def set_sector(track,sector,contents)
super(track,sector,contents)
if ((track>0) || (sector>9)) then
sector_usage_bitmap_sector=get_sector(0,2)
offset_of_byte_containing_this_sector=0x20+(track*2)+(sector/8)
byte_containing_this_sector=sector_usage_bitmap_sector[offset_of_byte_containing_this_sector]
byte_containing_this_sector=byte_containing_this_sector|(2**(7-(sector%8)))
sector_usage_bitmap_sector[offset_of_byte_containing_this_sector]=byte_containing_this_sector
set_sector(0,2,sector_usage_bitmap_sector)
end
end