Data Storage - Extended Boot Record

1 - About

An extended boot record (EBR), or extended partition boot record (EPBR), is a descriptor for a logical partition under the common DOS disk drive partitioning system.

An EBR consists of:

  • an extended partition table
  • and the signature word for the sector.

It exists for each logical drive in the extended partition. It contains the only information on the first side of the first cylinder of each logical drive in the extended partition.

At the end of the EBR is a 2-byte structure called a signature word or end of sector marker, which is always set to 0x55AA. A signature word also marks the end of an Master boot record (EBR) and the boot sector.

The boot sector in a logical drive is usually located at either Relative Sector 32 or 63. However, if there is no extended partition on a disk, there are no EBRs and no logical drives.

3 - Documentation / Reference

data_storage/ebr.txt ยท Last modified: 2018/12/07 16:00 by gerardnico