newbie's question

[horseriver]

hi:)

  I use fdisk to add a new partion on a image file. 
  I find the start of partion 1 is alwayes set to 63 by default.
  That means partion 1 start at 63*512=32256 byte.
  
  Here is my question: 
    
      1.  The region from 512th bytes to 32256th bytes will do what ?
          Why partion 1 don't follow MSR's location ?

      2.  The image's magic number is at which offset ?  

Thanks!