Parsing MBR

The Master Boot Record(MBR) contains the boot code and information about the partition table. It resides in the first 512 bytes (first sector) of a bootable disk.  The boot loader is in the first 446 bytes of MBR. A backup of MBR can help recover after a partition table corruption.
Some easy ways to understand MBR info and disk geometry:

Linux: dd + file commands

dd can be used to acquire the first sector of the bootable disk:

$ sudo dd if=/dev/sda of=mbr count=512

512+0 records in

512+0 records out

262144 bytes (262 kB) copied, 0.00553819 s, 47.3 MB/s

Information about partitions is obtained with file utility, that recognizes the dump as an MBR dump (by the MBR signature 0x55AA):

$ file mbr  

mbr: x86 boot sector; 

partition 1: ID=0x83, starthead 32, startsector 2048, 39061504 sectors; 

partition 2: ID=0x7, active, starthead 254, startsector 39070080, 44998065 sectors; 

partition 3: ID=0x83, starthead 254, startsector 84068145, 13671315 sectors; 

partition 4: ID=0x5, starthead 254, startsector 97739460, 214837245 sectors, code offset 0x63

In Windows:

Acquiring the MBR can be done with dd command (from UnxUtils):

>dd if=\\.\PhysicalDrive0 of=mbr count=1

1+0 records in

1+0 records out

Then, a small python script can be used to extract information, similar with file utility.

Other useful tools in Windows:

Information regarding disk geometry (Total Cylinders/Sectors/Tracks,  Sectors per Track, Tracks per cylinder) can be obtained with System Information utility from Windows:

The WinHex editor prints information about the first sector of every partition (provided also by file command):