- Volume boot record
A Volume Boot Record (also known as a volume boot sector or a partition boot sector, although the latter is not strictly correct) is a type of
boot sector , stored in a disc volume on ahard disk ,floppy disk , or similardata storage device , that contains code forbooting programs (usually, but not necessarily,operating system s) stored in other parts of the volume. On non-partitioned storage devices, it is the first sector of the device. On partitioned devices, it is the first sector of an individual partition on the device, with the first sector of the entire device instead being aMaster Boot Record (MBR).The code in volume boot records is invoked either directly by the machine's firmware or indirectly by an MBR or a
boot manager .Invoking a VBR via a boot manager is known as
chain loading . Somedual boot systems, such asNTLDR , take copies of the bootstrap code that individual operating systems install into a single partition's VBR and store them in disc files, loading the relevant VBR content from file after the boot loader has asked the user which operating system to bootstrap.In certain
file system formats, in addition to bootstrap code the VBR contains aBIOS parameter block that specifies the location and layout of the principal on-disc data structures for the file system.References
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