Structure of a LISP System Using Two-Level Storage In an ideal list-processing system there would be enough core memory to contain all the data and programs. Described in this paper are a number of techniques that have been used to build a LISP system utilizing a drum for its principal storage medium, with a surprisingly low time penalty for use of this slow storage device. The techniques include careful segmentation of system programs, allocation of virtual memory to allow address arithmetic for type determination, and a special algorithm for building reasonably linearized lists. A scheme for binding variables is described which is good in this environment and allows for complete compatibility between compiled and interpreted programs with no special declarations. CACM March, 1967 Bobrow, D. G. Murphy, D. L. CA670303 JB February 28, 1978 1:39 PM 1626 4 1626 1708 4 1626 1781 4 1626 1860 4 1626 2299 4 1626 1626 5 1626 1626 5 1626 1626 5 1626 1641 5 1626 1708 5 1626 1781 5 1626 1826 5 1626 1860 5 1626 2156 5 1626 2168 5 1626 2249 5 1626 2314 5 1626 2719 5 1626 2736 5 1626 2833 5 1626 123 6 1626 196 6 1626 919 6 1626 990 6 1626 1007 6 1626 1046 6 1626 1098 6 1626 1131 6 1626 1139 6 1626 1140 6 1626 1149 6 1626 1198 6 1626 1215 6 1626 1223 6 1626 1265 6 1626 1303 6 1626 1323 6 1626 1358 6 1626 1366 6 1626 1366 6 1626 1389 6 1626 1421 6 1626 1421 6 1626 1460 6 1626 1462 6 1626 1463 6 1626 1467 6 1626 1468 6 1626 1477 6 1626 1491 6 1626 1496 6 1626 1496 6 1626 1531 6 1626 1535 6 1626 1565 6 1626 1601 6 1626 1602 6 1626 1613 6 1626 1614 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1626 6 1626 1641 6 1626 1641 6 1626 1641 6 1626 1708 6 1626 1785 6 1626 1786 6 1626 1787 6 1626 1788 6 1626 205 6 1626 1826 6 1626 1826 6 1626 1826 6 1626 1826 6 1626 210 6 1626 210 6 1626 210 6 1626 224 6 1626 1853 6 1626 1853 6 1626 249 6 1626 1878 6 1626 288 6 1626 1972 6 1626 1972 6 1626 316 6 1626 378 6 1626 381 6 1626 398 6 1626 2082 6 1626 11 6 1626 2148 6 1626 2151 6 1626 2167 6 1626 2210 6 1626 2645 6 1626 2657 6 1626 2736 6 1626 404 6 1626 410 6 1626 463 6 1626 464 6 1626 483 6 1626 3184 6 1626 3184 6 1626 3188 6 1626 584 6 1626 600 6 1626 680 6 1626 691 6 1626 731 6 1626 763 6 1626 799 6 1626