Abstract
This paper is concerned with the design and performance of the telephone directory inquiry system newly adopted in Hong Kong. This system maintains three million telephone records and supports over forty thousand inquiries per hour at the peak. In the Hong Kong society the uses of English and Chinese (in particular, Cantonese) has been blending in a thrust of exciting language culture, giving rise to a variety of telephone inquires that traditional B-tree or hashing based telephone directory inquiry systems fail to handle. The efficiency and flexibility achieved by the new system stem from hosting all indexing data structures in the main memory; these data structures occupy about half giga-bytes and would have been considered too expensive to be placed in the main memory in the past.