On Reversible Subroutines and Computers that Run Backwards A computer design is describe which permits subroutines to be executed backward as well as forward, either with their instructions unchanged or replaced with conjugate instructions. It is shown that using this concept a number of new subroutine types can be developed with rather unusual properties. Since these properties are analogous to certain matrix operations, a parallel nomenclature is suggested for their classification. CACM September, 1965 Reily, E. D. Federighi, F. D. CA650906 JB March 6, 19787:33 PM 1200 5 1200 1200 5 1200 1200 5 1200 1945 5 1200 823 6 1200 914 6 1200 915 6 1200 917 6 1200 984 6 1200 989 6 1200 990 6 1200 1012 6 1200 1084 6 1200 1098 6 1200 1122 6 1200 1138 6 1200 1139 6 1200 1141 6 1200 1200 6 1200 1223 6 1200 1265 6 1200 1336 6 1200 1396 6 1200 1455 6 1200 1477 6 1200 1487 6 1200 1491 6 1200 1496 6 1200 483 6 1200 584 6 1200 669 6 1200 680 6 1200 763 6 1200