unit: sectors

/dev/sda1 : start=     2048, size= 31457280, Id=83
/dev/sda2 : start= 31459328, size=  2097152, Id=82
/dev/sda3 : start=        0, size=        0, Id= 0
/dev/sda4 : start=        0, size=        0, Id= 0
