Harumi Minemura

A High Speed Database Machine HDM

To meet the increasing demand for the speedup of relational database processing, we are developing a prototype of HDM (it stands for a High Speed Database Machine). HDM is a relational database machine which has a simple structure with five 32-bit microprocessors, Motorola’s MC 68020s. HDM can execute relational database processing very fast by the parallel processing and the best suited disk access method etc. The subset of SQL which includes almost all the basic functions is implemented on the HDM. It is still being developed, but the performance evaluation about selection, projection and join queries without indices has proved that HDM can execute these queries fairly faster than some other relational database systems. In this paper, we present the hardware and software design of HDM and the results of the performance evaluation.

A High Speed Database Machine HDM and its Performance Evaluation

To meet the increasing demand for speeding up relational database processing, we developed a database machine HDM and presented it at the 5th IWDM in 1987. Here, we present the results of a performance evaluation of HDM by ‘Wisconsin Benchmark’ and ‘Expanded Wisconsin Benchmark.’ The results of the evaluation show that HDM can execute various relational database operations fairly faster than some other database systems or database machines.

Poster on a distributed RAID VOD system

Summary form only given. We present an implementation of a VOD (video on demand) system that addresses the problem of increasing video stream supply capabilities. To obtain fundamental video stream transfer characteristics on Ethernet, we first performed an experiment in which it became clear that bottlenecks of the CPU of a video server were the most serious. To solve this problem we implemented a distributed RAID4 (Redundant Arrays of Inexpensive Disks) method video server. Distributed RAID means extending the RAID method usually applied to disks to the servers, so as to achieve improvements in performance and reliability. The great advantage of this architecture is that the linear performance improvement can be achieved by adding inexpensive servers of a diffusion model.

Prototype system of secure VOD

Secure digital contents delivery systems are to realize copyright protection and charging mechanism, and aim at secure delivery service of digital contents. Encrypted contents delivery and history (log) management are means to accomplish this purpose. Our final target is to realize a video-on-demand (VOD) system that can prevent illegal usage of video data and manage user history data to achieve a secure video delivery system on the Internet or Intranet. By now, mainly targeting client-server systems connected with enterprise LAN, we have implemented and evaluated a prototype system based on the investigation into the delivery method of encrypted video contents.