# File test/backup/DSK.rb, line 193
 def set_sector(track,sector,contents)
    physical_sector=INTERLEAVES[@sector_order][sector]
    start_byte=track*16*256+physical_sector*256
    (0..255).each do |byte|
      c=(contents[byte] || 0)
      @file_bytes[start_byte+byte]=c  
    end  
end