Technical information

The first entry of an EMBR partition table points to the logical partition belonging to that EMBR:

 Starting Sector = relative offset between this EMBR sector and the first sector of the logical

partition. Note: This will be the same value for each EMBR on the same hard disk; usually 63.

 Number of Sectors = total count of sectors for this logical partition. Note: Any unused sectors

between EBR and logical drive are not considered part of the logical drive.

The second entry of an EMBR partition table will contain zero-bytes if it's the last EMBR in the

extended partition; otherwise, it points to the next EMBR in the EMBR chain:

 Starting Sector = relative address of next EMBR within current extended partition. In other words:

Starting Sector = LBA address of next EMBR - LBA address of extended partition's first EMBR

 Number of Sectors = total count of sectors for next logical partition, but count starts from the next

EMBR sector.

Note 1: Unlike the first entry in an EMBR's partition table, this Number of Sectors count includes

the next logical partition's EMBR sector along with the other sectors in its otherwise unused track.

Note 2: Most operating systems that use the extended partitioning scheme (including Microsoft

MS-DOS and Windows, and Linux) ignore the "partition size" value in entries which point to

another EBR sector.

Remarks:

First, the diagrams above are not to scale: The thin white lines between each "EBR" and its logical

"partition" represent the remainder of an unused area usually 63 sectors in length; including the single

EBR sector (shown at a greatly exaggerated size).

Also, on some systems, a large gap of unused space may exist between the end of a logical partition

and the next EBR, or between the last logical partition and the end of the whole extended partition

itself, if any previously created logical partition has been deleted or resized (shrunk).

What the Starting and Total

Number of sectors values of an EBR's

2nd entry point to and enumerate.

What the Starting and

Total Number of sectors values of

1st entry point to and enumerate.