24. A system in accordance with claim 23 wherein linkages are located for removal by means for scanning all of the linkages of the same type as the linkages which are to be removed.
24. A system in accordance with claim 23 wherein linkages are located for removal by means for scanning all of the linkages of the same type as the linkages which are to be removed. 25. A system in accordance with claim 24 in which a particular class of linkages are stored in a table and which system includes means for operating the computer system to compress entries in the table after a linkage has been removed to maximize the space within the table that is available for additional linkages.