# File lib/image_formats/A2Dsk.rb, line 41
def set_sector(track,sector,sector_contents)
  raise "attempt to set_sector failed as no interleave defined" if self.class.interleave.nil?
  raise "invalid sector number " unless sector.between?(0,0x0F)
  physical_sector=self.class.interleave[sector]
  padded_sector_contents=(sector_contents+("\000"*256))[0,256]
  start_byte=track*16*256+physical_sector*256
  file_bytes[start_byte,256]=padded_sector_contents
end