Boot Sector

The boot sector is the first sector of any logical disk or partition. It contains information about the disk volume such as its capacity, as well as the bootstrapping program that loads and runs the operating system. A boot sector contains this program even if the disk volume does not have an operating system installed on it.

The term boot sector is often used synonymously with Volume Boot Record (VBR), although strictly, the VBR is only one type of boot sector, the other one being the Master Boot Record (MBR).