MBR analysis

A master boot record (MBR), or partition sector, is the 512-byte boot sector that is the first sector ("LBA Sector 0") of a partitioned data storage device such as a hard disk.
----Wikipedia

00 ~ 1BD 446byte boot code area
1BE ~ 1CD 16 byte partition 1
1CE ~ 1DD 16 byte partition 2
1DE ~ 1ED 16 byte partiion 3
1EE ~ 1FD 16 byte partition 4
1FE ~ 1FF 2 byte sigatur(55AA)

1. That's why there is only 4 physical partition.
2. The sigatur must be 55AA, otherwise the MBR is not available.

In 1BE ~ 1CD,
00~00 0x80 -- bootable 0x00 -- otherwise
01~03 CHS start address
04~04 partition type (83--linux 82--linux swap)
05~07 CHS end address
08~0B LBA start
0C~0F sector number

That's why there is only