Boot Sector

What Does Boot Sector Mean?

A boot sector is a reserved sector of a disk or storage device that contains the necessary data or code used to complete the boot process of a computer or disk.


A boot sector is also known as a boot block.

Techopedia Explains Boot Sector

A boot sector stores boot record data that gives instructions to a computer when it is started. There are two different types of boot sectors:

  • Master boot record (MBR)
  • Volume boot record (VBR)

For a partitioned disk, the boot sector consists of a master boot record. A non-partitioned disk consists of a volume boot record. The boot sector usually has boot sequence information, such as a list of disk partitions, startup program location or operating system (OS). When a computer is started, the data/program in the boot sector is loaded into the computer memory. This data may include the OS or any other startup program.

The boot sector is generally located at the start of a disk for rapid computer access.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.