“…Typical of this latter approach, in the present context, is the use of truncated search keys for access to bibliographical files in direct access stores, in which fixed-length character strings are the keys, as, for instance, in the system in operation at the Ohio College Library Center. 18 The problems encountered in the use of fixed-length truncated author and title search keys for monograph data are indicated by the fact that the search files using hash-addressing are operated, on average, at a density of only 62.5 percent. Once the density reaches 75 percent, the proportion of collisions and the resultant degradation in performance are such that the files are recreated at a density of only 50 percent.…”