary partitions, Windows limits it to 128 partitions |
| Firmware boot support | BIOS | UEFI |
| Data read or write support | All Windows operating systems | 32-bit Windows Vista and later64-bit Windows XP and later |
✦ 1. GPT breaks the limitation of MBR on disk and partition capacity: GPT supports larger partition and disk capacities, supporting a maximum of 9.4ZB of partition and disk capacity.
✦ 2. GPT can be used as boot disk for UEFI-based computers: More modern computers are usually UEFI-based computers, MBR disks cannot be used as boot disks for UEFI-based computers, and GPT is part of the UEFI standard, so the use of GPT partitioning scheme is the future trend.
✦ 3. GPT partition scheme is more secure: The GPT header contains a CRC check that can be used to determine whether the GPT header and the partition table are damaged, and there are backups of the GPT header and the partition table, so if the primary GPT header or the partition table is lost or damaged, it can be restored from the backup.
✦ 4. Windows 11 can only be installed to a GPT disk: Since Windows 11, Microsoft has mandated that Windows 11 must be installed on UEFI computers, which means we have to use GPT to install and run Windows 11.
If you bought a new UEFI-based computer, you want to transfer Windows from the old computer to the new computer to continue using the original work environment without reinstalling and configuring the Windows work environment. Or you installed Windows to an MBR disk by mistake on a UEFI-based computer (some UEFI computers are still compatible with booting Windows in Legacy BIOS mode, for more detailed information about Legacy BIOS and UEFI, please refer to Legacy BIOS VS UEFI), and you want to run Windows in true UEFI mode. Below we'll describe how to back up Windows operating system and then restore MBR system image to GPT disk.
Step 1. Download, install and run Hasleo Backup Suite Free. If you do not have a Windows backup image, please make a backup image for your Windows operating system first.
Step 2. Click "Restore" button in the navigation bar, and click "Browse image to restore" button in the operation area, then select the system backup image file you want to restore from the open file dialog box.
Step 3. Select the backup version you want to restore and click "System mode", then click the "Next" button.
Step 4. Select the destination disk you want to restore the Windows operating system to, and check the "Restore as GPT" checkbox, then click "Next".
Step 5. Adjust the size and location of the partitions according to your needs, then click "Proceed". A warning message may pop up to tell you that all data on the destination drive will be destroyed, click the "Yes" to continue if you do not have important data on the destination disk. Please note that if you choose to restore Windows to the original disk, Hasleo Backup Suite needs to be restarted to Pre-OS to complete the clone operation, just follow the prompts.
Step 6. Hasleo Backup Suite Free began restoring the Windows operating system to the destination disk. Please note that the time required for restore operation is related to the size of the data that needs to be restored, so please be patient.
Step 7. After the clone operation is complete, restart the computer and change the boot sequence to boot from the destination disk in UEFI mode.
✦ Head: A mechanical hard disk usually consists of multiple platters, and each platter usually has two heads (one on the front and one on the back of the platter), so a disk with four platters usually has eight heads as shown in the figure below. Heads are numbered from 0 and the valid range is between 0 and 254.
✦ Cylinder: A platter is divided into multiple concentric rings from the inside to the outside, which we call tracks. All platters of the same hard disk have the same number of tracks, and the tracks with the same track number on all platters are called cylinder. Cylinders are numbered from 0, the valid range is between 0 and 1023.
✦ Sector: All tracks on a disk are divided into the same number of units, which we call sectors, and the size of all sectors on a disk is the same, usually 512 bytes. Please note that all tracks on a platter have the same number of sectors, even though tracks on the periphery of the platter could theoretically have more sectors. Sectors in a track are numbered from 1, the valid range is between 1 and 63.
After knowing the number of cylinders, the number of disks and the sector size of a disk, we can calculate the capacity of a disk in the following way:hard disk capacity = number of cylinders × number of head × number of sectors per track × bytes per sector
If you are a computer hobbyist, you may have heard of the CHS (Cylinder-Head-Sector Addressing) and LBA (Logical Block Addressing) addressing methods for hard drives.
✦ CHS: If you have read the introduction in the previous section carefully, you should know that we can locate all sectors on a disk by cylinder number, head number and and the sector number in the track. Since the number of cylinders, tracks, and sectors per track has a maximum value, the CHS addressing method can only address disks up to 7.844 GB.
✦ LBA: For hard disks larger than 7.844 GB, the CHS addressing method obviously cannot address all sectors, so the Logical Block Addressing method was introduced to solve this problem. Logical Block Addressing simply numbers all sectors on the disk starting from 0, so there is no restriction on how CHS addresses it is. However, for compatibility reasons, CHS addressing still needs to be supported, at least for booting, which we won't discuss here.
This tutorial mainly describes how to use Hasleo Backup Suite to restore a MBR system backup image to GPT disk, and also introduces some knowledge related to restoring MBR system image to GPT disk, such as the physical structure of the hardware, CHS and LBA addressing methods, the difference between MBR and GPT, and the advantages of GPT.
As a professional Windows backup and cloning software, you can not only restore a MBR system backup image to GPT disk, but also restore a GPT system backup image to MBR disk.
