Trends in retrieval system performance

Computer technology is continually developing, with ongoing rapid improvements in processor speed and disk capacity. At the same time, demands on retrieval systems are increasing, with, in applications such as World-Wide Web search engines, growth in data volumes outstripping gains in hardware performance. We experimentally explore the relationship between hardware and data volumes using a new framework designed for retrieval systems. We show that changes in performance depend entirely on the application: in some cases, even with large increases in data volume, the faster hardware allows improvements in response time; but in other cases, performance degrades far more than either raw hardware statistics or speed on processor-bound tasks would suggest. Overall, it appears that seek times rather than processor limitations are a crucial bottleneck and there is little likelihood of reductions in retrieval system response time without improvements in disk performance.