040000 tree 24eabf391d729833829180e9950b272b6af5a243	DOS
040000 tree 364445ceaacbbf6137c89ade22b63b65125aeca7	SunOs
040000 tree 2210edbc9cba089f543be4bd631e88c02e35201f	UNIXs
040000 tree f314427a143ba28d97247014f2b6f9c3dbf2d9e1	WINDOWS