code: public long getHeaderSize() {
  		long headerSize = get(MSDOSHeaderKey.HEADER_PARAGRAPHS)
  				* PARAGRAPH_SIZE;
  		if (headerSize > peSigOffset) {
  			return peSigOffset;
  		}
  		assert headerSize >= 0;
  		return headerSize;
  	}
docs: TODO this is size of header + stub ?