# File lib/DSK.rb, line 72
        def    is_prodos?(sector_order)
                #block $02 - bytes $00/$01 are both $00, byte $04 is $F?, 
                #bytes $29-$2A = sectors ( 0x118 on a 35 track 5.25" disk)
                first_sector_in_block_2=INTERLEAVES[sector_order][4]
                first_sector_in_block_2=get_sector(0,4,sector_order)
                (first_sector_in_block_2[0..1]=="\x00\x00") && (first_sector_in_block_2[4]>=0xF0) && (first_sector_in_block_2[0x29]+first_sector_in_block_2[0x2a]*0x100==track_count*8)
        end