drive a: file="img720k"  cylinders=80 heads=2 sectors=9 mformat_only
drive b: file="img1200k" cylinders=80 heads=2 sectors=15 mformat_only
drive c: file="img1440k" cylinders=80 heads=2 sectors=18 mformat_only
drive d: file="img1743k" cylinders=83 heads=2 sectors=21 mformat_only