What is a Volume Boot Record (VBR)?

The Volume Boot Record , commonly known as the Partition Boot Sector, is a type of boot sector, stored on a specific partition on a hard drive or other storage device, containing the computer code necessary to start the boot process.

A component of the Volume Boot Record is specific to the operating system or the program itself and is what is used to load the operating system or software, called the Volume Boot Code. The other is the Disk Parameter Block or Media Parameter Block, which contains information about the volume such as label, capacity, serial number, etc.

VBR is also an acronym for Variable Bit Rate , unrelated to a boot sector but instead refers to the number of bits processed over time. It is the opposite of Constant Bit Rate (CBR or constant bit rate).

Volume Boot Record is often abbreviated as VBR, but sometimes also called Partition Boot Sector, Partition Boot Record, Boot Block and Volume Boot Sector.

Repair a Volume Boot Record

If the Volume Boot Code is corrupted or incorrectly configured, you can fix it by writing a new copy of the boot code to the system partition.

The steps involved in writing the new Volume Boot Code depend on the version of Windows you are using. Check out the article: How to write a new Partition Boot Sector to a Windows system partition.

More information about the Volume Boot Record

Volume Boot Record is created when the partition is formatted. VBR is on the first sector of the partition. However, if the device is not partitioned, such as when you are processing a floppy disk, then the Volume Boot Record is located in the first sector of the entire device.

The Master Boot Record is another type of boot sector. If a device has one or more partitions, the Master Boot Record is located in the first sector of the entire device.

All drives have only one Master Boot Record, but there may be multiple Volume Boot Records, for the simple fact that a storage device can contain multiple partitions, each with its own Volume Boot Record.

The computer code is saved in the Volume Boot Record, booted by the BIOS, the Master Boot Record or the boot manager. If the boot manager is used to call the Volume Boot Record, it is called chain loading (a method used by computer programs to replace the program currently executing with a new program, using Using a common data area to transfer information from the current program to the new program).

NTLDR is a boot loader for some versions of Windows (XP and above). If you have more than one operating system installed on the hard drive, it will take specific code that is related to many different operating systems and put them together into a Volume Boot Record, so that before any operating system Which boot, you can choose an operating system to boot. Newer versions of Windows have replaced NTLDR with BOOTMGR and winload.exe.

Also in the Volume Boot Record is information related to the partition's file system, such as NTFS or FAT, as well as where the MFT and MFT Mirror are located (if the partition is formatted in NTFS).

The Volume Boot Record is a general target for viruses because its code begins even before the operating system can load and automatically execute without any user intervention.