in 2002 the ata-6 specification introduced an optional 48 bits logical block addressing and declared chs addressing as obsolete, but still allowed to implement the ata-5 translations. unsurprisingly the chs to lba translation formula given below also matches the last ata-5 chs translation. in the ata-5 specification chs support was mandatory for up to 16 514 064 sectors and optional for larger disks. the ata-5 limit corresponds to chs codice_30 or equivalent disk capacities (16514064 = 16383×16×63 = 1032×254×63), and requires 24 = 14+4+6 bits (16383 + 1 = 2).